Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2182 insertions, 0 deletions

diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
new file mode 100644
index 000000000..896849bae
--- /dev/null
+++ b/vcl/skia/gdiimpl.cxx
@@ -0,0 +1,2182 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <skia/gdiimpl.hxx>
+
+#include <salgdi.hxx>
+#include <skia/salbmp.hxx>
+#include <vcl/idle.hxx>
+#include <vcl/svapp.hxx>
+#include <vcl/lazydelete.hxx>
+#include <vcl/gradient.hxx>
+#include <vcl/skia/SkiaHelper.hxx>
+#include <skia/utils.hxx>
+#include <skia/zone.hxx>
+
+#include <SkBitmap.h>
+#include <SkCanvas.h>
+#include <SkGradientShader.h>
+#include <SkPath.h>
+#include <SkRegion.h>
+#include <SkDashPathEffect.h>
+#include <GrBackendSurface.h>
+#include <SkTextBlob.h>
+#include <SkRSXform.h>
+
+#include <numeric>
+#include <basegfx/polygon/b2dpolygontools.hxx>
+#include <basegfx/polygon/b2dpolypolygontools.hxx>
+#include <basegfx/polygon/b2dpolypolygoncutter.hxx>
+#include <o3tl/sorted_vector.hxx>
+#include <rtl/math.hxx>
+
+using namespace SkiaHelper;
+
+namespace
+{
+// Create Skia Path from B2DPolygon
+// Note that polygons generally have the complication that when used
+// for area (fill) operations they usually miss the right-most and
+// bottom-most line of pixels of the bounding rectangle (see
+// https://lists.freedesktop.org/archives/libreoffice/2019-November/083709.html).
+// So be careful with rectangle->polygon conversions (generally avoid them).
+void addPolygonToPath(const basegfx::B2DPolygon& rPolygon, SkPath& rPath, sal_uInt32 nFirstIndex,
+                      sal_uInt32 nLastIndex, const sal_uInt32 nPointCount, const bool bClosePath,
+                      const bool bHasCurves, bool* hasOnlyOrthogonal = nullptr)
+{
+    assert(nFirstIndex < nPointCount);
+    assert(nLastIndex <= nPointCount);
+
+    if (nPointCount <= 1)
+        return;
+
+    bool bFirst = true;
+    sal_uInt32 nPreviousIndex = nFirstIndex == 0 ? nPointCount - 1 : nFirstIndex - 1;
+    basegfx::B2DPoint aPreviousPoint = rPolygon.getB2DPoint(nPreviousIndex);
+
+    for (sal_uInt32 nIndex = nFirstIndex; nIndex <= nLastIndex; nIndex++)
+    {
+        if (nIndex == nPointCount && !bClosePath)
+            continue;
+
+        // Make sure we loop the last point to first point
+        sal_uInt32 nCurrentIndex = nIndex % nPointCount;
+        basegfx::B2DPoint aCurrentPoint = rPolygon.getB2DPoint(nCurrentIndex);
+
+        if (bFirst)
+        {
+            rPath.moveTo(aCurrentPoint.getX(), aCurrentPoint.getY());
+            bFirst = false;
+        }
+        else if (!bHasCurves)
+        {
+            rPath.lineTo(aCurrentPoint.getX(), aCurrentPoint.getY());
+            // If asked for, check whether the polygon has a line that is not
+            // strictly horizontal or vertical.
+            if (hasOnlyOrthogonal != nullptr && aCurrentPoint.getX() != aPreviousPoint.getX()
+                && aCurrentPoint.getY() != aPreviousPoint.getY())
+                *hasOnlyOrthogonal = false;
+        }
+        else
+        {
+            basegfx::B2DPoint aPreviousControlPoint = rPolygon.getNextControlPoint(nPreviousIndex);
+            basegfx::B2DPoint aCurrentControlPoint = rPolygon.getPrevControlPoint(nCurrentIndex);
+
+            if (aPreviousControlPoint.equal(aPreviousPoint)
+                && aCurrentControlPoint.equal(aCurrentPoint))
+            {
+                rPath.lineTo(aCurrentPoint.getX(), aCurrentPoint.getY()); // a straight line
+                if (hasOnlyOrthogonal != nullptr && aCurrentPoint.getX() != aPreviousPoint.getX()
+                    && aCurrentPoint.getY() != aPreviousPoint.getY())
+                    *hasOnlyOrthogonal = false;
+            }
+            else
+            {
+                if (aPreviousControlPoint.equal(aPreviousPoint))
+                {
+                    aPreviousControlPoint
+                        = aPreviousPoint + ((aPreviousControlPoint - aCurrentPoint) * 0.0005);
+                }
+                if (aCurrentControlPoint.equal(aCurrentPoint))
+                {
+                    aCurrentControlPoint
+                        = aCurrentPoint + ((aCurrentControlPoint - aPreviousPoint) * 0.0005);
+                }
+                rPath.cubicTo(aPreviousControlPoint.getX(), aPreviousControlPoint.getY(),
+                              aCurrentControlPoint.getX(), aCurrentControlPoint.getY(),
+                              aCurrentPoint.getX(), aCurrentPoint.getY());
+                if (hasOnlyOrthogonal != nullptr)
+                    *hasOnlyOrthogonal = false;
+            }
+        }
+        aPreviousPoint = aCurrentPoint;
+        nPreviousIndex = nCurrentIndex;
+    }
+    if (bClosePath && nFirstIndex == 0 && nLastIndex == nPointCount)
+    {
+        rPath.close();
+    }
+}
+
+void addPolygonToPath(const basegfx::B2DPolygon& rPolygon, SkPath& rPath,
+                      bool* hasOnlyOrthogonal = nullptr)
+{
+    addPolygonToPath(rPolygon, rPath, 0, rPolygon.count(), rPolygon.count(), rPolygon.isClosed(),
+                     rPolygon.areControlPointsUsed(), hasOnlyOrthogonal);
+}
+
+void addPolyPolygonToPath(const basegfx::B2DPolyPolygon& rPolyPolygon, SkPath& rPath,
+                          bool* hasOnlyOrthogonal = nullptr)
+{
+    const sal_uInt32 nPolygonCount(rPolyPolygon.count());
+
+    if (nPolygonCount == 0)
+        return;
+
+    sal_uInt32 nPointCount = 0;
+    for (const auto& rPolygon : rPolyPolygon)
+        nPointCount += rPolygon.count() * 3; // because cubicTo is 3 elements
+    rPath.incReserve(nPointCount);
+
+    for (const auto& rPolygon : rPolyPolygon)
+    {
+        addPolygonToPath(rPolygon, rPath, hasOnlyOrthogonal);
+    }
+}
+
+// Check if the given polygon contains a straight line. If not, it consists
+// solely of curves.
+bool polygonContainsLine(const basegfx::B2DPolyPolygon& rPolyPolygon)
+{
+    if (!rPolyPolygon.areControlPointsUsed())
+        return true; // no curves at all
+    for (const auto& rPolygon : rPolyPolygon)
+    {
+        const sal_uInt32 nPointCount(rPolygon.count());
+        bool bFirst = true;
+
+        const bool bClosePath(rPolygon.isClosed());
+
+        sal_uInt32 nCurrentIndex = 0;
+        sal_uInt32 nPreviousIndex = nPointCount - 1;
+
+        basegfx::B2DPoint aCurrentPoint;
+        basegfx::B2DPoint aPreviousPoint;
+
+        for (sal_uInt32 nIndex = 0; nIndex <= nPointCount; nIndex++)
+        {
+            if (nIndex == nPointCount && !bClosePath)
+                continue;
+
+            // Make sure we loop the last point to first point
+            nCurrentIndex = nIndex % nPointCount;
+            if (bFirst)
+                bFirst = false;
+            else
+            {
+                basegfx::B2DPoint aPreviousControlPoint
+                    = rPolygon.getNextControlPoint(nPreviousIndex);
+                basegfx::B2DPoint aCurrentControlPoint
+                    = rPolygon.getPrevControlPoint(nCurrentIndex);
+
+                if (aPreviousControlPoint.equal(aPreviousPoint)
+                    && aCurrentControlPoint.equal(aCurrentPoint))
+                {
+                    return true; // found a straight line
+                }
+            }
+            aPreviousPoint = aCurrentPoint;
+            nPreviousIndex = nCurrentIndex;
+        }
+    }
+    return false; // no straight line found
+}
+
+// returns true if the source or destination rectangles are invalid
+bool checkInvalidSourceOrDestination(SalTwoRect const& rPosAry)
+{
+    return rPosAry.mnSrcWidth <= 0 || rPosAry.mnSrcHeight <= 0 || rPosAry.mnDestWidth <= 0
+           || rPosAry.mnDestHeight <= 0;
+}
+
+} // end anonymous namespace
+
+// Class that triggers flushing the backing buffer when idle.
+class SkiaFlushIdle : public Idle
+{
+    SkiaSalGraphicsImpl* mpGraphics;
+#ifndef NDEBUG
+    char* debugname;
+#endif
+
+public:
+    explicit SkiaFlushIdle(SkiaSalGraphicsImpl* pGraphics)
+        : Idle(get_debug_name(pGraphics))
+        , mpGraphics(pGraphics)
+    {
+        // We don't want to be swapping before we've painted.
+        SetPriority(TaskPriority::POST_PAINT);
+    }
+#ifndef NDEBUG
+    virtual ~SkiaFlushIdle() { free(debugname); }
+#endif
+    const char* get_debug_name(SkiaSalGraphicsImpl* pGraphics)
+    {
+#ifndef NDEBUG
+        // Idle keeps just a pointer, so we need to store the string
+        debugname = strdup(
+            OString("skia idle 0x" + OString::number(reinterpret_cast<sal_uIntPtr>(pGraphics), 16))
+                .getStr());
+        return debugname;
+#else
+        (void)pGraphics;
+        return "skia idle";
+#endif
+    }
+
+    virtual void Invoke() override
+    {
+        mpGraphics->performFlush();
+        Stop();
+        SetPriority(TaskPriority::HIGHEST);
+    }
+};
+
+SkiaSalGraphicsImpl::SkiaSalGraphicsImpl(SalGraphics& rParent, SalGeometryProvider* pProvider)
+    : mParent(rParent)
+    , mProvider(pProvider)
+    , mIsGPU(false)
+    , mLineColor(SALCOLOR_NONE)
+    , mFillColor(SALCOLOR_NONE)
+    , mXorMode(XorMode::None)
+    , mFlush(new SkiaFlushIdle(this))
+    , mScaling(1)
+{
+}
+
+SkiaSalGraphicsImpl::~SkiaSalGraphicsImpl()
+{
+    assert(!mSurface);
+    assert(!mWindowContext);
+}
+
+void SkiaSalGraphicsImpl::Init() {}
+
+void SkiaSalGraphicsImpl::createSurface()
+{
+    SkiaZone zone;
+    if (isOffscreen())
+        createOffscreenSurface();
+    else
+        createWindowSurface();
+    mClipRegion = vcl::Region(tools::Rectangle(0, 0, GetWidth(), GetHeight()));
+    mDirtyRect = SkIRect::MakeWH(GetWidth(), GetHeight());
+    setCanvasScalingAndClipping();
+
+    // We don't want to be swapping before we've painted.
+    mFlush->Stop();
+    mFlush->SetPriority(TaskPriority::POST_PAINT);
+}
+
+void SkiaSalGraphicsImpl::createWindowSurface(bool forceRaster)
+{
+    SkiaZone zone;
+    assert(!isOffscreen());
+    assert(!mSurface);
+    createWindowSurfaceInternal(forceRaster);
+    if (!mSurface)
+    {
+        switch (forceRaster ? RenderRaster : renderMethodToUse())
+        {
+            case RenderVulkan:
+                SAL_WARN("vcl.skia",
+                         "cannot create Vulkan GPU window surface, falling back to Raster");
+                destroySurface(); // destroys also WindowContext
+                return createWindowSurface(true); // try again
+            case RenderMetal:
+                SAL_WARN("vcl.skia",
+                         "cannot create Metal GPU window surface, falling back to Raster");
+                destroySurface(); // destroys also WindowContext
+                return createWindowSurface(true); // try again
+            case RenderRaster:
+                abort(); // This should not really happen, do not even try to cope with it.
+        }
+    }
+    mIsGPU = mSurface->getCanvas()->recordingContext() != nullptr;
+#ifdef DBG_UTIL
+    prefillSurface(mSurface);
+#endif
+}
+
+bool SkiaSalGraphicsImpl::isOffscreen() const
+{
+    if (mProvider == nullptr || mProvider->IsOffScreen())
+        return true;
+    // HACK: Sometimes (tdf#131939, tdf#138022, tdf#140288) VCL passes us a zero-sized window,
+    // and zero size is invalid for Skia, so force offscreen surface, where we handle this.
+    if (GetWidth() <= 0 || GetHeight() <= 0)
+        return true;
+    return false;
+}
+
+void SkiaSalGraphicsImpl::createOffscreenSurface()
+{
+    SkiaZone zone;
+    assert(isOffscreen());
+    assert(!mSurface);
+    // HACK: See isOffscreen().
+    int width = std::max(1, GetWidth());
+    int height = std::max(1, GetHeight());
+    // We need to use window scaling even for offscreen surfaces, because the common usage is rendering something
+    // into an offscreen surface and then copy it to a window, so without scaling here the result would be originally
+    // drawn without scaling and only upscaled when drawing to a window.
+    mScaling = getWindowScaling();
+    mSurface = createSkSurface(width * mScaling, height * mScaling);
+    assert(mSurface);
+    mIsGPU = mSurface->getCanvas()->recordingContext() != nullptr;
+}
+
+void SkiaSalGraphicsImpl::destroySurface()
+{
+    SkiaZone zone;
+    if (mSurface)
+    {
+        // check setClipRegion() invariant
+        assert(mSurface->getCanvas()->getSaveCount() == 3);
+        // if this fails, something forgot to use SkAutoCanvasRestore
+        assert(mSurface->getCanvas()->getTotalMatrix() == SkMatrix::Scale(mScaling, mScaling));
+    }
+    mSurface.reset();
+    mWindowContext.reset();
+    mIsGPU = false;
+    mScaling = 1;
+}
+
+void SkiaSalGraphicsImpl::performFlush()
+{
+    SkiaZone zone;
+    flushDrawing();
+    if (mSurface)
+    {
+        if (mDirtyRect.intersect(SkIRect::MakeWH(GetWidth(), GetHeight())))
+            flushSurfaceToWindowContext();
+        mDirtyRect.setEmpty();
+    }
+}
+
+void SkiaSalGraphicsImpl::flushSurfaceToWindowContext()
+{
+    sk_sp<SkSurface> screenSurface = mWindowContext->getBackbufferSurface();
+    if (screenSurface != mSurface)
+    {
+        // GPU-based window contexts require calling getBackbufferSurface()
+        // for every swapBuffers(), for this reason mSurface is an offscreen surface
+        // where we keep the contents (LO does not do full redraws).
+        // So here blit the surface to the window context surface and then swap it.
+        assert(isGPU()); // Raster should always draw directly to backbuffer to save copying
+        SkPaint paint;
+        paint.setBlendMode(SkBlendMode::kSrc); // copy as is
+        // We ignore mDirtyRect here, and mSurface already is in screenSurface coordinates,
+        // so no transformation needed.
+        screenSurface->getCanvas()->drawImage(makeCheckedImageSnapshot(mSurface), 0, 0,
+                                              SkSamplingOptions(), &paint);
+        screenSurface->flushAndSubmit(); // Otherwise the window is not drawn sometimes.
+        mWindowContext->swapBuffers(nullptr); // Must swap the entire surface.
+    }
+    else
+    {
+        // For raster mode use directly the backbuffer surface, it's just a bitmap
+        // surface anyway, and for those there's no real requirement to call
+        // getBackbufferSurface() repeatedly. Using our own surface would duplicate
+        // memory and cost time copying pixels around.
+        assert(!isGPU());
+        SkIRect dirtyRect = mDirtyRect;
+        if (mScaling != 1) // Adjust to mSurface coordinates if needed.
+            dirtyRect = scaleRect(dirtyRect, mScaling);
+        mWindowContext->swapBuffers(&dirtyRect);
+    }
+}
+
+void SkiaSalGraphicsImpl::DeInit() { destroySurface(); }
+
+void SkiaSalGraphicsImpl::preDraw()
+{
+    assert(comphelper::SolarMutex::get()->IsCurrentThread());
+    SkiaZone::enter(); // matched in postDraw()
+    checkSurface();
+    checkPendingDrawing();
+}
+
+void SkiaSalGraphicsImpl::postDraw()
+{
+    scheduleFlush();
+    // Skia (at least when using Vulkan) queues drawing commands and executes them only later.
+    // But tdf#136369 leads to creating and queueing many tiny bitmaps, which makes
+    // Skia slow, and may make it even run out of memory. So force a flush if such
+    // a problematic operation has been performed too many times without a flush.
+    // Note that the counter is a static variable, as all drawing shares the same Skia drawing
+    // context (and so the flush here will also flush all drawing).
+    if (pendingOperationsToFlush > 1000)
+    {
+        mSurface->flushAndSubmit();
+        pendingOperationsToFlush = 0;
+    }
+    SkiaZone::leave(); // matched in preDraw()
+    // If there's a problem with the GPU context, abort.
+    if (GrDirectContext* context = GrAsDirectContext(mSurface->getCanvas()->recordingContext()))
+    {
+        // Running out of memory on the GPU technically could be possibly recoverable,
+        // but we don't know the exact status of the surface (and what has or has not been drawn to it),
+        // so in practice this is unrecoverable without possible data loss.
+        if (context->oomed())
+        {
+            SAL_WARN("vcl.skia", "GPU context has run out of memory, aborting.");
+            abort();
+        }
+        // Unrecoverable problem.
+        if (context->abandoned())
+        {
+            SAL_WARN("vcl.skia", "GPU context has been abandoned, aborting.");
+            abort();
+        }
+    }
+}
+
+void SkiaSalGraphicsImpl::scheduleFlush()
+{
+    if (!isOffscreen())
+    {
+        if (!Application::IsInExecute())
+            performFlush(); // otherwise nothing would trigger idle rendering
+        else if (!mFlush->IsActive())
+            mFlush->Start();
+    }
+}
+
+// VCL can sometimes resize us without telling us, update the surface if needed.
+// Also create the surface on demand if it has not been created yet (it is a waste
+// to create it in Init() if it gets recreated later anyway).
+void SkiaSalGraphicsImpl::checkSurface()
+{
+    if (!mSurface)
+    {
+        createSurface();
+        SAL_INFO("vcl.skia.trace",
+                 "create(" << this << "): " << Size(mSurface->width(), mSurface->height()));
+    }
+    else if (GetWidth() * mScaling != mSurface->width()
+             || GetHeight() * mScaling != mSurface->height())
+    {
+        if (!avoidRecreateByResize())
+        {
+            Size oldSize(mSurface->width(), mSurface->height());
+            // Recreating a surface means that the old SkSurface contents will be lost.
+            // But if a window has been resized the windowing system may send repaint events
+            // only for changed parts and VCL would not repaint the whole area, assuming
+            // that some parts have not changed (this is what seems to cause tdf#131952).
+            // So carry over the old contents for windows, even though generally everything
+            // will be usually repainted anyway.
+            sk_sp<SkImage> snapshot;
+            if (!isOffscreen())
+            {
+                flushDrawing();
+                snapshot = makeCheckedImageSnapshot(mSurface);
+            }
+
+            destroySurface();
+            createSurface();
+
+            if (snapshot)
+            {
+                SkPaint paint;
+                paint.setBlendMode(SkBlendMode::kSrc); // copy as is
+                // Scaling by current mScaling is active, undo that. We assume that the scaling
+                // does not change.
+                resetCanvasScalingAndClipping();
+                mSurface->getCanvas()->drawImage(snapshot, 0, 0, SkSamplingOptions(), &paint);
+                setCanvasScalingAndClipping();
+            }
+            SAL_INFO("vcl.skia.trace", "recreate(" << this << "): old " << oldSize << " new "
+                                                   << Size(mSurface->width(), mSurface->height())
+                                                   << " requested "
+                                                   << Size(GetWidth(), GetHeight()));
+        }
+    }
+}
+
+bool SkiaSalGraphicsImpl::avoidRecreateByResize() const
+{
+    // Keep the old surface if VCL sends us a broken size (see isOffscreen()).
+    if (GetWidth() == 0 || GetHeight() == 0)
+        return true;
+    return false;
+}
+
+void SkiaSalGraphicsImpl::flushDrawing()
+{
+    if (!mSurface)
+        return;
+    checkPendingDrawing();
+    ++pendingOperationsToFlush;
+}
+
+void SkiaSalGraphicsImpl::setCanvasScalingAndClipping()
+{
+    SkCanvas* canvas = mSurface->getCanvas();
+    assert(canvas->getSaveCount() == 1);
+    // If HiDPI scaling is active, simply set a scaling matrix for the canvas. This means
+    // that all painting can use VCL coordinates and they'll be automatically translated to mSurface
+    // scaled coordinates. If that is not wanted, the scale() state needs to be temporarily unset.
+    // State such as mDirtyRect is not scaled, the scaling matrix applies to clipping too,
+    // and the rest needs to be handled explicitly.
+    // When reading mSurface contents there's no automatic scaling and it needs to be handled explicitly.
+    canvas->save(); // keep the original state without any scaling
+    canvas->scale(mScaling, mScaling);
+
+    // SkCanvas::clipRegion() can only further reduce the clip region,
+    // but we need to set the given region, which may extend it.
+    // So handle that by always having the full clip region saved on the stack
+    // and always go back to that. SkCanvas::restore() only affects the clip
+    // and the matrix.
+    canvas->save(); // keep scaled state without clipping
+    setCanvasClipRegion(canvas, mClipRegion);
+}
+
+void SkiaSalGraphicsImpl::resetCanvasScalingAndClipping()
+{
+    SkCanvas* canvas = mSurface->getCanvas();
+    assert(canvas->getSaveCount() == 3);
+    canvas->restore(); // undo clipping
+    canvas->restore(); // undo scaling
+}
+
+bool SkiaSalGraphicsImpl::setClipRegion(const vcl::Region& region)
+{
+    if (mClipRegion == region)
+        return true;
+    SkiaZone zone;
+    checkPendingDrawing();
+    checkSurface();
+    mClipRegion = region;
+    SAL_INFO("vcl.skia.trace", "setclipregion(" << this << "): " << region);
+    SkCanvas* canvas = mSurface->getCanvas();
+    assert(canvas->getSaveCount() == 3);
+    canvas->restore(); // undo previous clip state, see setCanvasScalingAndClipping()
+    canvas->save();
+    setCanvasClipRegion(canvas, region);
+    return true;
+}
+
+void SkiaSalGraphicsImpl::setCanvasClipRegion(SkCanvas* canvas, const vcl::Region& region)
+{
+    SkiaZone zone;
+    SkPath path;
+    // Always use region rectangles, regardless of what the region uses internally.
+    // That's what other VCL backends do, and trying to use addPolyPolygonToPath()
+    // in case a polygon is used leads to off-by-one errors such as tdf#133208.
+    RectangleVector rectangles;
+    region.GetRegionRectangles(rectangles);
+    path.incReserve(rectangles.size() + 1);
+    for (const tools::Rectangle& rectangle : rectangles)
+        path.addRect(SkRect::MakeXYWH(rectangle.getX(), rectangle.getY(), rectangle.GetWidth(),
+                                      rectangle.GetHeight()));
+    path.setFillType(SkPathFillType::kEvenOdd);
+    canvas->clipPath(path);
+}
+
+void SkiaSalGraphicsImpl::ResetClipRegion()
+{
+    setClipRegion(vcl::Region(tools::Rectangle(0, 0, GetWidth(), GetHeight())));
+}
+
+const vcl::Region& SkiaSalGraphicsImpl::getClipRegion() const { return mClipRegion; }
+
+sal_uInt16 SkiaSalGraphicsImpl::GetBitCount() const { return 32; }
+
+tools::Long SkiaSalGraphicsImpl::GetGraphicsWidth() const { return GetWidth(); }
+
+void SkiaSalGraphicsImpl::SetLineColor()
+{
+    checkPendingDrawing();
+    mLineColor = SALCOLOR_NONE;
+}
+
+void SkiaSalGraphicsImpl::SetLineColor(Color nColor)
+{
+    checkPendingDrawing();
+    mLineColor = nColor;
+}
+
+void SkiaSalGraphicsImpl::SetFillColor()
+{
+    checkPendingDrawing();
+    mFillColor = SALCOLOR_NONE;
+}
+
+void SkiaSalGraphicsImpl::SetFillColor(Color nColor)
+{
+    checkPendingDrawing();
+    mFillColor = nColor;
+}
+
+void SkiaSalGraphicsImpl::SetXORMode(bool set, bool invert)
+{
+    XorMode newMode = set ? (invert ? XorMode::Invert : XorMode::Xor) : XorMode::None;
+    if (newMode == mXorMode)
+        return;
+    checkPendingDrawing();
+    SAL_INFO("vcl.skia.trace", "setxormode(" << this << "): " << set << "/" << invert);
+    mXorMode = newMode;
+}
+
+void SkiaSalGraphicsImpl::SetROPLineColor(SalROPColor nROPColor)
+{
+    checkPendingDrawing();
+    switch (nROPColor)
+    {
+        case SalROPColor::N0:
+            mLineColor = Color(0, 0, 0);
+            break;
+        case SalROPColor::N1:
+            mLineColor = Color(0xff, 0xff, 0xff);
+            break;
+        case SalROPColor::Invert:
+            mLineColor = Color(0xff, 0xff, 0xff);
+            break;
+    }
+}
+
+void SkiaSalGraphicsImpl::SetROPFillColor(SalROPColor nROPColor)
+{
+    checkPendingDrawing();
+    switch (nROPColor)
+    {
+        case SalROPColor::N0:
+            mFillColor = Color(0, 0, 0);
+            break;
+        case SalROPColor::N1:
+            mFillColor = Color(0xff, 0xff, 0xff);
+            break;
+        case SalROPColor::Invert:
+            mFillColor = Color(0xff, 0xff, 0xff);
+            break;
+    }
+}
+
+void SkiaSalGraphicsImpl::drawPixel(tools::Long nX, tools::Long nY)
+{
+    drawPixel(nX, nY, mLineColor);
+}
+
+void SkiaSalGraphicsImpl::drawPixel(tools::Long nX, tools::Long nY, Color nColor)
+{
+    if (nColor == SALCOLOR_NONE)
+        return;
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawpixel(" << this << "): " << Point(nX, nY) << ":" << nColor);
+    addUpdateRegion(SkRect::MakeXYWH(nX, nY, 1, 1));
+    SkPaint paint = makePixelPaint(nColor);
+    // Apparently drawPixel() is actually expected to set the pixel and not draw it.
+    paint.setBlendMode(SkBlendMode::kSrc); // set as is, including alpha
+    if (mScaling != 1 && isUnitTestRunning())
+    {
+        // On HiDPI displays, draw a square on the entire non-hidpi "pixel" when running unittests,
+        // since tests often require precise pixel drawing.
+        paint.setStrokeWidth(1); // this will be scaled by mScaling
+        paint.setStrokeCap(SkPaint::kSquare_Cap);
+    }
+    getDrawCanvas()->drawPoint(toSkX(nX), toSkY(nY), paint);
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::drawLine(tools::Long nX1, tools::Long nY1, tools::Long nX2,
+                                   tools::Long nY2)
+{
+    if (mLineColor == SALCOLOR_NONE)
+        return;
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawline(" << this << "): " << Point(nX1, nY1) << "->"
+                                           << Point(nX2, nY2) << ":" << mLineColor);
+    addUpdateRegion(SkRect::MakeLTRB(nX1, nY1, nX2, nY2).makeSorted());
+    SkPaint paint = makeLinePaint();
+    paint.setAntiAlias(mParent.getAntiAlias());
+    if (mScaling != 1 && isUnitTestRunning())
+    {
+        // On HiDPI displays, do not draw hairlines, draw 1-pixel wide lines in order to avoid
+        // smoothing that would confuse unittests.
+        paint.setStrokeWidth(1); // this will be scaled by mScaling
+        paint.setStrokeCap(SkPaint::kSquare_Cap);
+    }
+    getDrawCanvas()->drawLine(toSkX(nX1), toSkY(nY1), toSkX(nX2), toSkY(nY2), paint);
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::privateDrawAlphaRect(tools::Long nX, tools::Long nY, tools::Long nWidth,
+                                               tools::Long nHeight, double fTransparency,
+                                               bool blockAA)
+{
+    preDraw();
+    SAL_INFO("vcl.skia.trace",
+             "privatedrawrect(" << this << "): " << SkIRect::MakeXYWH(nX, nY, nWidth, nHeight)
+                                << ":" << mLineColor << ":" << mFillColor << ":" << fTransparency);
+    addUpdateRegion(SkRect::MakeXYWH(nX, nY, nWidth, nHeight));
+    SkCanvas* canvas = getDrawCanvas();
+    if (mFillColor != SALCOLOR_NONE)
+    {
+        SkPaint paint = makeFillPaint(fTransparency);
+        paint.setAntiAlias(!blockAA && mParent.getAntiAlias());
+        // HACK: If the polygon is just a line, it still should be drawn. But when filling
+        // Skia doesn't draw empty polygons, so in that case ensure the line is drawn.
+        if (mLineColor == SALCOLOR_NONE && SkSize::Make(nWidth, nHeight).isEmpty())
+            paint.setStyle(SkPaint::kStroke_Style);
+        canvas->drawIRect(SkIRect::MakeXYWH(nX, nY, nWidth, nHeight), paint);
+    }
+    if (mLineColor != SALCOLOR_NONE && mLineColor != mFillColor) // otherwise handled by fill
+    {
+        SkPaint paint = makeLinePaint(fTransparency);
+        paint.setAntiAlias(!blockAA && mParent.getAntiAlias());
+        if (mScaling != 1 && isUnitTestRunning())
+        {
+            // On HiDPI displays, do not draw just a hairline but instead a full-width "pixel" when running unittests,
+            // since tests often require precise pixel drawing.
+            paint.setStrokeWidth(1); // this will be scaled by mScaling
+            paint.setStrokeCap(SkPaint::kSquare_Cap);
+        }
+        // The obnoxious "-1 DrawRect()" hack that I don't understand the purpose of (and I'm not sure
+        // if anybody does), but without it some cases do not work. The max() is needed because Skia
+        // will not draw anything if width or height is 0.
+        canvas->drawRect(SkRect::MakeXYWH(toSkX(nX), toSkY(nY),
+                                          std::max(tools::Long(1), nWidth - 1),
+                                          std::max(tools::Long(1), nHeight - 1)),
+                         paint);
+    }
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::drawRect(tools::Long nX, tools::Long nY, tools::Long nWidth,
+                                   tools::Long nHeight)
+{
+    privateDrawAlphaRect(nX, nY, nWidth, nHeight, 0.0, true);
+}
+
+void SkiaSalGraphicsImpl::drawPolyLine(sal_uInt32 nPoints, const Point* pPtAry)
+{
+    basegfx::B2DPolygon aPolygon;
+    aPolygon.append(basegfx::B2DPoint(pPtAry->getX(), pPtAry->getY()), nPoints);
+    for (sal_uInt32 i = 1; i < nPoints; ++i)
+        aPolygon.setB2DPoint(i, basegfx::B2DPoint(pPtAry[i].getX(), pPtAry[i].getY()));
+    aPolygon.setClosed(false);
+
+    drawPolyLine(basegfx::B2DHomMatrix(), aPolygon, 0.0, 1.0, nullptr, basegfx::B2DLineJoin::Miter,
+                 css::drawing::LineCap_BUTT, basegfx::deg2rad(15.0) /*default*/, false);
+}
+
+void SkiaSalGraphicsImpl::drawPolygon(sal_uInt32 nPoints, const Point* pPtAry)
+{
+    basegfx::B2DPolygon aPolygon;
+    aPolygon.append(basegfx::B2DPoint(pPtAry->getX(), pPtAry->getY()), nPoints);
+    for (sal_uInt32 i = 1; i < nPoints; ++i)
+        aPolygon.setB2DPoint(i, basegfx::B2DPoint(pPtAry[i].getX(), pPtAry[i].getY()));
+
+    drawPolyPolygon(basegfx::B2DHomMatrix(), basegfx::B2DPolyPolygon(aPolygon), 0.0);
+}
+
+void SkiaSalGraphicsImpl::drawPolyPolygon(sal_uInt32 nPoly, const sal_uInt32* pPoints,
+                                          const Point** pPtAry)
+{
+    basegfx::B2DPolyPolygon aPolyPolygon;
+    for (sal_uInt32 nPolygon = 0; nPolygon < nPoly; ++nPolygon)
+    {
+        sal_uInt32 nPoints = pPoints[nPolygon];
+        if (nPoints)
+        {
+            const Point* pSubPoints = pPtAry[nPolygon];
+            basegfx::B2DPolygon aPolygon;
+            aPolygon.append(basegfx::B2DPoint(pSubPoints->getX(), pSubPoints->getY()), nPoints);
+            for (sal_uInt32 i = 1; i < nPoints; ++i)
+                aPolygon.setB2DPoint(i,
+                                     basegfx::B2DPoint(pSubPoints[i].getX(), pSubPoints[i].getY()));
+
+            aPolyPolygon.append(aPolygon);
+        }
+    }
+
+    drawPolyPolygon(basegfx::B2DHomMatrix(), aPolyPolygon, 0.0);
+}
+
+bool SkiaSalGraphicsImpl::drawPolyPolygon(const basegfx::B2DHomMatrix& rObjectToDevice,
+                                          const basegfx::B2DPolyPolygon& rPolyPolygon,
+                                          double fTransparency)
+{
+    const bool bHasFill(mFillColor != SALCOLOR_NONE);
+    const bool bHasLine(mLineColor != SALCOLOR_NONE);
+
+    if (rPolyPolygon.count() == 0 || !(bHasFill || bHasLine) || fTransparency < 0.0
+        || fTransparency >= 1.0)
+        return true;
+
+    basegfx::B2DPolyPolygon aPolyPolygon(rPolyPolygon);
+    aPolyPolygon.transform(rObjectToDevice);
+
+    SAL_INFO("vcl.skia.trace", "drawpolypolygon(" << this << "): " << aPolyPolygon << ":"
+                                                  << mLineColor << ":" << mFillColor);
+
+    if (delayDrawPolyPolygon(aPolyPolygon, fTransparency))
+    {
+        scheduleFlush();
+        return true;
+    }
+
+    performDrawPolyPolygon(aPolyPolygon, fTransparency, mParent.getAntiAlias());
+    return true;
+}
+
+void SkiaSalGraphicsImpl::performDrawPolyPolygon(const basegfx::B2DPolyPolygon& aPolyPolygon,
+                                                 double fTransparency, bool useAA)
+{
+    preDraw();
+
+    SkPath polygonPath;
+    bool hasOnlyOrthogonal = true;
+    addPolyPolygonToPath(aPolyPolygon, polygonPath, &hasOnlyOrthogonal);
+    polygonPath.setFillType(SkPathFillType::kEvenOdd);
+    addUpdateRegion(polygonPath.getBounds());
+
+    // For lines we use toSkX()/toSkY() in order to pass centers of pixels to Skia,
+    // as that leads to better results with floating-point coordinates
+    // (e.g. https://bugs.chromium.org/p/skia/issues/detail?id=9611).
+    // But that means that we generally need to use it also for areas, so that they
+    // line up properly if used together (tdf#134346).
+    // On the other hand, with AA enabled and rectangular areas, this leads to fuzzy
+    // edges (tdf#137329). But since rectangular areas line up perfectly to pixels
+    // everywhere, it shouldn't be necessary to do this for them.
+    // So if AA is enabled, avoid this fixup for rectangular areas.
+    if (!useAA || !hasOnlyOrthogonal)
+    {
+        // We normally use pixel at their center positions, but slightly off (see toSkX/Y()).
+        // With AA lines that "slightly off" causes tiny changes of color, making some tests
+        // fail. Since moving AA-ed line slightly to a side doesn't cause any real visual
+        // difference, just place exactly at the center. tdf#134346
+        const SkScalar posFix = useAA ? toSkXYFix : 0;
+        polygonPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, nullptr);
+    }
+    if (mFillColor != SALCOLOR_NONE)
+    {
+        SkPaint aPaint = makeFillPaint(fTransparency);
+        aPaint.setAntiAlias(useAA);
+        // HACK: If the polygon is just a line, it still should be drawn. But when filling
+        // Skia doesn't draw empty polygons, so in that case ensure the line is drawn.
+        if (mLineColor == SALCOLOR_NONE && polygonPath.getBounds().isEmpty())
+            aPaint.setStyle(SkPaint::kStroke_Style);
+        getDrawCanvas()->drawPath(polygonPath, aPaint);
+    }
+    if (mLineColor != SALCOLOR_NONE && mLineColor != mFillColor) // otherwise handled by fill
+    {
+        SkPaint aPaint = makeLinePaint(fTransparency);
+        aPaint.setAntiAlias(useAA);
+        getDrawCanvas()->drawPath(polygonPath, aPaint);
+    }
+    postDraw();
+}
+
+namespace
+{
+struct LessThan
+{
+    bool operator()(const basegfx::B2DPoint& point1, const basegfx::B2DPoint& point2) const
+    {
+        if (basegfx::fTools::equal(point1.getX(), point2.getX()))
+            return basegfx::fTools::less(point1.getY(), point2.getY());
+        return basegfx::fTools::less(point1.getX(), point2.getX());
+    }
+};
+} // namespace
+
+bool SkiaSalGraphicsImpl::delayDrawPolyPolygon(const basegfx::B2DPolyPolygon& aPolyPolygon,
+                                               double fTransparency)
+{
+    // There is some code that needlessly subdivides areas into adjacent rectangles,
+    // but Skia doesn't line them up perfectly if AA is enabled (e.g. Cairo, Qt5 do,
+    // but Skia devs claim it's working as intended
+    // https://groups.google.com/d/msg/skia-discuss/NlKpD2X_5uc/Vuwd-kyYBwAJ).
+    // An example is tdf#133016, which triggers SvgStyleAttributes::add_stroke()
+    // implementing a line stroke as a bunch of polygons instead of just one, and
+    // SvgLinearAtomPrimitive2D::create2DDecomposition() creates a gradient
+    // as a series of polygons of gradually changing color. Those places should be
+    // changed, but try to merge those split polygons back into the original one,
+    // where the needlessly created edges causing problems will not exist.
+    // This means drawing of such polygons needs to be delayed, so that they can
+    // be possibly merged with the next one.
+    // Merge only polygons of the same properties (color, etc.), so the gradient problem
+    // actually isn't handled here.
+
+    // Only AA polygons need merging, because they do not line up well because of the AA of the edges.
+    if (!mParent.getAntiAlias())
+        return false;
+    // Only filled polygons without an outline are problematic.
+    if (mFillColor == SALCOLOR_NONE || mLineColor != SALCOLOR_NONE)
+        return false;
+    // Merge only simple polygons, real polypolygons most likely aren't needlessly split,
+    // so they do not need joining.
+    if (aPolyPolygon.count() != 1)
+        return false;
+    // If the polygon is not closed, it doesn't mark an area to be filled.
+    if (!aPolyPolygon.isClosed())
+        return false;
+    // If a polygon does not contain a straight line, i.e. it's all curves, then do not merge.
+    // First of all that's even more expensive, and second it's very unlikely that it's a polygon
+    // split into more polygons.
+    if (!polygonContainsLine(aPolyPolygon))
+        return false;
+
+    if (mLastPolyPolygonInfo.polygons.size() != 0
+        && (mLastPolyPolygonInfo.transparency != fTransparency
+            || !mLastPolyPolygonInfo.bounds.overlaps(aPolyPolygon.getB2DRange())))
+    {
+        checkPendingDrawing(); // Cannot be parts of the same larger polygon, draw the last and reset.
+    }
+    if (!mLastPolyPolygonInfo.polygons.empty())
+    {
+        assert(aPolyPolygon.count() == 1);
+        assert(mLastPolyPolygonInfo.polygons.back().count() == 1);
+        // Check if the new and the previous polygon share at least one point. If not, then they
+        // cannot be adjacent polygons, so there's no point in trying to merge them.
+        bool sharePoint = false;
+        const basegfx::B2DPolygon& poly1 = aPolyPolygon.getB2DPolygon(0);
+        const basegfx::B2DPolygon& poly2 = mLastPolyPolygonInfo.polygons.back().getB2DPolygon(0);
+        o3tl::sorted_vector<basegfx::B2DPoint, LessThan> poly1Points; // for O(n log n)
+        poly1Points.reserve(poly1.count());
+        for (sal_uInt32 i = 0; i < poly1.count(); ++i)
+            poly1Points.insert(poly1.getB2DPoint(i));
+        for (sal_uInt32 i = 0; i < poly2.count(); ++i)
+            if (poly1Points.find(poly2.getB2DPoint(i)) != poly1Points.end())
+            {
+                sharePoint = true;
+                break;
+            }
+        if (!sharePoint)
+            checkPendingDrawing(); // Draw the previous one and reset.
+    }
+    // Collect the polygons that can be possibly merged. Do the merging only once at the end,
+    // because it's not a cheap operation.
+    mLastPolyPolygonInfo.polygons.push_back(aPolyPolygon);
+    mLastPolyPolygonInfo.bounds.expand(aPolyPolygon.getB2DRange());
+    mLastPolyPolygonInfo.transparency = fTransparency;
+    return true;
+}
+
+// Tdf#140848 - basegfx::utils::mergeToSinglePolyPolygon() seems to have rounding
+// errors that sometimes cause it to merge incorrectly.
+static void roundPolygonPoints(basegfx::B2DPolyPolygon& polyPolygon)
+{
+    for (basegfx::B2DPolygon& polygon : polyPolygon)
+    {
+        polygon.makeUnique();
+        for (sal_uInt32 i = 0; i < polygon.count(); ++i)
+            polygon.setB2DPoint(i, basegfx::B2DPoint(basegfx::fround(polygon.getB2DPoint(i))));
+        // Control points are saved as vectors relative to points, so hopefully
+        // there's no need to round those.
+    }
+}
+
+void SkiaSalGraphicsImpl::checkPendingDrawing()
+{
+    if (mLastPolyPolygonInfo.polygons.size() != 0)
+    { // Flush any pending polygon drawing.
+        basegfx::B2DPolyPolygonVector polygons;
+        std::swap(polygons, mLastPolyPolygonInfo.polygons);
+        double transparency = mLastPolyPolygonInfo.transparency;
+        mLastPolyPolygonInfo.bounds.reset();
+        if (polygons.size() == 1)
+            performDrawPolyPolygon(polygons.front(), transparency, true);
+        else
+        {
+            for (basegfx::B2DPolyPolygon& p : polygons)
+                roundPolygonPoints(p);
+            performDrawPolyPolygon(basegfx::utils::mergeToSinglePolyPolygon(polygons), transparency,
+                                   true);
+        }
+    }
+}
+
+bool SkiaSalGraphicsImpl::drawPolyLine(const basegfx::B2DHomMatrix& rObjectToDevice,
+                                       const basegfx::B2DPolygon& rPolyLine, double fTransparency,
+                                       double fLineWidth, const std::vector<double>* pStroke,
+                                       basegfx::B2DLineJoin eLineJoin,
+                                       css::drawing::LineCap eLineCap, double fMiterMinimumAngle,
+                                       bool bPixelSnapHairline)
+{
+    if (!rPolyLine.count() || fTransparency < 0.0 || fTransparency > 1.0
+        || mLineColor == SALCOLOR_NONE)
+    {
+        return true;
+    }
+
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawpolyline(" << this << "): " << rPolyLine << ":" << mLineColor);
+
+    // Adjust line width for object-to-device scale.
+    fLineWidth = (rObjectToDevice * basegfx::B2DVector(fLineWidth, 0)).getLength();
+    // On HiDPI displays, do not draw hairlines, draw 1-pixel wide lines in order to avoid
+    // smoothing that would confuse unittests.
+    if (fLineWidth == 0 && mScaling != 1 && isUnitTestRunning())
+        fLineWidth = 1; // this will be scaled by mScaling
+
+    // Transform to DeviceCoordinates, get DeviceLineWidth, execute PixelSnapHairline
+    basegfx::B2DPolygon aPolyLine(rPolyLine);
+    aPolyLine.transform(rObjectToDevice);
+    if (bPixelSnapHairline)
+    {
+        aPolyLine = basegfx::utils::snapPointsOfHorizontalOrVerticalEdges(aPolyLine);
+    }
+
+    SkPaint aPaint = makeLinePaint(fTransparency);
+
+    switch (eLineJoin)
+    {
+        case basegfx::B2DLineJoin::Bevel:
+            aPaint.setStrokeJoin(SkPaint::kBevel_Join);
+            break;
+        case basegfx::B2DLineJoin::Round:
+            aPaint.setStrokeJoin(SkPaint::kRound_Join);
+            break;
+        case basegfx::B2DLineJoin::NONE:
+            break;
+        case basegfx::B2DLineJoin::Miter:
+            aPaint.setStrokeJoin(SkPaint::kMiter_Join);
+            // convert miter minimum angle to miter limit
+            aPaint.setStrokeMiter(1.0 / std::sin(fMiterMinimumAngle / 2.0));
+            break;
+    }
+
+    switch (eLineCap)
+    {
+        case css::drawing::LineCap_ROUND:
+            aPaint.setStrokeCap(SkPaint::kRound_Cap);
+            break;
+        case css::drawing::LineCap_SQUARE:
+            aPaint.setStrokeCap(SkPaint::kSquare_Cap);
+            break;
+        default: // css::drawing::LineCap_BUTT:
+            aPaint.setStrokeCap(SkPaint::kButt_Cap);
+            break;
+    }
+
+    aPaint.setStrokeWidth(fLineWidth);
+    aPaint.setAntiAlias(mParent.getAntiAlias());
+    // See the tdf#134346 comment above.
+    const SkScalar posFix = mParent.getAntiAlias() ? toSkXYFix : 0;
+
+    if (pStroke && std::accumulate(pStroke->begin(), pStroke->end(), 0.0) != 0)
+    {
+        std::vector<SkScalar> intervals;
+        // Transform size by the matrix.
+        for (double stroke : *pStroke)
+            intervals.push_back((rObjectToDevice * basegfx::B2DVector(stroke, 0)).getLength());
+        aPaint.setPathEffect(SkDashPathEffect::Make(intervals.data(), intervals.size(), 0));
+    }
+
+    // Skia does not support basegfx::B2DLineJoin::NONE, so in that case batch only if lines
+    // are not wider than a pixel.
+    if (eLineJoin != basegfx::B2DLineJoin::NONE || fLineWidth <= 1.0)
+    {
+        SkPath aPath;
+        aPath.incReserve(aPolyLine.count() * 3); // because cubicTo is 3 elements
+        addPolygonToPath(aPolyLine, aPath);
+        aPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, nullptr);
+        addUpdateRegion(aPath.getBounds());
+        getDrawCanvas()->drawPath(aPath, aPaint);
+    }
+    else
+    {
+        sal_uInt32 nPoints = aPolyLine.count();
+        bool bClosed = aPolyLine.isClosed();
+        bool bHasCurves = aPolyLine.areControlPointsUsed();
+        for (sal_uInt32 j = 0; j < nPoints; ++j)
+        {
+            SkPath aPath;
+            aPath.incReserve(2 * 3); // because cubicTo is 3 elements
+            addPolygonToPath(aPolyLine, aPath, j, j + 1, nPoints, bClosed, bHasCurves);
+            aPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, nullptr);
+            addUpdateRegion(aPath.getBounds());
+            getDrawCanvas()->drawPath(aPath, aPaint);
+        }
+    }
+
+    postDraw();
+
+    return true;
+}
+
+bool SkiaSalGraphicsImpl::drawPolyLineBezier(sal_uInt32, const Point*, const PolyFlags*)
+{
+    return false;
+}
+
+bool SkiaSalGraphicsImpl::drawPolygonBezier(sal_uInt32, const Point*, const PolyFlags*)
+{
+    return false;
+}
+
+bool SkiaSalGraphicsImpl::drawPolyPolygonBezier(sal_uInt32, const sal_uInt32*, const Point* const*,
+                                                const PolyFlags* const*)
+{
+    return false;
+}
+
+void SkiaSalGraphicsImpl::copyArea(tools::Long nDestX, tools::Long nDestY, tools::Long nSrcX,
+                                   tools::Long nSrcY, tools::Long nSrcWidth, tools::Long nSrcHeight,
+                                   bool /*bWindowInvalidate*/)
+{
+    if (nDestX == nSrcX && nDestY == nSrcY)
+        return;
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "copyarea("
+                                   << this << "): " << Point(nSrcX, nSrcY) << "->"
+                                   << SkIRect::MakeXYWH(nDestX, nDestY, nSrcWidth, nSrcHeight));
+    // Using SkSurface::draw() should be more efficient, but it's too buggy.
+    SalTwoRect rPosAry(nSrcX, nSrcY, nSrcWidth, nSrcHeight, nDestX, nDestY, nSrcWidth, nSrcHeight);
+    privateCopyBits(rPosAry, this);
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::copyBits(const SalTwoRect& rPosAry, SalGraphics* pSrcGraphics)
+{
+    preDraw();
+    SkiaSalGraphicsImpl* src;
+    if (pSrcGraphics)
+    {
+        assert(dynamic_cast<SkiaSalGraphicsImpl*>(pSrcGraphics->GetImpl()));
+        src = static_cast<SkiaSalGraphicsImpl*>(pSrcGraphics->GetImpl());
+        src->checkSurface();
+        src->flushDrawing();
+    }
+    else
+    {
+        src = this;
+        assert(mXorMode == XorMode::None);
+    }
+    auto srcDebug = [&]() -> std::string {
+        if (src == this)
+            return "(self)";
+        else
+        {
+            std::ostringstream stream;
+            stream << "(" << src << ")";
+            return stream.str();
+        }
+    };
+    SAL_INFO("vcl.skia.trace", "copybits(" << this << "): " << srcDebug() << ": " << rPosAry);
+    privateCopyBits(rPosAry, src);
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::privateCopyBits(const SalTwoRect& rPosAry, SkiaSalGraphicsImpl* src)
+{
+    assert(mXorMode == XorMode::None);
+    addUpdateRegion(SkRect::MakeXYWH(rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnDestWidth,
+                                     rPosAry.mnDestHeight));
+    SkPaint paint;
+    paint.setBlendMode(SkBlendMode::kSrc); // copy as is, including alpha
+    SkIRect srcRect = SkIRect::MakeXYWH(rPosAry.mnSrcX, rPosAry.mnSrcY, rPosAry.mnSrcWidth,
+                                        rPosAry.mnSrcHeight);
+    SkRect destRect = SkRect::MakeXYWH(rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnDestWidth,
+                                       rPosAry.mnDestHeight);
+
+    if (!SkIRect::Intersects(srcRect, SkIRect::MakeWH(src->GetWidth(), src->GetHeight()))
+        || !SkRect::Intersects(destRect, SkRect::MakeWH(GetWidth(), GetHeight())))
+        return;
+
+    if (src == this)
+    {
+        // Copy-to-self means that we'd take a snapshot, which would refcount the data,
+        // and then drawing would result in copy in write, copying the entire surface.
+        // Try to copy less by making a snapshot of only what is needed.
+        // A complication here is that drawImageRect() can handle coordinates outside
+        // of surface fine, but makeImageSnapshot() will crop to the surface area,
+        // so do that manually here in order to adjust also destination rectangle.
+        if (srcRect.x() < 0 || srcRect.y() < 0)
+        {
+            destRect.fLeft += -srcRect.x();
+            destRect.fTop += -srcRect.y();
+            srcRect.adjust(-srcRect.x(), -srcRect.y(), 0, 0);
+        }
+        // Note that right() and bottom() are not inclusive (are outside of the rect).
+        if (srcRect.right() - 1 > GetWidth() || srcRect.bottom() - 1 > GetHeight())
+        {
+            destRect.fRight += GetWidth() - srcRect.right();
+            destRect.fBottom += GetHeight() - srcRect.bottom();
+            srcRect.adjust(0, 0, GetWidth() - srcRect.right(), GetHeight() - srcRect.bottom());
+        }
+        // Scaling for source coordinates must be done manually.
+        if (src->mScaling != 1)
+            srcRect = scaleRect(srcRect, src->mScaling);
+        sk_sp<SkImage> image = makeCheckedImageSnapshot(src->mSurface, srcRect);
+        srcRect.offset(-srcRect.x(), -srcRect.y());
+        getDrawCanvas()->drawImageRect(image, SkRect::Make(srcRect), destRect,
+                                       makeSamplingOptions(rPosAry, mScaling, src->mScaling),
+                                       &paint, SkCanvas::kFast_SrcRectConstraint);
+    }
+    else
+    {
+        // Scaling for source coordinates must be done manually.
+        if (src->mScaling != 1)
+            srcRect = scaleRect(srcRect, src->mScaling);
+        // Do not use makeImageSnapshot(rect), as that one may make a needless data copy.
+        getDrawCanvas()->drawImageRect(makeCheckedImageSnapshot(src->mSurface),
+                                       SkRect::Make(srcRect), destRect,
+                                       makeSamplingOptions(rPosAry, mScaling, src->mScaling),
+                                       &paint, SkCanvas::kFast_SrcRectConstraint);
+    }
+}
+
+bool SkiaSalGraphicsImpl::blendBitmap(const SalTwoRect& rPosAry, const SalBitmap& rBitmap)
+{
+    if (checkInvalidSourceOrDestination(rPosAry))
+        return false;
+
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rBitmap));
+    const SkiaSalBitmap& rSkiaBitmap = static_cast<const SkiaSalBitmap&>(rBitmap);
+    // This is used by VirtualDevice in the alpha mode for the "alpha" layer which
+    // is actually one-minus-alpha (opacity). Therefore white=0xff=transparent,
+    // black=0x00=opaque. So the result is transparent only if both the inputs
+    // are transparent. Since for blending operations white=1.0 and black=0.0,
+    // kMultiply should handle exactly that (transparent*transparent=transparent,
+    // opaque*transparent=opaque). And guessing from the "floor" in TYPE_BLEND in opengl's
+    // combinedTextureFragmentShader.glsl, the layer is not even alpha values but
+    // simply yes-or-no mask.
+    // See also blendAlphaBitmap().
+    if (rSkiaBitmap.IsFullyOpaqueAsAlpha())
+    {
+        // Optimization. If the bitmap means fully opaque, it's all zero's. In CPU
+        // mode it should be faster to just copy instead of SkBlendMode::kMultiply.
+        drawBitmap(rPosAry, rSkiaBitmap);
+    }
+    else
+        drawBitmap(rPosAry, rSkiaBitmap, SkBlendMode::kMultiply);
+    return true;
+}
+
+bool SkiaSalGraphicsImpl::blendAlphaBitmap(const SalTwoRect& rPosAry,
+                                           const SalBitmap& rSourceBitmap,
+                                           const SalBitmap& rMaskBitmap,
+                                           const SalBitmap& rAlphaBitmap)
+{
+    if (checkInvalidSourceOrDestination(rPosAry))
+        return false;
+
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rSourceBitmap));
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rMaskBitmap));
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rAlphaBitmap));
+    const SkiaSalBitmap& rSkiaSourceBitmap = static_cast<const SkiaSalBitmap&>(rSourceBitmap);
+    const SkiaSalBitmap& rSkiaMaskBitmap = static_cast<const SkiaSalBitmap&>(rMaskBitmap);
+    const SkiaSalBitmap& rSkiaAlphaBitmap = static_cast<const SkiaSalBitmap&>(rAlphaBitmap);
+
+    if (rSkiaMaskBitmap.IsFullyOpaqueAsAlpha())
+    {
+        // Optimization. If the mask of the bitmap to be blended means it's actually opaque,
+        // just draw the bitmap directly (that's what the math below will result in).
+        drawBitmap(rPosAry, rSkiaSourceBitmap);
+        return true;
+    }
+    // This was originally implemented for the OpenGL drawing method and it is poorly documented.
+    // The source and mask bitmaps are the usual data and alpha bitmaps, and 'alpha'
+    // is the "alpha" layer of the VirtualDevice (the alpha in VirtualDevice is also stored
+    // as a separate bitmap). Now if I understand it correctly these two alpha masks first need
+    // to be combined into the actual alpha mask to be used. The formula for TYPE_BLEND
+    // in opengl's combinedTextureFragmentShader.glsl is
+    // "result_alpha = 1.0 - (1.0 - floor(alpha)) * mask".
+    // See also blendBitmap().
+
+    SkSamplingOptions samplingOptions = makeSamplingOptions(rPosAry, mScaling);
+    // First do the "( 1 - alpha ) * mask"
+    // (no idea how to do "floor", but hopefully not needed in practice).
+    sk_sp<SkShader> shaderAlpha
+        = SkShaders::Blend(SkBlendMode::kDstOut, rSkiaMaskBitmap.GetAlphaSkShader(samplingOptions),
+                           rSkiaAlphaBitmap.GetAlphaSkShader(samplingOptions));
+    // And now draw the bitmap with "1 - x", where x is the "( 1 - alpha ) * mask".
+    sk_sp<SkShader> shader = SkShaders::Blend(SkBlendMode::kSrcOut, shaderAlpha,
+                                              rSkiaSourceBitmap.GetSkShader(samplingOptions));
+    drawShader(rPosAry, shader);
+    return true;
+}
+
+void SkiaSalGraphicsImpl::drawBitmap(const SalTwoRect& rPosAry, const SalBitmap& rSalBitmap)
+{
+    if (checkInvalidSourceOrDestination(rPosAry))
+        return;
+
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rSalBitmap));
+    const SkiaSalBitmap& rSkiaSourceBitmap = static_cast<const SkiaSalBitmap&>(rSalBitmap);
+
+    drawBitmap(rPosAry, rSkiaSourceBitmap);
+}
+
+void SkiaSalGraphicsImpl::drawBitmap(const SalTwoRect& rPosAry, const SalBitmap& rSalBitmap,
+                                     const SalBitmap& rMaskBitmap)
+{
+    drawAlphaBitmap(rPosAry, rSalBitmap, rMaskBitmap);
+}
+
+void SkiaSalGraphicsImpl::drawMask(const SalTwoRect& rPosAry, const SalBitmap& rSalBitmap,
+                                   Color nMaskColor)
+{
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rSalBitmap));
+    const SkiaSalBitmap& skiaBitmap = static_cast<const SkiaSalBitmap&>(rSalBitmap);
+    drawShader(
+        rPosAry,
+        SkShaders::Blend(SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha.
+                         SkShaders::Color(toSkColor(nMaskColor)),
+                         skiaBitmap.GetAlphaSkShader(makeSamplingOptions(rPosAry, mScaling))));
+}
+
+std::shared_ptr<SalBitmap> SkiaSalGraphicsImpl::getBitmap(tools::Long nX, tools::Long nY,
+                                                          tools::Long nWidth, tools::Long nHeight)
+{
+    SkiaZone zone;
+    checkSurface();
+    SAL_INFO("vcl.skia.trace",
+             "getbitmap(" << this << "): " << SkIRect::MakeXYWH(nX, nY, nWidth, nHeight));
+    flushDrawing();
+    // TODO makeImageSnapshot(rect) may copy the data, which may be a waste if this is used
+    // e.g. for VirtualDevice's lame alpha blending, in which case the image will eventually end up
+    // in blendAlphaBitmap(), where we could simply use the proper rect of the image.
+    sk_sp<SkImage> image = makeCheckedImageSnapshot(
+        mSurface, scaleRect(SkIRect::MakeXYWH(nX, nY, nWidth, nHeight), mScaling));
+    std::shared_ptr<SkiaSalBitmap> bitmap = std::make_shared<SkiaSalBitmap>(image);
+    // If the surface is scaled for HiDPI, the bitmap needs to be scaled down, otherwise
+    // it would have incorrect size from the API point of view. The DirectImage::Yes handling
+    // in mergeCacheBitmaps() should access the original unscaled bitmap data to avoid
+    // pointless scaling back and forth.
+    if (mScaling != 1)
+    {
+        if (!isUnitTestRunning())
+            bitmap->Scale(1.0 / mScaling, 1.0 / mScaling, goodScalingQuality());
+        else
+        {
+            // Some tests require exact pixel values and would be confused by smooth-scaling.
+            // And some draw something smooth and not smooth-scaling there would break the checks.
+            if (isUnitTestRunning("BackendTest__testDrawHaflEllipseAAWithPolyLineB2D_")
+                || isUnitTestRunning("BackendTest__testDrawRectAAWithLine_")
+                || isUnitTestRunning("GraphicsRenderTest__testDrawRectAAWithLine"))
+            {
+                bitmap->Scale(1.0 / mScaling, 1.0 / mScaling, goodScalingQuality());
+            }
+            else
+                bitmap->Scale(1.0 / mScaling, 1.0 / mScaling, BmpScaleFlag::NearestNeighbor);
+        }
+    }
+    return bitmap;
+}
+
+Color SkiaSalGraphicsImpl::getPixel(tools::Long nX, tools::Long nY)
+{
+    SkiaZone zone;
+    checkSurface();
+    SAL_INFO("vcl.skia.trace", "getpixel(" << this << "): " << Point(nX, nY));
+    flushDrawing();
+    // This is presumably slow, but getPixel() should be generally used only by unit tests.
+    SkBitmap bitmap;
+    if (!bitmap.tryAllocN32Pixels(mSurface->width(), mSurface->height()))
+        abort();
+    if (!mSurface->readPixels(bitmap, 0, 0))
+        abort();
+    return fromSkColor(bitmap.getColor(nX * mScaling, nY * mScaling));
+}
+
+void SkiaSalGraphicsImpl::invert(basegfx::B2DPolygon const& rPoly, SalInvert eFlags)
+{
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "invert(" << this << "): " << rPoly << ":" << int(eFlags));
+    assert(mXorMode == XorMode::None);
+    SkPath aPath;
+    aPath.incReserve(rPoly.count());
+    addPolygonToPath(rPoly, aPath);
+    aPath.setFillType(SkPathFillType::kEvenOdd);
+    addUpdateRegion(aPath.getBounds());
+    SkAutoCanvasRestore autoRestore(getDrawCanvas(), true);
+    SkPaint aPaint;
+    // There's no blend mode for inverting as such, but kExclusion is 's + d - 2*s*d',
+    // so with d = 1.0 (all channels) it becomes effectively '1 - s', i.e. inverted color.
+    aPaint.setBlendMode(SkBlendMode::kExclusion);
+    aPaint.setColor(SkColorSetARGB(255, 255, 255, 255));
+    // TrackFrame just inverts a dashed path around the polygon
+    if (eFlags == SalInvert::TrackFrame)
+    {
+        // TrackFrame is not supposed to paint outside of the polygon (usually rectangle),
+        // but wider stroke width usually results in that, so ensure the requirement
+        // by clipping.
+        getDrawCanvas()->clipRect(aPath.getBounds(), SkClipOp::kIntersect, false);
+        aPaint.setStrokeWidth(2);
+        constexpr float intervals[] = { 4.0f, 4.0f };
+        aPaint.setStyle(SkPaint::kStroke_Style);
+        aPaint.setPathEffect(SkDashPathEffect::Make(intervals, SK_ARRAY_COUNT(intervals), 0));
+    }
+    else
+    {
+        aPaint.setStyle(SkPaint::kFill_Style);
+
+        // N50 inverts in checker pattern
+        if (eFlags == SalInvert::N50)
+        {
+            // This creates 2x2 checker pattern bitmap
+            // TODO Use createSkSurface() and cache the image
+            SkBitmap aBitmap;
+            aBitmap.allocN32Pixels(2, 2);
+            const SkPMColor white = SkPreMultiplyARGB(0xFF, 0xFF, 0xFF, 0xFF);
+            const SkPMColor black = SkPreMultiplyARGB(0xFF, 0x00, 0x00, 0x00);
+            SkPMColor* scanline;
+            scanline = aBitmap.getAddr32(0, 0);
+            *scanline++ = white;
+            *scanline++ = black;
+            scanline = aBitmap.getAddr32(0, 1);
+            *scanline++ = black;
+            *scanline++ = white;
+            aBitmap.setImmutable();
+            // The bitmap is repeated in both directions the checker pattern is as big
+            // as the polygon (usually rectangle)
+            aPaint.setShader(
+                aBitmap.makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, SkSamplingOptions()));
+        }
+    }
+    getDrawCanvas()->drawPath(aPath, aPaint);
+    postDraw();
+}
+
+void SkiaSalGraphicsImpl::invert(tools::Long nX, tools::Long nY, tools::Long nWidth,
+                                 tools::Long nHeight, SalInvert eFlags)
+{
+    basegfx::B2DRectangle aRectangle(nX, nY, nX + nWidth, nY + nHeight);
+    auto aRect = basegfx::utils::createPolygonFromRect(aRectangle);
+    invert(aRect, eFlags);
+}
+
+void SkiaSalGraphicsImpl::invert(sal_uInt32 nPoints, const Point* pPointArray, SalInvert eFlags)
+{
+    basegfx::B2DPolygon aPolygon;
+    aPolygon.append(basegfx::B2DPoint(pPointArray[0].getX(), pPointArray[0].getY()), nPoints);
+    for (sal_uInt32 i = 1; i < nPoints; ++i)
+    {
+        aPolygon.setB2DPoint(i, basegfx::B2DPoint(pPointArray[i].getX(), pPointArray[i].getY()));
+    }
+    aPolygon.setClosed(true);
+
+    invert(aPolygon, eFlags);
+}
+
+bool SkiaSalGraphicsImpl::drawEPS(tools::Long, tools::Long, tools::Long, tools::Long, void*,
+                                  sal_uInt32)
+{
+    return false;
+}
+
+// Create SkImage from a bitmap and possibly an alpha mask (the usual VCL one-minus-alpha),
+// with the given target size. Result will be possibly cached, unless disabled.
+// Especially in raster mode scaling and alpha blending may be expensive if done repeatedly.
+sk_sp<SkImage> SkiaSalGraphicsImpl::mergeCacheBitmaps(const SkiaSalBitmap& bitmap,
+                                                      const SkiaSalBitmap* alphaBitmap,
+                                                      const Size& targetSize)
+{
+    if (alphaBitmap)
+        assert(bitmap.GetSize() == alphaBitmap->GetSize());
+
+    if (targetSize.IsEmpty())
+        return {};
+    if (alphaBitmap && alphaBitmap->IsFullyOpaqueAsAlpha())
+        alphaBitmap = nullptr; // the alpha can be ignored
+    if (bitmap.PreferSkShader() && (!alphaBitmap || alphaBitmap->PreferSkShader()))
+        return {};
+
+    // If the bitmap has SkImage that matches the required size, try to use it, even
+    // if it doesn't match bitmap.GetSize(). This can happen with delayed scaling.
+    // This will catch cases such as some code pre-scaling the bitmap, which would make GetSkImage()
+    // scale, changing GetImageKey() in the process so we'd have to re-cache, and then we'd need
+    // to scale again in this function.
+    bool bitmapReady = false;
+    bool alphaBitmapReady = false;
+    if (const sk_sp<SkImage>& image = bitmap.GetSkImage(DirectImage::Yes))
+    {
+        assert(!bitmap.PreferSkShader());
+        if (imageSize(image) == targetSize)
+            bitmapReady = true;
+    }
+    // If the image usable and there's no alpha, then it matches exactly what's wanted.
+    if (bitmapReady && !alphaBitmap)
+        return bitmap.GetSkImage(DirectImage::Yes);
+    if (alphaBitmap)
+    {
+        if (!alphaBitmap->GetAlphaSkImage(DirectImage::Yes)
+            && alphaBitmap->GetSkImage(DirectImage::Yes)
+            && imageSize(alphaBitmap->GetSkImage(DirectImage::Yes)) == targetSize)
+        {
+            // There's a usable non-alpha image, try to convert it to alpha.
+            assert(!alphaBitmap->PreferSkShader());
+            const_cast<SkiaSalBitmap*>(alphaBitmap)->TryDirectConvertToAlphaNoScaling();
+        }
+        if (const sk_sp<SkImage>& image = alphaBitmap->GetAlphaSkImage(DirectImage::Yes))
+        {
+            assert(!alphaBitmap->PreferSkShader());
+            if (imageSize(image) == targetSize)
+                alphaBitmapReady = true;
+        }
+    }
+
+    if (bitmapReady && (!alphaBitmap || alphaBitmapReady))
+    {
+        // Try to find a cached image based on the already existing images.
+        OString key = makeCachedImageKey(bitmap, alphaBitmap, targetSize, DirectImage::Yes,
+                                         DirectImage::Yes);
+        if (sk_sp<SkImage> image = findCachedImage(key))
+        {
+            assert(imageSize(image) == targetSize);
+            return image;
+        }
+    }
+
+    // Probably not much point in caching of just doing a copy.
+    if (alphaBitmap == nullptr && targetSize == bitmap.GetSize())
+        return {};
+    // Image too small to be worth caching if not scaling.
+    if (targetSize == bitmap.GetSize() && targetSize.Width() < 100 && targetSize.Height() < 100)
+        return {};
+    // GPU-accelerated drawing with SkShader should be fast enough to not need caching.
+    if (isGPU())
+    {
+        // tdf#140925: But if this is such an extensive downscaling that caching the result
+        // would noticeably reduce amount of data processed by the GPU on repeated usage, do it.
+        int reduceRatio = bitmap.GetSize().Width() * bitmap.GetSize().Height() / targetSize.Width()
+                          / targetSize.Height();
+        if (reduceRatio < 10)
+            return {};
+    }
+    // Do not cache the result if it would take most of the cache and thus get evicted soon.
+    if (targetSize.Width() * targetSize.Height() * 4 > maxImageCacheSize() * 0.7)
+        return {};
+
+    // Use ready direct image if they are both available, now even the size doesn't matter
+    // (we'll scale as necessary and it's better to scale from the original). Require only
+    // that they are the same size, or that one prefers a shader or doesn't exist
+    // (i.e. avoid two images of different size).
+    bitmapReady = bitmap.GetSkImage(DirectImage::Yes) != nullptr;
+    alphaBitmapReady = alphaBitmap && alphaBitmap->GetAlphaSkImage(DirectImage::Yes) != nullptr;
+    if (bitmapReady && alphaBitmap && !alphaBitmapReady && !alphaBitmap->PreferSkShader())
+        bitmapReady = false;
+    if (alphaBitmapReady && !bitmapReady && bitmap.PreferSkShader())
+        alphaBitmapReady = false;
+
+    DirectImage bitmapType = bitmapReady ? DirectImage::Yes : DirectImage::No;
+    DirectImage alphaBitmapType = alphaBitmapReady ? DirectImage::Yes : DirectImage::No;
+
+    // Try to find a cached result, this time after possible delayed scaling.
+    OString key = makeCachedImageKey(bitmap, alphaBitmap, targetSize, bitmapType, alphaBitmapType);
+    if (sk_sp<SkImage> image = findCachedImage(key))
+    {
+        assert(imageSize(image) == targetSize);
+        return image;
+    }
+
+    // In some cases (tdf#134237) the target size may be very large. In that case it's
+    // better to rely on Skia to clip and draw only the necessary, rather than prepare
+    // a very large image only to not use most of it. Do this only after checking whether
+    // the image is already cached, since it might have been already cached in a previous
+    // call that had the draw area large enough to be seen as worth caching.
+    const Size drawAreaSize = mClipRegion.GetBoundRect().GetSize() * mScaling;
+    if (targetSize.Width() > drawAreaSize.Width() || targetSize.Height() > drawAreaSize.Height())
+    {
+        // This is a bit tricky. The condition above just checks that at least a part of the resulting
+        // image will not be used (it's larger then our drawing area). But this may often happen
+        // when just scrolling a document with a large image, where the caching may very well be worth it.
+        // Since the problem is mainly the cost of upscaling and then the size of the resulting bitmap,
+        // compute a ratio of how much this is going to be scaled up, how much this is larger than
+        // the drawing area, and then refuse to cache if it's too much.
+        const double upscaleRatio
+            = std::max(1.0, 1.0 * targetSize.Width() / bitmap.GetSize().Width()
+                                * targetSize.Height() / bitmap.GetSize().Height());
+        const double oversizeRatio = 1.0 * targetSize.Width() / drawAreaSize.Width()
+                                     * targetSize.Height() / drawAreaSize.Height();
+        const double ratio = upscaleRatio * oversizeRatio;
+        if (ratio > 4)
+        {
+            SAL_INFO("vcl.skia.trace", "mergecachebitmaps("
+                                           << this << "): not caching, ratio:" << ratio << ", "
+                                           << bitmap.GetSize() << "->" << targetSize << " in "
+                                           << drawAreaSize);
+            return {};
+        }
+    }
+
+    Size sourceSize;
+    if (bitmapReady)
+        sourceSize = imageSize(bitmap.GetSkImage(DirectImage::Yes));
+    else if (alphaBitmapReady)
+        sourceSize = imageSize(alphaBitmap->GetAlphaSkImage(DirectImage::Yes));
+    else
+        sourceSize = bitmap.GetSize();
+
+    // Generate a new result and cache it.
+    sk_sp<SkSurface> tmpSurface
+        = createSkSurface(targetSize, alphaBitmap ? kPremul_SkAlphaType : bitmap.alphaType());
+    if (!tmpSurface)
+        return nullptr;
+    SkCanvas* canvas = tmpSurface->getCanvas();
+    SkAutoCanvasRestore autoRestore(canvas, true);
+    SkPaint paint;
+    SkSamplingOptions samplingOptions;
+    if (targetSize != sourceSize)
+    {
+        SkMatrix matrix;
+        matrix.set(SkMatrix::kMScaleX, 1.0 * targetSize.Width() / sourceSize.Width());
+        matrix.set(SkMatrix::kMScaleY, 1.0 * targetSize.Height() / sourceSize.Height());
+        canvas->concat(matrix);
+        if (!isUnitTestRunning()) // unittests want exact pixel values
+            samplingOptions = makeSamplingOptions(matrix, 1);
+    }
+    if (alphaBitmap != nullptr)
+    {
+        canvas->clear(SK_ColorTRANSPARENT);
+        paint.setShader(
+            SkShaders::Blend(SkBlendMode::kDstOut, bitmap.GetSkShader(samplingOptions, bitmapType),
+                             alphaBitmap->GetAlphaSkShader(samplingOptions, alphaBitmapType)));
+        canvas->drawPaint(paint);
+    }
+    else if (bitmap.PreferSkShader())
+    {
+        paint.setShader(bitmap.GetSkShader(samplingOptions, bitmapType));
+        canvas->drawPaint(paint);
+    }
+    else
+        canvas->drawImage(bitmap.GetSkImage(bitmapType), 0, 0, samplingOptions, &paint);
+    if (isGPU())
+        SAL_INFO("vcl.skia.trace", "mergecachebitmaps(" << this << "): caching GPU downscaling:"
+                                                        << bitmap.GetSize() << "->" << targetSize);
+    sk_sp<SkImage> image = makeCheckedImageSnapshot(tmpSurface);
+    addCachedImage(key, image);
+    return image;
+}
+
+OString SkiaSalGraphicsImpl::makeCachedImageKey(const SkiaSalBitmap& bitmap,
+                                                const SkiaSalBitmap* alphaBitmap,
+                                                const Size& targetSize, DirectImage bitmapType,
+                                                DirectImage alphaBitmapType)
+{
+    OString key = OString::number(targetSize.Width()) + "x" + OString::number(targetSize.Height())
+                  + "_" + bitmap.GetImageKey(bitmapType);
+    if (alphaBitmap)
+        key += "_" + alphaBitmap->GetAlphaImageKey(alphaBitmapType);
+    return key;
+}
+
+bool SkiaSalGraphicsImpl::drawAlphaBitmap(const SalTwoRect& rPosAry, const SalBitmap& rSourceBitmap,
+                                          const SalBitmap& rAlphaBitmap)
+{
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rSourceBitmap));
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rAlphaBitmap));
+    const SkiaSalBitmap& rSkiaSourceBitmap = static_cast<const SkiaSalBitmap&>(rSourceBitmap);
+    const SkiaSalBitmap& rSkiaAlphaBitmap = static_cast<const SkiaSalBitmap&>(rAlphaBitmap);
+    // Use mergeCacheBitmaps(), which may decide to cache the result, avoiding repeated
+    // alpha blending or scaling.
+    SalTwoRect imagePosAry(rPosAry);
+    Size imageSize = rSourceBitmap.GetSize();
+    // If the bitmap will be scaled, prefer to do it in mergeCacheBitmaps(), if possible.
+    if ((rPosAry.mnSrcWidth != rPosAry.mnDestWidth || rPosAry.mnSrcHeight != rPosAry.mnDestHeight)
+        && rPosAry.mnSrcX == 0 && rPosAry.mnSrcY == 0
+        && rPosAry.mnSrcWidth == rSourceBitmap.GetSize().Width()
+        && rPosAry.mnSrcHeight == rSourceBitmap.GetSize().Height())
+    {
+        imagePosAry.mnSrcWidth = imagePosAry.mnDestWidth;
+        imagePosAry.mnSrcHeight = imagePosAry.mnDestHeight;
+        imageSize = Size(imagePosAry.mnSrcWidth, imagePosAry.mnSrcHeight);
+    }
+    sk_sp<SkImage> image
+        = mergeCacheBitmaps(rSkiaSourceBitmap, &rSkiaAlphaBitmap, imageSize * mScaling);
+    if (image)
+        drawImage(imagePosAry, image, mScaling);
+    else if (rSkiaAlphaBitmap.IsFullyOpaqueAsAlpha()
+             && !rSkiaSourceBitmap.PreferSkShader()) // alpha can be ignored
+        drawBitmap(rPosAry, rSkiaSourceBitmap);
+    else
+        drawShader(rPosAry,
+                   SkShaders::Blend(
+                       SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha.
+                       rSkiaSourceBitmap.GetSkShader(makeSamplingOptions(rPosAry, mScaling)),
+                       rSkiaAlphaBitmap.GetAlphaSkShader(makeSamplingOptions(rPosAry, mScaling))));
+    return true;
+}
+
+void SkiaSalGraphicsImpl::drawBitmap(const SalTwoRect& rPosAry, const SkiaSalBitmap& bitmap,
+                                     SkBlendMode blendMode)
+{
+    // Use mergeCacheBitmaps(), which may decide to cache the result, avoiding repeated
+    // scaling.
+    SalTwoRect imagePosAry(rPosAry);
+    Size imageSize = bitmap.GetSize();
+    // If the bitmap will be scaled, prefer to do it in mergeCacheBitmaps(), if possible.
+    if ((rPosAry.mnSrcWidth != rPosAry.mnDestWidth || rPosAry.mnSrcHeight != rPosAry.mnDestHeight)
+        && rPosAry.mnSrcX == 0 && rPosAry.mnSrcY == 0
+        && rPosAry.mnSrcWidth == bitmap.GetSize().Width()
+        && rPosAry.mnSrcHeight == bitmap.GetSize().Height())
+    {
+        imagePosAry.mnSrcWidth = imagePosAry.mnDestWidth;
+        imagePosAry.mnSrcHeight = imagePosAry.mnDestHeight;
+        imageSize = Size(imagePosAry.mnSrcWidth, imagePosAry.mnSrcHeight);
+    }
+    sk_sp<SkImage> image = mergeCacheBitmaps(bitmap, nullptr, imageSize * mScaling);
+    if (image)
+        drawImage(imagePosAry, image, mScaling, blendMode);
+    else if (bitmap.PreferSkShader())
+        drawShader(rPosAry, bitmap.GetSkShader(makeSamplingOptions(rPosAry, mScaling)), blendMode);
+    else
+        drawImage(rPosAry, bitmap.GetSkImage(), 1, blendMode);
+}
+
+void SkiaSalGraphicsImpl::drawImage(const SalTwoRect& rPosAry, const sk_sp<SkImage>& aImage,
+                                    int srcScaling, SkBlendMode eBlendMode)
+{
+    SkRect aSourceRect
+        = SkRect::MakeXYWH(rPosAry.mnSrcX, rPosAry.mnSrcY, rPosAry.mnSrcWidth, rPosAry.mnSrcHeight);
+    if (srcScaling != 1)
+        aSourceRect = scaleRect(aSourceRect, srcScaling);
+    SkRect aDestinationRect = SkRect::MakeXYWH(rPosAry.mnDestX, rPosAry.mnDestY,
+                                               rPosAry.mnDestWidth, rPosAry.mnDestHeight);
+
+    SkPaint aPaint = makeBitmapPaint();
+    aPaint.setBlendMode(eBlendMode);
+
+    preDraw();
+    SAL_INFO("vcl.skia.trace",
+             "drawimage(" << this << "): " << rPosAry << ":" << SkBlendMode_Name(eBlendMode));
+    addUpdateRegion(aDestinationRect);
+    getDrawCanvas()->drawImageRect(aImage, aSourceRect, aDestinationRect,
+                                   makeSamplingOptions(rPosAry, mScaling, srcScaling), &aPaint,
+                                   SkCanvas::kFast_SrcRectConstraint);
+    ++pendingOperationsToFlush; // tdf#136369
+    postDraw();
+}
+
+// SkShader can be used to merge multiple bitmaps with appropriate blend modes (e.g. when
+// merging a bitmap with its alpha mask).
+void SkiaSalGraphicsImpl::drawShader(const SalTwoRect& rPosAry, const sk_sp<SkShader>& shader,
+                                     SkBlendMode blendMode)
+{
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawshader(" << this << "): " << rPosAry);
+    SkRect destinationRect = SkRect::MakeXYWH(rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnDestWidth,
+                                              rPosAry.mnDestHeight);
+    addUpdateRegion(destinationRect);
+    SkPaint paint = makeBitmapPaint();
+    paint.setBlendMode(blendMode);
+    paint.setShader(shader);
+    SkCanvas* canvas = getDrawCanvas();
+    // Scaling needs to be done explicitly using a matrix.
+    SkAutoCanvasRestore autoRestore(canvas, true);
+    SkMatrix matrix = SkMatrix::Translate(rPosAry.mnDestX, rPosAry.mnDestY)
+                      * SkMatrix::Scale(1.0 * rPosAry.mnDestWidth / rPosAry.mnSrcWidth,
+                                        1.0 * rPosAry.mnDestHeight / rPosAry.mnSrcHeight)
+                      * SkMatrix::Translate(-rPosAry.mnSrcX, -rPosAry.mnSrcY);
+#ifndef NDEBUG
+    // Handle floating point imprecisions, round p1 to 2 decimal places.
+    auto compareRounded = [](const SkPoint& p1, const SkPoint& p2) {
+        return rtl::math::round(p1.x(), 2) == p2.x() && rtl::math::round(p1.y(), 2) == p2.y();
+    };
+#endif
+    assert(compareRounded(matrix.mapXY(rPosAry.mnSrcX, rPosAry.mnSrcY),
+                          SkPoint::Make(rPosAry.mnDestX, rPosAry.mnDestY)));
+    assert(compareRounded(
+        matrix.mapXY(rPosAry.mnSrcX + rPosAry.mnSrcWidth, rPosAry.mnSrcY + rPosAry.mnSrcHeight),
+        SkPoint::Make(rPosAry.mnDestX + rPosAry.mnDestWidth,
+                      rPosAry.mnDestY + rPosAry.mnDestHeight)));
+    canvas->concat(matrix);
+    SkRect sourceRect
+        = SkRect::MakeXYWH(rPosAry.mnSrcX, rPosAry.mnSrcY, rPosAry.mnSrcWidth, rPosAry.mnSrcHeight);
+    canvas->drawRect(sourceRect, paint);
+    postDraw();
+}
+
+bool SkiaSalGraphicsImpl::hasFastDrawTransformedBitmap() const
+{
+    // Return true even in raster mode, even that way Skia is faster than e.g. GraphicObject
+    // trying to handle stuff manually.
+    return true;
+}
+
+// Whether applying matrix needs image smoothing for the transformation.
+static bool matrixNeedsHighQuality(const SkMatrix& matrix)
+{
+    if (matrix.isIdentity())
+        return false;
+    if (matrix.isScaleTranslate())
+    {
+        if (abs(matrix.getScaleX()) == 1 && abs(matrix.getScaleY()) == 1)
+            return false; // Only at most flipping and keeping the size.
+        return true;
+    }
+    assert(!matrix.hasPerspective()); // we do not use this
+    if (matrix.getScaleX() == 0 && matrix.getScaleY() == 0)
+    {
+        // Rotating 90 or 270 degrees while keeping the size.
+        if ((matrix.getSkewX() == 1 && matrix.getSkewY() == -1)
+            || (matrix.getSkewX() == -1 && matrix.getSkewY() == 1))
+            return false;
+    }
+    return true;
+}
+
+namespace SkiaTests
+{
+bool matrixNeedsHighQuality(const SkMatrix& matrix) { return ::matrixNeedsHighQuality(matrix); }
+}
+
+bool SkiaSalGraphicsImpl::drawTransformedBitmap(const basegfx::B2DPoint& rNull,
+                                                const basegfx::B2DPoint& rX,
+                                                const basegfx::B2DPoint& rY,
+                                                const SalBitmap& rSourceBitmap,
+                                                const SalBitmap* pAlphaBitmap, double fAlpha)
+{
+    assert(dynamic_cast<const SkiaSalBitmap*>(&rSourceBitmap));
+    assert(!pAlphaBitmap || dynamic_cast<const SkiaSalBitmap*>(pAlphaBitmap));
+
+    const SkiaSalBitmap& rSkiaBitmap = static_cast<const SkiaSalBitmap&>(rSourceBitmap);
+    const SkiaSalBitmap* pSkiaAlphaBitmap = static_cast<const SkiaSalBitmap*>(pAlphaBitmap);
+
+    if (pSkiaAlphaBitmap && pSkiaAlphaBitmap->IsFullyOpaqueAsAlpha())
+        pSkiaAlphaBitmap = nullptr; // the alpha can be ignored
+
+    // Setup the image transformation,
+    // using the rNull, rX, rY points as destinations for the (0,0), (Width,0), (0,Height) source points.
+    const basegfx::B2DVector aXRel = rX - rNull;
+    const basegfx::B2DVector aYRel = rY - rNull;
+
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawtransformedbitmap(" << this << "): " << rSourceBitmap.GetSize()
+                                                        << " " << rNull << ":" << rX << ":" << rY);
+
+    addUpdateRegion(SkRect::MakeWH(GetWidth(), GetHeight())); // can't tell, use whole area
+    // Use mergeCacheBitmaps(), which may decide to cache the result, avoiding repeated
+    // alpha blending or scaling.
+    // The extra fAlpha blending is not cached, with the assumption that it usually gradually changes
+    // for each invocation.
+    // Pass size * mScaling to mergeCacheBitmaps() so that it prepares the size that will be needed
+    // after the mScaling-scaling matrix, but otherwise calculate everything else using the VCL coordinates.
+    Size imageSize(round(aXRel.getLength()), round(aYRel.getLength()));
+    sk_sp<SkImage> imageToDraw
+        = mergeCacheBitmaps(rSkiaBitmap, pSkiaAlphaBitmap, imageSize * mScaling);
+    if (imageToDraw)
+    {
+        SkMatrix matrix;
+        // Round sizes for scaling, so that sub-pixel differences don't
+        // trigger unnecessary scaling. Image has already been scaled
+        // by mergeCacheBitmaps() and we shouldn't scale here again
+        // unless the drawing is also skewed.
+        matrix.set(SkMatrix::kMScaleX, round(aXRel.getX()) / imageSize.Width());
+        matrix.set(SkMatrix::kMScaleY, round(aYRel.getY()) / imageSize.Height());
+        matrix.set(SkMatrix::kMSkewY, aXRel.getY() / imageSize.Width());
+        matrix.set(SkMatrix::kMSkewX, aYRel.getX() / imageSize.Height());
+        matrix.set(SkMatrix::kMTransX, rNull.getX());
+        matrix.set(SkMatrix::kMTransY, rNull.getY());
+        SkCanvas* canvas = getDrawCanvas();
+        SkAutoCanvasRestore autoRestore(canvas, true);
+        canvas->concat(matrix);
+        SkSamplingOptions samplingOptions;
+        // If the matrix changes geometry, we need to smooth-scale. If there's mScaling,
+        // that's already been handled by mergeCacheBitmaps().
+        if (matrixNeedsHighQuality(matrix))
+            samplingOptions = makeSamplingOptions(matrix, 1);
+        if (fAlpha == 1.0)
+        {
+            // Specify sizes to scale the image size back if needed (because of mScaling).
+            SkRect dstRect = SkRect::MakeWH(imageSize.Width(), imageSize.Height());
+            SkRect srcRect = SkRect::MakeWH(imageToDraw->width(), imageToDraw->height());
+            SkPaint paint = makeBitmapPaint();
+            canvas->drawImageRect(imageToDraw, srcRect, dstRect, samplingOptions, &paint,
+                                  SkCanvas::kFast_SrcRectConstraint);
+        }
+        else
+        {
+            SkPaint paint = makeBitmapPaint();
+            // Scale the image size back if needed.
+            SkMatrix scale = SkMatrix::Scale(1.0 / mScaling, 1.0 / mScaling);
+            paint.setShader(SkShaders::Blend(
+                SkBlendMode::kDstIn, imageToDraw->makeShader(samplingOptions, &scale),
+                SkShaders::Color(SkColorSetARGB(fAlpha * 255, 0, 0, 0))));
+            canvas->drawRect(SkRect::MakeWH(imageSize.Width(), imageSize.Height()), paint);
+        }
+    }
+    else
+    {
+        SkMatrix matrix;
+        const Size aSize = rSourceBitmap.GetSize();
+        matrix.set(SkMatrix::kMScaleX, aXRel.getX() / aSize.Width());
+        matrix.set(SkMatrix::kMScaleY, aYRel.getY() / aSize.Height());
+        matrix.set(SkMatrix::kMSkewY, aXRel.getY() / aSize.Width());
+        matrix.set(SkMatrix::kMSkewX, aYRel.getX() / aSize.Height());
+        matrix.set(SkMatrix::kMTransX, rNull.getX());
+        matrix.set(SkMatrix::kMTransY, rNull.getY());
+        SkCanvas* canvas = getDrawCanvas();
+        SkAutoCanvasRestore autoRestore(canvas, true);
+        canvas->concat(matrix);
+        SkSamplingOptions samplingOptions;
+        if (matrixNeedsHighQuality(matrix) || (mScaling != 1 && !isUnitTestRunning()))
+            samplingOptions = makeSamplingOptions(matrix, mScaling);
+        if (pSkiaAlphaBitmap)
+        {
+            SkPaint paint = makeBitmapPaint();
+            paint.setShader(SkShaders::Blend(SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha.
+                                             rSkiaBitmap.GetSkShader(samplingOptions),
+                                             pSkiaAlphaBitmap->GetAlphaSkShader(samplingOptions)));
+            if (fAlpha != 1.0)
+                paint.setShader(
+                    SkShaders::Blend(SkBlendMode::kDstIn, paint.refShader(),
+                                     SkShaders::Color(SkColorSetARGB(fAlpha * 255, 0, 0, 0))));
+            canvas->drawRect(SkRect::MakeWH(aSize.Width(), aSize.Height()), paint);
+        }
+        else if (rSkiaBitmap.PreferSkShader() || fAlpha != 1.0)
+        {
+            SkPaint paint = makeBitmapPaint();
+            paint.setShader(rSkiaBitmap.GetSkShader(samplingOptions));
+            if (fAlpha != 1.0)
+                paint.setShader(
+                    SkShaders::Blend(SkBlendMode::kDstIn, paint.refShader(),
+                                     SkShaders::Color(SkColorSetARGB(fAlpha * 255, 0, 0, 0))));
+            canvas->drawRect(SkRect::MakeWH(aSize.Width(), aSize.Height()), paint);
+        }
+        else
+        {
+            SkPaint paint = makeBitmapPaint();
+            canvas->drawImage(rSkiaBitmap.GetSkImage(), 0, 0, samplingOptions, &paint);
+        }
+    }
+    postDraw();
+    return true;
+}
+
+bool SkiaSalGraphicsImpl::drawAlphaRect(tools::Long nX, tools::Long nY, tools::Long nWidth,
+                                        tools::Long nHeight, sal_uInt8 nTransparency)
+{
+    privateDrawAlphaRect(nX, nY, nWidth, nHeight, nTransparency / 100.0);
+    return true;
+}
+
+bool SkiaSalGraphicsImpl::drawGradient(const tools::PolyPolygon& rPolyPolygon,
+                                       const Gradient& rGradient)
+{
+    if (rGradient.GetStyle() != GradientStyle::Linear
+        && rGradient.GetStyle() != GradientStyle::Axial
+        && rGradient.GetStyle() != GradientStyle::Radial)
+        return false; // unsupported
+    if (rGradient.GetSteps() != 0)
+        return false; // We can't tell Skia how many colors to use in the gradient.
+    preDraw();
+    SAL_INFO("vcl.skia.trace", "drawgradient(" << this << "): " << rPolyPolygon.getB2DPolyPolygon()
+                                               << ":" << static_cast<int>(rGradient.GetStyle()));
+    tools::Rectangle boundRect(rPolyPolygon.GetBoundRect());
+    if (boundRect.IsEmpty())
+        return true;
+    SkPath path;
+    if (rPolyPolygon.IsRect())
+    {
+        // Rect->Polygon conversion loses the right and bottom edge, fix that.
+        path.addRect(SkRect::MakeXYWH(boundRect.getX(), boundRect.getY(), boundRect.GetWidth(),
+                                      boundRect.GetHeight()));
+        boundRect.AdjustRight(1);
+        boundRect.AdjustBottom(1);
+    }
+    else
+        addPolyPolygonToPath(rPolyPolygon.getB2DPolyPolygon(), path);
+    path.setFillType(SkPathFillType::kEvenOdd);
+    addUpdateRegion(path.getBounds());
+
+    Gradient aGradient(rGradient);
+    tools::Rectangle aBoundRect;
+    Point aCenter;
+    aGradient.SetAngle(aGradient.GetAngle() + 2700_deg10);
+    aGradient.GetBoundRect(boundRect, aBoundRect, aCenter);
+
+    SkColor startColor
+        = toSkColorWithIntensity(rGradient.GetStartColor(), rGradient.GetStartIntensity());
+    SkColor endColor = toSkColorWithIntensity(rGradient.GetEndColor(), rGradient.GetEndIntensity());
+
+    sk_sp<SkShader> shader;
+    if (rGradient.GetStyle() == GradientStyle::Linear)
+    {
+        tools::Polygon aPoly(aBoundRect);
+        aPoly.Rotate(aCenter, aGradient.GetAngle() % 3600_deg10);
+        SkPoint points[2] = { SkPoint::Make(toSkX(aPoly[0].X()), toSkY(aPoly[0].Y())),
+                              SkPoint::Make(toSkX(aPoly[1].X()), toSkY(aPoly[1].Y())) };
+        SkColor colors[2] = { startColor, endColor };
+        SkScalar pos[2] = { SkDoubleToScalar(aGradient.GetBorder() / 100.0), 1.0 };
+        shader = SkGradientShader::MakeLinear(points, colors, pos, 2, SkTileMode::kClamp);
+    }
+    else if (rGradient.GetStyle() == GradientStyle::Axial)
+    {
+        tools::Polygon aPoly(aBoundRect);
+        aPoly.Rotate(aCenter, aGradient.GetAngle() % 3600_deg10);
+        SkPoint points[2] = { SkPoint::Make(toSkX(aPoly[0].X()), toSkY(aPoly[0].Y())),
+                              SkPoint::Make(toSkX(aPoly[1].X()), toSkY(aPoly[1].Y())) };
+        SkColor colors[3] = { endColor, startColor, endColor };
+        SkScalar border = SkDoubleToScalar(aGradient.GetBorder() / 100.0);
+        SkScalar pos[3]
+            = { std::min<SkScalar>(border, 0.5), 0.5, std::max<SkScalar>(1 - border, 0.5) };
+        shader = SkGradientShader::MakeLinear(points, colors, pos, 3, SkTileMode::kClamp);
+    }
+    else
+    {
+        // Move the center by (-1,-1) (the default VCL algorithm is a bit off-center that way,
+        // Skia is the opposite way).
+        SkPoint center = SkPoint::Make(toSkX(aCenter.X()) - 1, toSkY(aCenter.Y()) - 1);
+        SkScalar radius = std::max(aBoundRect.GetWidth() / 2.0, aBoundRect.GetHeight() / 2.0);
+        SkColor colors[2] = { endColor, startColor };
+        SkScalar pos[2] = { SkDoubleToScalar(aGradient.GetBorder() / 100.0), 1.0 };
+        shader = SkGradientShader::MakeRadial(center, radius, colors, pos, 2, SkTileMode::kClamp);
+    }
+
+    SkPaint paint = makeGradientPaint();
+    paint.setAntiAlias(mParent.getAntiAlias());
+    paint.setShader(shader);
+    getDrawCanvas()->drawPath(path, paint);
+    postDraw();
+    return true;
+}
+
+bool SkiaSalGraphicsImpl::implDrawGradient(const basegfx::B2DPolyPolygon& rPolyPolygon,
+                                           const SalGradient& rGradient)
+{
+    preDraw();
+    SAL_INFO("vcl.skia.trace",
+             "impldrawgradient(" << this << "): " << rPolyPolygon << ":" << rGradient.maPoint1
+                                 << "->" << rGradient.maPoint2 << ":" << rGradient.maStops.size());
+
+    SkPath path;
+    addPolyPolygonToPath(rPolyPolygon, path);
+    path.setFillType(SkPathFillType::kEvenOdd);
+    addUpdateRegion(path.getBounds());
+
+    SkPoint points[2]
+        = { SkPoint::Make(toSkX(rGradient.maPoint1.getX()), toSkY(rGradient.maPoint1.getY())),
+            SkPoint::Make(toSkX(rGradient.maPoint2.getX()), toSkY(rGradient.maPoint2.getY())) };
+    std::vector<SkColor> colors;
+    std::vector<SkScalar> pos;
+    for (const SalGradientStop& stop : rGradient.maStops)
+    {
+        colors.emplace_back(toSkColor(stop.maColor));
+        pos.emplace_back(stop.mfOffset);
+    }
+    sk_sp<SkShader> shader = SkGradientShader::MakeLinear(points, colors.data(), pos.data(),
+                                                          colors.size(), SkTileMode::kDecal);
+    SkPaint paint = makeGradientPaint();
+    paint.setAntiAlias(mParent.getAntiAlias());
+    paint.setShader(shader);
+    getDrawCanvas()->drawPath(path, paint);
+    postDraw();
+    return true;
+}
+
+static double toRadian(Degree10 degree10th) { return toRadians(3600_deg10 - degree10th); }
+static double toCos(Degree10 degree10th) { return SkScalarCos(toRadian(degree10th)); }
+static double toSin(Degree10 degree10th) { return SkScalarSin(toRadian(degree10th)); }
+
+void SkiaSalGraphicsImpl::drawGenericLayout(const GenericSalLayout& layout, Color textColor,
+                                            const SkFont& font, const SkFont& verticalFont)
+{
+    SkiaZone zone;
+    std::vector<SkGlyphID> glyphIds;
+    std::vector<SkRSXform> glyphForms;
+    std::vector<bool> verticals;
+    glyphIds.reserve(256);
+    glyphForms.reserve(256);
+    verticals.reserve(256);
+    DevicePoint aPos;
+    const GlyphItem* pGlyph;
+    int nStart = 0;
+    while (layout.GetNextGlyph(&pGlyph, aPos, nStart))
+    {
+        glyphIds.push_back(pGlyph->glyphId());
+        Degree10 angle = layout.GetOrientation();
+        if (pGlyph->IsVertical())
+            angle += 900_deg10;
+        SkRSXform form = SkRSXform::Make(toCos(angle), toSin(angle), aPos.getX(), aPos.getY());
+        glyphForms.emplace_back(std::move(form));
+        verticals.emplace_back(pGlyph->IsVertical());
+    }
+    if (glyphIds.empty())
+        return;
+
+    preDraw();
+    auto getBoundRect = [&layout]() {
+        tools::Rectangle rect;
+        layout.GetBoundRect(rect);
+        return rect;
+    };
+    SAL_INFO("vcl.skia.trace", "drawtextblob(" << this << "): " << getBoundRect() << ", "
+                                               << glyphIds.size() << " glyphs, " << textColor);
+
+    // Vertical glyphs need a different font, so split drawing into runs that each
+    // draw only consecutive horizontal or vertical glyphs.
+    std::vector<bool>::const_iterator pos = verticals.cbegin();
+    std::vector<bool>::const_iterator end = verticals.cend();
+    while (pos != end)
+    {
+        bool verticalRun = *pos;
+        std::vector<bool>::const_iterator rangeEnd = std::find(pos + 1, end, !verticalRun);
+        size_t index = pos - verticals.cbegin();
+        size_t count = rangeEnd - pos;
+        sk_sp<SkTextBlob> textBlob = SkTextBlob::MakeFromRSXform(
+            glyphIds.data() + index, count * sizeof(SkGlyphID), glyphForms.data() + index,
+            verticalRun ? verticalFont : font, SkTextEncoding::kGlyphID);
+        addUpdateRegion(textBlob->bounds());
+        SkPaint paint = makeTextPaint(textColor);
+        getDrawCanvas()->drawTextBlob(textBlob, 0, 0, paint);
+        pos = rangeEnd;
+    }
+    postDraw();
+}
+
+bool SkiaSalGraphicsImpl::supportsOperation(OutDevSupportType eType) const
+{
+    switch (eType)
+    {
+        case OutDevSupportType::B2DDraw:
+        case OutDevSupportType::TransparentRect:
+            return true;
+        default:
+            return false;
+    }
+}
+
+static int getScaling()
+{
+    // It makes sense to support the debugging flag on all platforms
+    // for unittests purpose, even if the actual windows cannot do it.
+    if (const char* env = getenv("SAL_FORCE_HIDPI_SCALING"))
+        return atoi(env);
+    return 1;
+}
+
+int SkiaSalGraphicsImpl::getWindowScaling() const
+{
+    static const int scaling = getScaling();
+    return scaling;
+}
+
+void SkiaSalGraphicsImpl::dump(const char* file) const
+{
+    assert(mSurface.get());
+    SkiaHelper::dump(mSurface, file);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */