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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
commit2aa4a82499d4becd2284cdb482213d541b8804dd (patch)
treeb80bf8bf13c3766139fbacc530efd0dd9d54394c /layout/base/ViewportUtils.h
parentInitial commit. (diff)
downloadfirefox-upstream.tar.xz
firefox-upstream.zip
Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* 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/. */
+
+#ifndef mozilla_ViewportUtils_h
+#define mozilla_ViewportUtils_h
+
+#include "Units.h"
+#include "mozilla/layers/ScrollableLayerGuid.h"
+
+class nsIFrame;
+
+namespace mozilla {
+
+class PresShell;
+
+class ViewportUtils {
+ public:
+ /* Return a transform to be applied to the coordinates of input events
+ targeting content inside the scroll frame identified by |aScrollId|, which
+ converts from "visual coordinates" (which are the coordinates events have
+ when they arrive from APZ) to "layout coordinates" (which are the
+ coordinates used in most places by layout code). The transform has two
+ components:
+ 1. The pres shell resolution, representing the pinch-zoom scale
+ (if the scroll frame |aScrollId| is inside the resolution, which
+ is most of the time).
+ 2. A translation representing async scrolling. This can contain:
+ - For any scroll frame, a scroll component resulting from the main
+ thread incompletely applying an APZ-requested scroll position.
+ - For the RCD-RSF only, a persistent component representing the
+ offset of the visual viewport relative to the layout viewport.
+ The translation is accumulated for all scroll frames form |aScrollId|
+ up to the root, using values populated in
+ APZCCallbackHelper::UpdateCallbackTransform. See that method's
+ documentation for additional details. */
+ template <typename Units = CSSPixel>
+ static gfx::Matrix4x4Typed<Units, Units> GetVisualToLayoutTransform(
+ layers::ScrollableLayerGuid::ViewID aScrollId);
+
+ /* The functions below apply GetVisualToLayoutTransform() or its inverse
+ * to various quantities.
+ *
+ * To determine the appropriate scroll id to pass into
+ * GetVisualToLayoutTransform(), these functions prefer to use the one
+ * from InputAPZContext::GetTargetLayerGuid() if one is available.
+ * If one is not available, they use the scroll id of the root scroll
+ * frame of the pres shell passed in as |aContext| as a fallback.
+ */
+ static nsPoint VisualToLayout(const nsPoint& aPt, PresShell* aContext);
+ static nsRect VisualToLayout(const nsRect& aRect, PresShell* aContext);
+ static nsPoint LayoutToVisual(const nsPoint& aPt, PresShell* aContext);
+
+ /*
+ * These functions convert the point/rect from layout to visual space
+ * by applying the inverse of GetLayoutToVisualTransform() of the root
+ * scrollframe of provided presShell.
+ */
+ static LayoutDevicePoint DocumentRelativeLayoutToVisual(
+ const LayoutDevicePoint& aPoint, PresShell* aShell);
+ static LayoutDeviceRect DocumentRelativeLayoutToVisual(
+ const LayoutDeviceRect& aRect, PresShell* aShell);
+ static LayoutDeviceRect DocumentRelativeLayoutToVisual(
+ const LayoutDeviceIntRect& aRect, PresShell* aShell);
+ static CSSRect DocumentRelativeLayoutToVisual(const CSSRect& aRect,
+ PresShell* aShell);
+
+ /*
+ * These convert aPt/aRect, which is the layout space of aCtx, into a
+ * screen-relative visual-space quantity. Formally, we can think of the input
+ * as being in RelativeTo{aCtx->PresShell()->GetRootFrame(),
+ * ViewportType::Layout} space. And then the function iterates up the chain of
+ * presContexts, transforming the point along, until it gets to the
+ * RelativeTo{aCtx->GetRootPresContext()->PresShell()->GetRootFrame(),
+ * ViewportType::Visual} space. Then it further transforms it into a
+ * screen-relative space. Unlike the GetTransformToAncestor family of helper
+ * methods, this transformation does NOT include CSS transforms. Also, unlike
+ * other ViewportUtils methods, the input is relative to `aCtx` which might be
+ * a sub-shell of the presShell with the resolution.
+ */
+ static LayoutDevicePoint ToScreenRelativeVisual(const LayoutDevicePoint& aPt,
+ nsPresContext* aCtx);
+ static LayoutDeviceRect ToScreenRelativeVisual(const LayoutDeviceRect& aRect,
+ nsPresContext* aCtx);
+
+ /**
+ * Returns non-null if |aFrame| is inside the async zoom container but its
+ * parent frame is not, thereby making |aFrame| a root of a subtree of
+ * frames representing content that is zoomed in. The value returned in such
+ * cases is the root scroll frame inside the async zoom container.
+
+ * Callers use this to identify points during frame tree traversal where the
+ * visual-to-layout transform needs to be applied.
+ */
+ static const nsIFrame* IsZoomedContentRoot(const nsIFrame* aFrame);
+};
+
+// Forward declare explicit instantiations of GetVisualToLayoutTransform() for
+// CSSPixel and LayoutDevicePixel, the only two types it gets used with.
+// These declarations promise to callers in any translation unit that _some_
+// translation unit (in this case, ViewportUtils.cpp) will contain the
+// definitions of these instantiations. This allows us to keep the definition
+// out-of-line in the source.
+extern template CSSToCSSMatrix4x4 ViewportUtils::GetVisualToLayoutTransform<
+ CSSPixel>(layers::ScrollableLayerGuid::ViewID);
+extern template LayoutDeviceToLayoutDeviceMatrix4x4
+ ViewportUtils::GetVisualToLayoutTransform<LayoutDevicePixel>(
+ layers::ScrollableLayerGuid::ViewID);
+
+} // namespace mozilla
+
+#endif /* mozilla_ViewportUtils_h */