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| -rw-r--r-- | layout/painting/nsCSSRenderingGradients.h | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/layout/painting/nsCSSRenderingGradients.h b/layout/painting/nsCSSRenderingGradients.h new file mode 100644 index 0000000000..549cd8c4b6 --- /dev/null +++ b/layout/painting/nsCSSRenderingGradients.h @@ -0,0 +1,170 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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 nsCSSRenderingGradients_h__ +#define nsCSSRenderingGradients_h__ + +#include "gfxRect.h" +#include "gfxUtils.h" +#include "nsStyleStruct.h" +#include "Units.h" +#include "mozilla/Maybe.h" +#include "mozilla/gfx/2D.h" +#include "mozilla/webrender/webrender_ffi.h" + +class gfxPattern; + +namespace mozilla { + +namespace layers { +class StackingContextHelper; +} // namespace layers + +namespace wr { +class DisplayListBuilder; +} // namespace wr + +// A resolved color stop, with a specific position along the gradient line and +// a color. +struct ColorStop { + ColorStop() : mPosition(0), mIsMidpoint(false) {} + ColorStop(double aPosition, bool aIsMidPoint, + const StyleAbsoluteColor& aColor) + : mPosition(aPosition), mIsMidpoint(aIsMidPoint), mColor(aColor) {} + double mPosition; // along the gradient line; 0=start, 1=end + bool mIsMidpoint; + StyleAbsoluteColor mColor; +}; + +template <class T> +class MOZ_STACK_CLASS ColorStopInterpolator { + public: + ColorStopInterpolator( + const nsTArray<ColorStop>& aStops, + const StyleColorInterpolationMethod& aStyleColorInterpolationMethod) + : mStyleColorInterpolationMethod(aStyleColorInterpolationMethod), + mStops(aStops) {} + + void CreateStops() { + for (uint32_t i = 0; i < mStops.Length() - 1; i++) { + const auto& start = mStops[i]; + const auto& end = mStops[i + 1]; + uint32_t extraStops = + (uint32_t)(floor(end.mPosition * kFullRangeExtraStops) - + floor(start.mPosition * kFullRangeExtraStops)); + extraStops = clamped(extraStops, 1U, kFullRangeExtraStops); + float step = 1.0f / (float)extraStops; + for (uint32_t extraStop = 0; extraStop <= extraStops; extraStop++) { + auto progress = (float)extraStop * step; + auto position = + start.mPosition + progress * (end.mPosition - start.mPosition); + StyleAbsoluteColor color = + Servo_InterpolateColor(mStyleColorInterpolationMethod, &end.mColor, + &start.mColor, progress); + static_cast<T*>(this)->CreateStop(float(position), + gfx::ToDeviceColor(color)); + } + } + } + + protected: + StyleColorInterpolationMethod mStyleColorInterpolationMethod; + const nsTArray<ColorStop>& mStops; + + // this could be made tunable, but at 1.0/128 the error is largely + // irrelevant, as WebRender re-encodes it to 128 pairs of stops. + // + // note that we don't attempt to place the positions of these stops + // precisely at intervals, we just add this many extra stops across the + // range where it is convenient. + inline static const uint32_t kFullRangeExtraStops = 128; +}; + +class nsCSSGradientRenderer final { + public: + /** + * Prepare a nsCSSGradientRenderer for a gradient for an element. + * aIntrinsicSize - the size of the source gradient. + */ + static nsCSSGradientRenderer Create(nsPresContext* aPresContext, + ComputedStyle* aComputedStyle, + const StyleGradient& aGradient, + const nsSize& aIntrinsiceSize); + + /** + * Draw the gradient to aContext + * aDest - where the first tile of gradient is + * aFill - the area to be filled with tiles of aDest + * aSrc - the area of the gradient that will fill aDest + * aRepeatSize - the distance from the origin of a tile + * to the next origin of a tile + * aDirtyRect - pixels outside of this area may be skipped + */ + void Paint(gfxContext& aContext, const nsRect& aDest, const nsRect& aFill, + const nsSize& aRepeatSize, const mozilla::CSSIntRect& aSrc, + const nsRect& aDirtyRect, float aOpacity = 1.0); + + /** + * Collect the gradient parameters + */ + void BuildWebRenderParameters(float aOpacity, wr::ExtendMode& aMode, + nsTArray<wr::GradientStop>& aStops, + LayoutDevicePoint& aLineStart, + LayoutDevicePoint& aLineEnd, + LayoutDeviceSize& aGradientRadius, + LayoutDevicePoint& aGradientCenter, + float& aGradientAngle); + + /** + * Build display items for the gradient + * aLayer - the layer to make this display item relative to + * aDest - where the first tile of gradient is + * aFill - the area to be filled with tiles of aDest + * aRepeatSize - the distance from the origin of a tile + * to the next origin of a tile + * aSrc - the area of the gradient that will fill aDest + */ + void BuildWebRenderDisplayItems(wr::DisplayListBuilder& aBuilder, + const layers::StackingContextHelper& aSc, + const nsRect& aDest, const nsRect& aFill, + const nsSize& aRepeatSize, + const mozilla::CSSIntRect& aSrc, + bool aIsBackfaceVisible, + float aOpacity = 1.0); + + private: + nsCSSGradientRenderer() + : mPresContext(nullptr), + mGradient(nullptr), + mRadiusX(0.0), + mRadiusY(0.0), + mAngle(0.0) {} + + /** + * Attempts to paint the tiles for a gradient by painting it once to an + * offscreen surface and then painting that offscreen surface with + * ExtendMode::Repeat to cover all tiles. + * + * Returns false if the optimization wasn't able to be used, in which case + * a fallback should be used. + */ + bool TryPaintTilesWithExtendMode( + gfxContext& aContext, gfxPattern* aGradientPattern, nscoord aXStart, + nscoord aYStart, const gfxRect& aDirtyAreaToFill, const nsRect& aDest, + const nsSize& aRepeatSize, bool aForceRepeatToCoverTiles); + + nsPresContext* mPresContext; + const StyleGradient* mGradient; + nsTArray<ColorStop> mStops; + gfxPoint mLineStart, mLineEnd; // only for linear/radial gradients + double mRadiusX, mRadiusY; // only for radial gradients + gfxPoint mCenter; // only for conic gradients + float mAngle; // only for conic gradients +}; + +} // namespace mozilla + +#endif /* nsCSSRenderingGradients_h__ */ |