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- /*
- * Copyright 2010 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef GrClip_DEFINED
- #define GrClip_DEFINED
- #include "include/core/SkRRect.h"
- #include "include/core/SkRect.h"
- #include "src/gpu/GrAppliedClip.h"
- #include "src/gpu/GrRenderTargetContext.h"
- class GrContext;
- /**
- * GrClip is an abstract base class for applying a clip. It constructs a clip mask if necessary, and
- * fills out a GrAppliedClip instructing the caller on how to set up the draw state.
- */
- class GrClip {
- public:
- virtual bool quickContains(const SkRect&) const = 0;
- virtual bool quickContains(const SkRRect& rrect) const {
- return this->quickContains(rrect.getBounds());
- }
- virtual void getConservativeBounds(int width, int height, SkIRect* devResult,
- bool* isIntersectionOfRects = nullptr) const = 0;
- /**
- * This computes a GrAppliedClip from the clip which in turn can be used to build a GrPipeline.
- * To determine the appropriate clipping implementation the GrClip subclass must know whether
- * the draw will enable HW AA or uses the stencil buffer. On input 'bounds' is a conservative
- * bounds of the draw that is to be clipped. After return 'bounds' has been intersected with a
- * conservative bounds of the clip. A return value of false indicates that the draw can be
- * skipped as it is fully clipped out.
- */
- virtual bool apply(GrRecordingContext*, GrRenderTargetContext*, bool useHWAA,
- bool hasUserStencilSettings, GrAppliedClip*, SkRect* bounds) const = 0;
- virtual ~GrClip() {}
- /**
- * This method quickly and conservatively determines whether the entire clip is equivalent to
- * intersection with a rrect. This will only return true if the rrect does not fully contain
- * the render target bounds. Moreover, the returned rrect need not be contained by the render
- * target bounds. We assume all draws will be implicitly clipped by the render target bounds.
- *
- * @param rtBounds The bounds of the render target that the clip will be applied to.
- * @param rrect If return is true rrect will contain the rrect equivalent to the clip within
- * rtBounds.
- * @param aa If return is true aa will indicate whether the rrect clip is antialiased.
- * @return true if the clip is equivalent to a single rrect, false otherwise.
- *
- */
- virtual bool isRRect(const SkRect& rtBounds, SkRRect* rrect, GrAA* aa) const = 0;
- /**
- * This is the maximum distance that a draw may extend beyond a clip's boundary and still count
- * count as "on the other side". We leave some slack because floating point rounding error is
- * likely to blame. The rationale for 1e-3 is that in the coverage case (and barring unexpected
- * rounding), as long as coverage stays within 0.5 * 1/256 of its intended value it shouldn't
- * have any effect on the final pixel values.
- */
- constexpr static SkScalar kBoundsTolerance = 1e-3f;
- /**
- * Returns true if the given query bounds count as entirely inside the clip.
- *
- * @param innerClipBounds device-space rect contained by the clip (SkRect or SkIRect).
- * @param queryBounds device-space bounds of the query region.
- */
- template <typename TRect>
- constexpr static bool IsInsideClip(const TRect& innerClipBounds, const SkRect& queryBounds) {
- return innerClipBounds.fRight > innerClipBounds.fLeft + kBoundsTolerance &&
- innerClipBounds.fBottom > innerClipBounds.fTop + kBoundsTolerance &&
- innerClipBounds.fLeft < queryBounds.fLeft + kBoundsTolerance &&
- innerClipBounds.fTop < queryBounds.fTop + kBoundsTolerance &&
- innerClipBounds.fRight > queryBounds.fRight - kBoundsTolerance &&
- innerClipBounds.fBottom > queryBounds.fBottom - kBoundsTolerance;
- }
- /**
- * Returns true if the given query bounds count as entirely outside the clip.
- *
- * @param outerClipBounds device-space rect that contains the clip (SkRect or SkIRect).
- * @param queryBounds device-space bounds of the query region.
- */
- template <typename TRect>
- constexpr static bool IsOutsideClip(const TRect& outerClipBounds, const SkRect& queryBounds) {
- return
- // Is the clip so small that it is effectively empty?
- outerClipBounds.fRight - outerClipBounds.fLeft <= kBoundsTolerance ||
- outerClipBounds.fBottom - outerClipBounds.fTop <= kBoundsTolerance ||
- // Are the query bounds effectively outside the clip?
- outerClipBounds.fLeft >= queryBounds.fRight - kBoundsTolerance ||
- outerClipBounds.fTop >= queryBounds.fBottom - kBoundsTolerance ||
- outerClipBounds.fRight <= queryBounds.fLeft + kBoundsTolerance ||
- outerClipBounds.fBottom <= queryBounds.fTop + kBoundsTolerance;
- }
- /**
- * Returns the minimal integer rect that counts as containing a given set of bounds.
- */
- static SkIRect GetPixelIBounds(const SkRect& bounds) {
- return SkIRect::MakeLTRB(SkScalarFloorToInt(bounds.fLeft + kBoundsTolerance),
- SkScalarFloorToInt(bounds.fTop + kBoundsTolerance),
- SkScalarCeilToInt(bounds.fRight - kBoundsTolerance),
- SkScalarCeilToInt(bounds.fBottom - kBoundsTolerance));
- }
- /**
- * Returns the minimal pixel-aligned rect that counts as containing a given set of bounds.
- */
- static SkRect GetPixelBounds(const SkRect& bounds) {
- return SkRect::MakeLTRB(SkScalarFloorToScalar(bounds.fLeft + kBoundsTolerance),
- SkScalarFloorToScalar(bounds.fTop + kBoundsTolerance),
- SkScalarCeilToScalar(bounds.fRight - kBoundsTolerance),
- SkScalarCeilToScalar(bounds.fBottom - kBoundsTolerance));
- }
- /**
- * Returns true if the given rect counts as aligned with pixel boundaries.
- */
- static bool IsPixelAligned(const SkRect& rect) {
- return SkScalarAbs(SkScalarRoundToScalar(rect.fLeft) - rect.fLeft) <= kBoundsTolerance &&
- SkScalarAbs(SkScalarRoundToScalar(rect.fTop) - rect.fTop) <= kBoundsTolerance &&
- SkScalarAbs(SkScalarRoundToScalar(rect.fRight) - rect.fRight) <= kBoundsTolerance &&
- SkScalarAbs(SkScalarRoundToScalar(rect.fBottom) - rect.fBottom) <= kBoundsTolerance;
- }
- };
- /**
- * GrHardClip never uses coverage FPs. It can only enforce the clip using the already-existing
- * stencil buffer contents and/or fixed-function state like scissor. Always aliased if MSAA is off.
- */
- class GrHardClip : public GrClip {
- public:
- /**
- * Sets the appropriate hardware state modifications on GrAppliedHardClip that will implement
- * the clip. On input 'bounds' is a conservative bounds of the draw that is to be clipped. After
- * return 'bounds' has been intersected with a conservative bounds of the clip. A return value
- * of false indicates that the draw can be skipped as it is fully clipped out.
- */
- virtual bool apply(int rtWidth, int rtHeight, GrAppliedHardClip* out, SkRect* bounds) const = 0;
- private:
- bool apply(GrRecordingContext*, GrRenderTargetContext* rtc, bool useHWAA,
- bool hasUserStencilSettings, GrAppliedClip* out, SkRect* bounds) const final {
- return this->apply(rtc->width(), rtc->height(), &out->hardClip(), bounds);
- }
- };
- /**
- * Specialized implementation for no clip.
- */
- class GrNoClip final : public GrHardClip {
- private:
- bool quickContains(const SkRect&) const final { return true; }
- bool quickContains(const SkRRect&) const final { return true; }
- void getConservativeBounds(int width, int height, SkIRect* devResult,
- bool* isIntersectionOfRects) const final {
- devResult->setXYWH(0, 0, width, height);
- if (isIntersectionOfRects) {
- *isIntersectionOfRects = true;
- }
- }
- bool apply(int rtWidth, int rtHeight, GrAppliedHardClip*, SkRect*) const final { return true; }
- bool isRRect(const SkRect&, SkRRect*, GrAA*) const override { return false; }
- };
- #endif
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