Make GrClip.h private

BUG=skia:

Change-Id: I4aa3c2707811ece3a63d161035e316c3bbc1cd15
Reviewed-on: https://skia-review.googlesource.com/9482
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

1 files changed, 143 insertions, 0 deletions

diff --git a/src/gpu/GrClip.h b/src/gpu/GrClip.h
new file mode 100644
index 0000000000..eb4eab2d0c
--- /dev/null
+++ b/src/gpu/GrClip.h
@@ -0,0 +1,143 @@
+/*
+ * 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 "GrTypes.h"
+#include "SkRRect.h"
+#include "SkRect.h"
+
+class GrAppliedClip;
+class GrContext;
+class GrRenderTargetContext;
+
+/**
+ * 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;
+    virtual bool apply(GrContext*, GrRenderTargetContext*, bool useHWAA,
+                       bool hasUserStencilSettings, GrAppliedClip* out) 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 outerClipBounds.fRight - outerClipBounds.fLeft <= kBoundsTolerance ||
+               outerClipBounds.fBottom - outerClipBounds.fTop <= kBoundsTolerance ||
+               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;
+    }
+};
+
+/**
+ * Specialized implementation for no clip.
+ */
+class GrNoClip final : public GrClip {
+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(GrContext*, GrRenderTargetContext*, bool, bool, GrAppliedClip*) const final {
+        return true;
+    }
+    bool isRRect(const SkRect&, SkRRect*, GrAA*) const override { return false; }
+};
+
+#endif