have canvas send discard instead of retain if the draw would overwrite everything
Motivation:
- perf win for clients that overwrite the surface after a snapshot.
- may allow us to eliminate SkDeferredCanvas, as this was its primary advantage.
BUG=skia:
Review URL: https://codereview.chromium.org/1236023004
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 941d868..5704358 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -17,6 +17,7 @@
#include "SkImage.h"
#include "SkMetaData.h"
#include "SkNinePatchIter.h"
+#include "SkPaintPriv.h"
#include "SkPathOps.h"
#include "SkPatchUtils.h"
#include "SkPicture.h"
@@ -36,6 +37,60 @@
#include "GrRenderTarget.h"
#endif
+/*
+ * Return true if the drawing this rect would hit every pixels in the canvas.
+ *
+ * Returns false if
+ * - rect does not contain the canvas' bounds
+ * - paint is not fill
+ * - paint would blur or otherwise change the coverage of the rect
+ */
+bool SkCanvas::wouldOverwriteEntireSurface(const SkRect* rect, const SkPaint* paint,
+ ShaderOverrideOpacity overrideOpacity) const {
+ SK_COMPILE_ASSERT((int)SkPaintPriv::kNone_ShaderOverrideOpacity ==
+ (int)kNone_ShaderOverrideOpacity,
+ need_matching_enums0);
+ SK_COMPILE_ASSERT((int)SkPaintPriv::kOpaque_ShaderOverrideOpacity ==
+ (int)kOpaque_ShaderOverrideOpacity,
+ need_matching_enums1);
+ SK_COMPILE_ASSERT((int)SkPaintPriv::kNotOpaque_ShaderOverrideOpacity ==
+ (int)kNotOpaque_ShaderOverrideOpacity,
+ need_matching_enums2);
+
+ const SkISize size = this->getBaseLayerSize();
+ const SkRect bounds = SkRect::MakeIWH(size.width(), size.height());
+ if (!this->getClipStack()->quickContains(bounds)) {
+ return false;
+ }
+
+ if (rect) {
+ if (!this->getTotalMatrix().rectStaysRect()) {
+ return false; // conservative
+ }
+
+ SkRect devRect;
+ this->getTotalMatrix().mapRect(&devRect, *rect);
+ if (devRect.contains(bounds)) {
+ return false;
+ }
+ }
+
+ if (paint) {
+ SkPaint::Style paintStyle = paint->getStyle();
+ if (!(paintStyle == SkPaint::kFill_Style ||
+ paintStyle == SkPaint::kStrokeAndFill_Style)) {
+ return false;
+ }
+ if (paint->getMaskFilter() || paint->getLooper()
+ || paint->getPathEffect() || paint->getImageFilter()) {
+ return false; // conservative
+ }
+ }
+ return SkPaintPriv::Overwrites(paint, (SkPaintPriv::ShaderOverrideOpacity)overrideOpacity);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
static bool gIgnoreSaveLayerBounds;
void SkCanvas::Internal_Private_SetIgnoreSaveLayerBounds(bool ignore) {
gIgnoreSaveLayerBounds = ignore;
@@ -80,9 +135,28 @@
typedef SkTLazy<SkPaint> SkLazyPaint;
-void SkCanvas::predrawNotify() {
+void SkCanvas::predrawNotify(bool willOverwritesEntireSurface) {
if (fSurfaceBase) {
- fSurfaceBase->aboutToDraw(SkSurface::kRetain_ContentChangeMode);
+ fSurfaceBase->aboutToDraw(willOverwritesEntireSurface
+ ? SkSurface::kDiscard_ContentChangeMode
+ : SkSurface::kRetain_ContentChangeMode);
+ }
+}
+
+void SkCanvas::predrawNotify(const SkRect* rect, const SkPaint* paint,
+ ShaderOverrideOpacity overrideOpacity) {
+ if (fSurfaceBase) {
+ SkSurface::ContentChangeMode mode = SkSurface::kRetain_ContentChangeMode;
+ // Since willOverwriteAllPixels() may not be complete free to call, we only do so if
+ // there is an outstanding snapshot, since w/o that, there will be no copy-on-write
+ // and therefore we don't care which mode we're in.
+ //
+ if (fSurfaceBase->outstandingImageSnapshot()) {
+ if (this->wouldOverwriteEntireSurface(rect, paint, overrideOpacity)) {
+ mode = SkSurface::kDiscard_ContentChangeMode;
+ }
+ }
+ fSurfaceBase->aboutToDraw(mode);
}
}
@@ -497,6 +571,12 @@
while (looper.next(type)) { \
SkDrawIter iter(this);
+#define LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(paint, type, bounds, auxOpaque) \
+ this->predrawNotify(bounds, &paint, auxOpaque); \
+ AutoDrawLooper looper(this, fProps, paint, false, bounds); \
+ while (looper.next(type)) { \
+ SkDrawIter iter(this);
+
#define LOOPER_END }
////////////////////////////////////////////////////////////////////////////
@@ -815,7 +895,8 @@
pixels = ((const char*)pixels - y * rowBytes - x * info.bytesPerPixel());
// Tell our owning surface to bump its generation ID
- this->predrawNotify();
+ const bool completeOverwrite = info.dimensions() == size;
+ this->predrawNotify(completeOverwrite);
// The device can assert that the requested area is always contained in its bounds
return device->writePixels(info, pixels, rowBytes, target.x(), target.y());
@@ -1866,7 +1947,7 @@
}
void SkCanvas::internalDrawPaint(const SkPaint& paint) {
- LOOPER_BEGIN(paint, SkDrawFilter::kPaint_Type, NULL)
+ LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(paint, SkDrawFilter::kPaint_Type, NULL, false)
while (iter.next()) {
iter.fDevice->drawPaint(iter, looper.paint());
@@ -1924,7 +2005,7 @@
}
}
- LOOPER_BEGIN(paint, SkDrawFilter::kRect_Type, bounds)
+ LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(paint, SkDrawFilter::kRect_Type, bounds, false)
while (iter.next()) {
iter.fDevice->drawRect(iter, r, looper.paint());
@@ -2082,7 +2163,8 @@
paint = lazy.init();
}
- LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, bounds)
+ LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(*paint, SkDrawFilter::kBitmap_Type, bounds,
+ image->isOpaque())
while (iter.next()) {
iter.fDevice->drawImageRect(iter, image, src, dst, looper.paint(), constraint);
@@ -2138,7 +2220,8 @@
paint = lazy.init();
}
- LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, bounds)
+ LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(*paint, SkDrawFilter::kBitmap_Type, bounds,
+ bitmap.isOpaque())
while (iter.next()) {
iter.fDevice->drawBitmapRect(iter, bitmap, src, dst, looper.paint(),