Change saveLayer() semantics to take unfiltered bounds.

src/core/SkCanvas.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkCanvasPriv.h"
@@ skipping 20 matching lines @@
 #include "SkTextFormatParams.h"
 #include "SkTLazy.h"
 #include "SkTraceEvent.h"
 
 #include <new>
 
 #if SK_SUPPORT_GPU
 #include "GrRenderTarget.h"
 #endif
 
+#ifndef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
+#define SK_SUPPORT_SRC_BOUNDS_BLOAT_FOR_IMAGEFILTERS
+#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 {
@@ skipping 350 matching lines @@
         // there is no existing paint colorfilter, so we can just return the imagefilter's
         return imgCF;
     }
 
     // The paint has both a colorfilter(paintCF) and an imagefilter-which-is-a-colorfilter(imgCF)
     // and we need to combine them into a single colorfilter.
     SkAutoTUnref<SkColorFilter> autoImgCF(imgCF);
     return SkColorFilter::CreateComposeFilter(imgCF, paintCF);
 }
 
+/**
+ * There are many bounds in skia. A circle's bounds is just its center extended by its radius.
+ * However, if we stroke a circle, then the "bounds" of that is larger, since it will now draw
+ * outside of its raw-bounds by 1/2 the stroke width.  SkPaint has lots of optional
+ * effects/attributes that can modify the effective bounds of a given primitive -- maskfilters,
+ * patheffects, stroking, etc.  This function takes a raw bounds and a paint, and returns the
+ * conservative "effective" bounds based on the settings in the paint... with one exception. This
+ * function does *not* look at the imagefilter, which can also modify the effective bounds. It is
+ * deliberately ignored.
+ */
+static const SkRect& apply_paint_to_bounds_sans_imagefilter(const SkPaint& paint,
+                                                            const SkRect& rawBounds,
+                                                            SkRect* storage) {
+    SkPaint tmpUnfiltered(paint);
+    tmpUnfiltered.setImageFilter(nullptr);
+    if (tmpUnfiltered.canComputeFastBounds()) {
+        return tmpUnfiltered.computeFastBounds(rawBounds, storage);
+    } else {
+        return rawBounds;
+    }
+}
+
 class AutoDrawLooper {
 public:
+    // "rawBounds" is the original bounds of the primitive about to be drawn, unmodified by the
+    // paint. It's used to determine the size of the offscreen layer for filters.
+    // If null, the clip will be used instead.
     AutoDrawLooper(SkCanvas* canvas, const SkSurfaceProps& props, const SkPaint& paint,
                    bool skipLayerForImageFilter = false,
-                   const SkRect* bounds = nullptr) : fOrigPaint(paint) {
+                   const SkRect* rawBounds = nullptr) : fOrigPaint(paint) {
         fCanvas = canvas;
         fFilter = canvas->getDrawFilter();
         fPaint = &fOrigPaint;
         fSaveCount = canvas->getSaveCount();
         fTempLayerForImageFilter = false;
         fDone = false;
 
         SkColorFilter* simplifiedCF = image_to_color_filter(fOrigPaint);
         if (simplifiedCF) {
             SkPaint* paint = set_if_needed(&fLazyPaintInit, fOrigPaint);
@@ skipping 14 matching lines @@
              *      return (fPaint). We then draw the primitive (using srcover) into a cleared
              *      buffer/surface.
              *  3. Restore the layer created in #1
              *      The imagefilter is passed the buffer/surface from the layer (now filled with the
              *      src pixels of the primitive). It returns a new "filtered" buffer, which we
              *      draw onto the previous layer using the xfermode from the original paint.
              */
             SkPaint tmp;
             tmp.setImageFilter(fPaint->getImageFilter());
             tmp.setXfermode(fPaint->getXfermode());
-            (void)canvas->internalSaveLayer(bounds, &tmp, SkCanvas::kARGB_ClipLayer_SaveFlag,
+#ifndef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
+            SkRect storage;
+            if (rawBounds) {
+                // Make rawBounds include all paint outsets except for those due to image filters.
+                rawBounds = &apply_paint_to_bounds_sans_imagefilter(*fPaint, *rawBounds, &storage);
+            }
+#endif
+            (void)canvas->internalSaveLayer(rawBounds, &tmp, SkCanvas::kARGB_ClipLayer_SaveFlag,
                                             SkCanvas::kFullLayer_SaveLayerStrategy);
             fTempLayerForImageFilter = true;
             // we remove the imagefilter/xfermode inside doNext()
         }
 
         if (SkDrawLooper* looper = paint.getLooper()) {
             void* buffer = fLooperContextAllocator.reserveT<SkDrawLooper::Context>(
                     looper->contextSize());
             fLooperContext = looper->createContext(canvas, buffer);
             fIsSimple = false;
@@ skipping 551 matching lines @@
 
 bool SkCanvas::clipRectBounds(const SkRect* bounds, SaveFlags flags,
                               SkIRect* intersection, const SkImageFilter* imageFilter) {
     SkIRect clipBounds;
     if (!this->getClipDeviceBounds(&clipBounds)) {
         return false;
     }
 
     const SkMatrix& ctm = fMCRec->fMatrix;  // this->getTotalMatrix()
 
+// This is a temporary hack, until individual filters can do their own
+// bloating, when this will be removed.
+#ifdef SK_SUPPORT_SRC_BOUNDS_BLOAT_FOR_IMAGEFILTERS
+    SkRect storage;
+#endif
     if (imageFilter) {
         imageFilter->filterBounds(clipBounds, ctm, &clipBounds);
+#ifdef SK_SUPPORT_SRC_BOUNDS_BLOAT_FOR_IMAGEFILTERS
+        if (bounds && imageFilter->canComputeFastBounds()) {
+            imageFilter->computeFastBounds(*bounds, &storage);
+            bounds = &storage;
+        } else {
+            bounds = nullptr;
+        }
+#endif
     }
     SkIRect ir;
     if (bounds) {
         SkRect r;
 
         ctm.mapRect(&r, *bounds);
         r.roundOut(&ir);
         // early exit if the layer's bounds are clipped out
         if (!ir.intersect(clipBounds)) {
             if (bounds_affects_clip(flags)) {
@@ skipping 924 matching lines @@
 
     SkRect r, storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
         // special-case 2 points (common for drawing a single line)
         if (2 == count) {
             r.set(pts[0], pts[1]);
         } else {
             r.set(pts, SkToInt(count));
         }
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastStrokeBounds(r, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastStrokeBounds(r, &storage))) {
+            return;
+        }
+        bounds = &r;
+#endif
     }
 
     SkASSERT(pts != nullptr);
 
     LOOPER_BEGIN(paint, SkDrawFilter::kPoint_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawPoints(iter, mode, count, pts, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawRect(const SkRect& r, const SkPaint& paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawRect()");
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
         // Skia will draw an inverted rect, because it explicitly "sorts" it downstream.
         // To prevent accidental rejecting at this stage, we have to sort it before we check.
         SkRect tmp(r);
         tmp.sort();
 
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(tmp, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastBounds(tmp, &storage))) {
+            return;
+        }
+        bounds = &r;
+#endif
     }
 
     LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(paint, SkDrawFilter::kRect_Type, bounds, false)
 
     while (iter.next()) {
         iter.fDevice->drawRect(iter, r, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawOval(const SkRect& oval, const SkPaint& paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawOval()");
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(oval, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastBounds(oval, &storage))) {
+            return;
+        }
+        bounds = &oval;
+#endif
     }
 
     LOOPER_BEGIN(paint, SkDrawFilter::kOval_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawOval(iter, oval, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawRRect(const SkRRect& rrect, const SkPaint& paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawRRect()");
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(rrect.getBounds(), &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastBounds(rrect.getBounds(), &storage))) {
+            return;
+        }
+        bounds = &rrect.getBounds();
+#endif
     }
 
     if (rrect.isRect()) {
         // call the non-virtual version
         this->SkCanvas::drawRect(rrect.getBounds(), paint);
         return;
     } else if (rrect.isOval()) {
         // call the non-virtual version
         this->SkCanvas::drawOval(rrect.getBounds(), paint);
         return;
     }
 
     LOOPER_BEGIN(paint, SkDrawFilter::kRRect_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawRRect(iter, rrect, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawDRRect(const SkRRect& outer, const SkRRect& inner,
                             const SkPaint& paint) {
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(outer.getBounds(), &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastBounds(outer.getBounds(), &storage))) {
+            return;
+        }
+        bounds = &outer.getBounds();
+#endif
     }
 
     LOOPER_BEGIN(paint, SkDrawFilter::kRRect_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawDRRect(iter, outer, inner, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawPath(const SkPath& path, const SkPaint& paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawPath()");
     if (!path.isFinite()) {
         return;
     }
 
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (!path.isInverseFillType() && paint.canComputeFastBounds()) {
         const SkRect& pathBounds = path.getBounds();
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(pathBounds, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint.computeFastBounds(pathBounds, &storage))) {
+            return;
+        }
+        bounds = &pathBounds;
+#endif
     }
 
     const SkRect& r = path.getBounds();
     if (r.width() <= 0 && r.height() <= 0) {
         if (path.isInverseFillType()) {
             this->internalDrawPaint(paint);
             return;
         }
     }
 
     LOOPER_BEGIN(paint, SkDrawFilter::kPath_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawPath(iter, path, looper.paint());
     }
 
     LOOPER_END
 }
 
 void SkCanvas::onDrawImage(const SkImage* image, SkScalar x, SkScalar y, const SkPaint* paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawImage()");
     SkRect bounds = SkRect::MakeXYWH(x, y,
                                      SkIntToScalar(image->width()), SkIntToScalar(image->height()));
     if (nullptr == paint || paint->canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         if (paint) {
             paint->computeFastBounds(bounds, &bounds);
         }
         if (this->quickReject(bounds)) {
             return;
         }
+#else
+        SkRect tmp = bounds;
+        if (paint) {
+            paint->computeFastBounds(tmp, &tmp);
+        }
+        if (this->quickReject(tmp)) {
+            return;
+        }
+#endif
     }
     
     SkLazyPaint lazy;
     if (nullptr == paint) {
         paint = lazy.init();
     }
     
     LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, &bounds)
     
     while (iter.next()) {
         iter.fDevice->drawImage(iter, image, x, y, looper.paint());
     }
     
     LOOPER_END
 }
 
 void SkCanvas::onDrawImageRect(const SkImage* image, const SkRect* src, const SkRect& dst,
                                const SkPaint* paint, SrcRectConstraint constraint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawImageRect()");
     SkRect storage;
     const SkRect* bounds = &dst;
     if (nullptr == paint || paint->canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         if (paint) {
             bounds = &paint->computeFastBounds(dst, &storage);
         }
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        storage = dst;
+        if (paint) {
+            paint->computeFastBounds(dst, &storage);
+        }
+        if (this->quickReject(storage)) {
+            return;
+        }
+#endif
     }
     SkLazyPaint lazy;
     if (nullptr == paint) {
         paint = lazy.init();
     }
     
     LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(*paint, SkDrawFilter::kBitmap_Type, bounds,
                                           image->isOpaque())
     
     while (iter.next()) {
@@ skipping 16 matching lines @@
         paint = lazy.init();
     }
 
     const SkMatrix matrix = SkMatrix::MakeTrans(x, y);
 
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint->canComputeFastBounds()) {
         bitmap.getBounds(&storage);
         matrix.mapRect(&storage);
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint->computeFastBounds(storage, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        SkRect tmp = storage;
+        if (this->quickReject(paint->computeFastBounds(tmp, &tmp))) {
+            return;
+        }
+        bounds = &storage;
+#endif
     }
 
     LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawBitmap(iter, bitmap, matrix, looper.paint());
     }
     
     LOOPER_END
 }
 
 // this one is non-virtual, so it can be called safely by other canvas apis
 void SkCanvas::internalDrawBitmapRect(const SkBitmap& bitmap, const SkRect* src,
                                       const SkRect& dst, const SkPaint* paint,
                                       SrcRectConstraint constraint) {
     if (bitmap.drawsNothing() || dst.isEmpty()) {
         return;
     }
 
     SkRect storage;
     const SkRect* bounds = &dst;
     if (nullptr == paint || paint->canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         if (paint) {
             bounds = &paint->computeFastBounds(dst, &storage);
         }
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint ? paint->computeFastBounds(dst, &storage) : dst)) {
+            return;
+        }
+#endif
     }
 
     SkLazyPaint lazy;
     if (nullptr == paint) {
         paint = lazy.init();
     }
 
     LOOPER_BEGIN_CHECK_COMPLETE_OVERWRITE(*paint, SkDrawFilter::kBitmap_Type, bounds,
                                           bitmap.isOpaque())
 
@@ skipping 11 matching lines @@
     this->internalDrawBitmapRect(bitmap, src, dst, paint, constraint);
 }
 
 void SkCanvas::onDrawImageNine(const SkImage* image, const SkIRect& center, const SkRect& dst,
                                const SkPaint* paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawImageNine()");
     
     SkRect storage;
     const SkRect* bounds = &dst;
     if (nullptr == paint || paint->canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         if (paint) {
             bounds = &paint->computeFastBounds(dst, &storage);
         }
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint ? paint->computeFastBounds(dst, &storage) : dst)) {
+            return;
+        }
+#endif
     }
     
     SkLazyPaint lazy;
     if (nullptr == paint) {
         paint = lazy.init();
     }
     
     LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, bounds)
     
     while (iter.next()) {
         iter.fDevice->drawImageNine(iter, image, center, dst, looper.paint());
     }
     
     LOOPER_END
 }
 
 void SkCanvas::onDrawBitmapNine(const SkBitmap& bitmap, const SkIRect& center, const SkRect& dst,
                                 const SkPaint* paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawBitmapNine()");
     SkDEBUGCODE(bitmap.validate();)
 
     SkRect storage;
     const SkRect* bounds = &dst;
     if (nullptr == paint || paint->canComputeFastBounds()) {
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         if (paint) {
             bounds = &paint->computeFastBounds(dst, &storage);
         }
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        if (this->quickReject(paint ? paint->computeFastBounds(dst, &storage) : dst)) {
+            return;
+        }
+#endif
     }
     
     SkLazyPaint lazy;
     if (nullptr == paint) {
         paint = lazy.init();
     }
     
     LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type, bounds)
     
     while (iter.next()) {
@@ skipping 152 matching lines @@
     LOOPER_END
 }
 
 void SkCanvas::onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
                               const SkPaint& paint) {
 
     SkRect storage;
     const SkRect* bounds = nullptr;
     if (paint.canComputeFastBounds()) {
         storage = blob->bounds().makeOffset(x, y);
+#ifdef SK_SAVE_LAYER_BOUNDS_ARE_FILTERED
         bounds = &paint.computeFastBounds(storage, &storage);
 
         if (this->quickReject(*bounds)) {
             return;
         }
+#else
+        SkRect tmp;
+        if (this->quickReject(paint.computeFastBounds(storage, &tmp))) {
+            return;
+        }
+        bounds = &storage;
+#endif
     }
 
     // We cannot filter in the looper as we normally do, because the paint is
     // incomplete at this point (text-related attributes are embedded within blob run paints).
     SkDrawFilter* drawFilter = fMCRec->fFilter;
     fMCRec->fFilter = nullptr;
 
     LOOPER_BEGIN(paint, SkDrawFilter::kText_Type, bounds)
 
     while (iter.next()) {
@@ skipping 408 matching lines @@
     }
 
     if (matrix) {
         canvas->concat(*matrix);
     }
 }
 
 SkAutoCanvasMatrixPaint::~SkAutoCanvasMatrixPaint() {
     fCanvas->restoreToCount(fSaveCount);
 }