commit 59dc0d22f557a20669126fa425baefe6dd4b727a
author reed <reed@google.com> Mon Oct 19 08:24:21 2015 -0700
committer Commit bot <commit-bot@chromium.org> Mon Oct 19 08:24:21 2015 -0700
tree 7514a50448adfa5c3f3755ff6ce88e520801d7d8
parent 1a197ea31e0aac7ea312e9a6c0d9f5df626b0350

change SkImage_Gpu to handle all filters (w/ and w/o gpu support

The result is that the set of "generic" imagefilters (e.g. SkColorFilterImageFilter) that use drawing commands to return their results will now stay in the same domain as their src (i.e. gpu-src --> gpu-dst).

ApplyFilterGM exercises this, and now asserts this same-domain invariant.

BUG=skia:4467

Review URL: https://codereview.chromium.org/1401053003

gm/spritebitmap.cpp

diff --git a/gm/spritebitmap.cpp b/gm/spritebitmap.cpp
index 5cf0ece..6aac09f 100644
--- a/gm/spritebitmap.cpp
+++ b/gm/spritebitmap.cpp
@@ -141,6 +141,11 @@
 // hence this cast function
 template <typename T> ImageFilterFactory IFCCast(T arg) { return arg; }
 
+// We expect that applying the filter will keep us in the same domain (raster or gpu)
+static void check_same_domain(SkImage* a, SkImage* b) {
+    SkASSERT(a->isTextureBacked() == b->isTextureBacked());
+}
+
 /**
  *  Compare output of drawSprite and drawBitmap (esp. clipping and imagefilters)
  */
@@ -180,6 +185,9 @@
             SkAutoTUnref<SkImage> image1(image0->applyFilter(filter, &offset1, true));
             SkAutoTUnref<SkImage> image2(image0->applyFilter(filter, &offset2, false));
 
+            check_same_domain(image0, image1);
+            check_same_domain(image0, image2);
+
             canvas->save();
             canvas->translate(30, 30);
             show_image(canvas, image0, SkIPoint::Make(0, 0));   // original

src/image/SkImage_Gpu.cpp

diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index 039bbdd..9eb909e 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -209,33 +209,52 @@
         }
     }
 
-    bool filterImage(const SkImageFilter*, const SkBitmap&, const SkImageFilter::Context&,
-                     SkBitmap*, SkIPoint*) override {
-        return false;
+    bool filterImage(const SkImageFilter* filter, const SkBitmap& src,
+                     const SkImageFilter::Context& ctx, SkBitmap* dst, SkIPoint* offset) override {
+        return filter->canFilterImageGPU() &&
+               filter->filterImageGPU(this, src, ctx, dst, offset);
     }
 };
 
+static SkIRect compute_fast_ibounds(SkImageFilter* filter, const SkIRect& srcBounds) {
+    SkRect fastBounds;
+    fastBounds.set(srcBounds);
+    filter->computeFastBounds(fastBounds, &fastBounds);
+    return fastBounds.roundOut();
+}
+
 SkImage* SkImage_Gpu::onApplyFilter(SkImageFilter* filter, SkIPoint* offsetResult,
                                     bool forceResultToOriginalSize) const {
-    if (!forceResultToOriginalSize || !filter->canFilterImageGPU()) {
-        return this->INHERITED::onApplyFilter(filter, offsetResult, forceResultToOriginalSize);
-    }
+    const SkIRect srcBounds = SkIRect::MakeWH(this->width(), this->height());
 
-    SkBitmap src;
-    GrWrapTextureInBitmap(fTexture, this->width(), this->height(), this->isOpaque(), &src);
+    if (forceResultToOriginalSize) {
+        SkBitmap src;
+        GrWrapTextureInBitmap(fTexture, this->width(), this->height(), this->isOpaque(), &src);
 
-    GrContext* context = fTexture->getContext();
-    SkGpuImageFilterProxy proxy(context);
-    SkImageFilter::Context ctx(SkMatrix::I(),
-                               SkIRect::MakeWH(this->width(), this->height()),
-                               SkImageFilter::Cache::Get());
+        const SkIRect clipBounds = srcBounds;
+        SkGpuImageFilterProxy proxy(fTexture->getContext());
+        SkImageFilter::Context ctx(SkMatrix::I(), clipBounds, SkImageFilter::Cache::Get());
 
-    SkBitmap dst;
-    if (filter->filterImageGPU(&proxy, src, ctx, &dst, offsetResult)) {
+        SkBitmap dst;
+        if (!filter->filterImage(&proxy, src, ctx, &dst, offsetResult)) {
+            return nullptr;
+        }
         return new SkImage_Gpu(dst.width(), dst.height(), kNeedNewImageUniqueID, dst.alphaType(),
                                dst.getTexture(), SkSurface::kNo_Budgeted);
     }
-    return nullptr;
+
+    const SkIRect dstR = compute_fast_ibounds(filter, srcBounds);
+
+    SkImageInfo info = SkImageInfo::MakeN32Premul(dstR.width(), dstR.height());
+    SkAutoTUnref<SkSurface> surface(this->onNewSurface(info));
+
+    SkPaint paint;
+    paint.setImageFilter(filter);
+    surface->getCanvas()->drawImage(this, SkIntToScalar(-dstR.x()), SkIntToScalar(-dstR.y()),
+                                    &paint);
+
+    offsetResult->set(dstR.x(), dstR.y());
+    return surface->newImageSnapshot();
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////