Add caching of the snapshot image form a surface

Notify the surface when the canvas draws into it, so it can invalidate the
cached image, and (if needed) perform a copy-on-write on the surface if it
was being shared with the image.
Review URL: https://codereview.appspot.com/6441115

git-svn-id: http://skia.googlecode.com/svn/trunk@5306 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 15 insertions, 0 deletions

diff --git a/gm/image.cpp b/gm/image.cpp
index 4ee90a4fc6..21286db731 100644
--- a/gm/image.cpp
+++ b/gm/image.cpp
@@ -11,6 +11,8 @@
 #include "SkStream.h"
 #include "SkData.h"
 
+extern GrContext* GetGr();
+
 static SkData* fileToData(const char path[]) {
     SkFILEStream stream(path);
     if (!stream.isValid()) {
@@ -57,9 +59,18 @@ static void test_surface(SkCanvas* canvas, SkSurface* surf) {
     drawContents(surf, SK_ColorRED);
     SkImage* imgR = surf->newImageShapshot();
 
+    if (true) {
+        SkImage* imgR2 = surf->newImageShapshot();
+        SkASSERT(imgR == imgR2);
+        imgR2->unref();
+    }
+
     drawContents(surf, SK_ColorGREEN);
     SkImage* imgG = surf->newImageShapshot();
 
+    // since we've drawn after we snapped imgR, imgG will be a different obj
+    SkASSERT(imgR != imgG);
+
     drawContents(surf, SK_ColorBLUE);
 
     SkPaint paint;
@@ -130,6 +141,10 @@ protected:
         test_surface(canvas, surf2);
     }
 
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return GM::kSkipPicture_Flag;
+    }
+
 private:
     typedef skiagm::GM INHERITED;
 };