Use Offscreen Surface for Split Screen

tools/viewer/sk_app/Window.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef Window_DEFINED
 #define Window_DEFINED
 
 #include "DisplayParams.h"
 #include "SkRect.h"
 #include "SkTouchGesture.h"
 #include "SkTypes.h"
 #include "SkJSONCPP.h"
 
 class SkCanvas;
+class SkSurface;
 
 namespace sk_app {
 
 class WindowContext;
 
 class Window {
 public:
     static Window* CreateNativeWindow(void* platformData);
 
     virtual ~Window() {};
@@ skipping 126 matching lines @@
     void onUIStateChanged(const SkString& stateName, const SkString& stateValue);
     void onPaint();
     void onResize(uint32_t width, uint32_t height);
 
     uint32_t width() { return fWidth; }
     uint32_t height() { return fHeight;  }
 
     virtual const DisplayParams& getDisplayParams();
     void setDisplayParams(const DisplayParams& params);
 
+    sk_sp<SkSurface> getOffscreenSurface(bool sRGB);

[djsollen, 2016/06/15 14:14:29]

why not pass SkSurfaceProps as an argument so that it is consistent with our
other APIs?

[liyuqian, 2016/06/15 16:43:12]

Because SkSurfaceProps is kind of complicated to construct. A lot of that work
is done in WindowContext::createRenderSurface. This simplified API reuses that
code. I'll add comment to this method to specify that this API is only for split
screen usage. Hopefully that will make things clear?

+
 protected:
     Window();
 
     uint32_t     fWidth;
     uint32_t     fHeight;
 
     OnCharFunc   fCharFunc;
     void*        fCharUserData;
     OnKeyFunc    fKeyFunc;
     void*        fKeyUserData;
@@ skipping 12 matching lines @@
     virtual void onInval() = 0;
 
     // Uncheck fIsContentInvalided to allow future inval/onInval.
     void markInvalProcessed();
 
     bool fIsContentInvalidated = false;  // use this to avoid duplicate invalidate events
 };
 
 }   // namespace sk_app
 #endif