commit 50da5043ad224fd6b6024ed73785a9502bf7978d
author chaviw <chaviw@google.com> Mon Apr 09 13:49:37 2018 -0700
committer Chavi Weingarten <chaviw@google.com> Thu Apr 12 19:34:58 2018 +0000
tree b6be4ec360db2ef03904fb9c7eb2007076e79fa4
parent 2788edd12f4f149dc8eadb561566edb66aa4f7e8

Set window to transparent when screenshotting layer.

Set the screenshot to transparent instead of black. This allows the
system to draw a color behind without having to crop out the area that
may not be drawn into.

Bug: 76442549
Test: When going to recents, area not drawn from layers is now
transparent instead of black.
Test: Transaction_test#CaptureTransparent

Change-Id: Id535eb753d3d1cae82658cd33423ce588aaa62f8

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 183c1eb..781a30c 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4597,7 +4597,7 @@
     public:
         LayerRenderArea(SurfaceFlinger* flinger, const sp<Layer>& layer, const Rect crop,
                         int32_t reqWidth, int32_t reqHeight, bool childrenOnly)
-              : RenderArea(reqHeight, reqWidth),
+              : RenderArea(reqHeight, reqWidth, CaptureFill::CLEAR),
                 mLayer(layer),
                 mCrop(crop),
                 mFlinger(flinger),
@@ -4834,8 +4834,9 @@
                                     renderArea.getRotationFlags());
     engine.disableTexturing();
 
+    const float alpha = RenderArea::getCaptureFillValue(renderArea.getCaptureFill());
     // redraw the screen entirely...
-    engine.clearWithColor(0, 0, 0, 1);
+    engine.clearWithColor(0, 0, 0, alpha);
 
     traverseLayers([&](Layer* layer) {
         if (filtering) layer->setFiltering(true);