commit 4a9ac37fe26644bb5253d15eec08be2edb896642
author Mathias Agopian <mathias@google.com> Tue Nov 01 14:39:06 2011 -0700
committer Mathias Agopian <mathias@google.com> Fri Nov 04 15:15:32 2011 -0700
tree 422d3aab1501234ff83d48bf1405310ea497fcef
parent d9440fe16641c73265d46f1f23d74cdc6d21a408

Fix rotation displays frame N-1 briefly while rotating

The ScreenShot layer is now created hidden. The screenshot itself
is aquired during the transaction when the layer is made visible.
This guarantees the screenshot and the layer happen atomically
with respect to screen updates.

Bug: 5534521
Change-Id: Ida23e1f13d5716ec83b78a15712e0646d6cf8729

services/surfaceflinger/LayerScreenshot.cpp

diff --git a/services/surfaceflinger/LayerScreenshot.cpp b/services/surfaceflinger/LayerScreenshot.cpp
index e30ccbf..68e6660 100644
--- a/services/surfaceflinger/LayerScreenshot.cpp
+++ b/services/surfaceflinger/LayerScreenshot.cpp
@@ -27,6 +27,7 @@
 #include "SurfaceFlinger.h"
 #include "DisplayHardware/DisplayHardware.h"
 
+
 namespace android {
 // ---------------------------------------------------------------------------
 
@@ -45,23 +46,64 @@
     }
 }
 
+status_t LayerScreenshot::captureLocked() {
+    GLfloat u, v;
+    status_t result = mFlinger->renderScreenToTextureLocked(0, &mTextureName, &u, &v);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    initTexture(u, v);
+    return NO_ERROR;
+}
+
 status_t LayerScreenshot::capture() {
     GLfloat u, v;
     status_t result = mFlinger->renderScreenToTexture(0, &mTextureName, &u, &v);
     if (result != NO_ERROR) {
         return result;
     }
+    initTexture(u, v);
+    return NO_ERROR;
+}
 
+void LayerScreenshot::initTexture(GLfloat u, GLfloat v) {
     glBindTexture(GL_TEXTURE_2D, mTextureName);
     glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-
     mTexCoords[0] = 0;         mTexCoords[1] = v;
     mTexCoords[2] = 0;         mTexCoords[3] = 0;
     mTexCoords[4] = u;         mTexCoords[5] = 0;
     mTexCoords[6] = u;         mTexCoords[7] = v;
+}
 
-    return NO_ERROR;
+void LayerScreenshot::initStates(uint32_t w, uint32_t h, uint32_t flags) {
+    LayerBaseClient::initStates(w, h, flags);
+    if (!(flags & ISurfaceComposer::eHidden)) {
+        capture();
+    }
+}
+
+uint32_t LayerScreenshot::doTransaction(uint32_t flags)
+{
+    const Layer::State& draw(drawingState());
+    const Layer::State& curr(currentState());
+
+    if (draw.flags & ISurfaceComposer::eLayerHidden) {
+        if (!(curr.flags & ISurfaceComposer::eLayerHidden)) {
+            // we're going from hidden to visible
+            status_t err = captureLocked();
+            if (err != NO_ERROR) {
+                LOGW("createScreenshotSurface failed (%s)", strerror(-err));
+            }
+        }
+    } else if (curr.flags & ISurfaceComposer::eLayerHidden) {
+        // we're going from visible to hidden
+        if (mTextureName) {
+            glDeleteTextures(1, &mTextureName);
+            mTextureName = 0;
+        }
+    }
+    return LayerBaseClient::doTransaction(flags);
 }
 
 void LayerScreenshot::onDraw(const Region& clip) const