refactored screenshot code

the core screenshot function now can capture the screen at any lower resolution
performing bilinear filtering.

we also now have some client code to interface with the screenshot service.

it's now possible to request a screenshot at a lower resolution.

Change-Id: I5a3b0e431421800e3aad601d9af8f94adffbc71f
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 1b21a8d..fb76720 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -271,6 +271,17 @@
     }
 }
 
+void Layer::drawForSreenShot() const
+{
+    bool currentFixedSize = mFixedSize;
+    bool currentBlending = mNeedsBlending;
+    const_cast<Layer*>(this)->mFixedSize = false;
+    const_cast<Layer*>(this)->mFixedSize = true;
+    LayerBase::drawForSreenShot();
+    const_cast<Layer*>(this)->mFixedSize = currentFixedSize;
+    const_cast<Layer*>(this)->mNeedsBlending = currentBlending;
+}
+
 void Layer::onDraw(const Region& clip) const
 {
     Texture tex(mBufferManager.getActiveTexture());
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 188da6a..caa6d17 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -70,6 +70,7 @@
     // LayerBase interface
     virtual void setGeometry(hwc_layer_t* hwcl);
     virtual void setPerFrameData(hwc_layer_t* hwcl);
+    virtual void drawForSreenShot() const;
     virtual void onDraw(const Region& clip) const;
     virtual uint32_t doTransaction(uint32_t transactionFlags);
     virtual void lockPageFlip(bool& recomputeVisibleRegions);
diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
index 3d049a7..14191cb 100644
--- a/services/surfaceflinger/LayerBase.cpp
+++ b/services/surfaceflinger/LayerBase.cpp
@@ -326,6 +326,12 @@
     onDraw(clip);
 }
 
+void LayerBase::drawForSreenShot() const
+{
+    const DisplayHardware& hw(graphicPlane(0).displayHardware());
+    onDraw( Region(hw.bounds()) );
+}
+
 void LayerBase::clearWithOpenGL(const Region& clip, GLclampf red,
                                 GLclampf green, GLclampf blue,
                                 GLclampf alpha) const
diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index c66dc34..bdee05b 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -121,6 +121,7 @@
      * to perform the actual drawing.  
      */
     virtual void draw(const Region& clip) const;
+    virtual void drawForSreenShot() const;
     
     /**
      * onDraw - draws the surface.
diff --git a/services/surfaceflinger/LayerBuffer.cpp b/services/surfaceflinger/LayerBuffer.cpp
index fdf9abc..c060895 100644
--- a/services/surfaceflinger/LayerBuffer.cpp
+++ b/services/surfaceflinger/LayerBuffer.cpp
@@ -132,6 +132,12 @@
     LayerBase::unlockPageFlip(planeTransform, outDirtyRegion);    
 }
 
+void LayerBuffer::drawForSreenShot() const
+{
+    const DisplayHardware& hw(graphicPlane(0).displayHardware());
+    clearWithOpenGL( Region(hw.bounds()) );
+}
+
 void LayerBuffer::onDraw(const Region& clip) const
 {
     sp<Source> source(getSource());
diff --git a/services/surfaceflinger/LayerBuffer.h b/services/surfaceflinger/LayerBuffer.h
index 1c0bf83..fece858 100644
--- a/services/surfaceflinger/LayerBuffer.h
+++ b/services/surfaceflinger/LayerBuffer.h
@@ -64,6 +64,7 @@
     virtual sp<LayerBaseClient::Surface> createSurface() const;
     virtual status_t ditch();
     virtual void onDraw(const Region& clip) const;
+    virtual void drawForSreenShot() const;
     virtual uint32_t doTransaction(uint32_t flags);
     virtual void unlockPageFlip(const Transform& planeTransform, Region& outDirtyRegion);
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 17b98a6..e6bdfd1 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1653,9 +1653,117 @@
 
 // ---------------------------------------------------------------------------
 
+status_t SurfaceFlinger::captureScreenImplLocked(DisplayID dpy,
+        sp<IMemoryHeap>* heap,
+        uint32_t* w, uint32_t* h, PixelFormat* f,
+        uint32_t sw, uint32_t sh)
+{
+    status_t result = PERMISSION_DENIED;
+
+    // only one display supported for now
+    if (UNLIKELY(uint32_t(dpy) >= DISPLAY_COUNT))
+        return BAD_VALUE;
+
+    if (!GLExtensions::getInstance().haveFramebufferObject())
+        return INVALID_OPERATION;
+
+    // get screen geometry
+    const DisplayHardware& hw(graphicPlane(dpy).displayHardware());
+    const uint32_t hw_w = hw.getWidth();
+    const uint32_t hw_h = hw.getHeight();
+
+    if ((sw > hw_w) || (sh > hw_h))
+        return BAD_VALUE;
+
+    sw = (!sw) ? hw_w : sw;
+    sh = (!sh) ? hw_h : sh;
+    const size_t size = sw * sh * 4;
+
+    // make sure to clear all GL error flags
+    while ( glGetError() != GL_NO_ERROR ) ;
+
+    // create a FBO
+    GLuint name, tname;
+    glGenRenderbuffersOES(1, &tname);
+    glBindRenderbufferOES(GL_RENDERBUFFER_OES, tname);
+    glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_RGBA8_OES, sw, sh);
+    glGenFramebuffersOES(1, &name);
+    glBindFramebufferOES(GL_FRAMEBUFFER_OES, name);
+    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES,
+            GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, tname);
+
+    GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES);
+    if (status == GL_FRAMEBUFFER_COMPLETE_OES) {
+
+        // invert everything, b/c glReadPixel() below will invert the FB
+        glViewport(0, 0, sw, sh);
+        glMatrixMode(GL_PROJECTION);
+        glPushMatrix();
+        glLoadIdentity();
+        glOrthof(0, hw_w, 0, hw_h, 0, 1);
+        glMatrixMode(GL_MODELVIEW);
+
+        // redraw the screen entirely...
+        glClearColor(0,0,0,1);
+        glClear(GL_COLOR_BUFFER_BIT);
+        const Vector< sp<LayerBase> >& layers(mVisibleLayersSortedByZ);
+        const size_t count = layers.size();
+        for (size_t i=0 ; i<count ; ++i) {
+            const sp<LayerBase>& layer(layers[i]);
+            layer->drawForSreenShot();
+        }
+
+        // XXX: this is needed on tegra
+        glScissor(0, 0, sw, sh);
+
+        // check for errors and return screen capture
+        if (glGetError() != GL_NO_ERROR) {
+            // error while rendering
+            result = INVALID_OPERATION;
+        } else {
+            // allocate shared memory large enough to hold the
+            // screen capture
+            sp<MemoryHeapBase> base(
+                    new MemoryHeapBase(size, 0, "screen-capture") );
+            void* const ptr = base->getBase();
+            if (ptr) {
+                // capture the screen with glReadPixels()
+                glReadPixels(0, 0, sw, sh, GL_RGBA, GL_UNSIGNED_BYTE, ptr);
+                if (glGetError() == GL_NO_ERROR) {
+                    *heap = base;
+                    *w = sw;
+                    *h = sh;
+                    *f = PIXEL_FORMAT_RGBA_8888;
+                    result = NO_ERROR;
+                }
+            } else {
+                result = NO_MEMORY;
+            }
+        }
+
+        glEnable(GL_SCISSOR_TEST);
+        glViewport(0, 0, hw_w, hw_h);
+        glMatrixMode(GL_PROJECTION);
+        glPopMatrix();
+        glMatrixMode(GL_MODELVIEW);
+
+
+    } else {
+        result = BAD_VALUE;
+    }
+
+    // release FBO resources
+    glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0);
+    glDeleteRenderbuffersOES(1, &tname);
+    glDeleteFramebuffersOES(1, &name);
+    return result;
+}
+
+
 status_t SurfaceFlinger::captureScreen(DisplayID dpy,
         sp<IMemoryHeap>* heap,
-        uint32_t* width, uint32_t* height, PixelFormat* format)
+        uint32_t* width, uint32_t* height, PixelFormat* format,
+        uint32_t sw, uint32_t sh)
 {
     // only one display supported for now
     if (UNLIKELY(uint32_t(dpy) >= DISPLAY_COUNT))
@@ -1671,12 +1779,15 @@
         uint32_t* w;
         uint32_t* h;
         PixelFormat* f;
+        uint32_t sw;
+        uint32_t sh;
         status_t result;
     public:
         MessageCaptureScreen(SurfaceFlinger* flinger, DisplayID dpy,
-                sp<IMemoryHeap>* heap, uint32_t* w, uint32_t* h, PixelFormat* f)
+                sp<IMemoryHeap>* heap, uint32_t* w, uint32_t* h, PixelFormat* f,
+                uint32_t sw, uint32_t sh)
             : flinger(flinger), dpy(dpy),
-              heap(heap), w(w), h(h), f(f), result(PERMISSION_DENIED)
+              heap(heap), w(w), h(h), f(f), sw(sw), sh(sh), result(PERMISSION_DENIED)
         {
         }
         status_t getResult() const {
@@ -1689,94 +1800,15 @@
             if (flinger->mSecureFrameBuffer)
                 return true;
 
-            // make sure to clear all GL error flags
-            while ( glGetError() != GL_NO_ERROR ) ;
+            result = flinger->captureScreenImplLocked(dpy,
+                    heap, w, h, f, sw, sh);
 
-            // get screen geometry
-            const DisplayHardware& hw(flinger->graphicPlane(dpy).displayHardware());
-            const uint32_t sw = hw.getWidth();
-            const uint32_t sh = hw.getHeight();
-            const Region screenBounds(hw.bounds());
-            const size_t size = sw * sh * 4;
-
-            // create a FBO
-            GLuint name, tname;
-            glGenRenderbuffersOES(1, &tname);
-            glBindRenderbufferOES(GL_RENDERBUFFER_OES, tname);
-            glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_RGBA8_OES, sw, sh);
-            glGenFramebuffersOES(1, &name);
-            glBindFramebufferOES(GL_FRAMEBUFFER_OES, name);
-            glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES,
-                    GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, tname);
-
-            GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES);
-            if (status == GL_FRAMEBUFFER_COMPLETE_OES) {
-
-                // invert everything, b/c glReadPixel() below will invert the FB
-                glMatrixMode(GL_PROJECTION);
-                glPushMatrix();
-                glLoadIdentity();
-                glOrthof(0, sw, 0, sh, 0, 1);
-                glMatrixMode(GL_MODELVIEW);
-
-                // redraw the screen entirely...
-                glClearColor(0,0,0,1);
-                glClear(GL_COLOR_BUFFER_BIT);
-                const Vector< sp<LayerBase> >& layers(
-                        flinger->mVisibleLayersSortedByZ);
-                const size_t count = layers.size();
-                for (size_t i=0 ; i<count ; ++i) {
-                    const sp<LayerBase>& layer(layers[i]);
-                    if (!strcmp(layer->getTypeId(), "LayerBuffer")) {
-                        // we cannot render LayerBuffer because it doens't
-                        // use OpenGL, and won't show-up in the FBO.
-                        continue;
-                    }
-                    layer->draw(screenBounds);
-                }
-
-                glMatrixMode(GL_PROJECTION);
-                glPopMatrix();
-                glMatrixMode(GL_MODELVIEW);
-
-                // check for errors and return screen capture
-                if (glGetError() != GL_NO_ERROR) {
-                    // error while rendering
-                    result = INVALID_OPERATION;
-                } else {
-                    // allocate shared memory large enough to hold the
-                    // screen capture
-                    sp<MemoryHeapBase> base(
-                            new MemoryHeapBase(size, 0, "screen-capture") );
-                    void* const ptr = base->getBase();
-                    if (ptr) {
-                        // capture the screen with glReadPixels()
-                        glReadPixels(0, 0, sw, sh, GL_RGBA, GL_UNSIGNED_BYTE, ptr);
-                        if (glGetError() == GL_NO_ERROR) {
-                            *heap = base;
-                            *w = sw;
-                            *h = sh;
-                            *f = PIXEL_FORMAT_RGBA_8888;
-                            result = NO_ERROR;
-                        }
-                    } else {
-                        result = NO_MEMORY;
-                    }
-                }
-            } else {
-                result = BAD_VALUE;
-            }
-
-            // release FBO resources
-            glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0);
-            glDeleteRenderbuffersOES(1, &tname);
-            glDeleteFramebuffersOES(1, &name);
             return true;
         }
     };
 
     sp<MessageBase> msg = new MessageCaptureScreen(this,
-            dpy, heap, width, height, format);
+            dpy, heap, width, height, format, sw, sh);
     status_t res = postMessageSync(msg);
     if (res == NO_ERROR) {
         res = static_cast<MessageCaptureScreen*>( msg.get() )->getResult();
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 6e9ecbd..732e57e 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -197,7 +197,9 @@
                                                       sp<IMemoryHeap>* heap,
                                                       uint32_t* width,
                                                       uint32_t* height,
-                                                      PixelFormat* format);
+                                                      PixelFormat* format,
+                                                      uint32_t reqWidth,
+                                                      uint32_t reqHeight);
 
             void                        screenReleased(DisplayID dpy);
             void                        screenAcquired(DisplayID dpy);
@@ -319,6 +321,11 @@
             void        commitTransaction();
 
 
+            status_t captureScreenImplLocked(DisplayID dpy,
+                    sp<IMemoryHeap>* heap,
+                    uint32_t* width, uint32_t* height, PixelFormat* format,
+                    uint32_t reqWidth = 0, uint32_t reqHeight = 0);
+
             friend class FreezeLock;
             sp<FreezeLock> getFreezeLock() const;
             inline void incFreezeCount() {
diff --git a/services/surfaceflinger/tests/screencap/screencap.cpp b/services/surfaceflinger/tests/screencap/screencap.cpp
index 9e893f4..6cf1504 100644
--- a/services/surfaceflinger/tests/screencap/screencap.cpp
+++ b/services/surfaceflinger/tests/screencap/screencap.cpp
@@ -42,7 +42,7 @@
     sp<IMemoryHeap> heap;
     uint32_t w, h;
     PixelFormat f;
-    status_t err = composer->captureScreen(0, &heap, &w, &h, &f);
+    status_t err = composer->captureScreen(0, &heap, &w, &h, &f, 0, 0);
     if (err != NO_ERROR) {
         fprintf(stderr, "screen capture failed: %s\n", strerror(-err));
         exit(0);