SurfaceFlinger: add a crop to the layer state

This change adds a crop rectangle specified in window coordinates to the layer
state.  The all window pixels outside this crop rectangle are treated as though
they were fully transparent.  This change also adds the plumbing necessary for
WindowManager to set that crop.

Change-Id: I582bc445dc8c97d4c943d4db8d582a6ef5a66081

include/gui/ISurfaceComposer.h

@@ -67,6 +67,7 @@ public:
         eTransparentRegionChanged   = 0x00000020,
         eVisibilityChanged          = 0x00000040,
         eFreezeTintChanged          = 0x00000080,
+        eCropChanged                = 0x00000100,
     };
 
     enum {

include/gui/Surface.h

@@ -72,6 +72,7 @@ public:
     status_t    setAlpha(float alpha=1.0f);
     status_t    setMatrix(float dsdx, float dtdx, float dsdy, float dtdy);
     status_t    setFreezeTint(uint32_t tint);
+    status_t    setCrop(const Rect& crop);
 
     static status_t writeSurfaceToParcel(
             const sp<SurfaceControl>& control, Parcel* parcel);

include/gui/SurfaceComposerClient.h

@@ -127,6 +127,7 @@ public:
     status_t    setMatrix(SurfaceID id, float dsdx, float dtdx, float dsdy, float dtdy);
     status_t    setPosition(SurfaceID id, float x, float y);
     status_t    setSize(SurfaceID id, uint32_t w, uint32_t h);
+    status_t    setCrop(SurfaceID id, const Rect& crop);
     status_t    destroySurface(SurfaceID sid);
 
 private:

include/private/gui/LayerState.h

@@ -23,6 +23,7 @@
 #include <utils/Errors.h>
 
 #include <ui/Region.h>
+#include <ui/Rect.h>
 #include <gui/ISurface.h>
 
 namespace android {
@@ -40,6 +41,7 @@ struct layer_state_t {
     {
         matrix.dsdx = matrix.dtdy = 1.0f;
         matrix.dsdy = matrix.dtdx = 0.0f;
+        crop.makeInvalid();
     }
 
     status_t    write(Parcel& output) const;
@@ -64,6 +66,7 @@ struct layer_state_t {
             uint8_t         mask;
             uint8_t         reserved;
             matrix22_t      matrix;
+            Rect            crop;
             // non POD must be last. see write/read
             Region          transparentRegion;
 };

include/ui/Rect.h

@@ -147,7 +147,7 @@ public:
     // a ROT90 then the output rectangle is defined in a space extending to
     // (height, width).  Otherwise the output rectangle is in the same space as
     // the input.
-    Rect transform(uint32_t xform, int32_t width, int32_t height);
+    Rect transform(uint32_t xform, int32_t width, int32_t height) const;
 };
 
 ANDROID_BASIC_TYPES_TRAITS(Rect)

libs/gui/Surface.cpp

@@ -164,6 +164,12 @@ status_t SurfaceControl::setFreezeTint(uint32_t tint) {
     const sp<SurfaceComposerClient>& client(mClient);
     return client->setFreezeTint(mToken, tint);
 }
+status_t SurfaceControl::setCrop(const Rect& crop) {
+    status_t err = validate();
+    if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
+    return client->setCrop(mToken, crop);
+}
 
 status_t SurfaceControl::validate() const
 {

libs/gui/SurfaceComposerClient.cpp

@@ -125,6 +125,8 @@ public:
             const sp<SurfaceComposerClient>& client, SurfaceID id,
             uint32_t tint);
     status_t setOrientation(int orientation);
+    status_t setCrop(const sp<SurfaceComposerClient>& client, SurfaceID id,
+            const Rect& crop);
 
     static void closeGlobalTransaction(bool synchronous) {
         Composer::getInstance().closeGlobalTransactionImpl(synchronous);
@@ -290,6 +292,17 @@ status_t Composer::setOrientation(int orientation) {
     return NO_ERROR;
 }
 
+status_t Composer::setCrop(const sp<SurfaceComposerClient>& client,
+        SurfaceID id, const Rect& crop) {
+    Mutex::Autolock _l(mLock);
+    layer_state_t* s = getLayerStateLocked(client, id);
+    if (!s)
+        return BAD_INDEX;
+    s->what |= ISurfaceComposer::eCropChanged;
+    s->crop = crop;
+    return NO_ERROR;
+}
+
 // ---------------------------------------------------------------------------
 
 SurfaceComposerClient::SurfaceComposerClient()
@@ -398,6 +411,10 @@ void SurfaceComposerClient::closeGlobalTransaction(bool synchronous) {
 
 // ----------------------------------------------------------------------------
 
+status_t SurfaceComposerClient::setCrop(SurfaceID id, const Rect& crop) {
+    return getComposer().setCrop(this, id, crop);
+}
+
 status_t SurfaceComposerClient::setFreezeTint(SurfaceID id, uint32_t tint) {
     return getComposer().setFreezeTint(this, id, tint);
 }

libs/ui/Rect.cpp

@@ -93,7 +93,7 @@ bool Rect::intersect(const Rect& with, Rect* result) const
     return !(result->isEmpty());
 }
 
-Rect Rect::transform(uint32_t xform, int32_t width, int32_t height) {
+Rect Rect::transform(uint32_t xform, int32_t width, int32_t height) const {
     Rect result(*this);
     if (xform & HAL_TRANSFORM_FLIP_H) {
         result = Rect(width - result.right, result.top,

services/surfaceflinger/Layer.cpp

@@ -141,47 +141,6 @@ void Layer::setName(const String8& name) {
 void Layer::validateVisibility(const Transform& globalTransform) {
     LayerBase::validateVisibility(globalTransform);
 
-    if (mCurrentScalingMode == NATIVE_WINDOW_SCALING_MODE_FREEZE &&
-            !mCurrentCrop.isEmpty()) {
-        // We need to shrink the window size to match the buffer crop
-        // rectangle.
-        const Layer::State& s(drawingState());
-        const Transform tr(globalTransform * s.transform);
-        float windowWidth = s.w;
-        float windowHeight = s.h;
-        float bufferWidth = mActiveBuffer->getWidth();
-        float bufferHeight = mActiveBuffer->getHeight();
-        if (mCurrentTransform & NATIVE_WINDOW_TRANSFORM_ROT_90) {
-            float tmp = bufferWidth;
-            bufferWidth = bufferHeight;
-            bufferHeight = tmp;
-        }
-        float xScale = float(windowWidth) / float(bufferWidth);
-        float yScale = float(windowHeight) / float(bufferHeight);
-
-        // Compute the crop in post-transform coordinates.
-        Rect crop(mCurrentCrop.transform(mCurrentTransform,
-                    mActiveBuffer->getWidth(), mActiveBuffer->getHeight()));
-
-        float left = ceil(xScale * float(crop.left));
-        float right = floor(xScale * float(crop.right));
-        float top = ceil(yScale * float(crop.top));
-        float bottom = floor(yScale * float(crop.bottom));
-
-        tr.transform(mVertices[0], left, top);
-        tr.transform(mVertices[1], left, bottom);
-        tr.transform(mVertices[2], right, bottom);
-        tr.transform(mVertices[3], right, top);
-
-        const DisplayHardware& hw(graphicPlane(0).displayHardware());
-        const uint32_t hw_h = hw.getHeight();
-        for (size_t i=0 ; i<4 ; i++)
-            mVertices[i][1] = hw_h - mVertices[i][1];
-
-        mTransformedBounds = tr.transform(
-                Rect(int(left), int(top), int(right), int(bottom)));
-    }
-
     // This optimization allows the SurfaceTexture to bake in
     // the rotation so hardware overlays can be used
     mSurfaceTexture->setTransformHint(getTransformHint());
@@ -259,6 +218,46 @@ status_t Layer::setBuffers( uint32_t w, uint32_t h,
     return NO_ERROR;
 }
 
+Rect Layer::computeBufferCrop() const {
+    // Start with the SurfaceTexture's buffer crop...
+    Rect crop;
+    if (!mCurrentCrop.isEmpty()) {
+        crop = mCurrentCrop;
+    } else  if (mActiveBuffer != NULL){
+        crop = Rect(mActiveBuffer->getWidth(), mActiveBuffer->getHeight());
+    } else {
+        crop = Rect(mTransformedBounds.width(), mTransformedBounds.height());
+    }
+
+    // ... then reduce that in the same proportions as the window crop reduces
+    // the window size.
+    const State& s(drawingState());
+    if (!s.crop.isEmpty()) {
+        // Transform the window crop to match the buffer coordinate system,
+        // which means using the inverse of the current transform set on the
+        // SurfaceTexture.
+        uint32_t invTransform = mCurrentTransform;
+        int winWidth = s.w;
+        int winHeight = s.h;
+        if (invTransform & NATIVE_WINDOW_TRANSFORM_ROT_90) {
+            invTransform ^= NATIVE_WINDOW_TRANSFORM_FLIP_V |
+                    NATIVE_WINDOW_TRANSFORM_FLIP_H;
+            winWidth = s.h;
+            winHeight = s.w;
+        }
+        Rect winCrop = s.crop.transform(invTransform, s.w, s.h);
+
+        float xScale = float(crop.width()) / float(winWidth);
+        float yScale = float(crop.height()) / float(winHeight);
+        crop.left += int(ceil(float(winCrop.left) * xScale));
+        crop.top += int(ceil(float(winCrop.top) * yScale));
+        crop.right -= int(ceil(float(winWidth - winCrop.right) * xScale));
+        crop.bottom -= int(ceil(float(winHeight - winCrop.bottom) * yScale));
+    }
+
+    return crop;
+}
+
 void Layer::setGeometry(hwc_layer_t* hwcl)
 {
     LayerBaseClient::setGeometry(hwcl);
@@ -293,23 +292,11 @@ void Layer::setGeometry(hwc_layer_t* hwcl)
         hwcl->transform = finalTransform;
     }
 
-    if (isCropped()) {
+    Rect crop = computeBufferCrop();
-        hwcl->sourceCrop.left   = mCurrentCrop.left;
+    hwcl->sourceCrop.left   = crop.left;
-        hwcl->sourceCrop.top    = mCurrentCrop.top;
+    hwcl->sourceCrop.top    = crop.top;
-        hwcl->sourceCrop.right  = mCurrentCrop.right;
+    hwcl->sourceCrop.right  = crop.right;
-        hwcl->sourceCrop.bottom = mCurrentCrop.bottom;
+    hwcl->sourceCrop.bottom = crop.bottom;
-    } else {
-        const sp<GraphicBuffer>& buffer(mActiveBuffer);
-        hwcl->sourceCrop.left   = 0;
-        hwcl->sourceCrop.top    = 0;
-        if (buffer != NULL) {
-            hwcl->sourceCrop.right  = buffer->width;
-            hwcl->sourceCrop.bottom = buffer->height;
-        } else {
-            hwcl->sourceCrop.right  = mTransformedBounds.width();
-            hwcl->sourceCrop.bottom = mTransformedBounds.height();
-        }
-    }
 }
 
 void Layer::setPerFrameData(hwc_layer_t* hwcl) {

services/surfaceflinger/Layer.h

@@ -101,6 +101,7 @@ private:
     uint32_t getEffectiveUsage(uint32_t usage) const;
     uint32_t getTransformHint() const;
     bool isCropped() const;
+    Rect computeBufferCrop() const;
     static bool getOpacityForFormat(uint32_t format);
 
     // -----------------------------------------------------------------------

services/surfaceflinger/LayerBase.cpp

@@ -93,6 +93,7 @@ void LayerBase::initStates(uint32_t w, uint32_t h, uint32_t flags)
     mCurrentState.flags         = layerFlags;
     mCurrentState.sequence      = 0;
     mCurrentState.transform.set(0, 0);
+    mCurrentState.crop.makeInvalid();
 
     // drawing state & current state are identical
     mDrawingState = mCurrentState;
@@ -172,6 +173,14 @@ bool LayerBase::setFlags(uint8_t flags, uint8_t mask) {
     requestTransaction();
     return true;
 }
+bool LayerBase::setCrop(const Rect& crop) {
+    if (mCurrentState.crop == crop)
+        return false;
+    mCurrentState.sequence++;
+    mCurrentState.crop = crop;
+    requestTransaction();
+    return true;
+}
 
 Rect LayerBase::visibleBounds() const
 {
@@ -229,15 +238,18 @@ void LayerBase::validateVisibility(const Transform& planeTransform)
     const bool transformed = tr.transformed();
     const DisplayHardware& hw(graphicPlane(0).displayHardware());
     const uint32_t hw_h = hw.getHeight();
+    const Rect& crop(s.crop);
 
-    uint32_t w = s.w;
+    Rect win(s.w, s.h);
-    uint32_t h = s.h;
+    if (!crop.isEmpty()) {
+        win.intersect(crop, &win);
+    }
 
     mNumVertices = 4;
-    tr.transform(mVertices[0], 0, 0);
+    tr.transform(mVertices[0], win.left,  win.top);
-    tr.transform(mVertices[1], 0, h);
+    tr.transform(mVertices[1], win.left,  win.bottom);
-    tr.transform(mVertices[2], w, h);
+    tr.transform(mVertices[2], win.right, win.bottom);
-    tr.transform(mVertices[3], w, 0);
+    tr.transform(mVertices[3], win.right, win.top);
     for (size_t i=0 ; i<4 ; i++)
         mVertices[i][1] = hw_h - mVertices[i][1];
 
@@ -260,7 +272,7 @@ void LayerBase::validateVisibility(const Transform& planeTransform)
     mOrientation = tr.getOrientation();
     mPlaneOrientation = planeTransform.getOrientation();
     mTransform = tr;
-    mTransformedBounds = tr.makeBounds(w, h);
+    mTransformedBounds = tr.transform(win);
 }
 
 void LayerBase::lockPageFlip(bool& recomputeVisibleRegions) {
@@ -391,15 +403,27 @@ void LayerBase::drawWithOpenGL(const Region& clip) const
         GLfloat v;
     };
 
+    Rect crop(s.w, s.h);
+    if (!s.crop.isEmpty()) {
+        crop = s.crop;
+    }
+    GLfloat left = GLfloat(crop.left) / GLfloat(s.w);
+    GLfloat top = GLfloat(crop.top) / GLfloat(s.h);
+    GLfloat right = GLfloat(crop.right) / GLfloat(s.w);
+    GLfloat bottom = GLfloat(crop.bottom) / GLfloat(s.h);
+
     TexCoords texCoords[4];
-    texCoords[0].u = 0;
+    texCoords[0].u = left;
-    texCoords[0].v = 1;
+    texCoords[0].v = top;
-    texCoords[1].u = 0;
+    texCoords[1].u = left;
-    texCoords[1].v = 0;
+    texCoords[1].v = bottom;
-    texCoords[2].u = 1;
+    texCoords[2].u = right;
-    texCoords[2].v = 0;
+    texCoords[2].v = bottom;
-    texCoords[3].u = 1;
+    texCoords[3].u = right;
-    texCoords[3].v = 1;
+    texCoords[3].v = top;
+    for (int i = 0; i < 4; i++) {
+        texCoords[i].v = 1.0f - texCoords[i].v;
+    }
 
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glVertexPointer(2, GL_FLOAT, 0, mVertices);

services/surfaceflinger/LayerBase.h

@@ -78,6 +78,7 @@ public:
                 uint32_t        tint;
                 Transform       transform;
                 Region          transparentRegion;
+                Rect            crop;
             };
 
     virtual void setName(const String8& name);
@@ -91,6 +92,7 @@ public:
             bool setMatrix(const layer_state_t::matrix22_t& matrix);
             bool setTransparentRegionHint(const Region& opaque);
             bool setFlags(uint8_t flags, uint8_t mask);
+            bool setCrop(const Rect& crop);
             
             void commitTransaction();
             bool requestTransaction();

services/surfaceflinger/SurfaceFlinger.cpp

@@ -1352,6 +1352,10 @@ uint32_t SurfaceFlinger::setClientStateLocked(
             if (layer->setFlags(s.flags, s.mask))
                 flags |= eTraversalNeeded;
         }
+        if (what & eCropChanged) {
+            if (layer->setCrop(s.crop))
+                flags |= eTraversalNeeded;
+        }
     }
     return flags;
 }