surfaceflinger: documents RenderArea
Bug: 113041375
Test: builds
Change-Id: I7cf73b862aac38a782c4d0b154ed2357e1ef8dfe
diff --git a/services/surfaceflinger/RenderArea.h b/services/surfaceflinger/RenderArea.h
index e38f462..9920f0a 100644
--- a/services/surfaceflinger/RenderArea.h
+++ b/services/surfaceflinger/RenderArea.h
@@ -8,8 +8,13 @@
namespace android {
+// RenderArea describes a rectangular area that layers can be rendered to.
+//
+// There is a logical render area and a physical render area. When a layer is
+// rendered to the render area, it is first transformed and clipped to the logical
+// render area. The transformed and clipped layer is then projected onto the
+// physical render area.
class RenderArea {
-
public:
enum class CaptureFill {CLEAR, OPAQUE};
@@ -20,23 +25,51 @@
virtual ~RenderArea() = default;
- virtual const ui::Transform& getTransform() const = 0;
- virtual Rect getBounds() const = 0;
- virtual int getHeight() const = 0;
- virtual int getWidth() const = 0;
- virtual bool isSecure() const = 0;
- virtual bool needsFiltering() const = 0;
- virtual Rect getSourceCrop() const = 0;
-
+ // Invoke drawLayers to render layers into the render area.
virtual void render(std::function<void()> drawLayers) { drawLayers(); }
- int getReqHeight() const { return mReqHeight; };
- int getReqWidth() const { return mReqWidth; };
- ui::Transform::orientation_flags getRotationFlags() const { return mRotationFlags; };
- status_t updateDimensions(int displayRotation);
+ // Returns true if the render area is secure. A secure layer should be
+ // blacked out / skipped when rendered to an insecure render area.
+ virtual bool isSecure() const = 0;
+ // Returns true if the otherwise disabled layer filtering should be
+ // enabled when rendering to this render area.
+ virtual bool needsFiltering() const = 0;
+
+ // Returns the transform to be applied on layers to transform them into
+ // the logical render area.
+ virtual const ui::Transform& getTransform() const = 0;
+
+ // Returns the size of the logical render area. Layers are clipped to the
+ // logical render area.
+ virtual int getWidth() const = 0;
+ virtual int getHeight() const = 0;
+ virtual Rect getBounds() const = 0;
+
+ // Returns the source crop of the render area. The source crop defines
+ // how layers are projected from the logical render area onto the physical
+ // render area. It can be larger than the logical render area. It can
+ // also be optionally rotated.
+ //
+ // Layers are first clipped to the source crop (in addition to being
+ // clipped to the logical render area already). The source crop and the
+ // layers are then rotated around the center of the source crop, and
+ // scaled to the physical render area linearly.
+ virtual Rect getSourceCrop() const = 0;
+
+ // Returns the rotation of the source crop and the layers.
+ ui::Transform::orientation_flags getRotationFlags() const { return mRotationFlags; };
+
+ // Returns the size of the physical render area.
+ int getReqWidth() const { return mReqWidth; };
+ int getReqHeight() const { return mReqHeight; };
+
+ // Returns the fill color of the physical render area. Regions not
+ // covered by any rendered layer should be filled with this color.
CaptureFill getCaptureFill() const { return mCaptureFill; };
+ status_t updateDimensions(int displayRotation);
+
private:
uint32_t mReqHeight;
uint32_t mReqWidth;