surfaceflinger: documents RenderArea

namespace android {

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 {

class RenderArea {

public:

public:

    enum class CaptureFill {CLEAR, OPAQUE};

    enum class CaptureFill {CLEAR, OPAQUE};

    virtual ~RenderArea() = default;

    virtual ~RenderArea() = default;

    virtual const Transform& getTransform() const = 0;

    // Invoke drawLayers to render layers into the render area.

    virtual Rect getBounds() const = 0;

    virtual void render(std::function<void()> drawLayers) { drawLayers(); }

    virtual int getHeight() const = 0;

    virtual int getWidth() const = 0;

    // 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;

    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;

    virtual bool needsFiltering() const = 0;

    // Returns the transform to be applied on layers to transform them into

    // the logical render area.

    virtual const 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;

    virtual Rect getSourceCrop() const = 0;

    virtual void render(std::function<void()> drawLayers) { drawLayers(); }

    // Returns the rotation of the source crop and the layers.

    Transform::orientation_flags getRotationFlags() const { return mRotationFlags; };

    int getReqHeight() const { return mReqHeight; };

    // Returns the size of the physical render area.

    int getReqWidth() const { return mReqWidth; };

    int getReqWidth() const { return mReqWidth; };

    Transform::orientation_flags getRotationFlags() const { return mRotationFlags; };

    int getReqHeight() const { return mReqHeight; };

    status_t updateDimensions(int displayRotation);

    // 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; };

    CaptureFill getCaptureFill() const { return mCaptureFill; };

    status_t updateDimensions(int displayRotation);

private:

private:

    uint32_t mReqHeight;

    uint32_t mReqHeight;

    uint32_t mReqWidth;

    uint32_t mReqWidth;