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Commit 74861ad4 authored by Peiyong Lin's avatar Peiyong Lin
Browse files

[SurfaceFlinger] Update comments to clarify transform. 

Clarify the source coordinate space and destination coordinate space for
transforms.

Bug: N/A
Test: N/A
Change-Id: I93f6770f8a1f03f81e30e42a80c3196ccb1b0fee
parent d72053c6

services/surfaceflinger/Layer.cpp

+3 −2
Original line number Diff line number Diff line
@@ -2453,6 +2453,7 @@ InputWindowInfo Layer::fillInputInfo() { 
        ySurfaceInset = std::round(ySurfaceInset * yScale);

    }



    // Transform the layer bounds from layer coordinate space to display coordinate space.

    Rect transformedLayerBounds = t.transform(layerBounds);



    // clamp inset to layer bounds
@@ -2477,7 +2478,7 @@ InputWindowInfo Layer::fillInputInfo() { 
        transformedLayerBounds.bottom = tmp;

    }



    // Input coordinate should match the layer bounds.

    // Input coordinates should be in display coordinate space.

    info.frameLeft = transformedLayerBounds.left;

    info.frameTop = transformedLayerBounds.top;

    info.frameRight = transformedLayerBounds.right;
@@ -2490,7 +2491,7 @@ InputWindowInfo Layer::fillInputInfo() { 
    // the final frame calculated.

    // 1. Take the original transform set on the window and get the inverse transform. This is

    //    used to get the final bounds in display space (ignorning the transform). Apply the

    //    inverse transform on the layerBounds to get the untransformed frame (in display space)

    //    inverse transform on the layerBounds to get the untransformed frame (in layer space)

    // 2. Take the top and left of the untransformed frame to get the real position on screen.

    //    Apply the layer transform on top/left so it includes any scale or rotation. These will

    //    be the new translation values for the transform.

services/surfaceflinger/Layer.h

+2 −1
Original line number Diff line number Diff line
@@ -1076,7 +1076,8 @@ private: 
    sp<Layer> getRootLayer();



    // Cached properties computed from drawing state

    // Effective transform taking into account parent transforms and any parent scaling.

    // Effective transform taking into account parent transforms and any parent scaling, which is

    // a transform from the current layer coordinate space to display(screen) coordinate space.

    ui::Transform mEffectiveTransform;



    // Bounds of the layer before any transformation is applied and before it has been cropped