SF: Switch computeBounds to return FloatRect
Switches Layer::computeBounds to return a FloatRect instead of a Rect.
During the computation of the bounds, we apply the layer transformation
to its nominal dimensions, clip it against its bounds (which are either
its parents bounds or the screen bounds), and apply the inverse of the
layer transformation.
Previously, the intermediate position (after transformation/clip, but
before inverse transformation) was stored as Rect, which is to say that
it was truncated to integer coordinates. After applying the inverse
transformation, this loss of precision can cause glitches where a layer
that should be clipped against, e.g., the side of the screen no longer
creates a watertight seal against that side.
In order to fix this, we now store the intermediate value as a FloatRect
and propagate float precision back through computeBounds. The callers of
computeBounds tend to then immediately apply the transform again, at
which point it is safe to round back to integer.
Bug: 64070729
Bug: 66431327
Bug: 69935057
Test: Modified android.view.cts.SurfaceViewSyncTest#
testSurfaceViewBigScale no longer produces bogus display frames
Change-Id: If5987ca4ad76657f9670a5f59258f896180352e2
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 13df1e2..a5d0c3a 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -285,6 +285,14 @@
return Region(win).subtract(exclude).getBounds();
}
+static FloatRect reduce(const FloatRect& win, const Region& exclude) {
+ if (CC_LIKELY(exclude.isEmpty())) {
+ return win;
+ }
+ // Convert through Rect (by rounding) for lack of FloatRegion
+ return Region(Rect{win}).subtract(exclude).getBounds().toFloatRect();
+}
+
Rect Layer::computeScreenBounds(bool reduceTransparentRegion) const {
const Layer::State& s(getDrawingState());
Rect win(s.active.w, s.active.h);
@@ -323,12 +331,12 @@
return win;
}
-Rect Layer::computeBounds() const {
+FloatRect Layer::computeBounds() const {
const Layer::State& s(getDrawingState());
return computeBounds(s.activeTransparentRegion);
}
-Rect Layer::computeBounds(const Region& activeTransparentRegion) const {
+FloatRect Layer::computeBounds(const Region& activeTransparentRegion) const {
const Layer::State& s(getDrawingState());
Rect win(s.active.w, s.active.h);
@@ -345,14 +353,16 @@
}
Transform t = getTransform();
+
+ FloatRect floatWin = win.toFloatRect();
if (p != nullptr) {
- win = t.transform(win);
- win.intersect(bounds, &win);
- win = t.inverse().transform(win);
+ floatWin = t.transform(floatWin);
+ floatWin = floatWin.intersect(bounds.toFloatRect());
+ floatWin = t.inverse().transform(floatWin);
}
// subtract the transparent region and snap to the bounds
- return reduce(win, activeTransparentRegion);
+ return reduce(floatWin, activeTransparentRegion);
}
Rect Layer::computeInitialCrop(const sp<const DisplayDevice>& hw) const {
@@ -528,7 +538,9 @@
Rect(activeCrop.right, activeCrop.top, s.active.w, activeCrop.bottom));
}
- Rect frame(t.transform(computeBounds(activeTransparentRegion)));
+ // computeBounds returns a FloatRect to provide more accuracy during the
+ // transformation. We then round upon constructing 'frame'.
+ Rect frame{t.transform(computeBounds(activeTransparentRegion))};
if (!s.finalCrop.isEmpty()) {
if (!frame.intersect(s.finalCrop, &frame)) {
frame.clear();
@@ -807,7 +819,7 @@
const Layer::State& s(getDrawingState());
const Transform renderAreaTransform(renderArea.getTransform());
const uint32_t height = renderArea.getHeight();
- Rect win = computeBounds();
+ FloatRect win = computeBounds();
vec2 lt = vec2(win.left, win.top);
vec2 lb = vec2(win.left, win.bottom);