Update view's alpha and layer docs
bug:8501661
Makes the performance issues and interaction with layer type/paint
more clear.
Additionally, corrects change from 47ab7d6612e2b5b8b66fb261dafef7c91264e173
to still allow displayList alpha to override layer paint
Change-Id: Ic94d75865700820489370461cd8ac9f9077a8d90
diff --git a/libs/hwui/DisplayList.cpp b/libs/hwui/DisplayList.cpp
index d985ad0..36c95f9 100644
--- a/libs/hwui/DisplayList.cpp
+++ b/libs/hwui/DisplayList.cpp
@@ -352,7 +352,9 @@
}
}
if (mAlpha < 1) {
- if (mCaching || !mHasOverlappingRendering) {
+ if (mCaching) {
+ ALOGD("%*sSetOverrideLayerAlpha %.2f", level * 2, "", mAlpha);
+ } else if (!mHasOverlappingRendering) {
ALOGD("%*sScaleAlpha %.2f", level * 2, "", mAlpha);
} else {
int flags = SkCanvas::kHasAlphaLayer_SaveFlag;
@@ -400,7 +402,9 @@
}
}
if (mAlpha < 1) {
- if (mCaching || !mHasOverlappingRendering) {
+ if (mCaching) {
+ renderer.setOverrideLayerAlpha(mAlpha);
+ } else if (!mHasOverlappingRendering) {
renderer.scaleAlpha(mAlpha);
} else {
// TODO: should be able to store the size of a DL at record time and not
@@ -513,6 +517,7 @@
DISPLAY_LIST_LOGD("%*sRestoreToCount %d", (level + 1) * 2, "", restoreTo);
handler(mRestoreToCountOp->reinit(restoreTo), PROPERTY_SAVECOUNT);
renderer.restoreToCount(restoreTo);
+ renderer.setOverrideLayerAlpha(1.0f);
}
}; // namespace uirenderer
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 4a5785c..1138998 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -114,6 +114,7 @@
mCaches(Caches::getInstance()), mExtensions(Extensions::getInstance()) {
mDrawModifiers.mShader = NULL;
mDrawModifiers.mColorFilter = NULL;
+ mDrawModifiers.mOverrideLayerAlpha = 1.0f;
mDrawModifiers.mHasShadow = false;
mDrawModifiers.mHasDrawFilter = false;
@@ -1074,7 +1075,7 @@
layer->setFilter(GL_LINEAR, true);
}
- float alpha = layer->getAlpha() / 255.0f * mSnapshot->alpha;
+ float alpha = getLayerAlpha(layer);
bool blend = layer->isBlend() || alpha < 1.0f;
drawTextureMesh(x, y, x + rect.getWidth(), y + rect.getHeight(),
layer->getTexture(), alpha, layer->getMode(), blend,
@@ -1112,7 +1113,7 @@
rects = safeRegion.getArray(&count);
}
- const float alpha = layer->getAlpha() / 255.0f * mSnapshot->alpha;
+ const float alpha = getLayerAlpha(layer);
const float texX = 1.0f / float(layer->getWidth());
const float texY = 1.0f / float(layer->getHeight());
const float height = rect.getHeight();
@@ -2237,7 +2238,7 @@
float left, float top, float right, float bottom, SkPaint* paint) {
int alpha;
SkXfermode::Mode mode;
- getAlphaAndModeDirect(paint, &alpha, &mode);
+ getAlphaAndMode(paint, &alpha, &mode);
return drawPatch(bitmap, xDivs, yDivs, colors, width, height, numColors,
left, top, right, bottom, alpha, mode);
@@ -2990,7 +2991,7 @@
if (layer->region.isRect()) {
composeLayerRect(layer, layer->regionRect);
} else if (layer->mesh) {
- const float a = layer->getAlpha() / 255.0f * mSnapshot->alpha;
+ const float a = getLayerAlpha(layer);
setupDraw();
setupDrawWithTexture();
setupDrawColor(a, a, a, a);
@@ -3446,10 +3447,24 @@
TextureVertex::setUV(v++, u2, v2);
}
-void OpenGLRenderer::getAlphaAndMode(SkPaint* paint, int* alpha, SkXfermode::Mode* mode) {
+void OpenGLRenderer::getAlphaAndMode(SkPaint* paint, int* alpha, SkXfermode::Mode* mode) const {
getAlphaAndModeDirect(paint, alpha, mode);
+ if (mDrawModifiers.mOverrideLayerAlpha < 1.0f) {
+ // if drawing a layer, ignore the paint's alpha
+ *alpha = mDrawModifiers.mOverrideLayerAlpha;
+ }
*alpha *= mSnapshot->alpha;
}
+float OpenGLRenderer::getLayerAlpha(Layer* layer) const {
+ float alpha;
+ if (mDrawModifiers.mOverrideLayerAlpha < 1.0f) {
+ alpha = mDrawModifiers.mOverrideLayerAlpha;
+ } else {
+ alpha = layer->getAlpha() / 255.0f;
+ }
+ return alpha * mSnapshot->alpha;
+}
+
}; // namespace uirenderer
}; // namespace android
diff --git a/libs/hwui/OpenGLRenderer.h b/libs/hwui/OpenGLRenderer.h
index 04a47fc..dd7a5a2 100644
--- a/libs/hwui/OpenGLRenderer.h
+++ b/libs/hwui/OpenGLRenderer.h
@@ -51,6 +51,7 @@
struct DrawModifiers {
SkiaShader* mShader;
SkiaColorFilter* mColorFilter;
+ float mOverrideLayerAlpha;
// Drop shadow
bool mHasShadow;
@@ -275,6 +276,9 @@
virtual void resetPaintFilter();
virtual void setupPaintFilter(int clearBits, int setBits);
+ // If this value is set to < 1.0, it overrides alpha set on layer (see drawBitmap, drawLayer)
+ void setOverrideLayerAlpha(float alpha) { mDrawModifiers.mOverrideLayerAlpha = alpha; }
+
SkPaint* filterPaint(SkPaint* paint);
bool storeDisplayState(DeferredDisplayState& state, int stateDeferFlags);
@@ -283,7 +287,6 @@
const DrawModifiers& getDrawModifiers() { return mDrawModifiers; }
void setDrawModifiers(const DrawModifiers& drawModifiers) { mDrawModifiers = drawModifiers; }
- // TODO: what does this mean? no perspective? no rotate?
ANDROID_API bool isCurrentTransformSimple() {
return mSnapshot->transform->isSimple();
}
@@ -325,7 +328,8 @@
/**
* Gets the alpha and xfermode out of a paint object. If the paint is null
* alpha will be 255 and the xfermode will be SRC_OVER. This method does
- * not multiply the paint's alpha by the current snapshot's alpha.
+ * not multiply the paint's alpha by the current snapshot's alpha, and does
+ * not replace the alpha with the overrideLayerAlpha
*
* @param paint The paint to extract values from
* @param alpha Where to store the resulting alpha
@@ -450,13 +454,21 @@
/**
* Gets the alpha and xfermode out of a paint object. If the paint is null
- * alpha will be 255 and the xfermode will be SRC_OVER.
+ * alpha will be 255 and the xfermode will be SRC_OVER. Accounts for both
+ * snapshot alpha, and overrideLayerAlpha
*
* @param paint The paint to extract values from
* @param alpha Where to store the resulting alpha
* @param mode Where to store the resulting xfermode
*/
- inline void getAlphaAndMode(SkPaint* paint, int* alpha, SkXfermode::Mode* mode);
+ inline void getAlphaAndMode(SkPaint* paint, int* alpha, SkXfermode::Mode* mode) const;
+
+ /**
+ * Gets the alpha from a layer, accounting for snapshot alpha and overrideLayerAlpha
+ *
+ * @param layer The layer from which the alpha is extracted
+ */
+ inline float getLayerAlpha(Layer* layer) const;
/**
* Safely retrieves the mode from the specified xfermode. If the specified