From 921a3138b7b3177eae3fa4942961f54077b5bc10 Mon Sep 17 00:00:00 2001 From: Mason Freed Date: Thu, 25 Jul 2019 09:45:22 -0700 Subject: [PATCH] Fix the filtering description to get opacity right With the previous description, opacity was implicitly included in the final set of filters applied to all content. But that's incorrect, at least according to expectation and behavior. Opacity is special here - it needs to be separately applied to the filtered backdrop, because if it is applied only at the end, the fully-opaque contents of B will have already painted over the filtered backdrop. There won't be any show-through of the backdrop, even though the expectation is to see it, given that opacity is less than 1. While that change is being made, I've also copied the other effects and clips to the backdrop-filtered image as well. These could possibly be defined to only apply once at the end, but the resulting image will be identical or nearly-so, and in practice, the implementation is typically closer to this new definition. --- filter-effects-2/Overview.bs | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/filter-effects-2/Overview.bs b/filter-effects-2/Overview.bs index 3c3c55e7..bdc14bd8 100644 --- a/filter-effects-2/Overview.bs +++ b/filter-effects-2/Overview.bs @@ -60,11 +60,12 @@ An element (call it B) with a backdrop-filter property other than ''backdrop-fil the following steps are performed: 1. Copy the Backdrop Root Image into a temporary buffer, such as a raster image. Call this buffer T’. 2. Apply the backdrop-filter’s filter operations to the entire contents of T'. -3. If element B has any transforms (between B and the Backdrop Root), apply the inverse of those transforms to the contents of T’. -4. Apply a clip to the contents of T’, using the border box of element B, including border-radius if specified. Note that the children of B are not considered for the sizing or location of this clip. -5. Draw all of element B, including its background, border, and any children elements, into T’. -6. If element B has any transforms, effects, or clips, apply those to T’. -7. Composite the contents of T’ into element B's parent, using source-over compositing. +3. If element B has any effects, opacity, or clips, apply those to T’. +4. Apply a clip to the contents of T’, using the transformed border box of element B, including border-radius if specified. Note that the children of B are not considered for the sizing or location of this clip. +5. Composite the contents of T’ into element B's parent, using source-over compositing. +6. Draw all of element B, including its background, border, and any children elements, into another temporary buffer B'. +7. If element B has any transforms, effects, opacity, or clips, apply those to B’. +8. Composite the contents of B’ into element B's parent, using source-over compositing. 
   spec:filter-effects-1; type:element; text:filter