This is used to create image masks that can be used to mask out
`compose` regions. For example, this can be used to mask out window body
so shadow won't be painted on them.
This could be more efficient than using rectangular regions for masking,
when there are a large number of rectangles; or more flexible, in the
case of window with rounded corners.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Currently there is some inconsistency in how image_op is implemented
across backends. The glx backend applies some of the image operations
lazily, and not always in the order the operations were made; while the
xrender backend applies the operations eagerly. This can lead to
different render result in some cases.
Instead of trying to preserving the order of operations, which would be
unnecessary, we re-model the API to better reflect the implementation.
We make it clear that setting the property doesn't change the image
data, and properties are only applied during composition and in a
specific order.
This makes sure the render result looks consistent across backends.
Should also improve the performance of the xrender backend, even if only
slightly.
Also distill out the property management code so they can be shared.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Yuxuan Shui