I am working with aniamted webp. I am referring google's documentation called WebP Container Specification
The doc says the following things about blending and disposal methods Blending Method:
Blending method (B): 1 bit Indicates how transparent pixels of the current frame are to be blended with corresponding pixels of the previous canvas:
0: Use alpha blending. After disposing of the previous frame, render the current frame on the canvas using alpha-blending (see below). If the current frame does not have an alpha channel, assume alpha value of 255, effectively replacing the rectangle.
1: Do not blend. After disposing of the previous frame, render the current frame on the canvas by overwriting the rectangle covered by the current frame.
And Here is about disposal method:
Disposal method (D): 1 bit Indicates how the current frame is to be treated after it has been displayed (before rendering the next frame) on the canvas:
0: Do not dispose. Leave the canvas as is.
1: Dispose to background color. Fill the rectangle on the canvas covered by the current frame with background color specified in the ANIM chunk.
My doubt is specifically about blending method."After disposing of previous frame..." and this statement is for both value of blending flag of current frame. let it be either 0 or 1, it says " after disposal of previouse frame" which means the previous frame must be disposed of. But the dispose flag of previous frame would contradict if it has value 1 for the disposal flag which means the previouse frame must be left as it is current frame would be drawn over it.
What is the meaning of "after disposing of previous frame..." statement?
