18
edits
Changes
m
One editorial change from pnglist I missed
The "canvas" is the area on the output device on which the frames are to be displayed. The contents of the canvas are not necessarily available to the decoder. As per the PNG Specification, if a `bKGD` chunk exists it may be used to fill the canvas if there is no preferrable background.
The "output buffer" is a pixel array with dimensions specified by the width and height parameters of the PNG `IHDR` chunk. Conceptually, each frame is constructed in the output buffer before being composited onto the canvas. The contents of the output buffer are available to the decoder. The corner pixels corners of the output buffer are mapped to the corners of the canvas.
"Fully transparent black" means red, green, blue and alpha components are all set to zero.
