Depending on the configuration, tries different compressions (lossy/lossless), dispose methods, blending methods etc to encode the current frame and o

Shift each byte of "x" by 3 bits while preserving by the sign bit.

Smoothen the luma components of transparent pixels. Return true if the whole block is transparent.

Horizontal sum of all four uint32_t values in 'sum'.

Update the cost at index i by going over all the stored intervals that overlap with i.

Given the distance_cost for pixel 'index', update the cost for all the pixels between 'start' and 'end' excluded.

Return the sum of all the 8b in the register.

Returns 1 on success.

Checking for the presence of non-opaque alpha.

helper function to cast away const */

4 pixels in, 2 pixels out

clean up the temporary component buffers

combined JPEG 'receive' and JPEG 'extend', since baseline always extends everything it receives.

returns 0..31 for the highest set bit

mallocs with size overflow checking