Re: Animations with image size matching output resolution

[Daniel J S. <dan...@ie...>]

Daniel J Sebald wrote:
> The size is still large compared to what 
> gifsicle creates.

I see what the issue is.  Although at the start of the animation file the GlobalCM is set so that the animation can reuse the same color map over and over, the gdImageGifAnimAdd routine indicates that the particular image in question should use it's own color map.

	gdImageGifAnimAdd(png_state.image, gpoutfile, 
		1 /* 0 = global 1 = local colormap */,
		0, 0 /* No offset */,
		png_state.frame_delay,
		gdDisposalNone, 
		png_state.frame_optimization ? png_state.previous_image : NULL);
	
Hence, GlobalCM is effectively turned off here.

I've recompiled after setting the above parameter to zero.  The file size is then on the order of that produced by gifsicle FROM THE FIRST ATTEMPT:

-rw-r--r--  1 sebald users   9818 Dec 30 16:05 test.gif
-rw-r--r--  1 sebald users   8691 Dec 30 15:43 test10.gif

HOWEVER, running that file through gifsicle creates a super-condensed file:

-rw-r--r--  1 sebald users    955 Dec 30 16:05 test11.gif

one which in gthumb has a very, very reduced dynamic range (basically black and one level above black).

So, something is not right here.  It's as if the global color map used to initiate the file is incorrect and setting the parameter from 1 to 0 forces all subsequent images to use that color map.  gifsicle thinks it can really compress such a series.

Dan