Animated GIF

ImageGear provides the ability to...

Read still and animated GIFs with a single function call.
Access all data contained within a GIF, including comments, local palettes, and animation sequencing information.
Create any type of GIF, including non-interlaced, interlaced, single image, multi image, animated, etc.
Write fully customized GIFs with comments, animation sequencing, and custom palettes.

An animated GIF file contains a series of input images and instructions on how to combine the images to form a series of output images. The IG_mult_...() functions provide access to the final output frames from this process. Each frame will have the same dimensions and bit depth. The bit depth can be 1, 4, or 8bpp. Palettes and durations of frames may vary. Animated GIF files do not contain audio data.

To access animated GIF files, you must have the LZW component attached.

There are currently two parameters specific to animated GIF that can be set using IG_mult_info_set():

IG_MULT_INFO_GIF_MIN_DELAY - default = 100ms
IG_MULT_INFO_GIF_MIN_DELAY_THRESHOLD - default = 10ms

These parameters exist because some animated GIF files have frames whose delays are specified as 0. Also, some frames have delays specified as 10ms or more when they are meant to be displayed for much longer. The default behavior of ImageGear is to enforce a minimum delay of 100ms for frames having delays specified as 10ms or less. This only affects the frame durations retrieved from IG_mult_current_frame_duration_get() and IG_mult_frame_duration_get().