Animation and Animated GIF's

Animation

relevant parameters in the ini file

• show_animation_window: controls whether or not to show the animation controls (if false, animation is not possible)

• ani_hit_latetime: determines when to start showing a hit w.r.t. the hit-time (ns)

• ani_hit_latetime: determines when to stop showing a hit w.r.t. the hit-time (ns)

• ani_start_time: the time to start the animation (ns)
• ani_stop_time: the time to stop the animation (ns)
• ani_timestep : time-step between two displayed images (ns)
• ani_max_sphere_size: in animation mode spheres are expanding with time, this is their max. size.

Animated GIF production

A3D is able to produce a so-called animated GIF file of an event. Animated GIF's are widely used on the world wide web to do simple animations. The GIF file will contain a 'movie' identical to an 'ordinary' A3D animation. Therefore A3D's animation mode can be used to tune the parameters (eg. start/stop times of the animation and the view-point) before a .GIF file is produced. The only difference between the animated GIF and A3D's animation will be the speed.

A3D produces animated GIFs in three stages.

• An 'ordinary' animation is started, but at each time step a screen-dump of the main graphics-window is made. This is saved as a .ppm (portable pixmap)file.
• All the .ppm files that where produced are converted to .gif files using the ppmtogif utility. This program is available on most unix-like systems.
• Finally the GIF's must be combined to form a single animation. A3D calls a third party program for this: gifsicle. This program is free and available from http://www.pdos.lcs.mit.edu/~eddietwo/gifsicle/. After gifsicle was called, all the temporary files will be cleaned up.

Concluding: For making animated GIF files, the programs ppmtogif and gifsicle must be in the path and enough disk space must be available for all the temporary ppm and gif files.

relevant parameters in the ini file

• anigif_minimize: if true gifsicle is called with an optimisation option that produces a smaller file.
• anigif_delay: delay between two frames (in 1/100 of a second) that should go into the .gif file.