GIF (Graphics Interchange Format)is a widely supported format for raster graphics, defined by Compuserve, Inc. All web browsers and most image-display programs can be used to display GIF files. PGPLOT uses the GIF87a variant, with up to 8 bits per pixel (256 colors).
The GIF specification incorporates the Lempel-Zev-Welch (LZW) compression algorithm which is the subject of a patent awarded to Unisys. Use of this technology, and in particular creation of GIF format files using this PGPLOT device driver, may require a license from Unisys.
/GIF
(landscape orientation),
/VGIF
(portrait orientation).
pgplot.gif
PGOPEN file name: File names used: pgplot#.gif pgplot1.gif, pgplot2.gif, pgplot3.gif, ... pgplot.gif pgplot.gif, pgplot.gif_2, pgplot.gif_3, ...If the supplied file name is ``-'', the output is sent to the standard output stream, so that it can, for example, be piped into a viewing program. This will only work for single-page plots.
PGPLOT_GIF_WIDTH
: width of image in pixels (default 850)PGPLOT_GIF_HEIGHT
: height of image in pixels (default 680)
The GIF87a images produced by PGPLOT do not have a way of specifying a transparent background. You can mark the background as transparent if you convert the file to GIF89a format using giftrans and specify that color index 0 should be transparent.
To use giftrans, just type
giftrans -t index GIF87a-file > GIF89a-file
This converts the GIF87a-file to a GIF89a-file, with the
index entry in the colormap made transparent. Invoke giftrans
with the -?
option to see a complete usage description.