set pixmap <index> "filename" at <position>
{width <w> | height <h> | size <w>,<h>}
{front|back|behind} {center}
show pixmaps
unset pixmaps
unset pixmap <index>
The set pixmap command is similar to set object in that it defines an
object that will appear on subsequent plots. The rectangular array of
red/green/blue/alpha values making up the pixmap are read from a png, jpeg,
or gif file. The position and extent occupied by the pixmap in the gnuplot
output may be specified in any coordinate system (see coordinates (p.
)).
The coordinates given by at 4#4position5#5 refer to the lower left
corner of the pixmap unless keyword center is present.
If the x-extent of the rendered pixmap is set using width 4#4x-extent5#5 the aspect ratio of the original image is retained and neither the aspect ratio nor the orientation of the pixmap changes with axis scaling or rotation. Similarly if the y-extent is set using height 4#4y-extent5#5. If both the x-extent and y-extent are given using size 4#4x-extent5#5 4#4y-extent5#5 this overrides the original aspect ratio. If no size is set then the original size in pixels is used (the effective size is then terminal-dependent).
Pixmaps are not clipped to the border of the plot. As an exception to the general behaviour of objects and layers, a pixmap assigned to layer behind is rendered for only the first plot in a multiplot. This allows all panels in a multiplot to share a single background pixmap.
Examples:
# Use a gradient as the background for all plotting
# Both x and y will be resized to fill the entire canvas
set pixmap 1 "gradient.png"
set pixmap 1 at screen 0, 0 size screen 1, 1 behind
# Place a logo at the lower right of each page plotted
set pixmap 2 "logo.jpg"
set pixmap 2 at screen 0.95, 0 width screen 0.05 behind
# Place a small image at some 3D coordinate
# It will move as if attached to the surface being plotted
# but will always face forward and remain upright
set pixmap 3 "image.png" at my_x, my_y, f(my_x,my_y) width screen .05
splot f(x,y)