SetPlotAreaBgImage — Set a graphic file to be used in the plot area background
$plot->SetPlotAreaBgImage($input_file
, [$mode
])
SetPlotAreaBgImage
sets an image file to be used as
the plot area background. The image can be scaled or tiled to fit.
$input_file
Path to the file to be used. The file can be any type allowed by GD, which usually includes JPEG, GIF, and PNG.
$mode
Optional display mode for the background image: one of the strings 'centeredtile', 'tile', or 'scale'. The default is 'tile'.
If a background image has been set, background color (set with SetPlotBgColor) is ignored.
SetPlotAreaBgImage sets a background for the plot area, while SetBgImage sets a background for the entire image area. If both are used, the plot area background overlays that portion of the overall background.