SetLegendBgColor — Set legend background color
$plot->SetLegendBgColor($color
)
If SetLegendBgColor
is not used, the legend background
color will be the same as the image background color.
The image background color is set with SetBackgroundColor,
and defaults to white.
If you position the legend outside the plot area, this function is useful to make it stand out more, by using a color that differs from image background color. Similarly, if your legend is positioned inside the plot area, but you have not changed the plot area background, you can use this function to make the legend stand out with a different background color.