SetShading — Set the size of the drop shadow for bar and pie charts.
$plot->SetShading($s)
SetShading sets the size in pixels of the drop shadow
used to give bar and pie charts a 3-D look. The 3-D look can be disabled by
setting the shading to zero.
$sDesired shading size in pixels. If this is set to 0, pie charts are flat (not rotated away from the screen) with no shadow, and bars in bar charts and stackedbar charts are drawn as rectangles without drop shadows.
The default is shading enabled with a size of 5 pixels.
If shading is turned off for bar and stackedbar charts, the bars will be drawn with borders. The color of the borders is set with SetDataBorderColors.