You can set a GC's paint type with the XSolarisOvlSetPaintType routine. XSolarisOvlSetPaintType specifies the type of paint rendered by subsequent Xlib drawing with the given GC. It controls whether Xlib drawing routines using this GC produce opaque or transparent pixels on overlay windows. The paint type specified applies to the GC until it is changed by another call to this routine. The paint type attribute applies to both the foreground and background GC attributes. The syntax and arguments are shown below.
void XSolarisOvlSetPaintType (Display *display, GC gc, XSolarisOvlPaintType paintType)
The value of paintType can be XSolarisOvlPaintOpaque or XSolarisOvlPaintTransparent.
If the value of paintType is XSolarisOvlPaintOpaque, the pixels generated by subsequent Xlib drawing routines with this GC will be opaque. This means the pixels will obscure underlying pixels. This is the default.
If the value of paintType is XSolarisOvlPaintTransparent, the pixels generated by subsequent Xlib drawing routines with this GC will be transparent. This means that, for these pixels, the color of the underlying pixels is displayed.