1.165.1 Instance variables

sdl_canvas <- size: size

Size of the canvas in pixels.

sdl_canvas <- layers: chain

The sdl_layer objects, the first drawn at the bottom.

sdl_canvas <- background: colour*

Colour drawn below the layers. With @nil (default), the canvas is transparent where no layer is drawn.

sdl_canvas <- clear: bool

If @on (default), the canvas is cleared to transparent before the layers are drawn. If @off, the pixels of the previous drawing are kept and the layers are drawn on top of them, e.g., for trails. Use sdl_canvas->render to draw again, and a translucent layer in sdl_canvas<-background colour to make old pixels fade.