/**
* Ensures that the canvas image is at least the specified dimensions and cleared to all
* transparent pixels. Also creates and adds the image layer to the parent layer if needed.
*/
public void prepare(IDimension dim) {
prepare(dim.width(), dim.height());
}
/** Creates the sizable widget with the given preferred size. */
public SizableWidget(IDimension size) {
this(size.width(), size.height());
}