Gets the bounds of the canvas, in canvas units.
By default, canvas units are pixels, though the units property can be used to change the units to points, inches or millimeters.
| this |
a Canvas. |
| left |
a pointer to a double to return the left edge, or null. |
| top |
a pointer to a double to return the top edge, or null. |
| right |
a pointer to a double to return the right edge, or null. |
| bottom |
a pointer to a double to return the bottom edge, or null. |