Using the Toolbar Eraser
Clicking the Eraser button with the mouse or pen will erase the current canvas layer to a selectable ‘erase to’ fill to option. If you mouse down on the Eraser button and then wait a few seconds a popup menu will appear below the eraser button that lets you select one of the different ‘erase to’ options.
For example, you can choose to erase to fixed colored background like white, black or the current source color. You can also choose to erase to the source image, the current region selection, the source alpha channel, a live video capture from your computer’s built in iSight camera, etc.
Whenever you choose a new ‘erase to’ option, the canvas is erased to the option you selected. After that, just pressing the Eraser button will erase to the option you previously selected.
Using the Canvas Erase menus
ll of the canvas erase functionality available in the Eraser button in the main operation toolbar is also available via menu commands in the main Canvas menu.
Selecting the Canvas : Erase menu command erases to your current ‘erase to’ option. Using this menu is equivalent to pressing the Eraser button in the main operation toolbar.
Running any of the Canvas : Erase to menu commands lets you change your ‘erase to’ option and will also erase to whatever you select at that time. You current ‘erase to’ option will be checked in the set of Canvas : Erase to menu list.
Note that the Canvas : Erase menu command is associated with a b menu command key. So you can use the menu command key shortcut instead of having to use the mouse to run the actual menu. This is a useful shortcut when working. On the mac for example you would press the command and b keys to run the erase menu command.
For More Information
For more information, check out this tip titled Erasing the Canvas and Setting the Canvas to the Source Image.