A method is performed at a device with one or more processors, memory, a touch-sensitive surface, and a display. The method includes receiving a line-drawing input. The method further includes rendering a line in a sketch area in accordance with the line-drawing input. The method further includes, while displaying the sketch area including the line, receiving a fill gesture directed to the line in the sketch area. The method further includes, in response to receiving the fill gesture, adding fill content in a first portion of the sketch area that corresponds to regions touched by the fill-gesture on the touch-sensitive surface and that is delineated and partially enclosed by the line in the sketch area.