Abstract: A method for erasing electronic handwriting on a clipboard includes: the coordinates of each handwriting point of the electronic handwriting are made to correspond to writing pressure on the clipboard and are stored, and the color depth of each handwriting point is made to be proportional to the writing pressure at the handwriting point; the coordinates of each erase point, on the clipboard, contacted by the eraser are made to correspond to erasing pressure applied to the clipboard by the eraser via the erase points; determining whether the coordinates of the erase points are the same as one of the coordinates in the handwriting points, and if so, then determining the color depth at that erase point according to a first non-negative rule; otherwise, the color depth at the erase point is the background color depth of the clipboard.

Abstract: A method for erasing electronic handwriting on a clipboard includes: the coordinates of each handwriting point of the electronic handwriting are made to correspond to writing pressure on the clipboard and are stored, and the color depth of each handwriting point is made to be proportional to the writing pressure at the handwriting point; the coordinates of each erase point, on the clipboard, contacted by the eraser are made to correspond to erasing pressure applied to the clipboard by the eraser via the erase points; determining whether the coordinates of the erase points are the same as one of the coordinates in the handwriting points, and if so, then determining the color depth at that erase point according to a first non-negative rule; otherwise, the color depth at the erase point is the background color depth of the clipboard.

Abstract: A method for displaying strokes on a canvas includes creating a canvas on a screen; determining the shape and size of stroke points displayed on the canvas, thus determining the distance between adjacent stroke points; recording an edge frame of a valid region coming into contact with a paintbrush in real time, wherein the valid region is a region on the screen located inside the edge of the canvas; according to the shape and size of the stroke points and the distance between the adjacent stroke points, determining positions of N stroke points on the canvas, so that all the valid regions coming into contact with the paintbrush are completely covered by the N stroke points, where N is an integer not less than 1; and refurbishing the colors of the regions corresponding to the N stroke points on the canvas from a base color to being colored.