用Screen FillRect?

输出结果：
Usage:

Screen('FillRect', windowPtr [,color] [,rect] )

Fill "rect". "color" is the clut index (scalar or [r g b] triplet or [r g b a]
quadruple) that you want to poke into each pixel; default produces white with
the standard CLUT for this window's pixelSize. Default "rect" is entire window,
so you can use this function to clear the window. Please note that clearing the
entire window will set the background color of the window to the clear color,
ie., future Screen('Flip') commands will clear to the new background clear color
specified in Screen('FillRect').
Instead of filling one rectangle, you can also specify a list of multiple
rectangles to be filled - this is much faster when you need to draw many
rectangles per frame. To fill n rectangles, provide "rect" as a 4 rows by n
columns matrix, each column specifying one rectangle, e.g., rect(1,5)=left
border of 5th rectange, rect(2,5)=top border of 5th rectangle, rect(3,5)=right
border of 5th rectangle, rect(4,5)=bottom border of 5th rectangle. If the
rectangles should have different colors, then provide "color" as a 3 or 4 row by
n column matrix, the i'th column specifiying the color of the i'th rectangle.

See also: FrameRect