Patent ID: 7307635
Filing Date: 2007-12-11
Classification: G09G

Abstract:
1. A pixel rotator comprising: a frame-buffer burst-reader that reads a frame buffer of pixels arranged in a display-scan order for display as a non-rotated image, the display-scan order having an image region of Y lines of X pixels per line that is logically divided into X/B blocks of Y lines and B pixels per line, wherein B is a number of pixels that are read together in a burst read of the frame buffer, the B pixels being adjacent pixels in a same line of the frame buffer; wherein X, Y, and B are whole numbers and B is at least 2; a line buffer that is written by the frame-buffer burst-reader and stores B*Y pixels; an offset generator that generates an offset for use by a block being read from the line buffer, the offset being increased by a factor of B within a modulus of B*Y−1 for each block read from the line buffer; and a pixel reader that reads pixels from the line buffer and send the pixels to a display for displaying the image region rotated as a rotated image of X lines of Y pixels per rotated line; wherein the pixel reader reads a rotated-display-order series of pixels that are offset from adjacent pixels by the offset, and that wrap around the line buffer using the modulus of B*Y−1, the pixel reader sending the rotated-display-order series of pixels to the display for displaying as the rotated image; wherein the frame-buffer burst-reader writes pixels in a next block to locations within the line buffer that the pixel reader read for displaying a current block, wherein locations written are offset from locations written by adjacent pixels in the next block by the offset, whereby pixels from the image region of the frame buffer in the display-scan order are re-ordered into the rotated-display-order series of pixels through writing and reading of the line buffer.