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15.5.660 tvread

tvread([ ix, iy, nx, ny] [, window] [, /greyscale])

tvread,[ ix, iy, nx, ny] , window [, /greyscale])

[x11] Returns part of window window, starting at ix, iy and of dimensions nx, ny. The window part defaults to the whole window, window to the last selected window (!window). By default, the raw pixel values are returned, without using color table information. If the result is displayed using tvraw, then the original image appears - if the color table has not been changed in the meantime. If keyword /greyscale is specified, then the read pixel values are translated into (grey) intensity values between 0 and 255 which are then returned.

If you read part of a window, then that part must be wholly within the confines of the screen at the time it is read. There is no such limitation on reading from a pixmap (with negative window).

Alias: xtvread

See also: xport, xtv, !window