get-pixel in bitmap-dc%

Gets the current color of a pixel in the bitmap.

Under X, interleaving drawing commands with get-pixel calls (for the same bitmap-dc% object) incurs a substantial performance penalty, except for interleaved calls to set-pixel, set-argb-pixels, and get-argb-pixels.

• (send a-bitmap-dc get-pixel x y color) -> boolean
     x : real number
     y : real number
     color : color% object

  Fills color with the color of the current pixel at position (x, y) in the drawing context. If the color is successfully obtained, the return value is #t, otherwise the result is #f.