RosettaCodeData/Task/Bitmap-Flood-fill/PL-I/bitmap-flood-fill-1.pli
2023-07-01 13:44:08 -04:00

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fill: procedure (x, y, fill_color) recursive; /* 12 May 2010 */
declare (x, y) fixed binary;
declare fill_color bit (24) aligned;
if x <= lbound(image, 2) | x >= hbound(image, 2) then return;
if y <= lbound(image, 1) | y >= hbound(image, 1) then return;
pixel_color = image (x,y); /* Obtain the color of the current pixel. */
if pixel_color ^= area_color then return;
/* the pixel has already been filled with fill_color, */
/* or we are not within the area to be filled. */
image(x, y) = fill_color; /* color the desired area. */
pixel_color = image (x,y-1); /* Obtain the color of the pixel to the north. */
if pixel_color = area_color then call fill (x, y-1, fill_color);
pixel_color = image (x-1,y); /* Obtain the color of the pixel to the west. */
if pixel_color = area_color then call fill (x-1, y, fill_color);
pixel_color = image (x+1,y); /* Obtain the color of the pixel to the east. */
if pixel_color = area_color then call fill (x+1, y, fill_color);
pixel_color = image (x,y+1); /* Obtain the color of the pixel to the south. */
if pixel_color = area_color then call fill (x, y+1, fill_color);
end fill;