25 lines
2.5 KiB
Rexx
25 lines
2.5 KiB
Rexx
/*REXX program demonstrates a method to perform a flood fill of an area. */
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black= '000000000000000000000000'b /*define the black color (using bits).*/
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red = '000000000000000011111111'b /* " " red " " " */
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green= '000000001111111100000000'b /* " " green " " " */
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white= '111111111111111111111111'b /* " " white " " " */
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/*image is defined to the test image. */
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hx= 125; hy= 125 /*define limits (X,Y) for the image. */
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area= white; call fill 125, 25, red /*fill the white area in red. */
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area= black; call fill 125, 125, green /*fill the center orb in green. */
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exit /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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fill: procedure expose image. hx hy area; parse arg x,y,fill_color /*obtain the args.*/
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if x<1 | x>hx | y<1 | y>hy then return /*X or Y are outside of the image area*/
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pixel= image.x.y /*obtain the color of the X,Y pixel. */
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if pixel \== area then return /*the pixel has already been filled */
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/*with the fill_color, or we are not */
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/*within the area to be filled. */
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image.x.y= fill_color /*color desired area with fill_color. */
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pixel= @(x , y-1); if pixel==area then call fill x , y-1, fill_color /*north*/
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pixel= @(x-1, y ); if pixel==area then call fill x-1, y , fill_color /*west */
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pixel= @(x+1, y ); if pixel==area then call fill x+1, y , fill_color /*east */
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pixel= @(x , y+1); if pixel==area then call fill x , y+1, fill_color /*south*/
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return
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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@: parse arg $x,$y; return image.$x.$y /*return with color of the X,Y pixel.*/
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