Bright Yellow Cow :: Blog

We're going to use the Graphics.GD bindings to the GD library written by Bjorn Bringert to do all the work:

> import Graphics.GD
> import Numeric (showHex, readHex)
> import System.Environment
> 
> 
> main = do
> 	[prefix, strSize,fg,bg] <- getArgs
> 	let size = read strSize
> 	img <- newImage (size,size)
> 	doAt img fg bg size (prefix++"_tl.png") (size-1,size-1)
> 	doAt img fg bg size  (prefix++"_tr.png") (0,size-1)
> 	doAt img fg bg size  (prefix++"_bl.png") (size-1,0)
> 	doAt img fg bg size  (prefix++"_br.png") (0,0)
> 	
> doAt img fg bg size name pos = do
> 	fillImage (torgb bg) img
> 	drawFilledEllipse pos (size*2-1,size*2-1) (torgb fg) img
> 	savePngFile name img
> 
> torgb s = 
> 	let
> 		[r,g,b] = fromHexStr s
> 	in
> 		rgb r g b
> 
> 
> fromHexStr :: String -> [Int]
> fromHexStr (a:b:tl) = (fromHex [a,b]):(fromHexStr tl)
> fromHexStr [] = []
> fromHex :: String -> Int
> fromHex s = 
> 	case readHex s of
> 		[(val,"")] -> fromIntegral (val)
> 		other -> error $! show other
> 

Usage is simple: "./makeCorners l 20 3D7AB8 FFFFFF" will make 4 images with quadrants of a circle in them, coloured #3D7AB8 on a white background. And that's it!