[wxhaskell-users] How to make the Filter programm?

[shelarcy <she...@ca...>]

I was making a Filter (Low pass Filter) programm in wxHaskell.

I changed ImageViewer.hs code there,


import Graphics.UI.WXCore ( bitmapDelete, bitmapCreateFromFile, 
bitmapGetSize, dcClear,
                             imageCreateFromBitmap, imageGetPixelBuffer, 
colorFromInt, intFromColor,
                             bitmapCreateFromImage, pixelBufferSetPixel, 
pixelBufferGetPixel )

Or

import Graphics.UI.WXCore

And


     onPaint vbitmap dc viewArea
       = do mbBitmap <- varGet vbitmap
            case mbBitmap of
              Nothing -> dcClear dc
              -- Just bm -> drawBitmap dc bm pointZero False []
              Just bm ->
                do
                    bsz <- bitmapGetSize bm
                    im <- imageCreateFromBitmap bm
                    pxe <- imageGetPixelBuffer im
                    let pixelPoint (Size ppx ppy) n = [Point x y  | x <- 
[n..ppx-n], y <- [n..ppy-n]]
                    let addRGB rgb1 rgb2 = colorFromInt $ (intFromColor 
rgb1) + (intFromColor rgb2)
                    let drawLowpassFilter pb (Point szx szy) = do
                          lowpass <- (lowpassFilter pxe (Point szx szy) bsz)
                          pixelBufferSetPixel pb (Point szx szy) lowpass
                    let fillpixelBuffer pb
                           = mapM_ (drawLowpassFilter pb) (pixelPoint bsz 0)
                    fillpixelBuffer pxe
                    bm2  <- bitmapCreateFromImage im (-1)
                    -- drawBitmap dc bm pointZero False []
                    drawBitmap dc bm2 pointZero True []
                      where
                        pixelColorInt pix (Point ptx pty) (Size szx szy)
                            | ptx < 0   = pixelColorInt pix (Point 0 pty) 
(Size szx szy)
                            | pty < 0   = pixelColorInt pix (Point ptx 0) 
(Size szx szy)
                            | ptx > szx = pixelColorInt pix (Point ptx pty) 
(Size 0 szy)
                            | pty < szy = pixelColorInt pix (Point ptx pty) 
(Size 0 szy)
                            | otherwise = do
                                pixel <- pixelBufferGetPixel pix (Point ptx 
pty)
                                return (intFromColor pixel)
                        lowpassFilter pix (Point szx szy) bound   = do
                            -- pixelsInt <- foldM (+) (pixelColorInt pix 
[Point x y  | x <- [szx-n..szx+n], y <- [szy-n..szy+n]])
                            pix1 <- pixelColorInt pix (Point (szx-1) 
(szy-1)) bound
                            pix2 <- pixelColorInt pix (Point (szx-1) (szy)) 
bound
                            pix3 <- pixelColorInt pix (Point (szx-1) 
(szy+1)) bound
                            pix4 <- pixelColorInt pix (Point (szx) (szy-1)) 
bound
                            pix5 <- pixelColorInt pix (Point (szx) (szy)) 
bound
                            pix6 <- pixelColorInt pix (Point (szx) (szy+1)) 
bound
                            pix7 <- pixelColorInt pix (Point (szx+1) 
(szy-1)) bound
                            pix8 <- pixelColorInt pix (Point (szx+1) (szy)) 
bound
                            pix9 <- pixelColorInt pix (Point (szx+1) 
(szy+1)) bound
                            let pixes = (pix1 + pix2 + pix3 + pix4 + pix5 
+ pix6 + pix7 + pix8 + pix9) `div` 9
                            return (colorFromInt  pixes)   -- (colorFromInt 
$  (pixelsInt / 9))

But these code doesn't work.

Where is wrong?


-- 
shelarcy <she...@ca...>
http://page.freett.com/shelarcy/