Question

I was trying to follow the tutorial on X11 haskell library, but got a problem –
the created window is positioned in lower left corner of a screen, instead of top left corner, and the drawing (in method drawInWin) doesn’t seem to do anything.

#!/usr/bin/runghc -Wall

module Main where
import Graphics.X11.Xlib
import System.Exit (exitWith, ExitCode(..))
import Control.Concurrent (threadDelay)

main :: IO ()
main = do
 dpy <- openDisplay ""
 let dflt = defaultScreen dpy
     border = blackPixel dpy dflt
     background = whitePixel dpy dflt
 rootw <- rootWindow dpy dflt
 win <- createSimpleWindow dpy rootw 0 0 100 100 1 border background
 setTextProperty dpy win "Hello World" wM_NAME
 mapWindow dpy win
 drawInWin dpy win
 sync dpy False
 threadDelay (10 * 1000000)
 exitWith ExitSuccess

drawInWin :: Display -> Window -> IO ()
drawInWin dpy win = do
 bgcolor <- initColor dpy "green"
 fgcolor <- initColor dpy "blue"
 gc <- createGC dpy win
 setForeground dpy gc bgcolor
 fillRectangle dpy win gc 0 0 100 100
 setForeground dpy gc fgcolor
 fillRectangle dpy win gc 2 2 96 96
 freeGC dpy gc

initColor :: Display -> String -> IO Pixel
initColor dpy color = do
 let colormap = defaultColormap dpy (defaultScreen dpy)
 (apros,real) <- allocNamedColor dpy colormap color
 return $ color_pixel apros

Basically, I need to create a simple window with a canvas, on which I will draw some lines.

What am I doing wrong in that snippet?

Versions:

X11 - 1.5.0.1
GHC - 6.12.1
OS - Linux Mint 10
Xorg - 1:7.5

Answer 1

There are a number of bugs related to 64-bit-correctness in the 1.5 release of the X11 bindings. These have been fixed in the 1.6 release, so upgrading should resolve these issues.