On Thu, Dec 04, 2008 at 01:07:06PM +0100, Norbert Wojtowicz wrote:

Hello,

I'm having problems getting a drawingArea to render, I've narrowed the program down to the following skeleton. Any suggestions on what I'm doing wrong? The label gets updated correctly, but the drawingArea just remains gray as if it was never rendered. I'm including an entire compilable skeleton in case someone wants to help me debug it. (I have a feeling I'm just missing something very obvious...)

Thanks in advance, Norbert

skeletonTest.hs:

module Main where import Graphics.UI.Gtk -- hiding (fill) import Graphics.UI.Gtk.Glade import Graphics.Rendering.Cairo.SVG import Graphics.Rendering.Cairo import Control.Monad

main = do initGUI let gFile = "brainSpin.glade" windowXmlM <- xmlNew gFile let windowXml = case windowXmlM of (Just windowXml) -> windowXml Nothing -> error "Can't find the glade file \"brainSpin.glade\" in the current directory" window <- xmlGetWidget windowXml castToWindow "brainSpinMain" onDestroy window mainQuit label <- xmlGetWidget windowXml castToLabel "label1" drawArea <- xmlGetWidget windowXml castToDrawingArea "drawArea" widgetShowAll window labelSetText label "foo"

-- THIS is the offending code. Originally I was working with SVGs, but I simplified -- it to this, just to track down the problem. It seems any Render () does not -- get updated in the drawArea let r = do setSourceRGB 0 0 0 paint drawin <- widgetGetDrawWindow drawArea renderWithDrawable drawin r

mainGUI

Drawing must be done when the widget is exposed. The changes in the code below are mainly taken from demo/svg/SvgViewer.hs. main = do svg <- svgNewFromFile "/path/to/svg/file" let (width, height) = svgGetSize svg initGUI let gFile = "brainSpin.glade" windowXmlM <- xmlNew gFile let windowXml = case windowXmlM of (Just windowXml) -> windowXml Nothing -> error "Can't find the glade file \"brainSpin.glade\" in the current directory" window <- xmlGetWidget windowXml castToWindow "brainSpinMain" onDestroy window mainQuit label <- xmlGetWidget windowXml castToLabel "label1" drawArea <- xmlGetWidget windowXml castToDrawingArea "drawArea" -- Here we go onSizeRequest drawArea $ return (Requisition width height) onExpose drawArea $ updateCanvas drawArea svg widgetShowAll window labelSetText label "foo" mainGUI updateCanvas :: DrawingArea -> SVG -> Event -> IO Bool updateCanvas canvas svg (Expose { eventArea=rect }) = do drawin <- widgetGetDrawWindow canvas let (width, height) = svgGetSize svg (width', height') <- widgetGetSize canvas renderWithDrawable drawin $ do scale (realToFrac width' / realToFrac width) (realToFrac height' / realToFrac height) svgRender svg return True Hope, that's what you expected. -Johann