Hi Michael, On 09/08/13 08:21, Michael Oswald wrote:

Hello,

I am currently writing an application which draws the structure of some packets with help of the diagrams library directly to a GTK GUI.

Now the packets can have several hundreds of parameters which have to be drawn so it takes some seconds to calculate the diagram itself. Of course this now blocks the GUI thread, so the basic idea was to put the calculation in a separate thread. Unfortunately this doesn't work as lazyness kicks in and the final diagram is calculated when it is rendered and not evaluated before. Using seq didn't help (because of WHNF) and there seems to be no deepseq instance for the diagrams.

Does somebody has an idea on how to speed this up / get the diagram evaluated strictly as especially scrolling the DrawingArea is now really a pain?

Cairo is thread safe* so you could render the whole thing (if it isn't super huge dimensions) to an image surface in the background thread, then displaying could be a matter of copying the correct part (for scrolling) of the surface to the DrawingArea. Something like this perhaps (untested, incomplete): ----8<---- import qualified Diagrams.(...) as D import qualified Graphics.Rendering.Cairo as C renderDiaToSurface width height diagram = do let w' = fromIntegral width h' = fromIntegral height opts = D.CairoOptions "" (D.Dims w' h') D.RenderOnly False (_, render) = D.renderDia D.Cairo opts diagram surface <- C.createImageSurface C.FormatARGB32 width height C.renderWith surface render return surface ... ----8<---- Hope this is useful, Claude * I had some very rare crashes in heavily threaded code, still not found the root cause... -- http://mathr.co.uk