> very large graphs. In the application the graphs are > scrollable, in this way you can see any details, but now I > need to have the whole graph as an image in order to > save/export; a screen capture does not work as it only > captures the actual scroll pane. > I tried to look at Fl_Image* Fl_Widget::image() but it > doesn't work: the graph is made of Fl_Widgets and not > directly of a large Fl_Image.
> The question is: is there any way to 'grab' the visualization > of a Fl_Scroll (or a Fl_Group)? I would expect an image at > some level in the fltk class hierarchy holding the image > which is actually rendered, I'm wondering how to copy such an image. Why should such an image exist? Most rendering systems will make use of the clipping regions that are current when they are drawing, and only draw the bits that can be seen. So in general, the whole image need not (and usually does not) exist anywhere. > Alternatively any suggestion about how to 'capture' the whole > Fl_Scroll content is welcome as well! I think I would render the entire scene into an fl_offscreen, then view that offscreen buffer through the scroll. Then when I wanted to get the image, I could read it back from the offscreen. This has a number of other advantages too, but also has some disadvantages... Not least that it is more complex to set up, and may conceivably be slower, too. Actually, when I did something like this, I didn't even bother with the Fl_Scroll at all - instead I used a pair of Fl_Scrollbar widgets to "simulate" a scroll region and simply selected the appropriate rectangle from the offscreen to blit onto the viewer widget (which was derived from Fl_Box). A later iteration added a crude "zoom" function that used the blit from the offscreen to also sub-sample the view, allowing me to "zoom out" and see the entire scene. Was a bit grainy, but worked OK. -- Ian SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. ******************************************************************** _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
