Hello all, Anyone know how to draw the widgets contained in a Fl_Scroll into an image file? I have searched the fltk.general and found this thread:
http://www.fltk.org/newsgroups.php?s1+gfltk.general+v39+T+Q"capture+widget+image"; I've tried manipulating the example for my needs, but it's not going too well. :) I have pasted my implementation so far at the bottom of this message. My idea/hopes is to have a button that will capture the contents of the Fl_Scroll and save a PNG image. I have the saving part implemented and test independent of this problem. When the button is pushed, the capture() method (see below) is called and returns a Fl_RGB_Image. I then write the image data to a PNG file. I think my biggest problem is that I don't fully understand the Fl_Offscreen and its associated functions. I have searched the HTML doxygen docs, but documentation for Fl_Offscreen, fl_begin_offscreen, etc. are missing. The image I am getting in the end is a jumbled mess of the "Hello World" string and random stuff from my desktop. Any tips or direction to some archived threads would be greatly appreciated. Thanks, Alvin Fl_RGB_Image* Fl_Canvas::capture() { if(children() <= 2) return NULL; int xdim = child(0)->w(); int ydim = child(0)->h(); window()->make_current(); // setup the offscreen buffer Fl_Offscreen offscr = fl_create_offscreen(xdim, ydim); // force children to draw into the offscreen buffer fl_begin_offscreen(offscr); Fl_Widget *o = NULL; for(int i = children()-1; i >= 0; --i) { o = child(i); if(o != &scrollbar && o != &hscrollbar) o->draw(); } fl_rectf(10, 10, 150, 100, FL_BLACK); fl_color(FL_WHITE); fl_font(FL_TIMES, 15); fl_draw("Hello, World!", 15, 10); fl_end_offscreen(); // copy?? fl_copy_offscreen(0, 0, xdim, ydim, offscr, 0, 0); // copy the offscreen buffer into a RGBA buffer uchar *offscreenImage = new uchar[xdim * ydim * 4]; memset(offscreenImage, 0, xdim * ydim * 4); fl_read_image(offscreenImage, x(), y(), xdim, ydim, 255); // Pack a Fl_RGB_Image and force its dtor to do the cleanup Fl_RGB_Image *rgb_img = new Fl_RGB_Image(offscreenImage, xdim, ydim, 4); rgb_img->alloc_array = 1; return rgb_img; } _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
