Re: [LAD] OT: gtk rectangle with opacity

From: hermann <brummer-@web.de>
Date: Sun Dec 27 2009 - 20:43:36 EET

Am Sonntag, den 27.12.2009, 19:39 +0100 schrieb hermann:
> gboolean box_expose(GtkWidget *wi, GdkEventExpose *ev, gpointer data)
> {
> cairo_t *cr;
> // create a cairo context //
> cr = gdk_cairo_create(wi->window);
>
> double x0 = wi->allocation.x;
> double y0 = wi->allocation.y;
> double rect_width = wi->allocation.width;
> double rect_height = wi->allocation.height;
>
> cairo_rectangle (cr, x0,y0,rect_width,rect_height+3);
> cairo_set_source_rgba (cr, 0, 0, 0, 0.5); // a set the opacity
> level
> cairo_fill (cr);
> cairo_destroy(cr);
  // EDIT:// don't forget to
       return false;
  //
> }
> draw a transparent black rectangle to the calling widget.
> You can connect it with to make sure it will redraw when needed.
>
> g_signal_connect(widget, "expose-event", G_CALLBACK(box_expose), NULL);
>
> more examples you could found here
> http://cairographics.org/samples/
>
> regards hermann
>
> Am Montag, den 28.12.2009, 04:30 +1100 schrieb Patrick Shirkey:
> > Hi,
> >
> > Does anyone have an example in c of drawing a gdk_rectangle with opacity
> > in the foreground color?
> >
> > There's several examples in python floating around that use the cairo
> > but I can't find a nice example in c.
> >
> >
> >
> >
> > Cheers.
> >
>
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Received on Mon Dec 28 00:15:02 2009

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