Re: drawing area does not refresh

[temp temp <titanogame yahoo com>]

Yes, but the problem is that I can't wait until the
the handler is called.
I want to be able to refresh it even if there is a
pause just after my call to function.

I am making a program treating images from a webcam.
For reasons that would be long to explain, I need to
be able to refresh the drawinarea directly even if
there is a pause (with getchar() for example) just
after my call to the function.

--- David Neèas (Yeti) <yeti physics muni cz> wrote:

> On Wed, May 10, 2006 at 09:29:31AM -0700, temp temp
> wrote:
> > I have a problem creating a function that will
> draw the contents of a buffer into a drawing area.
> > Here is the function I call when I want to draw
> the contents of "buffer" into the drawingarea
> designated by "area":
> > int draw_in_widget(GtkWidget *area,unsigned char*
> buffer,int img_height,int img_width,bool is_rgb)
> > {
> >     //conversion BGR->RGB
> >     if(!is_rgb)
> >     {
> >         unsigned char tmp;
> >         for(int i=0;i<img_width*img_height;i++)
> >         {
> >             tmp = buffer[3*i];//B->tmp
> >             buffer[3*i] = buffer[3*i+2];//R->B
> >             buffer[3*i+2] = tmp;//tmp->R   
> >         }    
> >     }
> >     
> >     gpointer destroy_fn_data;
> >     int area_width=area->allocation.width;
> >     int area_height=area->allocation.height;
> >     
> >     GdkPixbuf
*pixbuf_dest=gdk_pixbuf_new(GDK_COLORSPACE_RGB,FALSE,8,
> >         area_width,area_height);
> >     GdkPixbuf
*pixbuf_src=gdk_pixbuf_new_from_data(buffer,GDK_COLORSPACE_RGB,FALSE,8,
> >        
img_width,img_height,img_width*3,NULL,destroy_fn_data);
> >     GdkGC
> *gc=area->style->fg_gc[GTK_STATE_NORMAL];
> >     double scale_x=(double)area_width/img_width;
> >     double scale_y=(double)area_height/img_height;
> >     
> >     gtk_widget_queue_draw(area);
>
> You should not call gtk_widget_queue_draw() on a
> widget in
> its expose handler.  I wonder how the redrawing ever
> stops
> when each redraw attempts to invoke another
> redraw...
>
> >    
gdk_pixbuf_scale(pixbuf_src,pixbuf_dest,0,0,area_width,area_height,
> >         0,0,scale_x,scale_y,GDK_INTERP_TILES);
> >
> >     gdk_draw_pixbuf(area->window,gc,pixbuf_dest,
> >        
0,0,0,0,area_width,area_height,GDK_RGB_DITHER_NORMAL,0,0);
> >       
> >     gdk_pixbuf_unref(pixbuf_src);
> >     gdk_pixbuf_unref(pixbuf_dest);
> >     return(0);
> > }
> >
> >
> > The function adapts the size of the image
> contained in the buffer (of size
> 3*img_height*img_width) to the size of the drawing
> area.
> > My problem is that this function only works when
> placed in a "on_drawingarea1_expose_event" handler.
>
> To invoke redraw of a widget call
>
>     gtk_widget_queue_draw(widget);
>
> As a result, the expose handler will be called
> (somewhat
> later when the main loop comes to that).
>
> Yeti
>
>
> --
> Anonyms eat their boogers.


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com