drawing in a for-loop

[Ian Strascina <istrasci cs nmsu edu>]

OK, this is probably the stupidest post ever, but I need help drawing in a 
for-loop within a callback function...  I've done this before, but for 
some reason, I'm not getting expose events to refresh my GtkDrawingArea... 
My code looks like this (using gtkmm, but doesn't matter)...


void mainWindow::button_callback()
{
  //GtkDrawingArea is called '* area'
  width = GTK_WIDGET(area)->allocation.width;
  height = " " ".height;

  for (int i=0; i<200; i++)
  {
    gdk_draw_point(this->pixmap,GTK_WIDGET(area)->style->black_gc,i,i);
    gtk_widget_queue_draw_area((GtkWidget *) area,0,0,width,height);
    delay-for-a-split-second();
  }
}


bool mainWindow::drawingarea_expose(GdkEventExpose* exp)
{
  gdk_draw_drawable(GTK_WIDGET(area)->window,
                   GTK_WIDGET(area)->style->fg_gc[GTK_WIDGET_STATE(GTK_WIDGET(area))],
                   this->pixmap, exp->area.x, exp->area.y,
                   exp->area.x, exp->area.y, exp->area.width,
                   exp->area.height);

  return 0;
}



Obviously, this should draw a line one pixel at a time...  Everything is 
*drawn* correctly, but it doesn't display each pixel as it's drawn -- 
instead it just shows the whole line drawn to completion after the loop is 
done...  I need to see each pixel popping up individually... This is 
why I think it's an expose issue...

Don't worry, everything is defined, signals connected to the callbacks, 
etc...  I just want to know why this logic doesn't refresh the display 
after each iteration...  Please help...  Thanks...

	- Ian

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C makes it easy to shoot yourself in the foot; C++ makes it
harder, but when you do, it blows away your whole leg...
		-- Bjarne Stroustrup
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