Bug 4612

Created attachment 3414 [details] [review]
metric.gmBlackBox[XY] are unsigned, leading to much fun during comparison

I've got no reason to mistrust this fix.

Commit away!

2005-09-28  T Rowley  <tim.rowley@gmail.com>

       * ROADMAP: Note that Bug #4612 (Text not being drawn if first
       character entirely out of surface) is now fixed.

       * src/cairo-win32-font.c (_cairo_win32_scaled_font_glyph_bbox):
       Add cast so that sign conversion doesn't alter comparison.

Tim, did you mean that the bug occurs *only* when using the toy font API, or
that it occurs *even* when using the toy font API? Anyway, this bug bites also
in real GTK+/pango programs. In fact, the fix got rid of irritating display
glitches that could be reproduced even in a very trivial sample program. Thanks
very much for fixing this!

I got the below mail message with sample program. Luckily I didn't waste time
looking for other causes of the problem, but just checked whether cairo 1.0.2
would help... I had noticed the problem myself in Evolution, but thought that it
was caused by some much more complex scenario involving GtkPlug/Socket etc.

The message I got:

Below is a some code that produces a GTK Window, adds a GTK Label to it 
and shows both. The problem I'm having is that IF I drag a window on 
part of the Label, often, the text won't get redrawn correctly. This 
means I often get a Label that shows 'B' and nothing else. For some odd 
reason, the B always gets drawn no matter what. I would appreciate your 
take on this.

#include <gtk/gtk.h>

static void before_main_destroy(GtkWidget *widget, gpointer data);

int main(int argc, char *argv[])
{
  GtkWidget *window;
  GtkWidget *label;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "This is a window !");
  gtk_window_set_resizable (GTK_WINDOW (window), FALSE);
  g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK 
		    (before_main_destroy), NULL);

  label = gtk_label_new ("Brrr");
  gtk_container_add (GTK_CONTAINER (window), label);
  gtk_widget_show (label);

  gtk_widget_show(window);
  gdk_window_set_decorations (GDK_WINDOW(window->window), GDK_DECOR_TITLE |
GDK_DECOR_MENU);
 
  gtk_main ();
  
  return 0;
}

static void before_main_destroy(GtkWidget *widget, gpointer data)
{
  gtk_main_quit ();
}