[gtk/wip/otte/for-master] label: Don't do more work than necessary

[Benjamin Otte <otte src gnome org>]

commit 7f7809f523de11c2f215651fd65e74045d9a8e02
Author: Benjamin Otte <otte redhat com>
Date:   Thu Nov 11 05:21:43 2021 +0100

    label: Don't do more work than necessary
    
    We only want to determine the size pixel-exact, not pango-unit-exact, so
    don't spend lots of time wondering if text is half a pixel or a quarter
    pixel wider.

 gtk/gtklabel.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtklabel.c b/gtk/gtklabel.c
index 4d84d6fc8d..8f94d8ab36 100644
--- a/gtk/gtklabel.c
+++ b/gtk/gtklabel.c
@@ -1191,11 +1191,14 @@ get_width_for_height (GtkLabel *self,
       layout = gtk_label_get_measuring_layout (self, NULL, -1);
       pango_layout_get_size (layout, &max, NULL);
 
+      min = PANGO_PIXELS_CEIL (min);
+      max = PANGO_PIXELS_CEIL (max);
       while (min < max)
         {
           mid = (min + max) / 2;
-          layout = gtk_label_get_measuring_layout (self, layout, mid);
+          layout = gtk_label_get_measuring_layout (self, layout, mid * PANGO_SCALE);
           pango_layout_get_size (layout, &text_width, &text_height);
+          text_width = PANGO_PIXELS_CEIL (text_width);
           if (text_width > mid)
             min = mid = text_width;
           if (text_height > height)
@@ -1204,8 +1207,8 @@ get_width_for_height (GtkLabel *self,
             max = mid;
         }
 
-      *minimum_width = min;
-      *natural_width = min;
+      *minimum_width = min * PANGO_SCALE;
+      *natural_width = min * PANGO_SCALE;
     }
 
   g_object_unref (layout);