[gtk] gl renderer: Dont't try to draw glyphs at scale 0

[Timm Bäder <baedert src gnome org>]

commit d55fc8b7b151cbd8210a4229b611c95a15d3ea88
Author: Timm Bäder <mail baedert org>
Date:   Thu Jan 10 17:14:48 2019 +0100

    gl renderer: Dont't try to draw glyphs at scale 0
    
    Fixes #1475

 gsk/gl/gskglglyphcache.c        | 3 ++-
 gsk/gl/gskglglyphcacheprivate.h | 2 ++
 gsk/gl/gskglrenderer.c          | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/gsk/gl/gskglglyphcache.c b/gsk/gl/gskglglyphcache.c
index dd0a3a5143..dc8d5149a9 100644
--- a/gsk/gl/gskglglyphcache.c
+++ b/gsk/gl/gskglglyphcache.c
@@ -322,12 +322,13 @@ gsk_gl_glyph_cache_lookup (GskGLGlyphCache *cache,
       value->draw_height = ink_rect.height;
       value->timestamp = cache->timestamp;
       value->atlas = NULL; /* For now */
+      value->scale = (guint)(scale * 1024);
 
       key->font = g_object_ref (font);
       key->glyph = glyph;
       key->scale = (guint)(scale * 1024);
 
-      if (ink_rect.width > 0 && ink_rect.height > 0)
+      if (ink_rect.width > 0 && ink_rect.height > 0 && key->scale > 0)
         add_to_cache (cache, key, value);
 
       g_hash_table_insert (cache->hash_table, key, value);
diff --git a/gsk/gl/gskglglyphcacheprivate.h b/gsk/gl/gskglglyphcacheprivate.h
index 4f162c4e38..d93bbdcfc6 100644
--- a/gsk/gl/gskglglyphcacheprivate.h
+++ b/gsk/gl/gskglglyphcacheprivate.h
@@ -59,6 +59,8 @@ struct _GskGLCachedGlyph
   int draw_width;
   int draw_height;
 
+  float scale;
+
   guint64 timestamp;
 };
 
diff --git a/gsk/gl/gskglrenderer.c b/gsk/gl/gskglrenderer.c
index 1b3d15a794..cdac8a1410 100644
--- a/gsk/gl/gskglrenderer.c
+++ b/gsk/gl/gskglrenderer.c
@@ -496,7 +496,7 @@ render_text_node (GskGLRenderer   *self,
                                          text_scale);
 
       /* e.g. whitespace */
-      if (glyph->draw_width <= 0 || glyph->draw_height <= 0)
+      if (glyph->draw_width <= 0 || glyph->draw_height <= 0 || glyph->scale <= 0)
         goto next;
 
       cx = (double)(x_position + gi->geometry.x_offset) / PANGO_SCALE;