Fix slowdown and wrong font choosed by XSETTINGS changes. bug #5157.

* font.c (font_open_entity): Enable chache and call cached_font_ok
for the driver if defined.
(QCuser_spec): New symbol.
(font_spec_from_name): Save name as user-spec.
(font_load_for_lface): Keep user-spec instead of name.
(font_open_by_name): Save name as user-spec.
(syms_of_font): Initialize QCuser_spec.

* xftfont.c (xftfont_open): Call xftfont_add_rendering_parameters.
(xftfont_add_rendering_parameters, xftfont_cached_font_ok): New.
(syms_of_xftfont): Initialize xftfont_driver.cached_font_ok.

* font.h (struct font_driver): Add cached_font_ok.

* font-setting.el (font-setting-change-default-font): Use user-spec
  instead of name.

4 files changed, 136 insertions, 52 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 131abcb9f96..84b147418cb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,19 @@
 2010-01-06  Jan Djärv  <jan.h.d@swipnet.se>
 
+        * font.c (font_open_entity): Enable chache and call cached_font_ok
+        for the driver if defined.
+        (QCuser_spec): New symbol.
+        (font_spec_from_name): Save name as user-spec.
+        (font_load_for_lface): Keep user-spec instead of name.
+        (font_open_by_name): Save name as user-spec.
+        (syms_of_font): Initialize QCuser_spec.
+
+        * xftfont.c (xftfont_open): Call xftfont_add_rendering_parameters.
+        (xftfont_add_rendering_parameters, xftfont_cached_font_ok): New.
+        (syms_of_xftfont): Initialize xftfont_driver.cached_font_ok.
+
+        * font.h (struct font_driver): Add cached_font_ok.
+
         * xterm.c (x_clear_frame): Queue draw for scroll bars.
 
 2010-01-05  Jan Djärv  <jan.h.d@swipnet.se>
diff --git a/src/font.c b/src/font.c
index ec4cb874b52..2141fe651c3 100644
--- a/src/font.c
+++ b/src/font.c
@@ -2991,16 +2991,6 @@ font_open_entity (f, entity, pixel_size)
   else if (CONSP (Vface_font_rescale_alist))
     scaled_pixel_size = pixel_size * font_rescale_ratio (entity);
 
-#if 0
-  /* This doesn't work if you have changed hinting or any other parameter.
-     We need to make a new object in every case to be sure. */
-  for (objlist = AREF (entity, FONT_OBJLIST_INDEX); CONSP (objlist);
-       objlist = XCDR (objlist))
-    if (! NILP (AREF (XCAR (objlist), FONT_TYPE_INDEX))
-        && XFONT_OBJECT (XCAR (objlist))->pixel_size == pixel_size)
-      return  XCAR (objlist);
-#endif
-
   val = AREF (entity, FONT_TYPE_INDEX);
   for (driver_list = f->font_driver_list;
        driver_list && ! EQ (driver_list->driver->type, val);
@@ -3008,6 +2998,19 @@ font_open_entity (f, entity, pixel_size)
   if (! driver_list)
     return Qnil;
 
+  for (objlist = AREF (entity, FONT_OBJLIST_INDEX); CONSP (objlist);
+       objlist = XCDR (objlist))
+    {
+      Lisp_Object fn = XCAR (objlist);
+      if (! NILP (AREF (fn, FONT_TYPE_INDEX))
+          && XFONT_OBJECT (fn)->pixel_size == pixel_size)
+        {
+          if (driver_list->driver->cached_font_ok == NULL
+              || driver_list->driver->cached_font_ok (f, fn, entity))
+            return fn;
+        }
+    }
+
   font_object = driver_list->driver->open (f, entity, scaled_pixel_size);
   if (!NILP (font_object))
     ASET (font_object, FONT_SIZE_INDEX, make_number (pixel_size));
diff --git a/src/font.h b/src/font.h
index 1a09df2558c..798676d546e 100644
--- a/src/font.h
+++ b/src/font.h
@@ -689,6 +689,14 @@ struct font_driver
                                    int c, unsigned variations[256]));
 
   void (*filter_properties) P_ ((Lisp_Object font, Lisp_Object properties));
+
+  /* Optional.
+
+     Return non-zero if FONT_OBJECT can be used as a (cached) font
+     for ENTITY on frame F.  */
+  int (*cached_font_ok) P_ ((struct frame *f,
+                             Lisp_Object font_object,
+                             Lisp_Object entity));
 };
 
 
diff --git a/src/xftfont.c b/src/xftfont.c
index 82701ce0afe..26294ff16a6 100644
--- a/src/xftfont.c
+++ b/src/xftfont.c
@@ -237,6 +237,56 @@ xftfont_fix_match (pat, match)
     }
 }
 
+static void
+xftfont_add_rendering_parameters (pat, entity)
+     FcPattern *pat;
+     Lisp_Object entity;
+{
+  Lisp_Object tail;
+  int ival;
+
+  for (tail = AREF (entity, FONT_EXTRA_INDEX); CONSP (tail); tail = XCDR (tail))
+    {
+      Lisp_Object key = XCAR (XCAR (tail));
+      Lisp_Object val = XCDR (XCAR (tail));
+
+      if (EQ (key, QCantialias))
+          FcPatternAddBool (pat, FC_ANTIALIAS, NILP (val) ? FcFalse : FcTrue);
+      else if (EQ (key, QChinting))
+        FcPatternAddBool (pat, FC_HINTING, NILP (val) ? FcFalse : FcTrue);
+      else if (EQ (key, QCautohint))
+        FcPatternAddBool (pat, FC_AUTOHINT, NILP (val) ? FcFalse : FcTrue);
+      else if (EQ (key, QChintstyle))
+        {
+          if (INTEGERP (val))
+            FcPatternAddInteger (pat, FC_HINT_STYLE, XINT (val));
+          else if (SYMBOLP (val)
+                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
+            FcPatternAddInteger (pat, FC_HINT_STYLE, ival);
+        }
+      else if (EQ (key, QCrgba))
+        {
+          if (INTEGERP (val))
+            FcPatternAddInteger (pat, FC_RGBA, XINT (val));
+          else if (SYMBOLP (val)
+                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
+            FcPatternAddInteger (pat, FC_RGBA, ival);
+        }
+      else if (EQ (key, QClcdfilter))
+        {
+          if (INTEGERP (val))
+            FcPatternAddInteger (pat, FC_LCD_FILTER, ival = XINT (val));
+          else if (SYMBOLP (val)
+                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
+            FcPatternAddInteger (pat, FC_LCD_FILTER, ival);
+        }
+#ifdef FC_EMBOLDEN
+      else if (EQ (key, QCembolden))
+        FcPatternAddBool (pat, FC_EMBOLDEN, NILP (val) ? FcFalse : FcTrue);
+#endif
+    }
+}
+
 static Lisp_Object
 xftfont_open (f, entity, pixel_size)
      FRAME_PTR f;
@@ -245,7 +295,7 @@ xftfont_open (f, entity, pixel_size)
 {
   FcResult result;
   Display *display = FRAME_X_DISPLAY (f);
-  Lisp_Object val, filename, index, tail, font_object;
+  Lisp_Object val, filename, index, font_object;
   FcPattern *pat = NULL, *match;
   struct xftfont_info *xftfont_info = NULL;
   struct font *font;
@@ -253,7 +303,7 @@ xftfont_open (f, entity, pixel_size)
   XftFont *xftfont = NULL;
   int spacing;
   char name[256];
-  int len, i, ival;
+  int len, i;
   XGlyphInfo extents;
   FT_Face ft_face;
   FcMatrix *matrix;
@@ -297,46 +347,7 @@ xftfont_open (f, entity, pixel_size)
      over 10x20-ISO8859-1.pcf.gz).  */
   FcPatternAddCharSet (pat, FC_CHARSET, ftfont_get_fc_charset (entity));
 
-  for (tail = AREF (entity, FONT_EXTRA_INDEX); CONSP (tail); tail = XCDR (tail))
-    {
-      Lisp_Object key, val;
-
-      key = XCAR (XCAR (tail)), val = XCDR (XCAR (tail));
-      if (EQ (key, QCantialias))
-          FcPatternAddBool (pat, FC_ANTIALIAS, NILP (val) ? FcFalse : FcTrue);
-      else if (EQ (key, QChinting))
-        FcPatternAddBool (pat, FC_HINTING, NILP (val) ? FcFalse : FcTrue);
-      else if (EQ (key, QCautohint))
-        FcPatternAddBool (pat, FC_AUTOHINT, NILP (val) ? FcFalse : FcTrue);
-      else if (EQ (key, QChintstyle))
-        {
-          if (INTEGERP (val))
-            FcPatternAddInteger (pat, FC_HINT_STYLE, XINT (val));
-          else if (SYMBOLP (val)
-                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
-            FcPatternAddInteger (pat, FC_HINT_STYLE, ival);
-        }
-      else if (EQ (key, QCrgba))
-        {
-          if (INTEGERP (val))
-            FcPatternAddInteger (pat, FC_RGBA, XINT (val));
-          else if (SYMBOLP (val)
-                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
-            FcPatternAddInteger (pat, FC_RGBA, ival);
-        }
-      else if (EQ (key, QClcdfilter))
-        {
-          if (INTEGERP (val))
-            FcPatternAddInteger (pat, FC_LCD_FILTER, ival = XINT (val));
-          else if (SYMBOLP (val)
-                   && FcNameConstant (SDATA (SYMBOL_NAME (val)), &ival))
-            FcPatternAddInteger (pat, FC_LCD_FILTER, ival);
-        }
-#ifdef FC_EMBOLDEN
-      else if (EQ (key, QCembolden))
-        FcPatternAddBool (pat, FC_EMBOLDEN, NILP (val) ? FcFalse : FcTrue);
-#endif
-    }
+  xftfont_add_rendering_parameters (pat, entity);
 
   FcPatternAddString (pat, FC_FILE, (FcChar8 *) SDATA (filename));
   FcPatternAddInteger (pat, FC_INDEX, XINT (index));
@@ -712,6 +723,53 @@ xftfont_end_for_frame (f)
   return 0;
 }
 
+static int
+xftfont_cached_font_ok (f, font_object, entity)
+     struct frame *f;
+     Lisp_Object font_object;
+     Lisp_Object entity;
+
+{
+  struct xftfont_info *info = (struct xftfont_info *) XFONT_OBJECT (font_object);
+  FcPattern *oldpat = info->xftfont->pattern;
+  Display *display = FRAME_X_DISPLAY (f);
+  FcPattern *pat = FcPatternCreate ();
+  FcBool b1, b2;
+  int ok = 0, i1, i2, r1, r2;
+
+  xftfont_add_rendering_parameters (pat, entity);
+  XftDefaultSubstitute (display, FRAME_X_SCREEN_NUMBER (f), pat);
+
+  r1 = FcPatternGetBool (pat, FC_ANTIALIAS, 0, &b1);
+  r2 = FcPatternGetBool (oldpat, FC_ANTIALIAS, 0, &b2);
+  if (r1 != r2 || b1 != b2) goto out;
+  r1 = FcPatternGetBool (pat, FC_HINTING, 0, &b1);
+  r2 = FcPatternGetBool (oldpat, FC_HINTING, 0, &b2);
+  if (r1 != r2 || b1 != b2) goto out;
+  r1 = FcPatternGetBool (pat, FC_AUTOHINT, 0, &b1);
+  r2 = FcPatternGetBool (oldpat, FC_AUTOHINT, 0, &b2);
+  if (r1 != r2 || b1 != b2) goto out;
+#ifdef FC_EMBOLDEN
+  r1 = FcPatternGetBool (pat, FC_EMBOLDEN, 0, &b1);
+  r2 = FcPatternGetBool (oldpat, FC_EMBOLDEN, 0, &b2);
+  if (r1 != r2 || b1 != b2) goto out;
+#endif
+  r1 = FcPatternGetInteger (pat, FC_HINT_STYLE, 0, &i1);
+  r2 = FcPatternGetInteger (oldpat, FC_HINT_STYLE, 0, &i2);
+  if (r1 != r2 || i1 != i2) goto out;
+  r1 = FcPatternGetInteger (pat, FC_LCD_FILTER, 0, &i1);
+  r2 = FcPatternGetInteger (oldpat, FC_LCD_FILTER, 0, &i2);
+  if (r1 != r2 || i1 != i2) goto out;
+  r1 = FcPatternGetInteger (pat, FC_RGBA, 0, &i1);
+  r2 = FcPatternGetInteger (oldpat, FC_RGBA, 0, &i2);
+  if (r1 != r2 || i1 != i2) goto out;
+
+  ok = 1;
+ out:
+  FcPatternDestroy (pat);
+  return ok;
+}
+
 void
 syms_of_xftfont ()
 {
@@ -737,6 +795,7 @@ syms_of_xftfont ()
   xftfont_driver.text_extents = xftfont_text_extents;
   xftfont_driver.draw = xftfont_draw;
   xftfont_driver.end_for_frame = xftfont_end_for_frame;
+  xftfont_driver.cached_font_ok = xftfont_cached_font_ok;
 
   register_font_driver (&xftfont_driver, NULL);
 }