[metacity] libmetacity: add meta_theme_set_dpi

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 8823b220ae3e8718d598d738d99829b08f826b40
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Apr 2 19:05:58 2017 +0300

    libmetacity: add meta_theme_set_dpi

 libmetacity/meta-theme.c |   18 +++++++++++++++++-
 libmetacity/meta-theme.h |    3 +++
 src/ui/ui.c              |    2 ++
 3 files changed, 22 insertions(+), 1 deletions(-)
---
diff --git a/libmetacity/meta-theme.c b/libmetacity/meta-theme.c
index 02b29fa..3227d6a 100644
--- a/libmetacity/meta-theme.c
+++ b/libmetacity/meta-theme.c
@@ -45,6 +45,7 @@ struct _MetaTheme
 
   gboolean              composited;
   gint                  scale;
+  gdouble               dpi;
 
   PangoFontDescription *titlebar_font;
 
@@ -292,7 +293,7 @@ ensure_pango_context (MetaTheme *theme)
   options = gdk_screen_get_font_options (screen);
   pango_cairo_context_set_font_options (context, options);
 
-  dpi = gdk_screen_get_resolution (screen);
+  dpi = theme->dpi * theme->scale;
   pango_cairo_context_set_resolution (context, dpi);
 
   theme->context = context;
@@ -601,6 +602,7 @@ meta_theme_init (MetaTheme *theme)
 {
   theme->composited = TRUE;
   theme->scale = 1;
+  theme->dpi = 96.0;
 
   theme->variants = g_hash_table_new_full (g_str_hash, g_str_equal,
                                            g_free, g_object_unref);
@@ -808,6 +810,20 @@ meta_theme_set_composited (MetaTheme *theme,
 }
 
 void
+meta_theme_set_dpi (MetaTheme *theme,
+                    gdouble    dpi)
+{
+  if (theme->dpi == dpi)
+    return;
+
+  theme->dpi = dpi;
+
+  g_clear_object (&theme->context);
+  g_hash_table_remove_all (theme->font_descs);
+  g_hash_table_remove_all (theme->title_heights);
+}
+
+void
 meta_theme_set_scale (MetaTheme *theme,
                       gint       scale)
 {
diff --git a/libmetacity/meta-theme.h b/libmetacity/meta-theme.h
index c544bd3..622c8c3 100644
--- a/libmetacity/meta-theme.h
+++ b/libmetacity/meta-theme.h
@@ -125,6 +125,9 @@ void           meta_theme_set_composited    (MetaTheme                   *theme,
 void           meta_theme_set_scale         (MetaTheme                   *theme,
                                              gint                         scale);
 
+void           meta_theme_set_dpi           (MetaTheme                   *theme,
+                                             gdouble                      dpi);
+
 void           meta_theme_set_titlebar_font (MetaTheme                   *theme,
                                              const PangoFontDescription  *titlebar_font);
 
diff --git a/src/ui/ui.c b/src/ui/ui.c
index f2b9b05..06c14f8 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -114,6 +114,7 @@ notify_gtk_xft_dpi_cb (GtkSettings *settings,
   ui->dpi = get_xft_dpi (ui);
 
   meta_theme_set_scale (ui->theme, ui->scale);
+  meta_theme_set_dpi (ui->theme, ui->dpi);
 }
 
 void
@@ -823,6 +824,7 @@ load_theme (MetaUI        *ui,
 
   meta_theme_set_composited (theme, ui->composited);
   meta_theme_set_scale (theme, ui->scale);
+  meta_theme_set_dpi (theme, ui->dpi);
 
   titlebar_font = meta_prefs_get_titlebar_font ();
   meta_theme_set_titlebar_font (theme, titlebar_font);