[geary/wip/713746-document-font] Initial commit from patch (bgo#713746)

[Jim Nelson <jnelson src gnome org>]

commit 9950a4f35b7d4a1b0ea16ecad8877bc819752499
Author: Timo Kluck <tkluck infty nl>
Date:   Tue Jan 21 11:21:09 2014 -0800

    Initial commit from patch (bgo#713746)

 src/client/application/geary-config.vala           |    2 +-
 .../conversation-viewer/conversation-web-view.vala |   43 ++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletions(-)
---
diff --git a/src/client/application/geary-config.vala b/src/client/application/geary-config.vala
index 16d98ce..156a404 100644
--- a/src/client/application/geary-config.vala
+++ b/src/client/application/geary-config.vala
@@ -20,8 +20,8 @@ public class Configuration {
     public const string COMPOSE_AS_HTML_KEY = "compose-as-html";
     
     public Settings settings { get; private set; }
+    public Settings gnome_interface { get; private set; }
     
-    private Settings gnome_interface;
     private Settings? indicator_datetime;
     
     public int window_width {
diff --git a/src/client/conversation-viewer/conversation-web-view.vala 
b/src/client/conversation-viewer/conversation-web-view.vala
index 7c85a90..d5331e0 100644
--- a/src/client/conversation-viewer/conversation-web-view.vala
+++ b/src/client/conversation-viewer/conversation-web-view.vala
@@ -14,6 +14,9 @@ public class ConversationWebView : WebKit.WebView {
     private const string STYLE_NAME = "STYLE";
     private const string PREVENT_HIDE_STYLE = "nohide";
     
+    private const double MM_PER_INCH = 25.4;
+    private const double POINTS_PER_INCH = 72.0;
+    
     // HTML element that contains message DIVs.
     public WebKit.DOM.HTMLDivElement? container { get; private set; default = null; }
     
@@ -34,6 +37,9 @@ public class ConversationWebView : WebKit.WebView {
         config.enable_plugins = false;
         config.enable_developer_extras = Args.inspector;
         settings = config;
+
+        Configuration geary_config = GearyApplication.instance.config;
+        geary_config.gnome_interface.bind("document-font-name", this, "desktop-document-font", 
SettingsBindFlags.DEFAULT);
         
         // Hook up signals.
         load_finished.connect(on_load_finished);
@@ -150,6 +156,43 @@ public class ConversationWebView : WebKit.WebView {
         set_icon_src("#link_warning_template .close_link_warning", "close-symbolic");
     }
     
+    private double get_screen_dpi() {
+        Gdk.Screen screen = get_screen();
+        if (screen == null)
+            return 96.0;
+        double dpi = screen.get_resolution();
+        if (dpi != -1)
+            return dpi;
+        
+        double dp = Math.hypot(screen.get_width(), screen.get_height());
+        double di = Math.hypot(screen.get_width_mm(), screen.get_height_mm()) / MM_PER_INCH;
+    
+        return dp / di;
+    }
+    
+    private string _desktop_document_font;
+    public string desktop_document_font {
+        set {
+            Pango.FontDescription font_desc = Pango.FontDescription.from_string(value);
+            double dpi = get_screen_dpi();
+            double size_in_pixels;
+            if (font_desc.get_size_is_absolute()) {
+                size_in_pixels = font_desc.get_size() / (double) Pango.SCALE;
+            } else {
+                size_in_pixels = font_desc.get_size() * (dpi / POINTS_PER_INCH) / Pango.SCALE;
+            }
+            WebKit.WebSettings config = settings;
+            config.default_font_family = font_desc.get_family();
+            config.default_font_size = (int) size_in_pixels;
+            settings = config;
+            _desktop_document_font = value;
+        }
+        
+        get {
+            return _desktop_document_font;
+        }
+    }
+    
     private void load_user_style() {
         try {
             WebKit.DOM.Document document = get_dom_document();