Added DPI option to GlyphOptions to indicate the DPI for glyph raster…

…ization

webrender/src/display_list_flattener.rs

@@ -689,6 +689,7 @@ impl<'a> DisplayListFlattener<'a> {
                     item.glyphs(),
                     item.display_list().get(item.glyphs()).count(),
                     text_info.glyph_options,
+                    text_info.glyph_options.and_then(|options| options.dpi),
                 );
             }
             SpecificDisplayItem::Rectangle(ref info) => {
@@ -2010,6 +2011,7 @@ impl<'a> DisplayListFlattener<'a> {
         glyph_range: ItemRange<GlyphInstance>,
         glyph_count: usize,
         glyph_options: Option<GlyphOptions>,
+        dpi: Option<u32>,
     ) {
         let prim = {
             let instance_map = self.font_instances.read().unwrap();
@@ -2074,6 +2076,7 @@ impl<'a> DisplayListFlattener<'a> {
                 flags,
                 font_instance.platform_options,
                 font_instance.variations.clone(),
+                dpi,
             );
             TextRunPrimitiveCpu {
                 font: prim_font,

webrender/src/glyph_rasterizer.rs

@@ -147,6 +147,9 @@ pub struct FontInstance {
     //           or something similar to that.
     pub size: Au,
     pub color: ColorU,
+    /// DPI of the monitor that this font will be rendered with. 
+    /// Used by `FT_Set_Char_Size`. If set to `None`, will be 72 DPI
+    pub dpi: Option<u32>,
     pub bg_color: ColorU,
     pub render_mode: FontRenderMode,
     pub subpx_dir: SubpixelDirection,
@@ -167,11 +170,13 @@ impl FontInstance {
         flags: FontInstanceFlags,
         platform_options: Option<FontInstancePlatformOptions>,
         variations: Vec<FontVariation>,
+        dpi: Option<u32>,
     ) -> Self {
         FontInstance {
             font_key,
             size,
             color: color.into(),
+            dpi,
             bg_color,
             render_mode,
             subpx_dir,

webrender/src/platform/unix/font.rs

@@ -305,14 +305,15 @@ impl FontContext {
                 yx: (shape.skew_y * -65536.0) as FT_Fixed,
                 yy: (shape.scale_y * 65536.0) as FT_Fixed,
             };
+            let dpi = font.dpi.unwrap_or(72);
             unsafe {
                 FT_Set_Transform(face.face, &mut ft_shape, ptr::null_mut());
                 FT_Set_Char_Size(
                     face.face,
                     (req_size * x_scale * 64.0 + 0.5) as FT_F26Dot6,
                     (req_size * y_scale * 64.0 + 0.5) as FT_F26Dot6,
-                    0,
-                    0,
+                    dpi,
+                    dpi,
                 )
             }
         };

webrender/src/renderer.rs

@@ -1525,6 +1525,7 @@ impl Renderer {
             }
         })?;
 
+        let dpi = options.dpi;
         thread::Builder::new().name(rb_thread_name.clone()).spawn(move || {
             register_thread_with_profiler(rb_thread_name.clone());
             if let Some(ref thread_listener) = *thread_listener_for_render_backend {
@@ -1537,6 +1538,7 @@ impl Renderer {
                 texture_cache,
                 glyph_rasterizer,
                 blob_image_renderer,
+                dpi,
             );
 
             let mut backend = RenderBackend::new(
@@ -3854,6 +3856,8 @@ pub trait ThreadListener {
 
 pub struct RendererOptions {
     pub device_pixel_ratio: f32,
+    /// DPI of the monitor
+    pub dpi: Option<u32>,
     pub resource_override_path: Option<PathBuf>,
     pub enable_aa: bool,
     pub enable_dithering: bool,
@@ -3882,6 +3886,7 @@ impl Default for RendererOptions {
     fn default() -> Self {
         RendererOptions {
             device_pixel_ratio: 1.0,
+            dpi: None,
             resource_override_path: None,
             enable_aa: true,
             enable_dithering: true,

webrender/src/resource_cache.rs

@@ -254,7 +254,7 @@ pub struct ResourceCache {
     cached_glyphs: GlyphCache,
     cached_images: ImageCache,
     cached_render_tasks: RenderTaskCache,
-
+    dpi: Option<u32>,
     resources: Resources,
     state: State,
     current_frame_id: FrameId,
@@ -278,6 +278,7 @@ impl ResourceCache {
         texture_cache: TextureCache,
         glyph_rasterizer: GlyphRasterizer,
         blob_image_renderer: Option<Box<BlobImageRenderer>>,
+        dpi: Option<u32>,
     ) -> Self {
         ResourceCache {
             cached_glyphs: GlyphCache::new(),
@@ -291,6 +292,7 @@ impl ResourceCache {
             pending_image_requests: FastHashSet::default(),
             glyph_rasterizer,
             blob_image_renderer,
+            dpi,
         }
     }
 
@@ -426,6 +428,7 @@ impl ResourceCache {
             flags,
             platform_options,
             variations,
+            self.dpi,
         );
         self.resources.font_instances
             .write()

webrender_api/src/font.rs

@@ -199,13 +199,16 @@ impl Hash for FontVariation {
 pub struct GlyphOptions {
     pub render_mode: FontRenderMode,
     pub flags: FontInstanceFlags,
+    /// The DPI used for rasterizing this font
+    pub dpi: Option<u32>,
 }
 
 impl Default for GlyphOptions {
     fn default() -> Self {
         GlyphOptions {
             render_mode: FontRenderMode::Subpixel,
             flags: FontInstanceFlags::empty(),
+            dpi: None,
         }
     }
 }