Make default text size configurable in Settings

glow/src/backend.rs

@@ -18,6 +18,7 @@ pub struct Backend {
     quad_pipeline: quad::Pipeline,
     text_pipeline: text::Pipeline,
     triangle_pipeline: triangle::Pipeline,
+    default_text_size: u16,
 }
 
 impl Backend {
@@ -33,6 +34,7 @@ impl Backend {
             quad_pipeline,
             text_pipeline,
             triangle_pipeline,
+            default_text_size: settings.default_text_size,
         }
     }
 
@@ -192,6 +194,10 @@ impl backend::Text for Backend {
     const ICON_FONT: Font = font::ICONS;
     const CHECKMARK_ICON: char = font::CHECKMARK_ICON;
 
+    fn default_size(&self) -> u16 {
+        self.default_text_size
+    }
+
     fn measure(
         &self,
         contents: &str,

glow/src/settings.rs

@@ -11,6 +11,11 @@ pub struct Settings {
     /// If `None` is provided, a default system font will be chosen.
     pub default_font: Option<&'static [u8]>,
 
+    /// The default size of text.
+    ///
+    /// By default, it will be set to 20.
+    pub default_text_size: u16,
+
     /// The antialiasing strategy that will be used for triangle primitives.
     pub antialiasing: Option<Antialiasing>,
 }
@@ -19,6 +24,7 @@ impl Default for Settings {
     fn default() -> Settings {
         Settings {
             default_font: None,
+            default_text_size: 20,
             antialiasing: None,
         }
     }