[style] you can override the default body text style

egui/src/containers/collapsing_header.rs

@@ -223,7 +223,7 @@ impl CollapsingHeader {
         painter.galley(
             text_pos,
             galley,
-            label.text_style,
+            label.text_style_or_default(ui.style()),
             ui.style().interact(&response).stroke.color,
         );
 

egui/src/containers/window.rs

@@ -201,8 +201,8 @@ impl<'open> Window<'open> {
         // First interact (move etc) to avoid frame delay:
         let last_frame_outer_rect = area.state().rect();
         let interaction = if possible.movable || possible.resizable {
-            let title_bar_height =
+            let title_bar_height = title_label.font_height(ctx.fonts(), &ctx.style())
-                title_label.font_height(ctx.fonts()) + 1.0 * ctx.style().spacing.item_spacing.y; // this could be better
+                + 1.0 * ctx.style().spacing.item_spacing.y; // this could be better
             let margins = 2.0 * frame.margin + vec2(0.0, title_bar_height);
 
             window_interaction(
@@ -596,7 +596,7 @@ fn show_title_bar(
     collapsible: bool,
 ) -> TitleBar {
     let title_bar_and_rect = ui.horizontal_centered(|ui| {
-        ui.set_desired_height(title_label.font_height(ui.fonts()));
+        ui.set_desired_height(title_label.font_height(ui.fonts(), ui.style()));
 
         let item_spacing = ui.style().spacing.item_spacing;
         let button_size = ui.style().spacing.icon_width;

egui/src/context.rs

@@ -527,6 +527,7 @@ impl Context {
 
     pub fn inspection_ui(&self, ui: &mut Ui) {
         use crate::containers::*;
+        ui.style_mut().body_text_style = TextStyle::Monospace;
 
         CollapsingHeader::new("Input")
             .default_open(true)

egui/src/paint/fonts.rs

@@ -13,7 +13,8 @@ use super::{
 
 // TODO: rename
 #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-// #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
 pub enum TextStyle {
     Body,
     Button,

egui/src/style.rs

@@ -1,11 +1,19 @@
 #![allow(clippy::if_same_then_else)]
 
-use crate::{color::*, math::*, paint::Stroke, types::*};
+use crate::{
+    color::*,
+    math::*,
+    paint::{Stroke, TextStyle},
+    types::*,
+};
 
 /// Specifies the look and feel of a `Ui`.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Style {
+    /// Default `TextStyle` for normal text (i.e. for `Label` and `TextEdit`).
+    pub body_text_style: TextStyle,
+
     pub spacing: Spacing,
     pub interaction: Interaction,
     pub visuals: Visuals,
@@ -166,6 +174,7 @@ pub struct WidgetVisuals {
 impl Default for Style {
     fn default() -> Self {
         Self {
+            body_text_style: TextStyle::Body,
             spacing: Spacing::default(),
             interaction: Interaction::default(),
             visuals: Visuals::default(),
@@ -265,11 +274,18 @@ impl Style {
         }
 
         let Self {
+            body_text_style,
             spacing,
             interaction,
             visuals,
             animation_time,
         } = self;
+        ui.horizontal_centered(|ui| {
+            ui.label("Default text style:");
+            for &value in &[TextStyle::Body, TextStyle::Monospace] {
+                ui.radio_value(format!("{:?}", value), body_text_style, value);
+            }
+        });
         ui.collapsing("Spacing", |ui| spacing.ui(ui));
         ui.collapsing("Interaction", |ui| interaction.ui(ui));
         ui.collapsing("Visuals", |ui| visuals.ui(ui));

egui/src/widgets.rs

@@ -30,7 +30,7 @@ pub struct Label {
     pub(crate) text: String,
     pub(crate) multiline: bool,
     auto_shrink: bool,
-    pub(crate) text_style: TextStyle, // TODO: Option<TextStyle>, where None means "use the default for the ui"
+    pub(crate) text_style: Option<TextStyle>,
     pub(crate) text_color: Option<Srgba>,
 }
 
@@ -40,7 +40,7 @@ impl Label {
             text: text.into(),
             multiline: true,
             auto_shrink: false,
-            text_style: TextStyle::Body,
+            text_style: None,
             text_color: None,
         }
     }
@@ -62,8 +62,9 @@ impl Label {
         self
     }
 
+    /// If you do not set a `TextStyle`, the default `style.text_style`.
     pub fn text_style(mut self, text_style: TextStyle) -> Self {
-        self.text_style = text_style;
+        self.text_style = Some(text_style);
         self
     }
 
@@ -86,7 +87,8 @@ impl Label {
     }
 
     pub fn layout_width(&self, ui: &Ui, max_width: f32) -> font::Galley {
-        let font = &ui.fonts()[self.text_style];
+        let text_style = self.text_style_or_default(ui.style());
+        let font = &ui.fonts()[text_style];
         if self.multiline {
             font.layout_multiline(self.text.clone(), max_width) // TODO: avoid clone
         } else {
@@ -94,8 +96,9 @@ impl Label {
         }
     }
 
-    pub fn font_height(&self, fonts: &Fonts) -> f32 {
+    pub fn font_height(&self, fonts: &Fonts, style: &Style) -> f32 {
-        fonts[self.text_style].height()
+        let text_style = self.text_style_or_default(style);
+        fonts[text_style].height()
     }
 
     // TODO: this should return a LabelLayout which has a paint method.
@@ -107,11 +110,16 @@ impl Label {
     // This should be the easiest method of putting text anywhere.
 
     pub fn paint_galley(&self, ui: &mut Ui, pos: Pos2, galley: font::Galley) {
+        let text_style = self.text_style_or_default(ui.style());
         let text_color = self
             .text_color
             .unwrap_or_else(|| ui.style().visuals.text_color);
-        ui.painter()
+        ui.painter().galley(pos, galley, text_style, text_color);
-            .galley(pos, galley, self.text_style, text_color);
+    }
+
+    /// Read the text style, or get the default for the current style
+    pub fn text_style_or_default(&self, style: &Style) -> TextStyle {
+        self.text_style.unwrap_or_else(|| style.body_text_style)
     }
 }
 
@@ -180,7 +188,7 @@ impl Widget for Hyperlink {
         let Hyperlink { url, text } = self;
 
         let color = color::LIGHT_BLUE;
-        let text_style = TextStyle::Body;
+        let text_style = ui.style().body_text_style;
         let id = ui.make_child_id(&url);
         let font = &ui.fonts()[text_style];
         let galley = font.layout_multiline(text, ui.available().width());

egui/src/widgets/text_edit.rs

@@ -14,7 +14,7 @@ pub struct TextEdit<'t> {
     text: &'t mut String,
     id: Option<Id>,
     id_source: Option<Id>,
-    text_style: TextStyle, // TODO: Option<TextStyle>, where None means "use the default for the current Ui"
+    text_style: Option<TextStyle>,
     text_color: Option<Srgba>,
     multiline: bool,
     enabled: bool,
@@ -27,7 +27,7 @@ impl<'t> TextEdit<'t> {
             text,
             id: None,
             id_source: None,
-            text_style: TextStyle::Body,
+            text_style: None,
             text_color: None,
             multiline: true,
             enabled: true,
@@ -46,7 +46,7 @@ impl<'t> TextEdit<'t> {
     }
 
     pub fn text_style(mut self, text_style: TextStyle) -> Self {
-        self.text_style = text_style;
+        self.text_style = Some(text_style);
         self
     }
 
@@ -90,6 +90,7 @@ impl<'t> Widget for TextEdit<'t> {
 
         let mut state = ui.memory().text_edit.get(&id).cloned().unwrap_or_default();
 
+        let text_style = text_style.unwrap_or_else(|| ui.style().body_text_style);
         let font = &ui.fonts()[text_style];
         let line_spacing = font.line_spacing();
         let available_width = ui.available().width();