Expose text layout functions in Painter

egui/src/painter.rs

@@ -299,6 +299,9 @@ impl Painter {
     ///
     /// To center the text at the given position, use `anchor: (Center, Center)`.
     ///
+    /// To find out the size of text before painting it, use
+    /// [`Self::layout_no_wrap`] or [`Self::layout_multiline`].
+    ///
     /// Returns where the text ended up.
     #[allow(clippy::needless_pass_by_value)]
     pub fn text(
@@ -309,15 +312,40 @@ impl Painter {
         text_style: TextStyle,
         text_color: Color32,
     ) -> Rect {
-        let galley = self
+        let galley = self.layout_no_wrap(text_style, text.to_string());
-            .fonts()
-            .layout_multiline(text_style, text.to_string(), f32::INFINITY);
         let rect = anchor.anchor_rect(Rect::from_min_size(pos, galley.size));
         self.galley(rect.min, galley, text_color);
         rect
     }
 
-    /// Paint text that has already been layed out in a `Galley`.
+    /// Will line break at `\n`.
+    ///
+    /// Paint the results with [`Self::galley`].
+    /// Always returns at least one row.
+    #[inline(always)]
+    pub fn layout_no_wrap(&self, text_style: TextStyle, text: String) -> std::sync::Arc<Galley> {
+        self.layout_multiline(text_style, text, f32::INFINITY)
+    }
+
+    /// Will wrap text at the given width and line break at `\n`.
+    ///
+    /// Paint the results with [`Self::galley`].
+    /// Always returns at least one row.
+    #[inline(always)]
+    pub fn layout_multiline(
+        &self,
+        text_style: TextStyle,
+        text: String,
+        max_width_in_points: f32,
+    ) -> std::sync::Arc<Galley> {
+        self.fonts()
+            .layout_multiline(text_style, text, max_width_in_points)
+    }
+
+    /// Paint text that has already been layed out in a [`Galley`].
+    ///
+    /// You can create the `Galley` with [`Self::layout_no_wrap`] or [`Self::layout_multiline`].
+    #[inline(always)]
     pub fn galley(&self, pos: Pos2, galley: std::sync::Arc<Galley>, color: Color32) {
         self.galley_with_italics(pos, galley, color, false)
     }