Add fake italics (tilt text)

CHANGELOG.md

@@ -12,9 +12,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Added ⭐
 
 * Add support for secondary and middle mouse buttons.
+* Add `Label` methods for code, strong, strikethrough, underline and italics.
 * `egui::popup::popup_below_widget`: show a popup area below another widget.
 * Add `Slider::clamp_to_range(bool)`: if set, clamp the incoming and outgoing values to the slider range.
-* Add `Label` methods for code, strong, strikethrough and underline.
 
 ### Changed 🔧
 

egui/src/painter.rs

@@ -269,11 +269,23 @@ impl Painter {
 
     /// Paint text that has already been layed out in a `Galley`.
     pub fn galley(&self, pos: Pos2, galley: Galley, text_style: TextStyle, color: Color32) {
+        self.galley_with_italics(pos, galley, text_style, color, false)
+    }
+
+    pub fn galley_with_italics(
+        &self,
+        pos: Pos2,
+        galley: Galley,
+        text_style: TextStyle,
+        color: Color32,
+        fake_italics: bool,
+    ) {
         self.add(Shape::Text {
             pos,
             galley,
             text_style,
             color,
+            fake_italics,
         });
     }
 }

egui/src/widgets/label.rs

@@ -13,6 +13,7 @@ pub struct Label {
     strong: bool,
     strikethrough: bool,
     underline: bool,
+    italics: bool,
 }
 
 impl Label {
@@ -27,6 +28,7 @@ impl Label {
             strong: false,
             strikethrough: false,
             underline: false,
+            italics: false,
         }
     }
 
@@ -83,6 +85,12 @@ impl Label {
         self
     }
 
+    /// tilt the characters to the right.
+    pub fn italics(mut self) -> Self {
+        self.italics = true;
+        self
+    }
+
     pub fn small(self) -> Self {
         self.text_style(TextStyle::Small)
     }
@@ -133,6 +141,7 @@ impl Label {
             strong,
             strikethrough,
             underline,
+            italics,
             ..
         } = *self;
 
@@ -173,7 +182,8 @@ impl Label {
         }
 
         let text_style = self.text_style_or_default(ui.style());
-        ui.painter().galley(pos, galley, text_style, text_color);
+        ui.painter()
+            .galley_with_italics(pos, galley, text_style, text_color, italics);
     }
 
     /// Read the text style, or get the default for the current style

epaint/src/mesh.rs

@@ -114,37 +114,33 @@ impl Mesh {
     }
 
     /// Rectangle with a texture and color.
-    pub fn add_rect_with_uv(&mut self, pos: Rect, uv: Rect, color: Color32) {
+    pub fn add_rect_with_uv(&mut self, rect: Rect, uv: Rect, color: Color32) {
         #![allow(clippy::identity_op)]
 
         let idx = self.vertices.len() as u32;
         self.add_triangle(idx + 0, idx + 1, idx + 2);
         self.add_triangle(idx + 2, idx + 1, idx + 3);
 
-        let right_top = Vertex {
+        self.vertices.push(Vertex {
-            pos: pos.right_top(),
+            pos: rect.left_top(),
-            uv: uv.right_top(),
-            color,
-        };
-        let left_top = Vertex {
-            pos: pos.left_top(),
             uv: uv.left_top(),
             color,
-        };
+        });
-        let left_bottom = Vertex {
+        self.vertices.push(Vertex {
-            pos: pos.left_bottom(),
+            pos: rect.right_top(),
+            uv: uv.right_top(),
+            color,
+        });
+        self.vertices.push(Vertex {
+            pos: rect.left_bottom(),
             uv: uv.left_bottom(),
             color,
-        };
+        });
-        let right_bottom = Vertex {
+        self.vertices.push(Vertex {
-            pos: pos.right_bottom(),
+            pos: rect.right_bottom(),
             uv: uv.right_bottom(),
             color,
-        };
+        });
-        self.vertices.push(left_top);
-        self.vertices.push(right_top);
-        self.vertices.push(left_bottom);
-        self.vertices.push(right_bottom);
     }
 
     /// Uniformly colored rectangle.

epaint/src/shape.rs

@@ -46,6 +46,8 @@ pub enum Shape {
         galley: Galley,
         text_style: TextStyle, // TODO: Font?
         color: Color32,
+        /// If true, tilt the letters for an ugly italics effect
+        fake_italics: bool,
     },
     Mesh(Mesh),
 }
@@ -138,6 +140,7 @@ impl Shape {
             galley,
             text_style,
             color,
+            fake_italics: false,
         }
     }
 }

epaint/src/tessellator.rs

@@ -545,6 +545,7 @@ impl Tessellator {
                 galley,
                 text_style,
                 color,
+                fake_italics,
             } => {
                 if options.debug_paint_text_rects {
                     self.tessellate_rect(
@@ -557,7 +558,7 @@ impl Tessellator {
                         out,
                     );
                 }
-                self.tessellate_text(fonts, pos, &galley, text_style, color, out);
+                self.tessellate_text(fonts, pos, &galley, text_style, color, fake_italics, out);
             }
         }
     }
@@ -592,6 +593,7 @@ impl Tessellator {
         stroke_path(&path.0, Closed, stroke, self.options, out);
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub fn tessellate_text(
         &mut self,
         fonts: &Fonts,
@@ -599,6 +601,7 @@ impl Tessellator {
         galley: &super::Galley,
         text_style: super::TextStyle,
         color: Color32,
+        fake_italics: bool,
         out: &mut Mesh,
     ) {
         if color == Color32::TRANSPARENT {
@@ -636,12 +639,42 @@ impl Tessellator {
                     left_top.x = font.round_to_pixel(left_top.x); // Pixel-perfection.
                     left_top.y = font.round_to_pixel(left_top.y); // Pixel-perfection.
 
-                    let pos = Rect::from_min_max(left_top, left_top + glyph.size);
+                    let rect = Rect::from_min_max(left_top, left_top + glyph.size);
                     let uv = Rect::from_min_max(
                         pos2(glyph.min.0 as f32 / tex_w, glyph.min.1 as f32 / tex_h),
                         pos2(glyph.max.0 as f32 / tex_w, glyph.max.1 as f32 / tex_h),
                     );
-                    out.add_rect_with_uv(pos, uv, color);
+
+                    if fake_italics {
+                        let idx = out.vertices.len() as u32;
+                        out.add_triangle(idx, idx + 1, idx + 2);
+                        out.add_triangle(idx + 2, idx + 1, idx + 3);
+
+                        let top_offset = rect.height() * 0.25 * Vec2::X;
+
+                        out.vertices.push(Vertex {
+                            pos: rect.left_top() + top_offset,
+                            uv: uv.left_top(),
+                            color,
+                        });
+                        out.vertices.push(Vertex {
+                            pos: rect.right_top() + top_offset,
+                            uv: uv.right_top(),
+                            color,
+                        });
+                        out.vertices.push(Vertex {
+                            pos: rect.left_bottom(),
+                            uv: uv.left_bottom(),
+                            color,
+                        });
+                        out.vertices.push(Vertex {
+                            pos: rect.right_bottom(),
+                            uv: uv.right_bottom(),
+                            color,
+                        });
+                    } else {
+                        out.add_rect_with_uv(rect, uv, color);
+                    }
                 }
             }
             if line.ends_with_newline {