Draft TextInput widget structure

Also started a `todos` example to showcase it!

wgpu/src/renderer/scrollable.rs

@@ -56,7 +56,7 @@ impl scrollable::Renderer for Renderer {
         let (content, mouse_cursor) =
             scrollable.content.draw(self, content, cursor_position);
 
-        let primitive = Primitive::Clip {
+        let clip = Primitive::Clip {
             bounds,
             offset,
             content: Box::new(content),
@@ -107,19 +107,15 @@ impl scrollable::Renderer for Renderer {
                     };
 
                     Primitive::Group {
-                        primitives: vec![
-                            primitive,
-                            scrollbar_background,
-                            scrollbar,
-                        ],
+                        primitives: vec![clip, scrollbar_background, scrollbar],
                     }
                 } else {
                     Primitive::Group {
-                        primitives: vec![primitive, scrollbar],
+                        primitives: vec![clip, scrollbar],
                     }
                 }
             } else {
-                primitive
+                clip
             },
             if is_mouse_over_scrollbar
                 || scrollable.state.is_scrollbar_grabbed()

wgpu/src/renderer/text_input.rs

@@ -0,0 +1,100 @@
+use crate::{Primitive, Renderer};
+
+use iced_native::{
+    text::HorizontalAlignment, text::VerticalAlignment, text_input, Background,
+    Color, MouseCursor, Point, Rectangle, TextInput,
+};
+use std::f32;
+
+impl text_input::Renderer for Renderer {
+    fn default_size(&self) -> u16 {
+        // TODO: Make this configurable
+        20
+    }
+
+    fn draw<Message>(
+        &mut self,
+        text_input: &TextInput<Message>,
+        bounds: Rectangle,
+        text_bounds: Rectangle,
+        cursor_position: Point,
+    ) -> Self::Output {
+        let is_mouse_over = bounds.contains(cursor_position);
+
+        let border = Primitive::Quad {
+            bounds,
+            background: Background::Color(if is_mouse_over {
+                Color {
+                    r: 0.5,
+                    g: 0.5,
+                    b: 0.5,
+                    a: 1.0,
+                }
+            } else {
+                Color {
+                    r: 0.7,
+                    g: 0.7,
+                    b: 0.7,
+                    a: 1.0,
+                }
+            }),
+            border_radius: 5,
+        };
+
+        let input = Primitive::Quad {
+            bounds: Rectangle {
+                x: bounds.x + 1.0,
+                y: bounds.y + 1.0,
+                width: bounds.width - 2.0,
+                height: bounds.height - 2.0,
+            },
+            background: Background::Color(Color::WHITE),
+            border_radius: 5,
+        };
+
+        let value = Primitive::Clip {
+            bounds: text_bounds,
+            offset: 0,
+            content: Box::new(Primitive::Text {
+                content: if text_input.value.is_empty() {
+                    text_input.placeholder.clone()
+                } else {
+                    text_input.value.clone()
+                },
+                color: if text_input.value.is_empty() {
+                    Color {
+                        r: 0.7,
+                        g: 0.7,
+                        b: 0.7,
+                        a: 1.0,
+                    }
+                } else {
+                    Color {
+                        r: 0.9,
+                        g: 0.9,
+                        b: 0.9,
+                        a: 1.0,
+                    }
+                },
+                bounds: Rectangle {
+                    width: f32::INFINITY,
+                    ..text_bounds
+                },
+                size: f32::from(text_input.size.unwrap_or(self.default_size())),
+                horizontal_alignment: HorizontalAlignment::Left,
+                vertical_alignment: VerticalAlignment::Center,
+            }),
+        };
+
+        (
+            Primitive::Group {
+                primitives: vec![border, input, value],
+            },
+            if is_mouse_over {
+                MouseCursor::Text
+            } else {
+                MouseCursor::OutOfBounds
+            },
+        )
+    }
+}