Add image::Viewer widget

.github/workflows/test.yml

@@ -29,5 +29,5 @@ jobs:
       run: cargo check --package iced --target wasm32-unknown-unknown
     - name: Check compilation of `tour` example
       run: cargo build --package tour --target wasm32-unknown-unknown
-    - name: Check compilation of `pokedex` example
-      run: cargo build --package pokedex --target wasm32-unknown-unknown
+    - name: Check compilation of `todos` example
+      run: cargo build --package todos --target wasm32-unknown-unknown

examples/pokedex/src/main.rs

@@ -1,6 +1,6 @@
 use iced::{
     button, futures, image, Align, Application, Button, Column, Command,
-    Container, Element, Image, Length, Row, Settings, Text,
+    Container, Element, Length, Row, Settings, Text,
 };
 
 pub fn main() -> iced::Result {
@@ -112,16 +112,20 @@ struct Pokemon {
     name: String,
     description: String,
     image: image::Handle,
+    image_viewer: image::viewer::State,
 }
 
 impl Pokemon {
     const TOTAL: u16 = 807;
 
-    fn view(&self) -> Element<Message> {
+    fn view(&mut self) -> Element<Message> {
         Row::new()
             .spacing(20)
             .align_items(Align::Center)
-            .push(Image::new(self.image.clone()))
+            .push(image::Viewer::new(
+                &mut self.image_viewer,
+                self.image.clone(),
+            ))
             .push(
                 Column::new()
                     .spacing(20)
@@ -200,6 +204,7 @@ impl Pokemon {
                 .map(|c| if c.is_control() { ' ' } else { c })
                 .collect(),
             image,
+            image_viewer: image::viewer::State::new(),
         })
     }
 

graphics/src/widget/image.rs

@@ -1,11 +1,14 @@
 //! Display images in your user interface.
+pub mod viewer;
+
 use crate::backend::{self, Backend};
+
 use crate::{Primitive, Renderer};
 use iced_native::image;
 use iced_native::mouse;
 use iced_native::Layout;
 
-pub use iced_native::image::{Handle, Image};
+pub use iced_native::image::{Handle, Image, Viewer};
 
 impl<B> image::Renderer for Renderer<B>
 where

graphics/src/widget/image/viewer.rs

@@ -0,0 +1,55 @@
+//! Zoom and pan on an image.
+use crate::backend::{self, Backend};
+use crate::{Primitive, Renderer};
+
+use iced_native::image;
+use iced_native::image::viewer;
+use iced_native::mouse;
+use iced_native::{Rectangle, Size, Vector};
+
+impl<B> viewer::Renderer for Renderer<B>
+where
+    B: Backend + backend::Image,
+{
+    fn draw(
+        &mut self,
+        state: &viewer::State,
+        bounds: Rectangle,
+        image_size: Size,
+        translation: Vector,
+        handle: image::Handle,
+        is_mouse_over: bool,
+    ) -> Self::Output {
+        (
+            {
+                Primitive::Clip {
+                    bounds,
+                    content: Box::new(Primitive::Translate {
+                        translation,
+                        content: Box::new(Primitive::Image {
+                            handle,
+                            bounds: Rectangle {
+                                x: bounds.x,
+                                y: bounds.y,
+                                ..Rectangle::with_size(image_size)
+                            },
+                        }),
+                    }),
+                    offset: Vector::new(0, 0),
+                }
+            },
+            {
+                if state.is_cursor_grabbed() {
+                    mouse::Interaction::Grabbing
+                } else if is_mouse_over
+                    && (image_size.width > bounds.width
+                        || image_size.height > bounds.height)
+                {
+                    mouse::Interaction::Grab
+                } else {
+                    mouse::Interaction::Idle
+                }
+            },
+        )
+    }
+}

native/src/widget/image.rs

@@ -1,4 +1,7 @@
 //! Display images in your user interface.
+pub mod viewer;
+pub use viewer::Viewer;
+
 use crate::layout;
 use crate::{Element, Hasher, Layout, Length, Point, Rectangle, Size, Widget};