Merge remote-tracking branch 'tarkah/image-pane' into image-pane

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 +1,51 @@
+//! Zoom and pan on an image.
+use crate::backend::{self, Backend};
+use crate::{Primitive, Renderer};
+
+use iced_native::{
+    image::{self, viewer},
+    mouse, Rectangle, Vector,
+};
+
+impl<B> viewer::Renderer for Renderer<B>
+where
+    B: Backend + backend::Image,
+{
+    fn draw(
+        &mut self,
+        state: &viewer::State,
+        bounds: Rectangle,
+        image_bounds: Rectangle,
+        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: image_bounds,
+                        }),
+                    }),
+                    offset: Vector::new(0, 0),
+                }
+            },
+            {
+                if state.is_cursor_clicked() {
+                    mouse::Interaction::Grabbing
+                } else if is_mouse_over
+                    && (image_bounds.width > bounds.width
+                        || image_bounds.height > bounds.height)
+                {
+                    mouse::Interaction::Grab
+                } else {
+                    mouse::Interaction::Idle
+                }
+            },
+        )
+    }
+}