Allow to load an image from memory

New `image::Handle` opaque type uniquely identifying some `image::Data`,
allowing reliable caching.

5 files changed, 133 insertions, 33 deletions

diff --git a/native/src/widget/image.rs b/native/src/widget/image.rs
index 4c588c9d..c82525e4 100644
--- a/native/src/widget/image.rs
+++ b/native/src/widget/image.rs
@@ -2,7 +2,11 @@
 
 use crate::{layout, Element, Hasher, Layout, Length, Point, Size, Widget};
 
-use std::hash::Hash;
+use std::{
+    hash::{Hash, Hasher as _},
+    path::PathBuf,
+    rc::Rc,
+};
 
 /// A frame that displays an image while keeping aspect ratio.
 ///
@@ -17,7 +21,7 @@ use std::hash::Hash;
 /// <img src="https://github.com/hecrj/iced/blob/9712b319bb7a32848001b96bd84977430f14b623/examples/resources/ferris.png?raw=true" width="300">
 #[derive(Debug)]
 pub struct Image {
-    path: String,
+    handle: Handle,
     width: Length,
     height: Length,
 }
@@ -26,9 +30,9 @@ impl Image {
     /// Creates a new [`Image`] with the given path.
     ///
     /// [`Image`]: struct.Image.html
-    pub fn new<T: Into<String>>(path: T) -> Self {
+    pub fn new<T: Into<Handle>>(handle: T) -> Self {
         Image {
-            path: path.into(),
+            handle: handle.into(),
             width: Length::Shrink,
             height: Length::Shrink,
         }
@@ -68,7 +72,7 @@ where
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let (width, height) = renderer.dimensions(&self.path);
+        let (width, height) = renderer.dimensions(&self.handle);
 
         let aspect_ratio = width as f32 / height as f32;
 
@@ -96,7 +100,7 @@ where
         layout: Layout<'_>,
         _cursor_position: Point,
     ) -> Renderer::Output {
-        renderer.draw(&self.path, layout)
+        renderer.draw(self.handle.clone(), layout)
     }
 
     fn hash_layout(&self, state: &mut Hasher) {
@@ -105,6 +109,79 @@ where
     }
 }
 
+/// An [`Image`] handle.
+///
+/// [`Image`]: struct.Image.html
+#[derive(Debug, Clone)]
+pub struct Handle {
+    id: u64,
+    data: Rc<Data>,
+}
+
+impl Handle {
+    /// Creates an image [`Handle`] pointing to the image of the given path.
+    ///
+    /// [`Handle`]: struct.Handle.html
+    pub fn from_path<T: Into<PathBuf>>(path: T) -> Handle {
+        Self::from_data(Data::Path(path.into()))
+    }
+
+    /// Creates an image [`Handle`] containing the image data directly.
+    ///
+    /// [`Handle`]: struct.Handle.html
+    pub fn from_bytes(bytes: Vec<u8>) -> Handle {
+        Self::from_data(Data::Bytes(bytes))
+    }
+
+    fn from_data(data: Data) -> Handle {
+        let mut hasher = Hasher::default();
+        data.hash(&mut hasher);
+
+        Handle {
+            id: hasher.finish(),
+            data: Rc::new(data),
+        }
+    }
+
+    /// Returns the uniquie identifier of the [`Handle`].
+    ///
+    /// [`Handle`]: struct.Handle.html
+    pub fn id(&self) -> u64 {
+        self.id
+    }
+
+    /// Returns a reference to the image [`Data`].
+    ///
+    /// [`Data`]: enum.Data.html
+    pub fn data(&self) -> &Data {
+        &self.data
+    }
+}
+
+impl From<String> for Handle {
+    fn from(path: String) -> Handle {
+        Handle::from_path(path)
+    }
+}
+
+impl From<&str> for Handle {
+    fn from(path: &str) -> Handle {
+        Handle::from_path(path)
+    }
+}
+
+/// The data of an [`Image`].
+///
+/// [`Image`]: struct.Image.html
+#[derive(Debug, Clone, Hash)]
+pub enum Data {
+    /// File data
+    Path(PathBuf),
+
+    /// In-memory data
+    Bytes(Vec<u8>),
+}
+
 /// The renderer of an [`Image`].
 ///
 /// Your [renderer] will need to implement this trait before being able to use
@@ -116,12 +193,12 @@ pub trait Renderer: crate::Renderer {
     /// Returns the dimensions of an [`Image`] located on the given path.
     ///
     /// [`Image`]: struct.Image.html
-    fn dimensions(&self, path: &str) -> (u32, u32);
+    fn dimensions(&self, handle: &Handle) -> (u32, u32);
 
     /// Draws an [`Image`].
     ///
     /// [`Image`]: struct.Image.html
-    fn draw(&mut self, path: &str, layout: Layout<'_>) -> Self::Output;
+    fn draw(&mut self, handle: Handle, layout: Layout<'_>) -> Self::Output;
 }
 
 impl<'a, Message, Renderer> From<Image> for Element<'a, Message, Renderer>
diff --git a/wgpu/src/image.rs b/wgpu/src/image.rs
index 5dc972ac..479eb841 100644
--- a/wgpu/src/image.rs
+++ b/wgpu/src/image.rs
@@ -1,11 +1,14 @@
 use crate::Transformation;
-use iced_native::Rectangle;
+use iced_native::{
+    image::{Data, Handle},
+    Rectangle,
+};
 
 use std::{cell::RefCell, collections::HashMap, mem, rc::Rc};
 
 #[derive(Debug)]
 pub struct Pipeline {
-    cache: RefCell<HashMap<String, Memory>>,
+    cache: RefCell<HashMap<u64, Memory>>,
 
     pipeline: wgpu::RenderPipeline,
     uniforms: wgpu::Buffer,
@@ -197,23 +200,36 @@ impl Pipeline {
         }
     }
 
-    pub fn dimensions(&self, path: &str) -> (u32, u32) {
-        self.load(path);
+    pub fn dimensions(&self, handle: &Handle) -> (u32, u32) {
+        self.load(handle);
 
-        self.cache.borrow().get(path).unwrap().dimensions()
+        self.cache.borrow().get(&handle.id()).unwrap().dimensions()
     }
 
-    fn load(&self, path: &str) {
-        if !self.cache.borrow().contains_key(path) {
-            let memory = if let Ok(image) = image::open(path) {
-                Memory::Host {
-                    image: image.to_bgra(),
+    fn load(&self, handle: &Handle) {
+        if !self.cache.borrow().contains_key(&handle.id()) {
+            let memory = match handle.data() {
+                Data::Path(path) => {
+                    if let Ok(image) = image::open(path) {
+                        Memory::Host {
+                            image: image.to_bgra(),
+                        }
+                    } else {
+                        Memory::NotFound
+                    }
+                }
+                Data::Bytes(bytes) => {
+                    if let Ok(image) = image::load_from_memory(&bytes) {
+                        Memory::Host {
+                            image: image.to_bgra(),
+                        }
+                    } else {
+                        Memory::Invalid
+                    }
                 }
-            } else {
-                Memory::NotFound
             };
 
-            let _ = self.cache.borrow_mut().insert(path.to_string(), memory);
+            let _ = self.cache.borrow_mut().insert(handle.id(), memory);
         }
     }
 
@@ -245,12 +261,12 @@ impl Pipeline {
         //
         // [1]: https://github.com/nical/guillotiere
         for image in instances {
-            self.load(&image.path);
+            self.load(&image.handle);
 
             if let Some(texture) = self
                 .cache
                 .borrow_mut()
-                .get_mut(&image.path)
+                .get_mut(&image.handle.id())
                 .unwrap()
                 .upload(device, encoder, &self.texture_layout)
             {
@@ -327,6 +343,7 @@ enum Memory {
         height: u32,
     },
     NotFound,
+    Invalid,
 }
 
 impl Memory {
@@ -335,6 +352,7 @@ impl Memory {
             Memory::Host { image } => image.dimensions(),
             Memory::Device { width, height, .. } => (*width, *height),
             Memory::NotFound => (1, 1),
+            Memory::Invalid => (1, 1),
         }
     }
 
@@ -417,12 +435,13 @@ impl Memory {
             }
             Memory::Device { bind_group, .. } => Some(bind_group.clone()),
             Memory::NotFound => None,
+            Memory::Invalid => None,
         }
     }
 }
 
 pub struct Image {
-    pub path: String,
+    pub handle: Handle,
     pub position: [f32; 2],
     pub scale: [f32; 2],
 }
diff --git a/wgpu/src/primitive.rs b/wgpu/src/primitive.rs
index 9efd74f6..04264e5d 100644
--- a/wgpu/src/primitive.rs
+++ b/wgpu/src/primitive.rs
@@ -1,5 +1,5 @@
 use iced_native::{
-    Background, Color, Font, HorizontalAlignment, Rectangle, Vector,
+    image, Background, Color, Font, HorizontalAlignment, Rectangle, Vector,
     VerticalAlignment,
 };
 
@@ -41,8 +41,8 @@ pub enum Primitive {
     },
     /// An image primitive
     Image {
-        /// The path of the image
-        path: String,
+        /// The handle of the image
+        handle: image::Handle,
         /// The bounds of the image
         bounds: Rectangle,
     },
diff --git a/wgpu/src/renderer.rs b/wgpu/src/renderer.rs
index f27a4b8a..ad081383 100644
--- a/wgpu/src/renderer.rs
+++ b/wgpu/src/renderer.rs
@@ -229,9 +229,9 @@ impl Renderer {
                     border_radius: *border_radius as f32,
                 });
             }
-            Primitive::Image { path, bounds } => {
+            Primitive::Image { handle, bounds } => {
                 layer.images.push(Image {
-                    path: path.clone(),
+                    handle: handle.clone(),
                     position: [bounds.x, bounds.y],
                     scale: [bounds.width, bounds.height],
                 });
diff --git a/wgpu/src/renderer/widget/image.rs b/wgpu/src/renderer/widget/image.rs
index 0006dde1..70dc5d97 100644
--- a/wgpu/src/renderer/widget/image.rs
+++ b/wgpu/src/renderer/widget/image.rs
@@ -2,14 +2,18 @@ use crate::{Primitive, Renderer};
 use iced_native::{image, Layout, MouseCursor};
 
 impl image::Renderer for Renderer {
-    fn dimensions(&self, path: &str) -> (u32, u32) {
-        self.image_pipeline.dimensions(path)
+    fn dimensions(&self, handle: &image::Handle) -> (u32, u32) {
+        self.image_pipeline.dimensions(handle)
     }
 
-    fn draw(&mut self, path: &str, layout: Layout<'_>) -> Self::Output {
+    fn draw(
+        &mut self,
+        handle: image::Handle,
+        layout: Layout<'_>,
+    ) -> Self::Output {
         (
             Primitive::Image {
-                path: String::from(path),
+                handle,
                 bounds: layout.bounds(),
             },
             MouseCursor::OutOfBounds,