Introduce egui_extras with RetainedImage for loading svg,png,jpeg,… (#1282)

eframe/examples/svg.rs

@@ -1,82 +1,23 @@
 //! A good way of displaying an SVG image in egui.
 //!
-//! Requires the dependencies `resvg`, `tiny-skia`, `usvg`
+//! Requires the dependency `egui_extras` with the `svg` feature.
+
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
+
 use eframe::{egui, epi};
 
-/// Load an SVG and rasterize it into an egui image.
-fn load_svg_data(svg_data: &[u8]) -> Result<egui::ColorImage, String> {
-    let mut opt = usvg::Options::default();
-    opt.fontdb.load_system_fonts();
-
-    let rtree = usvg::Tree::from_data(svg_data, &opt.to_ref()).map_err(|err| err.to_string())?;
-
-    let pixmap_size = rtree.svg_node().size.to_screen_size();
-    let [w, h] = [pixmap_size.width(), pixmap_size.height()];
-
-    let mut pixmap = tiny_skia::Pixmap::new(w, h)
-        .ok_or_else(|| format!("Failed to create SVG Pixmap of size {}x{}", w, h))?;
-
-    resvg::render(
-        &rtree,
-        usvg::FitTo::Original,
-        tiny_skia::Transform::default(),
-        pixmap.as_mut(),
-    )
-    .ok_or_else(|| "Failed to render SVG".to_owned())?;
-
-    let image = egui::ColorImage::from_rgba_unmultiplied(
-        [pixmap.width() as _, pixmap.height() as _],
-        pixmap.data(),
-    );
-
-    Ok(image)
-}
-
-// ----------------------------------------------------------------------------
-
-/// An SVG image to be shown in egui
-struct SvgImage {
-    image: egui::ColorImage,
-    texture: Option<egui::TextureHandle>,
-}
-
-impl SvgImage {
-    /// Pass itn the bytes of an SVG that you've loaded from disk
-    pub fn from_svg_data(bytes: &[u8]) -> Result<Self, String> {
-        Ok(Self {
-            image: load_svg_data(bytes)?,
-            texture: None,
-        })
-    }
-
-    pub fn show_max_size(&mut self, ui: &mut egui::Ui, max_size: egui::Vec2) -> egui::Response {
-        let mut desired_size = egui::vec2(self.image.width() as _, self.image.height() as _);
-        desired_size *= (max_size.x / desired_size.x).min(1.0);
-        desired_size *= (max_size.y / desired_size.y).min(1.0);
-        self.show_size(ui, desired_size)
-    }
-
-    pub fn show_size(&mut self, ui: &mut egui::Ui, desired_size: egui::Vec2) -> egui::Response {
-        // We need to convert the SVG to a texture to display it:
-        // Future improvement: tell backend to do mip-mapping of the image to
-        // make it look smoother when downsized.
-        let svg_texture = self
-            .texture
-            .get_or_insert_with(|| ui.ctx().load_texture("svg", self.image.clone()));
-        ui.image(svg_texture, desired_size)
-    }
-}
-
-// ----------------------------------------------------------------------------
-
 struct MyApp {
-    svg_image: SvgImage,
+    svg_image: egui_extras::RetainedImage,
 }
 
 impl Default for MyApp {
     fn default() -> Self {
         Self {
-            svg_image: SvgImage::from_svg_data(include_bytes!("rustacean-flat-happy.svg")).unwrap(),
+            svg_image: egui_extras::RetainedImage::from_svg_bytes(
+                "rustacean-flat-happy.svg",
+                include_bytes!("rustacean-flat-happy.svg"),
+            )
+            .unwrap(),
         }
     }
 }