1 files changed, 194 insertions, 0 deletions
diff --git a/wgpu/src/image/vector.rs b/wgpu/src/image/vector.rs
new file mode 100644
index 00000000..2c03d36b
--- /dev/null
+++ b/wgpu/src/image/vector.rs
@@ -0,0 +1,194 @@
+use crate::core::svg;
+use crate::core::{Color, Size};
+use crate::image::atlas::{self, Atlas};
+
+use resvg::tiny_skia;
+use resvg::usvg;
+use std::collections::{HashMap, HashSet};
+use std::fs;
+
+/// Entry in cache corresponding to an svg handle
+pub enum Svg {
+    /// Parsed svg
+    Loaded(usvg::Tree),
+    /// Svg not found or failed to parse
+    NotFound,
+}
+
+impl Svg {
+    /// Viewport width and height
+    pub fn viewport_dimensions(&self) -> Size<u32> {
+        match self {
+            Svg::Loaded(tree) => {
+                let size = tree.size;
+
+                Size::new(size.width() as u32, size.height() as u32)
+            }
+            Svg::NotFound => Size::new(1, 1),
+        }
+    }
+}
+
+/// Caches svg vector and raster data
+#[derive(Debug, Default)]
+pub struct Cache {
+    svgs: HashMap<u64, Svg>,
+    rasterized: HashMap<(u64, u32, u32, ColorFilter), atlas::Entry>,
+    svg_hits: HashSet<u64>,
+    rasterized_hits: HashSet<(u64, u32, u32, ColorFilter)>,
+}
+
+type ColorFilter = Option<[u8; 4]>;
+
+impl Cache {
+    /// Load svg
+    pub fn load(&mut self, handle: &svg::Handle) -> &Svg {
+        use usvg::TreeParsing;
+
+        if self.svgs.contains_key(&handle.id()) {
+            return self.svgs.get(&handle.id()).unwrap();
+        }
+
+        let svg = match handle.data() {
+            svg::Data::Path(path) => {
+                let tree = fs::read_to_string(path).ok().and_then(|contents| {
+                    usvg::Tree::from_str(&contents, &usvg::Options::default())
+                        .ok()
+                });
+
+                tree.map(Svg::Loaded).unwrap_or(Svg::NotFound)
+            }
+            svg::Data::Bytes(bytes) => {
+                match usvg::Tree::from_data(bytes, &usvg::Options::default()) {
+                    Ok(tree) => Svg::Loaded(tree),
+                    Err(_) => Svg::NotFound,
+                }
+            }
+        };
+
+        let _ = self.svgs.insert(handle.id(), svg);
+        self.svgs.get(&handle.id()).unwrap()
+    }
+
+    /// Load svg and upload raster data
+    pub fn upload(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        handle: &svg::Handle,
+        color: Option<Color>,
+        [width, height]: [f32; 2],
+        scale: f32,
+        atlas: &mut Atlas,
+    ) -> Option<&atlas::Entry> {
+        let id = handle.id();
+
+        let (width, height) = (
+            (scale * width).ceil() as u32,
+            (scale * height).ceil() as u32,
+        );
+
+        let color = color.map(Color::into_rgba8);
+        let key = (id, width, height, color);
+
+        // TODO: Optimize!
+        // We currently rerasterize the SVG when its size changes. This is slow
+        // as heck. A GPU rasterizer like `pathfinder` may perform better.
+        // It would be cool to be able to smooth resize the `svg` example.
+        if self.rasterized.contains_key(&key) {
+            let _ = self.svg_hits.insert(id);
+            let _ = self.rasterized_hits.insert(key);
+
+            return self.rasterized.get(&key);
+        }
+
+        match self.load(handle) {
+            Svg::Loaded(tree) => {
+                if width == 0 || height == 0 {
+                    return None;
+                }
+
+                // TODO: Optimize!
+                // We currently rerasterize the SVG when its size changes. This is slow
+                // as heck. A GPU rasterizer like `pathfinder` may perform better.
+                // It would be cool to be able to smooth resize the `svg` example.
+                let mut img = tiny_skia::Pixmap::new(width, height)?;
+
+                let tree_size = tree.size.to_int_size();
+
+                let target_size = if width > height {
+                    tree_size.scale_to_width(width)
+                } else {
+                    tree_size.scale_to_height(height)
+                };
+
+                let transform = if let Some(target_size) = target_size {
+                    let tree_size = tree_size.to_size();
+                    let target_size = target_size.to_size();
+
+                    tiny_skia::Transform::from_scale(
+                        target_size.width() / tree_size.width(),
+                        target_size.height() / tree_size.height(),
+                    )
+                } else {
+                    tiny_skia::Transform::default()
+                };
+
+                resvg::Tree::from_usvg(tree)
+                    .render(transform, &mut img.as_mut());
+
+                let mut rgba = img.take();
+
+                if let Some(color) = color {
+                    rgba.chunks_exact_mut(4).for_each(|rgba| {
+                        if rgba[3] > 0 {
+                            rgba[0] = color[0];
+                            rgba[1] = color[1];
+                            rgba[2] = color[2];
+                        }
+                    });
+                }
+
+                let allocation =
+                    atlas.upload(device, encoder, width, height, &rgba)?;
+
+                log::debug!("allocating {} {}x{}", id, width, height);
+
+                let _ = self.svg_hits.insert(id);
+                let _ = self.rasterized_hits.insert(key);
+                let _ = self.rasterized.insert(key, allocation);
+
+                self.rasterized.get(&key)
+            }
+            Svg::NotFound => None,
+        }
+    }
+
+    /// Load svg and upload raster data
+    pub fn trim(&mut self, atlas: &mut Atlas) {
+        let svg_hits = &self.svg_hits;
+        let rasterized_hits = &self.rasterized_hits;
+
+        self.svgs.retain(|k, _| svg_hits.contains(k));
+        self.rasterized.retain(|k, entry| {
+            let retain = rasterized_hits.contains(k);
+
+            if !retain {
+                atlas.remove(entry);
+            }
+
+            retain
+        });
+        self.svg_hits.clear();
+        self.rasterized_hits.clear();
+    }
+}
+
+impl std::fmt::Debug for Svg {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Svg::Loaded(_) => write!(f, "Svg::Loaded"),
+            Svg::NotFound => write!(f, "Svg::NotFound"),
+        }
+    }
+}