Add basic SVG rendering functionality

Cargo.toml

@@ -31,6 +31,8 @@ tga = ["image/tga"]
 gif = ["image/gif"]
 bmp = ["image/bmp"]
 
+svg = ["dep:resvg"]
+
 obj = ["wavefront_obj"]
 gltf = ["dep:gltf"]
 stl = ["dep:stl_io"]
@@ -50,6 +52,7 @@ gltf = { version = "1", optional = true, features=["KHR_materials_ior", "KHR_mat
 wavefront_obj = { version = "10", optional = true }
 stl_io = { version = "0.8.2", optional = true }
 image = { version = "0.24", optional = true, default-features = false}
+resvg = { version = "0.43.0", optional = true }
 pcd-rs = { version = "0.10", optional = true, features = ["derive"] }
 data-url = {version = "0.3", optional = true }
 serde = {version= "1", optional = true, features = ["derive", "rc"] }

src/io.rs

@@ -133,16 +133,20 @@ use std::path::{Path, PathBuf};
 impl Deserialize for crate::Texture2D {
     fn deserialize(path: impl AsRef<std::path::Path>, raw_assets: &mut RawAssets) -> Result<Self> {
         let path = raw_assets.match_path(path.as_ref())?;
+        let extension = path
+            .extension()
+            .map(|e| e.to_str().unwrap())
+            .unwrap_or("image")
+            .to_string();
         #[allow(unused_variables)]
         let bytes = raw_assets.get(&path)?;
 
         #[cfg(not(feature = "image"))]
-        return Err(Error::FeatureMissing(
-            path.extension()
-                .map(|e| e.to_str().unwrap())
-                .unwrap_or("image")
-                .to_string(),
-        ));
+        return Err(Error::FeatureMissing(extension));
+
+        if cfg!(feature = "svg") && "svg" == extension {
+            return img::deserialize_svg(path, bytes);
+        }
 
         #[cfg(feature = "image")]
         img::deserialize_img(path, bytes)

src/io/img.rs

@@ -72,6 +72,45 @@ pub fn deserialize_img(path: impl AsRef<Path>, bytes: &[u8]) -> Result<Texture2D
     })
 }
 
+#[cfg(feature = "svg")]
+pub fn deserialize_svg(path: impl AsRef<Path>, bytes: &[u8]) -> Result<Texture2D> {
+    use cgmath::num_traits::ToPrimitive;
+
+    let name = path
+        .as_ref()
+        .to_str()
+        .filter(|s| !s.starts_with("data:"))
+        .unwrap_or("default")
+        .to_owned();
+    let tree = resvg::usvg::Tree::from_data(bytes, &resvg::usvg::Options::default())?;
+    // TODO: should we have more error checking here?
+    let (width, height) = (
+        tree.size().width().to_u32().unwrap(),
+        tree.size().height().to_u32().unwrap(),
+    );
+    let mut pixmap = resvg::tiny_skia::Pixmap::new(width, height).unwrap();
+    resvg::render(
+        &tree,
+        resvg::tiny_skia::Transform::default(),
+        &mut pixmap.as_mut(),
+    );
+
+    // process the data to our desired RGBAU8 format
+    let texture_data: Vec<[u8; 4]> = pixmap
+        .pixels()
+        .iter()
+        .map(|pixel| [pixel.red(), pixel.green(), pixel.blue(), pixel.alpha()])
+        .collect();
+
+    Ok(Texture2D {
+        name,
+        data: TextureData::RgbaU8(texture_data),
+        width,
+        height,
+        ..Default::default()
+    })
+}
+
 pub fn serialize_img(tex: &Texture2D, path: &Path) -> Result<RawAssets> {
     #![allow(unreachable_code)]
     #![allow(unused_variables)]
@@ -266,4 +305,21 @@ mod test {
         assert_eq!(tex.width, 1024);
         assert_eq!(tex.height, 512);
     }
+
+    #[cfg(feature = "svg")]
+    #[test]
+    pub fn svg() {
+        let tex: crate::Texture2D = crate::io::load_and_deserialize("test_data/test.svg").unwrap();
+        if let crate::TextureData::RgbaU8(data) = tex.data {
+            assert_eq!(data[0], [0, 0, 0, 0]);
+            assert_eq!(data[25036], [0, 51, 255, 255]);
+            assert_eq!(data[20062], [255, 0, 0, 255]);
+            assert_eq!(data[58095], [0, 255, 0, 255]);
+        } else {
+            panic!("Wrong texture data");
+        }
+
+        assert_eq!(tex.width, 320);
+        assert_eq!(tex.height, 240);
+    }
 }

src/lib.rs

@@ -218,6 +218,11 @@ pub enum Error {
     #[cfg(feature = "image")]
     #[error("error while parsing an image file")]
     Image(#[from] image::ImageError),
+
+    #[cfg(feature = "svg")]
+    #[error("error while parsing svg file")]
+    Svg(#[from] resvg::usvg::Error),
+
     #[cfg(feature = "obj")]
     #[error("error while parsing an .obj file")]
     Obj(#[from] wavefront_obj::ParseError),