Merge branch 'master' into shape_own

.travis.yml

@@ -1,4 +1,5 @@
 os:
+  - osx
   - linux
 
 language: rust
@@ -13,6 +14,7 @@ cache: cargo
 before_script:
   - rustup component add rustfmt
 script:
+  - if [[ "$TRAVIS_OS_NAME" = "osx" ]]; then brew update; brew install cairo; fi
   - if [[ "$TRAVIS_RUST_VERSION" = stable ]]; then cargo fmt --all -- --check; fi
   - RUSTFLAGS="-D warnings" cargo check --all --exclude piet-direct2d || exit
   - cargo build --all --exclude piet-direct2d

README.md

@@ -9,11 +9,29 @@ This repo is structured as a core API crate, "piet" and a separate crate for eac
 
 A companion for Bézier path representation and geometry is [kurbo].
 
-The library is of course named after [Piet Mondrian]. It's abstract and hopefully will be used for drawing lots of rectangles.
+## Roadmap
+
+Since the project is in its infant stages, there's not currently a set roadmap. For a good idea of what the library will eventually be capable of see [this list][resvg backend requirements] of requirements to be a backend 2D graphics library for the SVG rendering library resvg.
+
+## Contributing
 
 Contributions are welcome! It's in early stages, so there are lots of opportunities to fill things out.
 
+You can find other collaborators at [xi.zulipchat.com][zulip] under the #druid stream.
+
+## Inspirations
+
+Piet's interface is largely inspired by the [Skia Graphics Library] as well as the [C++ 2D graphics api proposal] although piet aims to be much more lightweight and modular.
+
+## The Name
+
+The library is of course named after [Piet Mondrian]. It's abstract and hopefully will be used for drawing lots of rectangles.
+
 [blog post]: https://raphlinus.github.io/rust/graphics/2018/10/11/2d-graphics.html
 [druid]: https://github.com/xi-editor/druid
 [kurbo]: https://github.com/linebender/kurbo
+[resvg backend requirements]: https://github.com/RazrFalcon/resvg/blob/master/docs/backend_requirements.md
+[zulip]: https://xi.zulipchat.com
+[Skia Graphics Library]: https://skia.org
+[C++ 2D graphics api proposal]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0267r8.pdf
 [Piet Mondrian]: https://en.wikipedia.org/wiki/Piet_Mondrian

piet-cairo/README.md

@@ -16,12 +16,14 @@ The need for text shaping will be common to many low-level renderers that are no
 
 ## Building on non-Linux
 
-Cairo is quite portable, and it is quite feasible to build on other systems. However, the [cairo-rs] crate seems to expect a library to be provided, rather than building it from sources. On Windows, I've been using prebuilt binary releases from [cairo-windows].
+Cairo is quite portable, and it is quite feasible to build on other systems. However, the [cairo-rs] crate seems to expect a library to be provided, rather than building it from sources.
 
-See the [Gtk-rs requirements] page for more detailed instructions how to get it properly installed. On macOS with Homebrew, the following should work:
+On Windows, I've been using prebuilt binary releases from [cairo-windows].
+
+On macOS with Homebrew, the following should work:
 
 ```shell
-brew install gtk+3
+brew install cairo
 ```
 
 TODO: nicer installation instructions (contributions welcome)

piet-test/src/lib.rs

@@ -48,10 +48,10 @@ fn draw_picture_0(rc: &mut impl RenderContext) {
 
     rc.stroke(Line::new((80.0, 12.0), (80.0 + w, 12.0)), &brush, 1.0, None);
 
-    rc.save();
-    rc.transform(Affine::rotate(0.1));
-    rc.draw_text(&layout, (80.0, 10.0), &brush);
-    rc.restore();
+    rc.with_save(|rc| {
+        rc.transform(Affine::rotate(0.1));
+        rc.draw_text(&layout, (80.0, 10.0), &brush);
+    });
 
     let clip_path = star(Vec2::new(90.0, 45.0), 10.0, 30.0, 24);
     rc.clip(clip_path, FillRule::NonZero);

piet/src/render_context.rs

@@ -108,6 +108,9 @@ pub trait RenderContext {
     /// Pushes the current context state onto a stack, to be popped by
     /// [`restore`](#method.restore).
     ///
+    /// Prefer [`with_save`](#method.with_save) if possible, as that statically
+    /// enforces balance of save/restore pairs.
+    ///
     /// The context state currently consists of a clip region and an affine
     /// transform, but is expected to grow in the near future.
     fn save(&mut self);
@@ -118,6 +121,16 @@ pub trait RenderContext {
     /// that method for details.
     fn restore(&mut self);
 
+    /// Do graphics operations with the context state saved and then restored.
+    ///
+    /// Equivalent to [`save`](#method.save), calling `f`, then
+    /// [`restore`](#method.restore). See those methods for more details.
+    fn with_save(&mut self, f: impl FnOnce(&mut Self)) {
+        self.save();
+        f(self);
+        self.restore();
+    }
+
     /// Finish any pending operations.
     ///
     /// This will generally be called by a shell after all user drawing