Merge pull request #1748 from iced-rs/feature/software-renderer

Software renderer, runtime renderer fallback, and core consolidation

7 files changed, 538 insertions, 41 deletions

diff --git a/renderer/src/backend.rs b/renderer/src/backend.rs
new file mode 100644
index 00000000..e77b708b
--- /dev/null
+++ b/renderer/src/backend.rs
@@ -0,0 +1,98 @@
+use crate::core::text;
+use crate::core::{Font, Point, Size};
+use crate::graphics::backend;
+
+use std::borrow::Cow;
+
+#[allow(clippy::large_enum_variant)]
+pub enum Backend {
+    #[cfg(feature = "wgpu")]
+    Wgpu(iced_wgpu::Backend),
+    #[cfg(feature = "tiny-skia")]
+    TinySkia(iced_tiny_skia::Backend),
+}
+
+macro_rules! delegate {
+    ($backend:expr, $name:ident, $body:expr) => {
+        match $backend {
+            #[cfg(feature = "wgpu")]
+            Self::Wgpu($name) => $body,
+            #[cfg(feature = "tiny-skia")]
+            Self::TinySkia($name) => $body,
+        }
+    };
+}
+
+impl iced_graphics::Backend for Backend {
+    fn trim_measurements(&mut self) {
+        delegate!(self, backend, backend.trim_measurements());
+    }
+}
+
+impl backend::Text for Backend {
+    const ICON_FONT: Font = Font::Name("Iced-Icons");
+    const CHECKMARK_ICON: char = '\u{f00c}';
+    const ARROW_DOWN_ICON: char = '\u{e800}';
+
+    fn default_font(&self) -> Font {
+        delegate!(self, backend, backend.default_font())
+    }
+
+    fn default_size(&self) -> f32 {
+        delegate!(self, backend, backend.default_size())
+    }
+
+    fn measure(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+    ) -> (f32, f32) {
+        delegate!(self, backend, backend.measure(contents, size, font, bounds))
+    }
+
+    fn hit_test(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+        position: Point,
+        nearest_only: bool,
+    ) -> Option<text::Hit> {
+        delegate!(
+            self,
+            backend,
+            backend.hit_test(
+                contents,
+                size,
+                font,
+                bounds,
+                position,
+                nearest_only
+            )
+        )
+    }
+
+    fn load_font(&mut self, font: Cow<'static, [u8]>) {
+        delegate!(self, backend, backend.load_font(font));
+    }
+}
+
+#[cfg(feature = "image")]
+impl backend::Image for Backend {
+    fn dimensions(&self, handle: &crate::core::image::Handle) -> Size<u32> {
+        delegate!(self, backend, backend.dimensions(handle))
+    }
+}
+
+#[cfg(feature = "svg")]
+impl backend::Svg for Backend {
+    fn viewport_dimensions(
+        &self,
+        handle: &crate::core::svg::Handle,
+    ) -> Size<u32> {
+        delegate!(self, backend, backend.viewport_dimensions(handle))
+    }
+}
diff --git a/renderer/src/compositor.rs b/renderer/src/compositor.rs
new file mode 100644
index 00000000..218e7e33
--- /dev/null
+++ b/renderer/src/compositor.rs
@@ -0,0 +1,185 @@
+use crate::core::Color;
+use crate::graphics::compositor::{Information, SurfaceError};
+use crate::graphics::{Error, Viewport};
+use crate::{Renderer, Settings};
+
+use raw_window_handle::{HasRawDisplayHandle, HasRawWindowHandle};
+
+pub enum Compositor<Theme> {
+    #[cfg(feature = "wgpu")]
+    Wgpu(iced_wgpu::window::Compositor<Theme>),
+    #[cfg(feature = "tiny-skia")]
+    TinySkia(iced_tiny_skia::window::Compositor<Theme>),
+}
+
+pub enum Surface {
+    #[cfg(feature = "wgpu")]
+    Wgpu(iced_wgpu::window::Surface),
+    #[cfg(feature = "tiny-skia")]
+    TinySkia(iced_tiny_skia::window::Surface),
+}
+
+impl<Theme> crate::graphics::Compositor for Compositor<Theme> {
+    type Settings = Settings;
+    type Renderer = Renderer<Theme>;
+    type Surface = Surface;
+
+    fn new<W: HasRawWindowHandle + HasRawDisplayHandle>(
+        settings: Self::Settings,
+        compatible_window: Option<&W>,
+    ) -> Result<(Self, Self::Renderer), Error> {
+        #[cfg(feature = "wgpu")]
+        let new_wgpu = |settings: Self::Settings, compatible_window| {
+            let (compositor, backend) = iced_wgpu::window::compositor::new(
+                iced_wgpu::Settings {
+                    default_font: settings.default_font,
+                    default_text_size: settings.default_text_size,
+                    antialiasing: settings.antialiasing,
+                    ..iced_wgpu::Settings::from_env()
+                },
+                compatible_window,
+            )?;
+
+            Ok((
+                Self::Wgpu(compositor),
+                Renderer::new(crate::Backend::Wgpu(backend)),
+            ))
+        };
+
+        #[cfg(feature = "tiny-skia")]
+        let new_tiny_skia = |settings: Self::Settings, _compatible_window| {
+            let (compositor, backend) = iced_tiny_skia::window::compositor::new(
+                iced_tiny_skia::Settings {
+                    default_font: settings.default_font,
+                    default_text_size: settings.default_text_size,
+                },
+            );
+
+            Ok((
+                Self::TinySkia(compositor),
+                Renderer::new(crate::Backend::TinySkia(backend)),
+            ))
+        };
+
+        let fail = |_, _| Err(Error::GraphicsAdapterNotFound);
+
+        let candidates = &[
+            #[cfg(feature = "wgpu")]
+            new_wgpu,
+            #[cfg(feature = "tiny-skia")]
+            new_tiny_skia,
+            fail,
+        ];
+
+        let mut error = Error::GraphicsAdapterNotFound;
+
+        for candidate in candidates {
+            match candidate(settings, compatible_window) {
+                Ok((compositor, renderer)) => {
+                    return Ok((compositor, renderer))
+                }
+                Err(new_error) => {
+                    error = new_error;
+                }
+            }
+        }
+
+        Err(error)
+    }
+
+    fn create_surface<W: HasRawWindowHandle + HasRawDisplayHandle>(
+        &mut self,
+        window: &W,
+        width: u32,
+        height: u32,
+    ) -> Surface {
+        match self {
+            #[cfg(feature = "wgpu")]
+            Self::Wgpu(compositor) => {
+                Surface::Wgpu(compositor.create_surface(window, width, height))
+            }
+            #[cfg(feature = "tiny-skia")]
+            Self::TinySkia(compositor) => Surface::TinySkia(
+                compositor.create_surface(window, width, height),
+            ),
+        }
+    }
+
+    fn configure_surface(
+        &mut self,
+        surface: &mut Surface,
+        width: u32,
+        height: u32,
+    ) {
+        match (self, surface) {
+            #[cfg(feature = "wgpu")]
+            (Self::Wgpu(compositor), Surface::Wgpu(surface)) => {
+                compositor.configure_surface(surface, width, height);
+            }
+            #[cfg(feature = "tiny-skia")]
+            (Self::TinySkia(compositor), Surface::TinySkia(surface)) => {
+                compositor.configure_surface(surface, width, height);
+            }
+            #[allow(unreachable_patterns)]
+            _ => panic!(
+                "The provided surface is not compatible with the compositor."
+            ),
+        }
+    }
+
+    fn fetch_information(&self) -> Information {
+        match self {
+            #[cfg(feature = "wgpu")]
+            Self::Wgpu(compositor) => compositor.fetch_information(),
+            #[cfg(feature = "tiny-skia")]
+            Self::TinySkia(compositor) => compositor.fetch_information(),
+        }
+    }
+
+    fn present<T: AsRef<str>>(
+        &mut self,
+        renderer: &mut Self::Renderer,
+        surface: &mut Self::Surface,
+        viewport: &Viewport,
+        background_color: Color,
+        overlay: &[T],
+    ) -> Result<(), SurfaceError> {
+        renderer.with_primitives(|backend, primitives| {
+            match (self, backend, surface) {
+                #[cfg(feature = "wgpu")]
+                (
+                    Self::Wgpu(compositor),
+                    crate::Backend::Wgpu(backend),
+                    Surface::Wgpu(surface),
+                ) => iced_wgpu::window::compositor::present(
+                    compositor,
+                    backend,
+                    surface,
+                    primitives,
+                    viewport,
+                    background_color,
+                    overlay,
+                ),
+                #[cfg(feature = "tiny-skia")]
+                (
+                    Self::TinySkia(compositor),
+                    crate::Backend::TinySkia(backend),
+                    Surface::TinySkia(surface),
+                ) => iced_tiny_skia::window::compositor::present(
+                    compositor,
+                    backend,
+                    surface,
+                    primitives,
+                    viewport,
+                    background_color,
+                    overlay,
+                ),
+                #[allow(unreachable_patterns)]
+                _ => panic!(
+                    "The provided renderer or surface are not compatible \
+                    with the compositor."
+                ),
+            }
+        })
+    }
+}
diff --git a/renderer/src/geometry.rs b/renderer/src/geometry.rs
new file mode 100644
index 00000000..21ef2c06
--- /dev/null
+++ b/renderer/src/geometry.rs
@@ -0,0 +1,179 @@
+mod cache;
+
+pub use cache::Cache;
+
+use crate::core::{Point, Rectangle, Size, Vector};
+use crate::graphics::geometry::{Fill, Geometry, Path, Stroke, Text};
+use crate::Backend;
+
+pub enum Frame {
+    #[cfg(feature = "wgpu")]
+    Wgpu(iced_wgpu::geometry::Frame),
+    #[cfg(feature = "tiny-skia")]
+    TinySkia(iced_tiny_skia::geometry::Frame),
+}
+
+macro_rules! delegate {
+    ($frame:expr, $name:ident, $body:expr) => {
+        match $frame {
+            #[cfg(feature = "wgpu")]
+            Self::Wgpu($name) => $body,
+            #[cfg(feature = "tiny-skia")]
+            Self::TinySkia($name) => $body,
+        }
+    };
+}
+
+impl Frame {
+    pub fn new<Theme>(renderer: &crate::Renderer<Theme>, size: Size) -> Self {
+        match renderer.backend() {
+            #[cfg(feature = "wgpu")]
+            Backend::Wgpu(_) => {
+                Frame::Wgpu(iced_wgpu::geometry::Frame::new(size))
+            }
+            #[cfg(feature = "tiny-skia")]
+            Backend::TinySkia(_) => {
+                Frame::TinySkia(iced_tiny_skia::geometry::Frame::new(size))
+            }
+        }
+    }
+
+    /// Returns the width of the [`Frame`].
+    #[inline]
+    pub fn width(&self) -> f32 {
+        delegate!(self, frame, frame.width())
+    }
+
+    /// Returns the height of the [`Frame`].
+    #[inline]
+    pub fn height(&self) -> f32 {
+        delegate!(self, frame, frame.height())
+    }
+
+    /// Returns the dimensions of the [`Frame`].
+    #[inline]
+    pub fn size(&self) -> Size {
+        delegate!(self, frame, frame.size())
+    }
+
+    /// Returns the coordinate of the center of the [`Frame`].
+    #[inline]
+    pub fn center(&self) -> Point {
+        delegate!(self, frame, frame.center())
+    }
+
+    /// Draws the given [`Path`] on the [`Frame`] by filling it with the
+    /// provided style.
+    pub fn fill(&mut self, path: &Path, fill: impl Into<Fill>) {
+        delegate!(self, frame, frame.fill(path, fill));
+    }
+
+    /// Draws an axis-aligned rectangle given its top-left corner coordinate and
+    /// its `Size` on the [`Frame`] by filling it with the provided style.
+    pub fn fill_rectangle(
+        &mut self,
+        top_left: Point,
+        size: Size,
+        fill: impl Into<Fill>,
+    ) {
+        delegate!(self, frame, frame.fill_rectangle(top_left, size, fill));
+    }
+
+    /// Draws the stroke of the given [`Path`] on the [`Frame`] with the
+    /// provided style.
+    pub fn stroke<'a>(&mut self, path: &Path, stroke: impl Into<Stroke<'a>>) {
+        delegate!(self, frame, frame.stroke(path, stroke));
+    }
+
+    /// Draws the characters of the given [`Text`] on the [`Frame`], filling
+    /// them with the given color.
+    ///
+    /// __Warning:__ Text currently does not work well with rotations and scale
+    /// transforms! The position will be correctly transformed, but the
+    /// resulting glyphs will not be rotated or scaled properly.
+    ///
+    /// Additionally, all text will be rendered on top of all the layers of
+    /// a [`Canvas`]. Therefore, it is currently only meant to be used for
+    /// overlays, which is the most common use case.
+    ///
+    /// Support for vectorial text is planned, and should address all these
+    /// limitations.
+    ///
+    /// [`Canvas`]: crate::widget::Canvas
+    pub fn fill_text(&mut self, text: impl Into<Text>) {
+        delegate!(self, frame, frame.fill_text(text));
+    }
+
+    /// Stores the current transform of the [`Frame`] and executes the given
+    /// drawing operations, restoring the transform afterwards.
+    ///
+    /// This method is useful to compose transforms and perform drawing
+    /// operations in different coordinate systems.
+    #[inline]
+    pub fn with_save(&mut self, f: impl FnOnce(&mut Frame)) {
+        delegate!(self, frame, frame.push_transform());
+
+        f(self);
+
+        delegate!(self, frame, frame.pop_transform());
+    }
+
+    /// Executes the given drawing operations within a [`Rectangle`] region,
+    /// clipping any geometry that overflows its bounds. Any transformations
+    /// performed are local to the provided closure.
+    ///
+    /// This method is useful to perform drawing operations that need to be
+    /// clipped.
+    #[inline]
+    pub fn with_clip(&mut self, region: Rectangle, f: impl FnOnce(&mut Frame)) {
+        let mut frame = match self {
+            #[cfg(feature = "wgpu")]
+            Self::Wgpu(_) => {
+                Self::Wgpu(iced_wgpu::geometry::Frame::new(region.size()))
+            }
+            #[cfg(feature = "tiny-skia")]
+            Self::TinySkia(_) => Self::TinySkia(
+                iced_tiny_skia::geometry::Frame::new(region.size()),
+            ),
+        };
+
+        f(&mut frame);
+
+        let translation = Vector::new(region.x, region.y);
+
+        match (self, frame) {
+            #[cfg(feature = "wgpu")]
+            (Self::Wgpu(target), Self::Wgpu(frame)) => {
+                target.clip(frame, translation);
+            }
+            #[cfg(feature = "tiny-skia")]
+            (Self::TinySkia(target), Self::TinySkia(frame)) => {
+                target.clip(frame, translation);
+            }
+            #[allow(unreachable_patterns)]
+            _ => unreachable!(),
+        };
+    }
+
+    /// Applies a translation to the current transform of the [`Frame`].
+    #[inline]
+    pub fn translate(&mut self, translation: Vector) {
+        delegate!(self, frame, frame.translate(translation));
+    }
+
+    /// Applies a rotation in radians to the current transform of the [`Frame`].
+    #[inline]
+    pub fn rotate(&mut self, angle: f32) {
+        delegate!(self, frame, frame.rotate(angle));
+    }
+
+    /// Applies a scaling to the current transform of the [`Frame`].
+    #[inline]
+    pub fn scale(&mut self, scale: f32) {
+        delegate!(self, frame, frame.scale(scale));
+    }
+
+    pub fn into_geometry(self) -> Geometry {
+        Geometry(delegate!(self, frame, frame.into_primitive()))
+    }
+}
diff --git a/graphics/src/widget/canvas/cache.rs b/renderer/src/geometry/cache.rs
index 52217bbb..2a3534d0 100644
--- a/graphics/src/widget/canvas/cache.rs
+++ b/renderer/src/geometry/cache.rs
@@ -1,22 +1,11 @@
-use crate::widget::canvas::{Frame, Geometry};
-use crate::Primitive;
+use crate::core::Size;
+use crate::geometry::{Frame, Geometry};
+use crate::graphics::Primitive;
+use crate::Renderer;
 
-use iced_native::Size;
-use std::{cell::RefCell, sync::Arc};
+use std::cell::RefCell;
+use std::sync::Arc;
 
-enum State {
-    Empty,
-    Filled {
-        bounds: Size,
-        primitive: Arc<Primitive>,
-    },
-}
-
-impl Default for State {
-    fn default() -> Self {
-        State::Empty
-    }
-}
 /// A simple cache that stores generated [`Geometry`] to avoid recomputation.
 ///
 /// A [`Cache`] will not redraw its geometry unless the dimensions of its layer
@@ -26,6 +15,16 @@ pub struct Cache {
     state: RefCell<State>,
 }
 
+#[derive(Debug, Default)]
+enum State {
+    #[default]
+    Empty,
+    Filled {
+        bounds: Size,
+        primitive: Arc<Primitive>,
+    },
+}
+
 impl Cache {
     /// Creates a new empty [`Cache`].
     pub fn new() -> Self {
@@ -49,8 +48,9 @@ impl Cache {
     /// Otherwise, the previously stored [`Geometry`] will be returned. The
     /// [`Cache`] is not cleared in this case. In other words, it will keep
     /// returning the stored [`Geometry`] if needed.
-    pub fn draw(
+    pub fn draw<Theme>(
         &self,
+        renderer: &Renderer<Theme>,
         bounds: Size,
         draw_fn: impl FnOnce(&mut Frame),
     ) -> Geometry {
@@ -62,19 +62,19 @@ impl Cache {
         } = self.state.borrow().deref()
         {
             if *cached_bounds == bounds {
-                return Geometry::from_primitive(Primitive::Cached {
-                    cache: primitive.clone(),
+                return Geometry(Primitive::Cache {
+                    content: primitive.clone(),
                 });
             }
         }
 
-        let mut frame = Frame::new(bounds);
+        let mut frame = Frame::new(renderer, bounds);
         draw_fn(&mut frame);
 
         let primitive = {
             let geometry = frame.into_geometry();
 
-            Arc::new(geometry.into_primitive())
+            Arc::new(geometry.0)
         };
 
         *self.state.borrow_mut() = State::Filled {
@@ -82,19 +82,6 @@ impl Cache {
             primitive: primitive.clone(),
         };
 
-        Geometry::from_primitive(Primitive::Cached { cache: primitive })
-    }
-}
-
-impl std::fmt::Debug for State {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            State::Empty => write!(f, "Empty"),
-            State::Filled { primitive, bounds } => f
-                .debug_struct("Filled")
-                .field("primitive", primitive)
-                .field("bounds", bounds)
-                .finish(),
-        }
+        Geometry(Primitive::Cache { content: primitive })
     }
 }
diff --git a/renderer/src/lib.rs b/renderer/src/lib.rs
new file mode 100644
index 00000000..ba737b11
--- /dev/null
+++ b/renderer/src/lib.rs
@@ -0,0 +1,22 @@
+#[cfg(not(any(feature = "wgpu", feature = "tiny-skia")))]
+compile_error!("No backend selected. Enable at least one backend feature: `wgpu` or `tiny-skia`.");
+
+pub mod compositor;
+
+#[cfg(feature = "geometry")]
+pub mod geometry;
+
+mod backend;
+mod settings;
+
+pub use iced_graphics as graphics;
+pub use iced_graphics::core;
+
+pub use backend::Backend;
+pub use compositor::Compositor;
+pub use settings::Settings;
+
+/// The default graphics renderer for [`iced`].
+///
+/// [`iced`]: https://github.com/iced-rs/iced
+pub type Renderer<Theme> = iced_graphics::Renderer<Backend, Theme>;
diff --git a/renderer/src/settings.rs b/renderer/src/settings.rs
new file mode 100644
index 00000000..d32c87d3
--- /dev/null
+++ b/renderer/src/settings.rs
@@ -0,0 +1,31 @@
+use crate::core::Font;
+use crate::graphics::Antialiasing;
+
+/// The settings of a [`Backend`].
+///
+/// [`Backend`]: crate::Backend
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Settings {
+    /// The default [`Font`] to use.
+    pub default_font: Font,
+
+    /// The default size of text.
+    ///
+    /// By default, it will be set to `16.0`.
+    pub default_text_size: f32,
+
+    /// The antialiasing strategy that will be used for triangle primitives.
+    ///
+    /// By default, it is `None`.
+    pub antialiasing: Option<Antialiasing>,
+}
+
+impl Default for Settings {
+    fn default() -> Settings {
+        Settings {
+            default_font: Font::SansSerif,
+            default_text_size: 16.0,
+            antialiasing: None,
+        }
+    }
+}
diff --git a/graphics/src/widget.rs b/renderer/src/widget.rs
index e7fab97c..6c0c2a83 100644
--- a/graphics/src/widget.rs
+++ b/renderer/src/widget.rs
@@ -1,16 +1,11 @@
-//! Use the graphical widgets supported out-of-the-box.
 #[cfg(feature = "canvas")]
-#[cfg_attr(docsrs, doc(cfg(feature = "canvas")))]
 pub mod canvas;
 
 #[cfg(feature = "canvas")]
-#[doc(no_inline)]
 pub use canvas::Canvas;
 
 #[cfg(feature = "qr_code")]
-#[cfg_attr(docsrs, doc(cfg(feature = "qr_code")))]
 pub mod qr_code;
 
 #[cfg(feature = "qr_code")]
-#[doc(no_inline)]
 pub use qr_code::QRCode;