Themes: GAT & MultiTheme

Cargo.toml

@@ -12,6 +12,11 @@ repository = "https://github.com/dhardy/kas"
 [features]
 # Enables usage of unstable Rust features
 nightly = []
+
+# Use Generic Associated Types (experimental)
+# Currently (Feb 2020) compiler support is poor.
+gat = []
+
 # Enables documentation of APIs for toolkits and internal use.
 # This API is not intended for use by end-user applications and
 # thus is omitted from built documentation by default.
@@ -21,6 +26,7 @@ internal_doc = []
 [dependencies]
 log = "0.4"
 smallvec = "1.1"
+stack_dst = { version = "0.6", features = ["unsize"], optional = true }
 
 [dependencies.kas-macros]
 version = "0.2.0"

kas-macros/src/layout.rs

@@ -326,7 +326,7 @@ pub(crate) fn derive(
         fn draw(
             &self,
             draw_handle: &mut dyn kas::theme::DrawHandle,
-            mgr: &kas::event::Manager
+            mgr: &kas::event::ManagerState
         ) {
             use kas::{geom::Coord, WidgetCore};
             if #is_frame {

kas-wgpu/Cargo.toml

@@ -12,6 +12,12 @@ repository = "https://github.com/dhardy/kas"
 [features]
 default = ["clipboard", "font-kit"]
 
+# Use Generic Associated Types (experimental)
+gat = ["kas/gat"]
+
+# Use stack_dst crate for sized unsized types
+stack_dst = ["kas/stack_dst"]
+
 [dependencies]
 kas = { path = "..", version = "0.2.0", features = ["winit"] }
 font-kit = { version = "0.4.0", optional = true }

kas-wgpu/examples/custom-theme.rs

@@ -5,6 +5,7 @@
 
 //! Custom theme demo
 #![feature(proc_macro_hygiene)]
+#![cfg_attr(feature = "gat", feature(generic_associated_types))]
 
 use std::cell::Cell;
 
@@ -51,7 +52,11 @@ thread_local! {
 
 impl Theme<DrawPipe> for CustomTheme {
     type Window = <ShadedTheme as Theme<DrawPipe>>::Window;
+
+    #[cfg(not(feature = "gat"))]
     type DrawHandle = <ShadedTheme as Theme<DrawPipe>>::DrawHandle;
+    #[cfg(feature = "gat")]
+    type DrawHandle<'a> = <ShadedTheme as Theme<DrawPipe>>::DrawHandle<'a>;
 
     fn new_window(&self, draw: &mut DrawPipe, dpi_factor: f32) -> Self::Window {
         Theme::<DrawPipe>::new_window(&self.inner, draw, dpi_factor)
@@ -61,13 +66,23 @@ impl Theme<DrawPipe> for CustomTheme {
         Theme::<DrawPipe>::update_window(&self.inner, window, dpi_factor);
     }
 
+    #[cfg(not(feature = "gat"))]
     unsafe fn draw_handle(
         &self,
         draw: &mut DrawPipe,
-        theme_window: &mut Self::Window,
+        window: &mut Self::Window,
         rect: Rect,
     ) -> Self::DrawHandle {
-        self.inner.draw_handle(draw, theme_window, rect)
+        self.inner.draw_handle(draw, window, rect)
+    }
+    #[cfg(feature = "gat")]
+    fn draw_handle<'a>(
+        &'a self,
+        draw: &'a mut DrawPipe,
+        window: &'a mut Self::Window,
+        rect: Rect,
+    ) -> Self::DrawHandle<'a> {
+        self.inner.draw_handle(draw, window, rect)
     }
 
     fn get_fonts<'a>(&self) -> Vec<Font<'a>> {

kas-wgpu/examples/gallery.rs

@@ -97,6 +97,9 @@ fn main() -> Result<(), kas_wgpu::Error> {
                             -> VoidResponse
                         {
                             println!("Theme: {:?}", name);
+                            #[cfg(not(feature = "stack_dst"))]
+                            println!("Warning: switching themes requires feature 'stack_dst'");
+
                             mgr.adjust_theme(|theme| theme.set_theme(name));
                             VoidResponse::None
                         }
@@ -132,7 +135,14 @@ fn main() -> Result<(), kas_wgpu::Error> {
         },
     );
 
-    let theme = kas_wgpu::theme::MultiTheme::new();
+    #[cfg(feature = "stack_dst")]
+    let theme = kas::theme::MultiTheme::builder()
+        .add("shaded", kas_wgpu::theme::ShadedTheme::new())
+        .add("flat", kas_wgpu::theme::FlatTheme::new())
+        .build();
+    #[cfg(not(feature = "stack_dst"))]
+    let theme = kas_wgpu::theme::ShadedTheme::new();
+
     let mut toolkit = kas_wgpu::Toolkit::new(theme)?;
     toolkit.add(window)?;
     toolkit.run()

kas-wgpu/src/lib.rs

@@ -5,6 +5,8 @@
 
 //! Toolkit for kas
 
+#![cfg_attr(feature = "gat", feature(generic_associated_types))]
+
 pub mod draw;
 mod event_loop;
 mod font;

kas-wgpu/src/theme/dimensions.rs

@@ -81,13 +81,21 @@ impl DimensionsWindow {
 }
 
 impl theme::Window<DrawPipe> for DimensionsWindow {
+    #[cfg(not(feature = "gat"))]
     type SizeHandle = SizeHandle<'static>;
+    #[cfg(feature = "gat")]
+    type SizeHandle<'a> = SizeHandle<'a>;
 
+    #[cfg(not(feature = "gat"))]
     unsafe fn size_handle<'a>(&'a mut self, draw: &'a mut DrawPipe) -> Self::SizeHandle {
         // We extend lifetimes (unsafe) due to the lack of associated type generics.
         let handle = SizeHandle::new(draw, &self.dims);
         std::mem::transmute::<SizeHandle<'a>, SizeHandle<'static>>(handle)
     }
+    #[cfg(feature = "gat")]
+    fn size_handle<'a>(&'a mut self, draw: &'a mut DrawPipe) -> Self::SizeHandle<'a> {
+        SizeHandle::new(draw, &self.dims)
+    }
 
     fn as_any_mut(&mut self) -> &mut dyn Any {
         self

kas-wgpu/src/theme/flat_theme.rs

@@ -56,7 +56,11 @@ pub struct DrawHandle<'a> {
 
 impl theme::Theme<DrawPipe> for FlatTheme {
     type Window = DimensionsWindow;
+
+    #[cfg(not(feature = "gat"))]
     type DrawHandle = DrawHandle<'static>;
+    #[cfg(feature = "gat")]
+    type DrawHandle<'a> = DrawHandle<'a>;
 
     fn new_window(&self, _draw: &mut DrawPipe, dpi_factor: f32) -> Self::Window {
         DimensionsWindow::new(DIMS, self.font_size, dpi_factor)
@@ -66,6 +70,7 @@ impl theme::Theme<DrawPipe> for FlatTheme {
         window.dims = Dimensions::new(DIMS, self.font_size, dpi_factor);
     }
 
+    #[cfg(not(feature = "gat"))]
     unsafe fn draw_handle<'a>(
         &'a self,
         draw: &'a mut DrawPipe,
@@ -83,6 +88,22 @@ impl theme::Theme<DrawPipe> for FlatTheme {
             pass: 0,
         }
     }
+    #[cfg(feature = "gat")]
+    fn draw_handle<'a>(
+        &'a self,
+        draw: &'a mut DrawPipe,
+        window: &'a mut Self::Window,
+        rect: Rect,
+    ) -> Self::DrawHandle<'a> {
+        DrawHandle {
+            draw,
+            window,
+            cols: &self.cols,
+            rect,
+            offset: Coord::ZERO,
+            pass: 0,
+        }
+    }
 
     fn get_fonts<'a>(&self) -> Vec<Font<'a>> {
         vec![crate::font::get_font()]

kas-wgpu/src/theme/mod.rs

@@ -7,11 +7,9 @@
 
 mod dimensions;
 mod flat_theme;
-mod multi_theme;
 mod shaded_theme;
 
 pub(crate) use dimensions::{Dimensions, DimensionsParams, DimensionsWindow};
 
 pub use flat_theme::FlatTheme;
-pub use multi_theme::MultiTheme;
 pub use shaded_theme::ShadedTheme;