update deps, add widget_index!, improve examples/markdown

crates/kas-core/Cargo.toml

@@ -79,7 +79,8 @@ path = "../kas-macros"
 
 [dependencies.kas-text]
 version = "0.4.2"
-#git = "https://github.com/kas-gui/kas-text.git"
+git = "https://github.com/kas-gui/kas-text.git"
+rev = "179278f"
 
 [dependencies.winit]
 # Provides translations for several winit types

crates/kas-core/src/event/handler.rs

@@ -96,8 +96,8 @@ pub trait SendEvent: Handler {
     ///     return Response::Unused;
     /// }
     /// match self.find_child_index(&id) {
-    ///     Some(0) => self.child0.send(mgr, id, event).into(),
-    ///     Some(1) => self.child1.send(mgr, id, event).into(),
+    ///     Some(widget_index![self.child0]) => self.child0.send(mgr, id, event).into(),
+    ///     Some(widget_index![self.child1]) => self.child1.send(mgr, id, event).into(),
     ///     // ...
     ///     _ => {
     ///         debug_assert_eq!(self.id(), id);

crates/kas-core/src/layout/sizer.rs

@@ -187,6 +187,7 @@ impl SolveCache {
         mgr: &mut SetRectMgr,
         mut rect: Rect,
         inner_margin: bool,
+        print_heirarchy: bool,
     ) {
         let start = std::time::Instant::now();
 
@@ -220,11 +221,13 @@ impl SolveCache {
         widget.set_rect(mgr, rect, AlignHints::NONE);
 
         trace!(target: "kas_perf", "layout::apply_rect: {}ms", start.elapsed().as_millis());
-        trace!(
-            "layout::apply_rect: size={:?}, hierarchy:{}",
-            rect.size,
-            WidgetHeirarchy(widget, 0),
-        );
+        if print_heirarchy {
+            trace!(
+                "layout::apply_rect: size={:?}, hierarchy:{}",
+                rect.size,
+                WidgetHeirarchy(widget, 0),
+            );
+        }
 
         self.refresh_rules = false;
     }

crates/kas-macros/Cargo.toml

@@ -29,7 +29,7 @@ proc-macro-error = "1.0"
 version = "1.0.14"
 # We need 'extra-traits' for equality testing
 # We need 'full' for parsing macros within macro arguments
-features = ["extra-traits", "full"]
+features = ["extra-traits", "full", "visit-mut"]
 
 [build-dependencies]
 version_check = "0.9"

crates/kas-macros/src/lib.rs

@@ -22,6 +22,7 @@ mod make_layout;
 mod make_widget;
 pub(crate) mod where_clause;
 mod widget;
+mod widget_index;
 
 /// A variant of the standard `derive` macro
 ///
@@ -277,3 +278,20 @@ pub fn derive_empty_msg(input: TokenStream) -> TokenStream {
     };
     toks.into()
 }
+
+/// Index of a child widget
+///
+/// This macro is usable only within a [`widget!`] macro.
+///
+/// Example usage: `widget_index![self.a]`. If `a` is a child widget (a field
+/// marked with the `#[widget]` attribute), then this expands to the child
+/// widget's index (as used by [`WidgetChildren`]). Otherwise, this is an error.
+///
+/// [`WidgetChildren`]: https://docs.rs/kas/latest/kas/trait.WidgetChildren.html
+#[proc_macro_error]
+#[proc_macro]
+pub fn widget_index(input: TokenStream) -> TokenStream {
+    let input2 = input.clone();
+    let _ = parse_macro_input!(input2 as widget_index::BaseInput);
+    input
+}

crates/kas-macros/src/widget.rs

@@ -12,6 +12,7 @@ use syn::spanned::Spanned;
 use syn::{parse_quote, Result};
 
 pub(crate) fn widget(mut args: Widget) -> Result<TokenStream> {
+    crate::widget_index::visit_widget(&mut args);
     let mut toks = quote! { #args };
 
     let name = &args.ident;
@@ -42,6 +43,9 @@ pub(crate) fn widget(mut args: Widget) -> Result<TokenStream> {
                         "impl conflicts with use of #[widget(derive=FIELD)]"
                     );
                 }
+                if !args.children.is_empty() {
+                    emit_warning!(impl_.span(), "use of `#![widget]` on children with custom `WidgetChildren` implementation");
+                }
                 impl_widget_children = false;
             } else if *path == parse_quote! { ::kas::WidgetConfig }
                 || *path == parse_quote! { kas::WidgetConfig }

crates/kas-macros/src/widget_index.rs

@@ -0,0 +1,98 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License in the LICENSE-APACHE file or at:
+//     https://www.apache.org/licenses/LICENSE-2.0
+
+use crate::args::{self, Widget};
+use proc_macro2::Span;
+use proc_macro_error::emit_error;
+use syn::parse::{Parse, ParseStream};
+use syn::spanned::Spanned;
+use syn::visit_mut::{self, VisitMut};
+use syn::{parse_quote, Error, Lit, Member, Result, Token};
+
+#[allow(non_camel_case_types)]
+mod kw {
+    syn::custom_keyword!(error_emitted);
+}
+
+pub struct BaseInput;
+impl Parse for BaseInput {
+    fn parse(input: ParseStream) -> Result<Self> {
+        if input.peek(Lit) {
+            // Okay: macro was expanded internally (or user wrote a number...)
+            let _ = input.parse::<Lit>()?;
+            if input.is_empty() {
+                return Ok(Self);
+            }
+        } else if input.peek(kw::error_emitted) {
+            // An error was already emitted by the visitor
+            let _ = input.parse::<kw::error_emitted>()?;
+            if input.is_empty() {
+                return Ok(Self);
+            }
+        }
+
+        let msg = "usage of `widget_index!` invalid outside of `widget!` macro";
+        Err(Error::new(Span::call_site(), msg))
+    }
+}
+
+pub struct WidgetInput {
+    pub ident: Member,
+}
+
+impl Parse for WidgetInput {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let _ = input.parse::<Token![self]>()?;
+        let _ = input.parse::<Token![.]>()?;
+        let ident = input.parse()?;
+
+        Ok(WidgetInput { ident })
+    }
+}
+
+struct Visitor<'a> {
+    children: &'a [args::Child],
+}
+impl<'a> VisitMut for Visitor<'a> {
+    fn visit_macro_mut(&mut self, node: &mut syn::Macro) {
+        // HACK: we cannot expand the macro here since we do not have an Expr
+        // to replace. Instead we can only modify the macro's tokens.
+        // WARNING: if the macro's tokens are modified before printing an error
+        // message is emitted then the span of that error message is incorrect.
+
+        if node.path == parse_quote! { widget_index } {
+            let args = match syn::parse2::<WidgetInput>(node.tokens.clone()) {
+                Ok(args) => args,
+                Err(err) => {
+                    emit_error!(node.tokens.span(), "{}", err);
+                    node.tokens = parse_quote! { error_emitted };
+                    return;
+                }
+            };
+
+            for (i, child) in self.children.iter().enumerate() {
+                if args.ident == child.ident {
+                    node.tokens = parse_quote! { #i };
+                    return;
+                }
+            }
+
+            emit_error!(args.ident.span(), "does not match any child widget");
+            node.tokens = parse_quote! { error_emitted };
+            return;
+        }
+
+        visit_mut::visit_macro_mut(self, node);
+    }
+}
+
+pub fn visit_widget(node: &mut Widget) {
+    let children = &node.children;
+    let mut obj = Visitor { children };
+
+    for impl_ in &mut node.extra_impls {
+        obj.visit_item_impl_mut(impl_);
+    }
+}

crates/kas-resvg/Cargo.toml

@@ -27,8 +27,8 @@ svg = ["resvg", "usvg"]
 
 [dependencies]
 tiny-skia = { version = "0.6.1" }
-resvg = { version = "0.18.0", optional = true }
-usvg = { version = "0.18.0", optional = true }
+resvg = { version = "0.22.0", optional = true }
+usvg = { version = "0.22.0", optional = true }
 
 # We must rename this package since macros expect kas to be in scope:
 kas = { version = "0.10.0", package = "kas-core", path = "../kas-core" }

crates/kas-resvg/src/svg.rs

@@ -12,7 +12,7 @@ use kas::geom::Vec2;
 use kas::layout::MarginSelector;
 use kas::prelude::*;
 use std::path::PathBuf;
-use tiny_skia::Pixmap;
+use tiny_skia::{Pixmap, Transform};
 
 widget! {
     /// An SVG image loaded from a path
@@ -113,6 +113,7 @@ widget! {
                     keep_named_groups: false,
                     default_size: usvg::Size::new(def_size, def_size).unwrap(),
                     fontdb,
+                    image_href_resolver: &Default::default(),
                 };
 
                 let tree = usvg::Tree::from_data(&data, &opts).unwrap();
@@ -172,7 +173,8 @@ widget! {
                         let (w, h) = (pm.width(), pm.height());
 
                         // alas, we cannot tell resvg to skip the aspect-ratio-scaling!
-                        resvg::render(tree, usvg::FitTo::Height(h), pm.as_mut());
+                        let transform = Transform::identity();
+                        resvg::render(tree, usvg::FitTo::Height(h), transform, pm.as_mut());
 
                         let id = mgr.draw_shared().image_alloc((w, h)).unwrap();
                         mgr.draw_shared().image_upload(id, pm.data(), ImageFormat::Rgba8);

crates/kas-wgpu/Cargo.toml

@@ -60,7 +60,8 @@ default-features = false
 
 [dependencies.kas-text]
 version = "0.4.2"
-#git = "https://github.com/kas-gui/kas-text.git"
+git = "https://github.com/kas-gui/kas-text.git"
+rev = "179278f"
 
 [build-dependencies]
 glob = "0.3"

crates/kas-wgpu/src/window.rs

@@ -111,7 +111,7 @@ impl<C: CustomPipe, T: Theme<DrawPipe<C>>> Window<C, T> {
             next_avail_frame_time: time,
             queued_frame_time: Some(time),
         };
-        r.apply_size(shared);
+        r.apply_size(shared, true);
 
         trace!("Window::new completed in {}µs", time.elapsed().as_micros());
         Ok(r)
@@ -191,9 +191,9 @@ impl<C: CustomPipe, T: Theme<DrawPipe<C>>> Window<C, T> {
         }
         if action.contains(TkAction::RESIZE) {
             self.solve_cache.invalidate_rule_cache();
-            self.apply_size(shared);
+            self.apply_size(shared, false);
         } else if action.contains(TkAction::SET_SIZE) {
-            self.apply_size(shared);
+            self.apply_size(shared, false);
         }
         /*if action.contains(TkAction::Popup) {
             let widget = &mut self.widget;
@@ -280,11 +280,11 @@ impl<C: CustomPipe, T: Theme<DrawPipe<C>>> Window<C, T> {
         self.ev_state.full_configure(&mut tkw, &mut *self.widget);
 
         self.solve_cache.invalidate_rule_cache();
-        self.apply_size(shared);
+        self.apply_size(shared, false);
         trace!("reconfigure completed in {}µs", time.elapsed().as_micros());
     }
 
-    fn apply_size(&mut self, shared: &mut SharedState<C, T>) {
+    fn apply_size(&mut self, shared: &mut SharedState<C, T>, first: bool) {
         let time = Instant::now();
         let rect = Rect::new(Coord::ZERO, self.sc_size());
         debug!("Resizing window to rect = {:?}", rect);
@@ -296,7 +296,7 @@ impl<C: CustomPipe, T: Theme<DrawPipe<C>>> Window<C, T> {
             &mut shared.draw,
             &mut self.ev_state,
         );
-        solve_cache.apply_rect(widget.as_widget_mut(), &mut mgr, rect, true);
+        solve_cache.apply_rect(widget.as_widget_mut(), &mut mgr, rect, true, first);
         widget.resize_popups(&mut mgr);
 
         let restrict_dimensions = self.widget.restrict_dimensions();
@@ -329,7 +329,7 @@ impl<C: CustomPipe, T: Theme<DrawPipe<C>>> Window<C, T> {
 
         // Note that on resize, width adjustments may affect height
         // requirements; we therefore refresh size restrictions.
-        self.apply_size(shared);
+        self.apply_size(shared, false);
 
         trace!(
             "do_resize completed in {}µs (including apply_size time)",

crates/kas-widgets/src/scrollbar.rs

@@ -647,23 +647,23 @@ widget! {
             }
 
             match self.find_child_index(&id) {
-                Some(0) => self.horiz_bar
+                Some(widget_index![self.horiz_bar]) => self.horiz_bar
                     .send(mgr, id, event)
                     .try_into()
                     .unwrap_or_else(|msg| {
                         let offset = Offset(msg, self.inner.scroll_offset().1);
                         self.inner.set_scroll_offset(mgr, offset);
                         Response::Used
                     }),
-                Some(1) => self.vert_bar
+                Some(widget_index![self.vert_bar]) => self.vert_bar
                     .send(mgr, id, event)
                     .try_into()
                     .unwrap_or_else(|msg| {
                         let offset = Offset(self.inner.scroll_offset().0, msg);
                         self.inner.set_scroll_offset(mgr, offset);
                         Response::Used
                     }),
-                Some(2) => {
+                Some(widget_index![self.inner]) => {
                     let r = self.inner.send(mgr, id, event);
                     // We assume the inner already updated its positions; this is just to set bars
                     if matches!(r, Response::Pan(_) | Response::Scrolled | Response::Focus(_)) {

crates/kas-widgets/src/window.rs

@@ -261,6 +261,6 @@ impl<W: Widget> Window<W> {
             Rect::new(Coord(x, y), Size::new(w, h))
         };
 
-        cache.apply_rect(widget, mgr, rect, false);
+        cache.apply_rect(widget, mgr, rect, false, true);
     }
 }