Enable Text widget (#143)

* Fix and enable text widget * Add more String views (`&'static str`, `Cow<'static, str>`) --------- Co-authored-by: Philipp Mildenberger <[email protected]>
linebender · Nov 9, 2023 · 1656532 · 1656532
1 parent 71d1db0
commit 1656532
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Showing 7 changed files with 175 additions and 53 deletions.
diff --git a/examples/hello.rs b/examples/hello.rs
@@ -16,6 +16,7 @@ fn app_logic(data: &mut i32) -> impl View<i32> {
             *data += 1;
         }),
         h_stack((
+            "Buttons: ",
             button("decrease", |data| {
                 println!("clicked decrease");
                 *data -= 1;

diff --git a/src/view/button.rs b/src/view/button.rs
@@ -14,8 +14,9 @@
 
 use std::any::Any;
 
-use crate::view::ViewMarker;
-use crate::{view::Id, widget::ChangeFlags, MessageResult};
+use crate::view::{Id, ViewMarker};
+use crate::widget::ChangeFlags;
+use crate::MessageResult;
 
 use super::{Cx, View};
 

diff --git a/src/view/mod.rs b/src/view/mod.rs
@@ -17,7 +17,7 @@ mod button;
 // mod layout_observer;
 // mod list;
 // mod scroll_view;
-// mod text;
+mod text;
 // mod use_state;
 mod linear_layout;
 mod list;

diff --git a/src/view/text.rs b/src/view/text.rs
@@ -12,27 +12,107 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::any::Any;
+use std::borrow::Cow;
 
-use crate::{event::MessageResult, id::Id, widget::ChangeFlags};
+use crate::view::{Id, ViewMarker};
+use crate::widget::ChangeFlags;
 
 use super::{Cx, View};
 
+impl ViewMarker for String {}
+
 impl<T, A> View<T, A> for String {
     type State = ();
 
-    type Element = crate::widget::text::TextWidget;
+    type Element = crate::widget::TextWidget;
+
+    fn build(&self, cx: &mut Cx) -> (crate::view::Id, Self::State, Self::Element) {
+        let (id, element) =
+            cx.with_new_id(|_| crate::widget::TextWidget::new(Cow::from(self.clone())));
+        (id, (), element)
+    }
+
+    fn rebuild(
+        &self,
+        _cx: &mut Cx,
+        prev: &Self,
+        _id: &mut Id,
+        _state: &mut Self::State,
+        element: &mut Self::Element,
+    ) -> ChangeFlags {
+        if prev != self {
+            element.set_text(Cow::from(self.clone()))
+        } else {
+            ChangeFlags::empty()
+        }
+    }
+
+    fn message(
+        &self,
+        _id_path: &[xilem_core::Id],
+        _state: &mut Self::State,
+        message: Box<dyn std::any::Any>,
+        _app_state: &mut T,
+    ) -> xilem_core::MessageResult<A> {
+        xilem_core::MessageResult::Stale(message)
+    }
+}
+
+impl ViewMarker for &'static str {}
+
+impl<T, A> View<T, A> for &'static str {
+    type State = ();
+
+    type Element = crate::widget::TextWidget;
+
+    fn build(&self, cx: &mut Cx) -> (crate::view::Id, Self::State, Self::Element) {
+        let (id, element) = cx.with_new_id(|_| crate::widget::TextWidget::new(Cow::from(*self)));
+        (id, (), element)
+    }
+
+    fn rebuild(
+        &self,
+        _cx: &mut Cx,
+        prev: &Self,
+        _id: &mut Id,
+        _state: &mut Self::State,
+        element: &mut Self::Element,
+    ) -> ChangeFlags {
+        if prev != self {
+            element.set_text(Cow::from(*self))
+        } else {
+            ChangeFlags::empty()
+        }
+    }
+
+    fn message(
+        &self,
+        _id_path: &[xilem_core::Id],
+        _state: &mut Self::State,
+        message: Box<dyn std::any::Any>,
+        _app_state: &mut T,
+    ) -> xilem_core::MessageResult<A> {
+        xilem_core::MessageResult::Stale(message)
+    }
+}
+
+impl ViewMarker for Cow<'static, str> {}
+
+impl<T, A> View<T, A> for Cow<'static, str> {
+    type State = ();
+
+    type Element = crate::widget::TextWidget;
 
-    fn build(&self, cx: &mut Cx) -> (Id, Self::State, Self::Element) {
-        let (id, element) = cx.with_new_id(|_| crate::widget::text::TextWidget::new(self.clone()));
+    fn build(&self, cx: &mut Cx) -> (crate::view::Id, Self::State, Self::Element) {
+        let (id, element) = cx.with_new_id(|_| crate::widget::TextWidget::new(self.clone()));
         (id, (), element)
     }
 
     fn rebuild(
         &self,
         _cx: &mut Cx,
         prev: &Self,
-        _id: &mut crate::id::Id,
+        _id: &mut Id,
         _state: &mut Self::State,
         element: &mut Self::Element,
     ) -> ChangeFlags {
@@ -43,13 +123,13 @@ impl<T, A> View<T, A> for String {
         }
     }
 
-    fn event(
+    fn message(
         &self,
-        _id_path: &[crate::id::Id],
+        _id_path: &[xilem_core::Id],
         _state: &mut Self::State,
-        _event: Box<dyn Any>,
+        message: Box<dyn std::any::Any>,
         _app_state: &mut T,
-    ) -> MessageResult<A> {
-        MessageResult::Stale
+    ) -> xilem_core::MessageResult<A> {
+        xilem_core::MessageResult::Stale(message)
     }
 }
diff --git a/src/widget/contexts.rs b/src/widget/contexts.rs
@@ -321,7 +321,7 @@ impl_context_method!(
         }
     }
 );
-// Methods on all contexts besides LayoutCx.
+// Methods on LayoutCx and PaintCx
 //
 // These Methods return information about the widget
 impl_context_method!(LayoutCx<'_, '_>, PaintCx<'_, '_>, {

diff --git a/src/widget/mod.rs b/src/widget/mod.rs
@@ -22,7 +22,7 @@ mod linear_layout;
 mod piet_scene_helpers;
 mod raw_event;
 //mod scroll_view;
-//mod text;
+mod text;
 #[allow(clippy::module_inception)]
 mod widget;
 
@@ -33,4 +33,5 @@ pub use button::Button;
 pub use contexts::{AccessCx, CxState, EventCx, LayoutCx, LifeCycleCx, PaintCx, UpdateCx};
 pub use linear_layout::LinearLayout;
 pub use raw_event::{Event, LifeCycle, MouseEvent, ViewContext};
+pub use text::TextWidget;
 pub use widget::{AnyWidget, Widget};
diff --git a/src/widget/text.rs b/src/widget/text.rs
@@ -12,44 +12,82 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use parley::Layout;
+use parley::{FontContext, Layout};
+use std::borrow::Cow;
 use vello::{
-    kurbo::{Affine, Point, Size},
+    kurbo::{Affine, Size},
     peniko::{Brush, Color},
-    SceneBuilder, SceneFragment,
+    SceneBuilder,
 };
 
 use crate::text::ParleyBrush;
 
 use super::{
-    align::{FirstBaseline, LastBaseline, SingleAlignment, VertAlignment},
-    contexts::LifeCycleCx,
-    AlignCx, ChangeFlags, EventCx, LayoutCx, LifeCycle, PaintCx, RawEvent, UpdateCx, Widget,
+    contexts::LifeCycleCx, BoxConstraints, ChangeFlags, Event, EventCx, LayoutCx, LifeCycle,
+    PaintCx, UpdateCx, Widget,
 };
 
 pub struct TextWidget {
-    text: String,
+    text: Cow<'static, str>,
     layout: Option<Layout<ParleyBrush>>,
-    is_wrapped: bool,
 }
 
 impl TextWidget {
-    pub fn new(text: String) -> TextWidget {
-        TextWidget {
-            text,
-            is_wrapped: false,
-            layout: None,
-        }
+    pub fn new(text: Cow<'static, str>) -> TextWidget {
+        TextWidget { text, layout: None }
     }
 
-    pub fn set_text(&mut self, text: String) -> ChangeFlags {
+    pub fn set_text(&mut self, text: Cow<'static, str>) -> ChangeFlags {
         self.text = text;
         ChangeFlags::LAYOUT | ChangeFlags::PAINT
     }
+
+    fn get_layout_mut(&mut self, font_cx: &mut FontContext) -> &mut Layout<ParleyBrush> {
+        // Ensure Parley layout is initialised
+        if self.layout.is_none() {
+            let mut lcx = parley::LayoutContext::new();
+            let mut layout_builder = lcx.ranged_builder(font_cx, &self.text, 1.0);
+            layout_builder.push_default(&parley::style::StyleProperty::Brush(ParleyBrush(
+                Brush::Solid(Color::rgb8(255, 255, 255)),
+            )));
+            self.layout = Some(layout_builder.build());
+        }
+
+        self.layout.as_mut().unwrap()
+    }
+
+    fn layout_text(&mut self, font_cx: &mut FontContext, bc: &BoxConstraints) -> Size {
+        // Compute max_advance from box constraints
+        let max_advance = if bc.max().width.is_finite() {
+            Some(bc.max().width as f32)
+        } else if bc.min().width.is_sign_negative() {
+            Some(0.0)
+        } else {
+            None
+        };
+
+        // Layout text
+        let layout = self.get_layout_mut(font_cx);
+        layout.break_all_lines(max_advance, parley::layout::Alignment::Start);
+
+        // // Debug print
+        // println!(
+        //     "max: {:?}. w: {}, h: {}",
+        //     max_advance,
+        //     layout.width(),
+        //     layout.height()
+        // );
+
+        // Return dimensions
+        Size {
+            width: layout.width() as f64,
+            height: layout.height() as f64,
+        }
+    }
 }
 
 impl Widget for TextWidget {
-    fn event(&mut self, _cx: &mut EventCx, _event: &RawEvent) {}
+    fn event(&mut self, _cx: &mut EventCx, _event: &Event) {}
 
     fn lifecycle(&mut self, _cx: &mut LifeCycleCx, _event: &LifeCycle) {}
 
@@ -59,32 +97,33 @@ impl Widget for TextWidget {
         cx.request_layout();
     }
 
-    fn measure(&mut self, cx: &mut LayoutCx) -> (Size, Size) {
-        let min_size = Size::ZERO;
-        let max_size = Size::new(50.0, 50.0);
-        self.is_wrapped = false;
-        (min_size, max_size)
+    fn compute_max_intrinsic(
+        &mut self,
+        axis: crate::Axis,
+        cx: &mut LayoutCx,
+        bc: &super::BoxConstraints,
+    ) -> f64 {
+        let size = self.layout_text(cx.font_cx(), bc);
+        match axis {
+            crate::Axis::Horizontal => size.width,
+            crate::Axis::Vertical => size.height,
+        }
     }
 
-    fn layout(&mut self, cx: &mut LayoutCx, proposed_size: Size) -> Size {
-        let mut lcx = parley::LayoutContext::new();
-        let mut layout_builder = lcx.ranged_builder(cx.font_cx(), &self.text, 1.0);
-        layout_builder.push_default(&parley::style::StyleProperty::Brush(ParleyBrush(
-            Brush::Solid(Color::rgb8(255, 255, 255)),
-        )));
-        let mut layout = layout_builder.build();
-        // Question for Chad: is this needed?
-        layout.break_all_lines(None, parley::layout::Alignment::Start);
-        self.layout = Some(layout);
-        cx.widget_state.max_size
+    fn layout(&mut self, cx: &mut LayoutCx, bc: &BoxConstraints) -> Size {
+        cx.request_paint();
+        self.layout_text(cx.font_cx(), bc)
     }
 
-    fn align(&self, cx: &mut AlignCx, alignment: SingleAlignment) {}
-
-    fn paint(&mut self, cx: &mut PaintCx, builder: &mut SceneBuilder) {
+    fn paint(&mut self, _cx: &mut PaintCx, builder: &mut SceneBuilder) {
         if let Some(layout) = &self.layout {
-            let transform = Affine::translate((40.0, 40.0));
-            crate::text::render_text(builder, transform, &layout);
+            crate::text::render_text(builder, Affine::IDENTITY, layout);
         }
     }
+
+    fn accessibility(&mut self, cx: &mut super::AccessCx) {
+        let mut builder = accesskit::NodeBuilder::new(accesskit::Role::StaticText);
+        builder.set_value(self.text.clone());
+        cx.push_node(builder);
+    }
 }