1 files changed, 83 insertions, 0 deletions
diff --git a/wgpu/src/renderer/text.rs b/wgpu/src/renderer/text.rs
new file mode 100644
index 00000000..8fbade4e
--- /dev/null
+++ b/wgpu/src/renderer/text.rs
@@ -0,0 +1,83 @@
+use crate::{Primitive, Renderer};
+use iced_native::{text, Color, Layout, MouseCursor, Node, Style, Text};
+
+use wgpu_glyph::{GlyphCruncher, Section};
+
+use std::cell::RefCell;
+use std::f32;
+
+impl text::Renderer for Renderer {
+    fn node(&self, text: &Text) -> Node {
+        let glyph_brush = self.glyph_brush.clone();
+        let content = text.content.clone();
+
+        // TODO: Investigate why stretch tries to measure this MANY times
+        // with every ancestor's bounds.
+        // Bug? Using the library wrong? I should probably open an issue on
+        // the stretch repository.
+        // I noticed that the first measure is the one that matters in
+        // practice. Here, we use a RefCell to store the cached measurement.
+        let measure = RefCell::new(None);
+        let size = text.size.map(f32::from).unwrap_or(20.0);
+
+        let style = Style::default().width(text.width);
+
+        iced_native::Node::with_measure(style, move |bounds| {
+            let mut measure = measure.borrow_mut();
+
+            if measure.is_none() {
+                let bounds = (
+                    match bounds.width {
+                        iced_native::Number::Undefined => f32::INFINITY,
+                        iced_native::Number::Defined(w) => w,
+                    },
+                    match bounds.height {
+                        iced_native::Number::Undefined => f32::INFINITY,
+                        iced_native::Number::Defined(h) => h,
+                    },
+                );
+
+                let text = Section {
+                    text: &content,
+                    scale: wgpu_glyph::Scale { x: size, y: size },
+                    bounds,
+                    ..Default::default()
+                };
+
+                let (width, height) = if let Some(bounds) =
+                    glyph_brush.borrow_mut().glyph_bounds(&text)
+                {
+                    (bounds.width(), bounds.height())
+                } else {
+                    (0.0, 0.0)
+                };
+
+                let size = iced_native::Size { width, height };
+
+                // If the text has no width boundary we avoid caching as the
+                // layout engine may just be measuring text in a row.
+                if bounds.0 == f32::INFINITY {
+                    return size;
+                } else {
+                    *measure = Some(size);
+                }
+            }
+
+            measure.unwrap()
+        })
+    }
+
+    fn draw(&mut self, text: &Text, layout: Layout<'_>) -> Self::Output {
+        (
+            Primitive::Text {
+                content: text.content.clone(),
+                size: f32::from(text.size.unwrap_or(20)),
+                bounds: layout.bounds(),
+                color: text.color.unwrap_or(Color::BLACK),
+                horizontal_alignment: text.horizontal_alignment,
+                vertical_alignment: text.vertical_alignment,
+            },
+            MouseCursor::OutOfBounds,
+        )
+    }
+}