Fix text bounds in `iced_wgpu` on nonintegral DPI

2 files changed, 18 insertions, 2 deletions

diff --git a/wgpu/src/renderer.rs b/wgpu/src/renderer.rs
index d3bdc878..52764248 100644
--- a/wgpu/src/renderer.rs
+++ b/wgpu/src/renderer.rs
@@ -344,11 +344,27 @@ impl Renderer {
             for text in layer.text.iter() {
                 // Target physical coordinates directly to avoid blurry text
                 let text = wgpu_glyph::Section {
+                    // TODO: We `round` here to avoid rerasterizing text when
+                    // its position changes slightly. This can make text feel a
+                    // bit "jumpy". We may be able to do better once we improve
+                    // our text rendering/caching pipeline.
                     screen_position: (
                         (text.screen_position.0 * dpi).round(),
                         (text.screen_position.1 * dpi).round(),
                     ),
-                    bounds: (text.bounds.0 * dpi, text.bounds.1 * dpi),
+                    // TODO: Fix precision issues with some DPI factors.
+                    //
+                    // The `ceil` here can cause some words to render on the
+                    // same line when they should not.
+                    //
+                    // Ideally, `wgpu_glyph` should be able to compute layout
+                    // using logical positions, and then apply the proper
+                    // DPI scaling. This would ensure that both measuring and
+                    // rendering follow the same layout rules.
+                    bounds: (
+                        (text.bounds.0 * dpi).ceil(),
+                        (text.bounds.1 * dpi).ceil(),
+                    ),
                     scale: wgpu_glyph::Scale {
                         x: text.scale.x * dpi,
                         y: text.scale.y * dpi,
diff --git a/wgpu/src/text.rs b/wgpu/src/text.rs
index 3205fe55..81fc1fb5 100644
--- a/wgpu/src/text.rs
+++ b/wgpu/src/text.rs
@@ -91,7 +91,7 @@ impl Pipeline {
 
             // TODO: This is a bit hacky. We are loading the debug font as the
             // first font in the `draw_brush`. The `measure_brush` does not
-            // contain this font.
+            // contain this font, hence we subtract 1.
             //
             // This should go away once we improve the debug view and integrate
             // it as just another UI app.