Code review and make scaling ratio dynamic

editor/src/messages/portfolio/document/overlays/overlays_message.rs

@@ -5,7 +5,7 @@ use crate::messages::prelude::*;
 #[derive(PartialEq, Clone, Debug, serde::Serialize, serde::Deserialize)]
 pub enum OverlaysMessage {
 	Draw,
-
+	SetDevicePixelRatio { ratio: f64 },
 	// Serde functionality isn't used but is required by the message system macros
 	AddProvider(#[serde(skip, default = "empty_provider")] OverlayProvider),
 	RemoveProvider(#[serde(skip, default = "empty_provider")] OverlayProvider),

editor/src/messages/portfolio/document/overlays/overlays_message_handler.rs

@@ -11,7 +11,6 @@ pub struct OverlaysMessageHandler {
 	pub overlay_providers: HashSet<OverlayProvider>,
 	canvas: Option<web_sys::HtmlCanvasElement>,
 	context: Option<web_sys::CanvasRenderingContext2d>,
-	#[allow(dead_code)]
 	device_pixel_ratio: Option<f64>,
 }
 
@@ -42,12 +41,12 @@ impl MessageHandler<OverlaysMessage, OverlaysMessageData<'_>> for OverlaysMessag
 
 				let size = ipp.viewport_bounds.size().as_uvec2();
 
-				let device_pixel_ratio = *self.device_pixel_ratio.get_or_insert_with(|| web_sys::window().map(|w| w.device_pixel_ratio()).unwrap_or(1.0));
+				let device_pixel_ratio = self.device_pixel_ratio.unwrap_or(1.);
 
 				let [a, b, c, d, e, f] = DAffine2::from_scale(DVec2::splat(device_pixel_ratio)).to_cols_array();
-				context.set_transform(a, b, c, d, e, f).expect("scaling is necessary to support HiDPI displays");
+				let _ = context.set_transform(a, b, c, d, e, f);
 				context.clear_rect(0., 0., ipp.viewport_bounds.size().x, ipp.viewport_bounds.size().y);
-				context.reset_transform().expect("scaling is necessary to support HiDPI displays");
+				let _ = context.reset_transform();
 
 				if overlays_visible {
 					responses.add(DocumentMessage::GridOverlays(OverlayContext {
@@ -71,6 +70,10 @@ impl MessageHandler<OverlaysMessage, OverlaysMessageData<'_>> for OverlaysMessag
 					self.canvas, self.context
 				);
 			}
+			OverlaysMessage::SetDevicePixelRatio { ratio } => {
+				self.device_pixel_ratio = Some(ratio);
+				responses.add(OverlaysMessage::Draw);
+			}
 			OverlaysMessage::AddProvider(message) => {
 				self.overlay_providers.insert(message);
 			}

editor/src/messages/portfolio/document/overlays/utility_types.rs

@@ -26,11 +26,8 @@ pub struct OverlayContext {
 	#[specta(skip)]
 	pub render_context: web_sys::CanvasRenderingContext2d,
 	pub size: DVec2,
-	// The device pixel ratio is a property provided
-	// by the browser window and is the css pixel size
-	// divided by the physical pixel size. It allows
-	// better pixel density of visualizations on
-	// high dpi displays (such as Retina displays).
+	// The device pixel ratio is a property provided by the browser window and is the CSS pixel size divided by the physical monitor's pixel size.
+	// It allows better pixel density of visualizations on high-DPI displays where the OS display scaling is not 100%, or where the browser is zoomed.
 	pub device_pixel_ratio: f64,
 }
 // Message hashing isn't used but is required by the message system macros
@@ -44,8 +41,9 @@ impl OverlayContext {
 	}
 
 	pub fn dashed_quad(&mut self, quad: Quad, color_fill: Option<&str>, dash_width: Option<f64>, dash_gap_width: Option<f64>, dash_offset: Option<f64>) {
-		// Set the dash pattern
 		self.start_dpi_aware_transform();
+
+		// Set the dash pattern
 		if let Some(dash_width) = dash_width {
 			let dash_gap_width = dash_gap_width.unwrap_or(1.);
 			let array = js_sys::Array::new();
@@ -89,6 +87,7 @@ impl OverlayContext {
 		if dash_offset.is_some() && dash_offset != Some(0.) {
 			self.render_context.set_line_dash_offset(0.);
 		}
+
 		self.end_dpi_aware_transform();
 	}
 
@@ -97,8 +96,9 @@ impl OverlayContext {
 	}
 
 	pub fn dashed_line(&mut self, start: DVec2, end: DVec2, color: Option<&str>, dash_width: Option<f64>, dash_gap_width: Option<f64>, dash_offset: Option<f64>) {
-		// Set the dash pattern
 		self.start_dpi_aware_transform();
+
+		// Set the dash pattern
 		if let Some(dash_width) = dash_width {
 			let dash_gap_width = dash_gap_width.unwrap_or(1.);
 			let array = js_sys::Array::new();
@@ -136,11 +136,13 @@ impl OverlayContext {
 		if dash_offset.is_some() && dash_offset != Some(0.) {
 			self.render_context.set_line_dash_offset(0.);
 		}
+
 		self.end_dpi_aware_transform();
 	}
 
 	pub fn manipulator_handle(&mut self, position: DVec2, selected: bool, color: Option<&str>) {
 		self.start_dpi_aware_transform();
+
 		let position = position.round() - DVec2::splat(0.5);
 
 		self.render_context.begin_path();
@@ -153,6 +155,7 @@ impl OverlayContext {
 		self.render_context.set_stroke_style_str(color.unwrap_or(COLOR_OVERLAY_BLUE));
 		self.render_context.fill();
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 
@@ -162,21 +165,19 @@ impl OverlayContext {
 		self.square(position, None, Some(color_fill), Some(color_stroke));
 	}
 
-	/// Transforms the Canvas Context To Adjust for DPI
+	/// Transforms the canvas context to adjust for DPI scaling
 	///
-	/// Overwrites all existing tranforms.
-	/// This operation can be reversed with [`Self::reset_transform`].
+	/// Overwrites all existing tranforms. This operation can be reversed with [`Self::reset_transform`].
 	fn start_dpi_aware_transform(&self) {
 		let [a, b, c, d, e, f] = DAffine2::from_scale(DVec2::splat(self.device_pixel_ratio)).to_cols_array();
 		self.render_context
 			.set_transform(a, b, c, d, e, f)
 			.expect("transform should be able to be set to be able to account for DPI");
 	}
 
-	/// Untransforms the Canvas Context To Adjust for DPI
+	/// Un-transforms the Canvas context to adjust for DPI scaling
 	///
-	/// Warning: this function doesn't only reset the
-	/// DPI adjustment, it resets the entire transform.
+	/// Warning: this function doesn't only reset the DPI scaling adjustment, it resets the entire transform.
 	fn end_dpi_aware_transform(&self) {
 		self.render_context.reset_transform().expect("transform should be able to be reset to be able to account for DPI");
 	}
@@ -190,12 +191,14 @@ impl OverlayContext {
 		let corner = position - DVec2::splat(size) / 2.;
 
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		self.render_context.rect(corner.x, corner.y, size, size);
 		self.render_context.set_fill_style_str(color_fill);
 		self.render_context.set_stroke_style_str(color_stroke);
 		self.render_context.fill();
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 
@@ -207,10 +210,12 @@ impl OverlayContext {
 		let corner = position - DVec2::splat(size) / 2.;
 
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		self.render_context.rect(corner.x, corner.y, size, size);
 		self.render_context.set_fill_style_str(color_fill);
 		self.render_context.fill();
+
 		self.end_dpi_aware_transform();
 	}
 
@@ -220,12 +225,14 @@ impl OverlayContext {
 		let position = position.round();
 
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		self.render_context.arc(position.x, position.y, radius, 0., TAU).expect("Failed to draw the circle");
 		self.render_context.set_fill_style_str(color_fill);
 		self.render_context.set_stroke_style_str(color_stroke);
 		self.render_context.fill();
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 
@@ -291,6 +298,7 @@ impl OverlayContext {
 		let (x, y) = (position.round() - DVec2::splat(0.5)).into();
 
 		self.start_dpi_aware_transform();
+
 		// Circle
 
 		self.render_context.begin_path();
@@ -315,11 +323,15 @@ impl OverlayContext {
 		self.render_context.move_to(x, y - crosshair_radius);
 		self.render_context.line_to(x, y + crosshair_radius);
 		self.render_context.stroke();
+
+		self.render_context.set_line_cap("butt");
+
 		self.end_dpi_aware_transform();
 	}
 
 	pub fn outline_vector(&mut self, vector_data: &VectorData, transform: DAffine2) {
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		let mut last_point = None;
 		for (_, bezier, start_id, end_id) in vector_data.segment_bezier_iter() {
@@ -331,20 +343,24 @@ impl OverlayContext {
 
 		self.render_context.set_stroke_style_str(COLOR_OVERLAY_BLUE);
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 
 	pub fn outline_bezier(&mut self, bezier: Bezier, transform: DAffine2) {
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		self.bezier_command(bezier, transform, true);
 		self.render_context.set_stroke_style_str(COLOR_OVERLAY_BLUE);
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 
 	fn bezier_command(&self, bezier: Bezier, transform: DAffine2, move_to: bool) {
 		self.start_dpi_aware_transform();
+
 		let Bezier { start, end, handles } = bezier.apply_transformation(|point| transform.transform_point2(point));
 		if move_to {
 			self.render_context.move_to(start.x, start.y);
@@ -355,11 +371,13 @@ impl OverlayContext {
 			bezier_rs::BezierHandles::Quadratic { handle } => self.render_context.quadratic_curve_to(handle.x, handle.y, end.x, end.y),
 			bezier_rs::BezierHandles::Cubic { handle_start, handle_end } => self.render_context.bezier_curve_to(handle_start.x, handle_start.y, handle_end.x, handle_end.y, end.x, end.y),
 		}
+
 		self.end_dpi_aware_transform();
 	}
 
 	pub fn outline(&mut self, subpaths: impl Iterator<Item = impl Borrow<Subpath<PointId>>>, transform: DAffine2) {
 		self.start_dpi_aware_transform();
+
 		self.render_context.begin_path();
 		for subpath in subpaths {
 			let subpath = subpath.borrow();
@@ -406,6 +424,7 @@ impl OverlayContext {
 
 		self.render_context.set_stroke_style_str(COLOR_OVERLAY_BLUE);
 		self.render_context.stroke();
+
 		self.end_dpi_aware_transform();
 	}
 

frontend/src/components/panels/Document.svelte

@@ -370,7 +370,22 @@
 	}
 
 	onMount(() => {
-		devicePixelRatio = window.devicePixelRatio;
+		// Not compatible with Safari:
+		// <https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio#browser_compatibility>
+		// <https://bugs.webkit.org/show_bug.cgi?id=124862>
+		let removeUpdatePixelRatio: (() => void) | undefined = undefined;
+		const updatePixelRatio = () => {
+			removeUpdatePixelRatio?.();
+			const mediaQueryList = matchMedia(`(resolution: ${window.devicePixelRatio}dppx)`);
+			// The event is one-time use, so we have to set up a new listener and remove the old one every time
+			mediaQueryList.addEventListener("change", updatePixelRatio);
+			removeUpdatePixelRatio = () => mediaQueryList.removeEventListener("change", updatePixelRatio);
+
+			devicePixelRatio = window.devicePixelRatio;
+			editor.handle.setDevicePixelRatio(devicePixelRatio);
+		};
+		updatePixelRatio();
+
 		// Update rendered SVGs
 		editor.subscriptions.subscribeJsMessage(UpdateDocumentArtwork, async (data) => {
 			await tick();

frontend/wasm/src/editor_api.rs

@@ -352,6 +352,13 @@ impl EditorHandle {
 		self.dispatch(message);
 	}
 
+	/// Inform the overlays system of the current device pixel ratio
+	#[wasm_bindgen(js_name = setDevicePixelRatio)]
+	pub fn set_device_pixel_ratio(&self, ratio: f64) {
+		let message = OverlaysMessage::SetDevicePixelRatio { ratio };
+		self.dispatch(message);
+	}
+
 	/// Mouse movement within the screenspace bounds of the viewport
 	#[wasm_bindgen(js_name = onMouseMove)]
 	pub fn on_mouse_move(&self, x: f64, y: f64, mouse_keys: u8, modifiers: u8) {