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web: Handle missing OffscreenCanvas for canvas font renderer #22696

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Merged
kjarosh merged 1 commit into from
Jan 6, 2026
Merged

web: Handle missing OffscreenCanvas for canvas font renderer #22696

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14 changes: 13 additions & 1 deletion web/src/ui/font_renderer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,10 @@ impl CanvasFontRenderer {
const SCALE: f64 = 20.0;

pub fn new(italic: bool, bold: bool, font_family: &str) -> Result<Self, JsValue> {
// TODO Firefox <105, Safari <16.4 do not support OffscreenCanvas
if !Self::is_offscreen_canvas_supported() {
return Err(JsValue::from_str("OffscreenCanvas unsupported"));
}

let canvas = OffscreenCanvas::new(1024, 1024)?;

let ctx = canvas.get_context("2d")?.expect("2d context");
Expand All @@ -51,6 +54,15 @@ impl CanvasFontRenderer {
})
}

// TODO Remove it when we stop supporting Firefox <105, Safari <16.4
fn is_offscreen_canvas_supported() -> bool {
let global = js_sys::global();
match js_sys::Reflect::get(&global, &JsValue::from_str("OffscreenCanvas")) {
Ok(value) => !value.is_undefined(),
Err(_) => false,
}
}

fn to_font_str(italic: bool, bold: bool, size: f64, font_family: &str) -> String {
let italic = if italic { "italic " } else { "" };
let bold = if bold { "bold " } else { "" };
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