Fix underlines, relative to 'bottom' baseline

src/renderer/CanvasRenderer.js

@@ -212,7 +212,7 @@ export default class CanvasRenderer implements RenderTarget<HTMLCanvasElement> {
                             const {baseline} = this.options.fontMetrics.getMetrics(font);
                             this.rectangle(
                                 text.bounds.left,
-                                Math.round(text.bounds.top + baseline),
+                                Math.round(text.bounds.top + text.bounds.height - baseline),
                                 text.bounds.width,
                                 1,
                                 textDecorationColor