To add on to the text note, it's actually even more annoying with Canvas to draw it correctly. None of the major browsers implement a TextMetrics object (the return of ctx.measureText) that has anything more than the width of the text. https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics
How anyone thought it was OK not to ship that is beyond me, but it means that when laying out content on the canvas you have to write a hack for the font height and hope it's good enough for most cases. I think there is a polyfill available but I believe it works by rendering the text in SVG and measuring it there which seems to defeat the purpose of doing it on canvas.
How anyone thought it was OK not to ship that is beyond me, but it means that when laying out content on the canvas you have to write a hack for the font height and hope it's good enough for most cases. I think there is a polyfill available but I believe it works by rendering the text in SVG and measuring it there which seems to defeat the purpose of doing it on canvas.