If you take a look at my recently improved syntax tree generator, you might notice that the appearance of the lines depends on what browser you’re using. That’s because anti-aliasing is an implementation-defined feature for HTML5
<canvas> (source). When you tell the canvas to draw a line, how that line looks depends entirely on what browser you’re using. This is a terrible oversight on the part of WHATWG, the group responsible for the HTML5 standard. It’s nice to have your page to look similar across browsers. However, you definitely want your primitives, such as lines and circles to look identical across browsers. Otherwise, it defeats the purpose of having something as low level as
<canvas>, which is to provide more fine-grained control of appearance than CSS does.