Imperative painting on Canvas using JavaScript

Declaring graphical items is nice and easy, but as programmers, we're more used to writing imperative code, and some things are easier expressed as an algorithm rather than as a description of the final result to be achieved. It is easy to use QML to encode a definition of a primitive shape such as a rectangle in a compact way—all we need is to mark the origin point of the rectangle, its width, height, and optionally, a color. Writing down a declarative definition of a complex shape consisting of many control points positioned in given absolute coordinates, possibly with an outline in some parts of it, maybe accompanied by an image or two, is still possible in a language such as QML; however, this will result in a much more verbose and much less readable definition. This is a case where using an imperative approach might...