Let me first check whether this is actually possible to do. Else we can sparen uns the ganze Dreck.
Two ideas:
Literal sizing of the HTML element to enlarge the canvas (that's going to make a port to mobile a nightmare)
Sizing of the graph line. This keeps the graphs size constant but scales the graphs stock value line to fit the size of the canvas, effectively squishing itself, the longer it exists (we may run out of horizontal space with this option).
Let me first check whether this is actually possible to do. Else we can sparen uns the ganze Dreck.
Two ideas: