Created attachment 465824 [details] repo of canvas drawImage issue Here's an example where a canvas is 400x200 It sets the scale to 2x2 eg: ctx.scale(2,2) It then copies the canvas to itself with ctx.drawImage(ctx.canvas 2, 0, 398, 200, // these values are in source pixels (ie, 400x200) 0, 0, 199, 100); // these values are in transformed pixels (ie, 200x100) this works in Firefox and Chrome but fails in Safari https://jsgist.org/?src=fedaf98f88bb57622af24481944bbefc Attached a stand alone repo