[Try to] use prototype.apply for class Graphics

[espruino-discuss]

Posted at 2019-11-16 by @MaBecker

Working on a Pixl,js with firmware 2v04 .

Sometimes parameter for function are stored in arrays and apply is used to convert array to parameter.

var numbers = [0,3,5,9,4];
console.log(Math.max.apply(null, numbers));
// output is 9

Try to use this for g.drawString()

var p = ["Hello", 10, 10];
g.clear();
g.flip();
g.setFont("4x6",2);
g.drawString.apply(null,p);
g.flip();

Screen does not show "Hello".

Is this the correct syntax to use it in class Graphics?

[gfwilliams]

Posted at 2019-11-16 by @gfwilliams

Is this the correct syntax to use it in class Graphics?

Almos :) The first argument of apply and call is the this argument. It doesn't matter for Math.max because max doesn't care about knowing it's called via Math, but drawString needs to know which Graphics instance it's called on.

If you do g.drawString.apply(g,p); you should be fine

[espruino-discuss]

Posted at 2019-11-16 by @MaBecker

Thanks :)

So g.drawString() also can be called this way g["drawString"]("Hello",10,10); and g["drawString"].apply(g,p); works too.