transform a ArrayBuffer to an array

[espruino-discuss3]

Posted at 2018-01-24 by Mrbbp

Hello,

i'm trying to work with arrayBuffer but i'm bad...
I'm using exemple in the graphics library at Internal Use

require("Font4x7").add(Graphics);
var g = Graphics.createArrayBuffer(5,7,1, {zigzag:true});
g.setFont4x7();
g.drawString("hello",compteur,0);

Graphics.prototype.print = function() {
  for (var y=0;y<this.getHeight();y++)
    console.log(new Uint8Array(this.buffer,this.getWidth()*y,this.getWidth()));
};

when i use the g.print()it does not produce an array of 0 and 1...
but that...

new Uint8Array([112, 240, 199, 7, 4])
new Uint8Array(5)
new Uint8Array(5)
new Uint8Array(5)
new Uint8Array(5)
new Uint8Array(5)
new Uint8Array(5)

i would like to send via Serial an array of row and colum as in the exemple of print()

thanks for you help

[espruino-discuss3]

Posted at 2018-01-25 by @gfwilliams

The issue is that you're using 1 bit per pixel, so 8 bits are in each byte - and you're trying to retrieve bytes. If you used:

var g = Graphics.createArrayBuffer(5,7,8, {zigzag:true});

Then I'm pretty sure that'll work fine. I'm not sure what you're planning but you may find you don't want the zigzag:true either, as that will make alternate scanlines reversed.

---

Posted at 2018-01-25 by Mrbbp

Hye, Gordon
I need of a byte array (0,1) (pixel OFF, pixel ON) row by raw.
the matrix is on/off not in 8bits.
or i do not understand what is an arrayBuffer...

in your example it is suppose to do that (it's exactly what i need to transfer to my display via serial):

//0,0,0,0,0,0,0,0
//0,1,1,0,0,0,1,1
//0,1,1,0,0,0,1,1
//0,0,1,1,0,1,1,0
//0,0,0,1,1,1,0,0
//0,0,1,1,0,1,1,0
//0,1,1,0,0,0,1,1
//0,1,1,0,0,0,1,1

it does not... why?

---

Posted at 2018-01-25 by @gfwilliams

Graphics.prototype.print = function() {
  for (var y=0;y<this.getHeight();y++)
    console.log(new Uint8Array(this.buffer,this.getWidth()*y,this.getWidth()).toString());
};
var g = Graphics.createArrayBuffer(8,8,8);
g.setColor(1);
g.drawString("X",0,0);
g.print();

 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v95.43 Copyright 2017 G.Williams
>1,0,1,0,0,0,0,0
1,0,1,0,0,0,0,0
0,1,0,0,0,0,0,0
1,0,1,0,0,0,0,0
1,0,1,0,0,0,0,0
0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0

I added .toString because now it outputs new Uint8Array([0,0,0,0,0,0,0,0]) as new Uint8Array(8) to save space.

And the output is different because the default font has changed.

---

Posted at 2018-01-26 by Mrbbp

Hello,
As i enable to control the flipdot hannio' display ( see forum) with an espruino.
I'm trying to communicate to an arduino which control the display.
Spi and i2c are in use in the arduino so i do with serial. It's not really good (i suppose i'm trying comm to fast) but i'm able iniate a com between the boards...
I'm able to transfer array, but at the moment, not the arrayBuffer.

Regards

---

Posted at 2018-01-26 by @gfwilliams

Ahh - try Serial.println(new Uint8Array(...).toString()). I'd have thought that would output something like 0,0,1,0,0,1,0,0\r\n that should be pretty easy to receive.

---

Posted at 2018-01-26 by Mrbbp

yes, great the use of println()... there is a final CR, easy to detect to call the refresh display function.
thanks.

é.