CODEWITHSUNDEEP
carduinoesp32e-ink
luegm.dev
luegm.dev

Reputation: 161

enlarge QRCode display on epaper

Can someone please help me rewrite this code to make the QRcode to use the whole display size (200x200)?

I'm using this display:
https://www.waveshare.com/1.54inch-e-paper-module.htm

Here is the libary which I use to create the QRCode:
https://github.com/ricmoo/qrcode/

Here is a picture of the current state:
click for picture

This is my code:

#include <SPI.h>
#include "epd1in54_V2.h"
#include "qrcode.h"
#include "epdpaint.h"

//set the pins of the ESP32
Epd epd(33, 25, 26, 27);        // my Pins ESP32 (Reset, DC, CS, Busy)
unsigned char image[1024];
Paint paint(image, 0, 0);
QRCode qrcode;

#define BLACK     0
#define WHITE   1

void setup()
{
  uint8_t qrcodeData[qrcode_getBufferSize(3)];
    qrcode_initText(&qrcode, qrcodeData, 3, 0, "https://vinotes.app");

    epd.LDirInit();
    epd.Clear();

    paint.SetWidth(45);
    paint.SetHeight(45);
    paint.Clear(WHITE);
    for (int y = 0; y < qrcode.size; y++) {
        for (int x = 0; x < qrcode.size; x++) {
            if (qrcode_getModule(&qrcode, x, y)) {
                paint.DrawPixel(x, y, BLACK);
            }
        }
    }

    epd.SetFrameMemory(paint.GetImage(), 0, 0, paint.GetWidth(), paint.GetHeight());
    epd.DisplayFrame();
    epd.Sleep();
}

void loop()
{

}

Upvotes: -1

Views: 142

Answers (1)

pmacfarlane
pmacfarlane

Reputation: 4297

Instead of iterating over the size of your QR code, iterate over the size of your display, and request QR modules using coordinates divided by the scaling factor.

There is a very good example in the TouchGFX documentation. (I know you're not using that, but the same principle applies.)

e.g. if you want to scale up your QR code by a factor of 4 (psuedo-ish code):

#define SCALE_FACTOR 4

for (int y = 0; y < HEIGHT; ++y)
{
    for (int x = 0, x < WIDTH; ++x)
    {
        setPixel(x, y, getModule(x / SCALE_FACTOR, y / SCALE_FACTOR));
    }
}

You'll want to figure out the maximum scaling factor that will fit, and maybe add some offsets to center the image.

Edit: To be clear, don't actually iterate over the literal width and height of your display, otherwise you won't get a square QR code. The upper bounds of both loops would be (qrcode.size * SCALING_FACTOR).

Upvotes: 1

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