Dynamically generate and display QR code

[BGuth.1]

I am using 4.16.1 TouchGFX designer tool. Is it possible to generate QR code for a given string and PIN code in run time and display? Please advice.

[MM..1]

Yes Dynamic Bitmaps | TouchGFX Documentation

[ktrofimo]

I have used https://github.com/ricmoo/QRCode library.

Made a simple wrapper class QRCode.cpp

#include <gui/widgets/qrcode/QRCode.hpp>
#include <gui/widgets/qrcode/qrcode.h>
#include <stdlib.h>
 
QR::QR( const char * text )
{
	 qrcode = new QRCode();
	 qrcodeData = (uint8_t *)malloc( qrcode_getBufferSize(1) );
	 qrcode_initText( qrcode, qrcodeData, 1, 0, text );
}
 
QR::~QR()
{
	free( qrcodeData );
	delete qrcode;
}
 
bool QR::at(uint16_t x, uint16_t y) const
{
    return qrcode_getModule( qrcode, x, y );
}
 
uint16_t QR::getWidth() const
{
    return qrcode->size;
}
 
uint16_t QR::getHeight() const
{
    return qrcode->size;
}

and a custom widget QRCodeWidget.cpp

#include <gui/widgets/qrcode/QRCodeWidget.hpp>
#include <touchgfx/hal/HAL.hpp>
 
QRCodeWidget::QRCodeWidget() : 
    code(0),
    scale(1)
{
}
 
void QRCodeWidget::setQRCode(QR *qrCode)
{
    code = qrCode;
    updateSize();
}
 
void QRCodeWidget::draw(const touchgfx::Rect& invalidatedArea) const
{
    if(!code)
    {
        return;
    }
 
    touchgfx::Rect absolute = getAbsoluteRect();
 
    uint16_t *framebuffer = touchgfx::HAL::getInstance()->lockFrameBuffer();
 
    for(int y = invalidatedArea.y; y < invalidatedArea.bottom(); y++)
    {
        for(int x = invalidatedArea.x; x < invalidatedArea.right(); x++)
        {
        	int offset=0;
        	switch(touchgfx::HAL::DISPLAY_ROTATION)
        	{
        	case touchgfx::rotate0:
        		offset = absolute.x + x + (absolute.y + y) * touchgfx::HAL::DISPLAY_WIDTH;
        		break;
        	case touchgfx::rotate90:
        		offset = (touchgfx::HAL::DISPLAY_WIDTH-(absolute.x + x)-1) * touchgfx::HAL::DISPLAY_HEIGHT
					+ (absolute.y + y);
        		break;
        	}
    		framebuffer[offset] = code->at(x / scale, y / scale) ? 0x0000 : 0xffff;
 
        }
    }
 
    touchgfx::HAL::getInstance()->unlockFrameBuffer();
}
 
touchgfx::Rect QRCodeWidget::getSolidRect() const
{
    return touchgfx::Rect(0,0,getWidth(), getHeight());
}
 
void QRCodeWidget::setScale(uint8_t s)
{
    scale = s;
    updateSize();
}
 
void QRCodeWidget::updateSize()
{
    if(code)
    {
        setWidth(code->getWidth() * scale);
        setHeight(code->getHeight() * scale);
    }    
}

Using is quite straightforward:

#include <gui/common/QrCodeWidget.hpp>
#include <gui/model/QrCode.hpp>
 
QRCodeWidget qrCode;
QR *code;
 
char string[50];
sprintf( string, "http://iwtm.com" );
code = new QR( string );
qrCode.setXY(10,20);
qrCode.setQRCode(code);
qrCode.setScale(8);
add(qrCode);

[BGuth.1]

Thank you for your reply. I appreciate it. Just so I understand it better, would you mind sharing QrCodeWidget.hpp and QrCode.hpp too please.

[ktrofimo]

QRCode.hpp

#ifndef QR_CODE_HPP
#define QR_CODE_HPP
 
#include <touchgfx/hal/Types.hpp>
#include "qrcode.h"
 
/**
* @class QRCode
* 
* @brief An interface for getting the value of a qr code at a particular x,y position
*
*        This implementation generates random values for the different x,y coordinates.
*        A real qr code will probably save the qr code values in an array like structure and report these instead.
*/
class QR
{
public:
	QR( const char * text );
	~QR();
    /**
     * @fn bool QRCode::at(uint16_t x, uint16_t y);
     *
     * @brief Get the qr code value at a particular coordinate
     *
     * @param x x coordinate
     * @param y y coordinate
     *
     * @return The value of the qr code at the supplied coordinate
     */
    bool at(uint16_t x, uint16_t y) const;
 
    /**
     * @fn uint16_t QRCode::getWidth();
     *
     * @brief Get the width of the qr code
     *
     * @return The width
     */
    uint16_t getWidth() const;
 
    /**
     * @fn uint16_t QRCode::getHeight();
     *
     * @brief Get the height of the qr code
     *
     * @return The height
     */
    uint16_t getHeight() const;
    QRCode   *qrcode;
    uint8_t  *qrcodeData;
};
 
#endif

QRCodeWidget.hpp

#ifndef QR_CODE_WIDGET_HPP
#define QR_CODE_WIDGET_HPP
 
#include <touchgfx/widgets/Widget.hpp>
#include <gui/model/QRCode.hpp>
#include <touchgfx/hal/Types.hpp>
 
/**
* @class QRCodeWidget
* 
* @brief A widget for displaying a QRCode
* 
*        The widget will be drawn in black and white.
*        The values of the supplied QRCode will determine the appearance
*        The widget can be scaled in order to display the qr code in an appropriate size
*
*        @sa touchgfx::Widget
*/
class QRCodeWidget : public touchgfx::Widget
{
public:
    /**
     * @fn QRCodeWidget::QRCodeWidget();
     *
     * @brief Default constructor
     */
    QRCodeWidget();
 
    /**
     * @fn virtual void QRCodeWidget::draw(const touchgfx::Rect& invalidatedArea) const;
     *
     * @brief Draw the part of the qr code that is inside the invalidated area
     *        
     * @param invalidatedArea The region of this drawable that needs to be redrawn
     *
     * @sa touchgfx::Drawable
     */
    virtual void draw(const touchgfx::Rect& invalidatedArea) const;
 
    /**
     * @fn virtual touchgfx::Rect QRCodeWidget::getSolidRect() const;
     *
     * @brief Report this widget as being completely solid
     *
     * @return The solid rect.
     */
    virtual touchgfx::Rect getSolidRect() const;
 
    /**
     * @fn void QRCodeWidget::setQRCode(QRCode *code);
     *
     * @brief Set the qr code to display
     */
    void setQRCode(QR *code);
 
    /**
     * @fn void QRCodeWidget::setScale(uint8_t s);
     *
     * @brief Set the scaling factor of the widget
     */
    void setScale(uint8_t s);
 
private:
    void updateSize();
 
    QR *code;
    uint8_t scale;
};
 
#endif

[BGuth.1]

I am trying it out. I included qrcode.c and qrcode.h from the https://github.com/ricmoo/QRCode library, and your QrCode.cpp, QrCode.hpp, QRCodeWidget.cpp and QRCodeWidget.hpp in my TouchGFX environment. I get below error. Am I missing any other files? Please advice.

[ktrofimo]

Where did you place .h and .hpp files? Are they in project paths? Are .c and .cpp included in project?

These are regular compiler errors - check your project settings...​

[BGuth.1]

I first put source and includes at TouchGFX\gui\src\widget\qrcode and TouchGFX\gui\include\gui\widget\qrcode respectively. That seems to be one folder level deep than necessary. So I moved to TouchGFX\gui\src\qrcode and TouchGFX\gui\include\gui\qrcode. Now TouchGFX sees them and tries to compile them when I click run simulator button.

Is this how you placed too? how did you tell TouchGFX to treat qrcode.c as a C file and not C++?

[mids400]

Hi, would you mind to share with me some many files, which they missing for me.

- Widget.cpp & .hpp

- Types.cpp & .hpp

- HAL.cpp & .hpp

Thanks in advanced

Mahdi