How to change color qr generating to another color of black

ahmed salah

9y5.2kLearn iOS Programming

I working in visual studio 2015 windows form application

I generating qr using messagetoolkit library and it working good without any problem

I face only one problem i need to change color of qr to another color different to

black as blue or red or green like that

so that how to do color qr code using messagetoolkit

my code

MessagingToolkit.QRCode.Codec.QRCodeEncoder encoder = new MessagingToolkit.QRCode.Codec.QRCodeEncoder();
encoder.QRCodeScale = 8;
Bitmap bmp = encoder.Encode(textBox1.Text);
pictureBox1.Image = bmp;
bmp.Save(sv.FileName, ImageFormat.Jpeg);

13 Replies

Know the answer? Post it — somebody with the same question will find it here.

Uehara Ayaka9y ago
refer to this article

http://www.c-sharpcorner.com/UploadFile/38268a/generating-qr-code-in-C-Sharp/
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Amit Gupta9y ago
@Ahmed
1. You haven't answer the important part. Have you checked the qrcode library? Are they allow user to choose the qrcode color?

2. If not then try some changes on the previous snippet as below
if (actualColor ==Color.Black)
                   newBitmap.SetPixel(i, j, newColor);
           //    else
              //     newBitmap.SetPixel(i, j, actualColor);
Feel free, if you have any doubt
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ahmed salah9y ago
I attached my sample
i have only form1 windows form
have controls
picturebox1
textbox1
button1
i write in textbox then click button to generate
result of qr generating will display in picture box
what i need to display with color red without using color black
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ahmed salah9y ago
I attached my sample
i have only form1 windows form
have controls
picturebox1
textbox1
button1
i write in textbox then click button to generate
result of qr generating will display in picture box
what i need to display with color red without using color black
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Amit Gupta9y ago
It would also be helpful if you can upload your sample qr code to us for better understanding
0
ahmed salah9y ago
this is output
result of ChangeColor function
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ahmed salah9y ago
thank you for reply
it not what i need
i need to change color black of qr code
to red
but when i apply solution you give me
it convert all picture to red
i need balck line of qr convert to red
now i cannot read qr
the output result as below
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Amit Gupta9y ago
Instead of using the setpixel function, I ll suggest to look at the properties of your qrcode library, it might allow you to choose the color.

Good luck !!
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Amit Gupta9y ago
Add this function to your code
public static Bitmap ChangeColor(Bitmap scrBitmap, Color color)
      {
         //You can change your new color here. Red,Green,LawnGreen any..
         Color newColor = color;
         Color actualColor;
         //make an empty bitmap the same size as scrBitmap
         Bitmap newBitmap = new Bitmap(scrBitmap.Width, scrBitmap.Height);
         for (int i = 0; i < scrBitmap.Width; i++)
         {
            for (int j = 0; j < scrBitmap.Height; j++)
            {
               //get the pixel from the scrBitmap image
               actualColor = scrBitmap.GetPixel(i, j);
               // > 150 because.. Images edges can be of low pixel colr. if we set all pixel color to new then there will be no smoothness left.
               if (actualColor.A > 150)
                   newBitmap.SetPixel(i, j, newColor);
               else
                   newBitmap.SetPixel(i, j, actualColor);
            }
         }
         return newBitmap;
      }
  }
Calling the above function from your code
MessagingToolkit.QRCode.Codec.QRCodeEncoder encoder = new MessagingToolkit.QRCode.Codec.QRCodeEncoder();
                   encoder.QRCodeScale = 8;
                   Bitmap bmp =ChangeColor ( encoder.Encode(textBox1.Text), Color.Red);
                   pictureBox1.Image = bmp;
                   bmp.Save(sv.FileName, ImageFormat.Jpeg);
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ahmed salah9y ago
only one minute if possible
i see article
i get this function
static Bitmap ReplaceColor(Bitmap source,
                           Color toReplace,
                           Color replacement)
{
    var target = new Bitmap(source.Width, source.Height);

    for (int x = 0; x < source.Width; ++x)
    {
        for (int y = 0; y < source.Height; ++y)
        {
            var color = source.GetPixel(x, y);
            target.SetPixel(x, y, color == toReplace ? replacement : color);
        }
    }

    return target;
}
how to set this function according to my code
if possible help me
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Amit Gupta9y ago
Look at the link, just you need to pass your bitmap as parameter.

Visit the accepted answer there.
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ahmed salah9y ago
how to make set pixel to code above
if possible
0
Amit Gupta9y ago
Use setpixel to change the color
http://stackoverflow.com/questions/17208254/how-to-change-pixel-color-of-an-image-in-c-net
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