QImage QRGB 64 bit pixel

csing

Hello,

I am trying to convert my pngs from QImage::Format_RGB888 to QImage::Format_RGBA64. Although I can create the image as the RGBA64 format just fine, I am not sure how to manipulate the color channels and pixels? Right now I use the pixel() function which will return a qrgb type which truncates the qrgb64 type values. for example

QRgb rgbPixel = loadImage.pixel(i,j);

How can I convert this into a Qrgb64 type values and get each of the individual channels? Thank you!

SGaist

Hi,

What kind of manipulation do you have in mind ?

Christian Ehrlicher

@csing said in QImage QRGB 64 bit pixel:

How can I convert this into a Qrgb64 type values and get each of the individual channels? Thank you!

Use QImage::scanLine() and cast to QRgba64

csing

@SGaist I want to be able to extract the red blue and green values from each of the pixels of the image.

SGaist

Then why change the format of the image in that case ?

csing

@Christian-Ehrlicher Hi, I am not sure if I am doing it correctly but it is still returning the range of the blue values are still all under 256 when I am debugging it. Here is what I wrote to test the method. Please let me know if you see something I am wrong. Thanks!

      for(int i = 0; i < loadImage.height(); i++) {
          pixel64 = (QRgba64 *)loadImage.scanLine(i);
          blue = qBlue(*pixel64);
      }

@SGaist The end goal I am trying to reach is to be able to produce a higher-bit pngs rather than a 8-bit png and from my understanding is that the Format_RGB888 and using pixel() will crop off some of the bits.

Christian Ehrlicher

What data type is your 'blue' variable of? Are you sure your image has really the format QImage::Format_RGBA64?

csing

@Christian-Ehrlicher Thank you for pointing out the scanline method. I have figured it out. I should be using pixel64.blue() instead of qBlue() which will return a 8 bit value instead. Thank you for your help!