For a list of colors, I have a corresponding list of QImage, format mono. The mono images have been processed in such a way that a single pixel can be black from all images. Nov 19, 2015  Array of QImage other than QImage::FormatIndexed8. Ask Question 0. Until now I had a QImage with QImage::FormatIndexed8. I fill the array with the needed color datay.width+x = i and everything works fine. But now i need RGB instead of Indexed8 so I use QImage::FormatRGB32.

1. Qimage Save Example
2. Qimage Python

Im trying to initialise a blank QImage widget in a pyside gui but its throwing errors and I cant figure out what I'm supposed to do from the docs, does anyone know what steps i need to do to get this QImage Widget working

and here's the error i get:

jonathan topfjonathan topf

2 Answers

EDIT: when giving this answer, the question was a different one than now..

Qimage Save Example

fill expects an int argument instead of a QColor element.

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Use

instead of

I hope this works exactly the same on pyside as in c++. Here is the documentation: http://doc.qt.nokia.com/4.7-snapshot/qcolor.html#qRgb

MischMisch

The main issue is that a QImage is not a widget so it cannot be added to a layout. Below is the code for initialising the Qimage with a red background and placing it inside a QLabel widget. I also change the image format to ARGB32 so that the image is formatted with 4 x 8 bit values for Alpha, Red, Green and blue.

jonathan topfjonathan topf

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I have been able to display an image in a label in Qt using something like the following:

So fullCharArray is an array of unsigned chars that have been mapped from the 2D array imageData, in other words, it is imheight * imwidth bytes.

The problem is, it seems like only a portion of my image is showing in the label. The image is very large. I would like to display the full image, scaled down to fit in the label, with the aspect ratio preserved.

Also, that QImage format was the only one I could find that seemed to give me a close representation of the image I am wanting to display, is that what I should expect? I am only using one byte per pixel (unsigned char - values from 0 to 255), and it seems liek RGB32 doesnt make much sense for that data type, but none of the other ones displayed anything remotely correct

edit:Following dan gallaghers advice, I implemented this code:

But this causes my program to 'unexpectedly finish' with code 0

Qimage Python

DerekDerek

3 Answers

QImage has a scaled member. So you want to change your setPixmap call to something like:

Note that scaled does not modify the original image qi; it returns a new QImage that is a scaled copy of the original.

Re-Edit:

To convert from 1-byte grayscale to 4-byte RGB grayscale:

Then scale qi and use the scaled copy as the pixmap for viewLabel.

Qt doesn't support grayscale image construction directly. You need to use 8-bit indexed color image:

Stephen ChuStephen Chu

I've also faced similar problem - QImage::scaled returned black images. The quick work-around which worked in my case was to convert QImage to QPixmap, scale and convert back then. Like this:

where 'image' is the original image.I was not aware of format-problem, before reading this thread - but indeed, my images are 1-Bit black-white.

Regards,Valentin Heinitz

Valentin HeinitzValentin Heinitz

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