Apr 10, 2011

Convert a QIcon (or just a QImage) to base64 and QString

I found difficult to find somewhere a method to convert a QIcon object to a QString to be displayed in base64. I needed it for implementing a nice feature for QuickView mode in Arora. I wanted to display in the HTML template the icon (logo.icon) of each domain. Therefore, I needed the QIcon to be converted to a QString containing the base64 encoding of the image. Moreover, the distribution of the QT Framework I downloaded for Mac Os X seems to block some useful constructors for QString objects

I would like to share with you how I did it:

We convert the QIcon object to a QImage through another conversion to a QPixmap object at line 2. Then we create a QByteArray and a QBuffer associated to the byte-array. We call the save() method of the QImage object that saves the image in PNG format inside the byte-array, using the buffer.
At the end, we call the byteArray.base64() method that returns a copy of the byte-array, converted to base64. From that object we call its data() method to retrieve a char* representation of the byte-array, creating the QString.

Hope this could help who runs into my problem.

written by dgraziotin

Dr. Daniel Graziotin received his PhD in computer science, software engineering at the Free University of Bozen-Bolzano, Italy. His research interests include human aspects in empirical software engineering with psychological measurements, Web engineering, and open science. He researches, publishes, and reviews for venues in software engineering, human-computer interaction, and psychology. Daniel is the founder of the psychoempirical software engineering discipline and guidelines. He is associate editor at the Journal of Open Research Software, academic editor at the Research Ideas and Outcomes (RIO) journal, and academic editor at the Open Communications in Computer Science journal. He is the local coordinator of the Italian Open science local group for the Open Knowledge Foundation. He is a member of ACM, SIGSOFT, and IEEE.

  • Shantanu Tushar Oct 23, 2011 Reply

    This helped a lot ! Thanks 🙂

  • Rohit Mar 26, 2013 Reply


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