Thou shalt programme
There are scenarios where you would need to find the sum or the average of all values in a QByteArray. This can specially happen if you are trying to send data using COM ports to devices that require the average or sum (or a similar combination) of all elements in order to check the integrity of data.
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Qt Framework implements many convenience functions inside QByteArray for quickly handling of raw data. One of the widely used encoding methods is Base64 and if you’re with Qt, you can easily convert any string (QString) to/from Base64.
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You can convert QBuffer to QString using buffer function of the QBuffer. Here is how you can do it.
QBuffer b;
b.open(QBuffer::ReadWrite);
b.write("http://amin-ahmadi.com");
QString str = b.buffer();
qDebug() << str; // "http://amin-ahmadi.com"
b.close();
Qt Framework includes a class called QBuffer that can be used to access a QByteArray (internal QByteArray to be precise) as if it is a file. So you can use Stream readers and writers to access data in it similar to a QFile.
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You might have come across the following (Not Acceptable) error when trying to download files from some websites using Qt. This error message is generated by ModSecurity and it usually means that for some reason the web server does not allow downloading of the file using the method you are trying. In my case it was because of the User-Agent Header set to a value not allowed by the server. So here is how I fixed it:
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You can create a QPixmap and convert it to QImage if you just want to have a QImage for modification and manipulation. Here, you can use the following code to achieve this:
int width = 100;
int height = 200;
QImage image = QPixmap(width, height).toImage();
Sometimes when you share a URL in Facebook you notice that there is no description or thumbnail image in the shared link. This happens mostly because there is no image and/or description in the URL you are trying to share. In order to find out what is missing from the URL’s contents that causes this issue, you can use Facebook’s Sharing Debugger Tool.
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To be able to watermark your RAW (CR2 and CRW) files taken using a Canon EOS camera you first need to convert them to JPG, and then add your watermark (for example your website address or your name) to them. In this post I am going to describe how to do it for free.
Qt offers convenient classes for basic image processing and pixel manipulation. In this article I am going to describe how you can change the hue level of a whole image using QImage class in Qt.
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OpenCV 2.4.13 was released just a few days ago and as a tradition I had to check if a static build with Microsoft Visual C++ 2010 (MSVC2010) 32-bit produced any errors or not. Fortunately, everything went quite smoothly (except a few common warnings here and there) and I was able to successfully build it so if you need to build the latest OpenCV release statically using MSVC2010 you can follow the steps below:
Continue reading “How to Build OpenCV 2.4.13 Static/Dynamic with MSVC2010”