Utilizing the power of the GPU, and OpenGL in particular, for Computer Vision and Image Processing purposes has always been a favorite topic of mine. It’s quite easy to find many examples around (even among official Qt example projects) to deal with and learn more about this topic but I figured there are no clear and step by step examples for people who are absolutely new to it. This post aims to cover a number of topics, including the following, in a step by step and simple manner:
Continue reading “Using OpenGL in Qt for Processing Images”
- How to use QOffscreenSurface class for off-screen rendering using OpenGL
- How to use QOpenGLFramebufferObject to create Frame Buffer objects
- How to use Vertex Shaders to perform Geometric Image Transformations
- How to use Fragment Shaders to perform Image Filtering and per-pixel operations
- How to convert a texture to QImage
Qt provides an extremely simple mechanism for deploying applications on macOS, thanks to macdeployqt tool. Unfortunately, the same does not apply to Qt for macOS applications that reference 3rd party libraries such as OpenCV. In this post, I’ll describe the manual but simple process of adding 3rd party libraries into macOS Application packages in order to eliminate the need for installing those libraries on our target computers.
Continue reading “Deploying Qt+OpenCV Applications on macOS”
I just released Perspective Cropper application for Windows platforms. I created this app a few months ago to quickly crop and correct the perspective distortion in a huge set of scanned documents and images. The pictures were taken using my smartphone from papers and documents laid on a table and from a few old family albums. Almost all of them had a lit bit of unwanted borders and perspective distortions and my goal was to just keep the parts I needed and remove the unwanted parts in addition to the correct and upright view of the images, as if they were scanned using a scanner.
Continue reading “Perspective Cropper 1.2.1 for Windows”
Qt Installer Framework provides a simple way of creating cross-platform installers and setup files. Some of the questions that are asked quite a lot, but unfortunately are not as well-documented as they should be, is about the “Execute” method which is used to run executable files during installation. In this post I’ve tried to clarify a couple of points about it with a couple of simple examples.
Continue reading “Qt Installer Framework – How to Run an Executable During Installation”
I usually build OpenCV with the BUILD_opencv_world option which makes it quite easy to configure my Qt projects and work fast. But when it comes to deploying OpenCV powered applications, I still prefer to use the modular and default OpenCV build in order to deploy only the required DLLs and end up with a smaller installer file size.
Continue reading “Configuring Qt for Windows Projects to Use OpenCV 4.1.0”
Following up on this post from last year, I’d like to share a couple of simple scripts that you can use to build OpenCV 3 or 4 on Windows, macOS and Linux operating systems. Needless to say, they require CMake and proper build tool sets on each platform.
Continue reading “OpenCV Build Scripts for Windows, macOS and Linux”
In this post I’ll describe the way to deal with Windows Registry in terms of writing and reading Registry Keys. This is done using QSettings class in general, so let’s see how, with a couple of simple examples.
Continue reading “Working with Windows Registry Using Qt”
One thing I noticed while searching for a simple, generic and pure C++ Timer class online, was the huge amount of answers that were floating around and none of them fit the exact description I was looking for. As a Qt Framework user I wanted to have something as close to QTimer as possible, or maybe even something like Timer class in .NET Framework and C# language. Well, I ended up writing one myself using what I could gather and this post is the summary of it all.
Continue reading “Creating a Pure C++11 Generic Timer Class”
Android Qt projects require AndroidManifest.xml file for a a number of reasons, including the definition of required permissions and so on. Creating this file on the other hand, and adding it to your Android Qt project requires a few strict instructions that are provided in this post.
Continue reading “How to Create AndroidManifest.xml Using Qt Creator”
I wanted to create my own personal stand-alone YouTube Player with Minimize to System Tray functionality. In other words I wanted it to be minimized to the System Tray when I closed it and displayed again when I clicked its icon in System Tray. I actually did it the other day and the whole thing led to this post. So, in this post I’ll describe How to use Qt/C++ to create your own YouTube Player with Minimize to Tray functionality in less than 10 minutes.
Continue reading “Implementing Minimize To Tray Functionality Using Qt/C++”