QChartist

QChartist is a free and open source technical analysis charting software. Its purpose is to provide a complete set of tools to perform technical analysis on charts and data. It helps to make forecasts mainly for markets but can also be used for weather or any quantifiable data. The program is flexible and its functionalities can be easily extended. You can draw geometrical shapes on your charts or plot programmable indicators from your data.
There are many paid charting softwares available on the market but good free charting softwares are rare.
The project started in 2010. I needed a flexible software for technical analysis purposes. Since then, the program became more and more professional.