How to fix error with freetype while installing all packages from a requirements.txt file?

If you are using Linux OS:

1. Remove matplotlib==1.3.1 from requirements.txt
2. Try to install matplotlib with sudo apt-get install python-matplotlib
3. Install all packages again from requirements.txt
   • For Python 2: run pip install -r requirements.txt
   • For Python 3: run pip3 install -r requirements.txt
4. pip freeze > requirements.txt

If you are using Windows OS:

1. python -m pip install -U pip setuptools
2. python -m pip install matplotlib