Abstract:Research design and implementation of the graphics zoom function has a practical value in the software development. Especially in the well test interpretation software, there is a lot of double logarithmic and semi-logarithmic coordinate system, the zoom function is the basis of other functions. In the paper, the author systematic discuss the graphical zoom function design and its algorithm derivation in the ordinary Cartesian coordinate system, the double logarithmic and semi-logarithmic coordinate system, give the coordinate conversion formula, subsequently taking the well test interpretation software as example, which developed by the ideas in the VS2010 environment, carry out a detailed test and the test results show that the software, which is designed and implemented by the ideas, is more stable and more reliable.