Effect on Application by Mechanism of GDI Rendering Functions and Solutions

GDI drawing-functions in Windows API were analyzed and found that GDI drawing-function mapped the world coordinate system (Cartesian coordinate system) origin (0, 0) to the pixel center between (0, 0) and (1, 1) of the device coordinate system (screen coordinates). It pointed out that in order to maintain the same graphic geometric characteristics and avoiding overprinting, GDI drawing functions compromised with the endpoints and the boundary pixels, which caused some strange phenomenon many programmers have not found and it was difficult to understand. In response to these phenomena, explanations are given. In addition, the effect on some applications is pointed out and solutions are proposed.