Supports display of English characters, Chinese characters and pictures. English characters have built-in ascii code, while Chinese characters and pictures need to be provided by users. Characters can be displayed normally or rotated 90 degrees counterclockwise. Pictures and Chinese characters are all modeled in vertical orientation, with the principle of high position on top, left before right, top before bottom. Support multi-layer, can operate on any layer individually. Layers can be added and removed at any time, the top layer is not allowed to be removed. The buf of multi-layer can be defined in data segment, bss segment and heap segment. Support drawing points, drawing lines, drawing function images, drawing lines and function images support complementary unconnected points. Drawing function adopts matlab-like function interface form. Support print function. Support all clear screen, part of the region clear screen function. Support full-screen rainbow image display function, convenient for testing.