To get that to work, the graphics environment needs to know the start and end coordinates of the viewport.

要让这成为可能，这个图形环境就需要知道viewport的起点和终点。

youdao

To get that to work, the graphics environment needs to know the start and end coordinates of the viewport.

要让这成为可能，这个图形环境就需要知道viewport的起点和终点。

youdao