AGG lesson 26 cutting function

AGG has four types of tailoring, which work at different levels

1. Base renderer Base Render

Unless the basic renderer's method of drawing line segments is called directly, in general, it is called at the time of render_scanline to crop, at which time a lot of useless work has been done. For example, if the vertex source is beyond the scope of the screen, a lot of resources have been wasted before calling the render_scanline function, such as calling the add_path function of the rasterizer object.

2 rasterizer rasterizer

Rasterizer is mainly used to generate the details of line segments based on vertex sources. Calling clipping at this time can save a lot of resources.

3 agg::conv_clip_polygon

Please take a closer look at the example of agg::conv_clip_polygon

4 agg::conv_clip_polyline

Please take a closer look at the example of agg::conv_clip_polyline