AGG的渲染流程：
vertex source-->coordinate conversion pipeline-->scanline rasterizer -->renderers-->rendering buffer-->screen output
样例代码如下：
#include "platform/agg_platform_support.h" #include "agg_basics.h" #include "agg_rendering_buffer.h" #include "agg_pixfmt_rgb.h" #include "agg_alpha_mask_u8.h" #include "agg_pixfmt_amask_adaptor.h" #include "agg_rasterizer_scanline_aa.h" #include "agg_scanline_u.h" #include "agg_renderer_scanline.h" #include "agg_ellipse.h" #include "agg_conv_contour.h" #include "agg_conv_stroke.h" enum { flip_y = true}; class the_application : public agg::platform_support { public: the_application(agg::pix_format_e format, bool flip_y): agg::platform_support(format,flip_y) {} virtual ~the_application() { } virtual void on_init(){} virtual void on_draw() { unsigned i; //renderer buffer agg::rendering_buffer rbuf = this->rbuf_window(); //renderers agg::pixfmt_bgr24 pixf(rbuf);//底层像素渲染对象，对渲染内存进行包装了 typedef agg::renderer_base<agg::pixfmt_bgr24> ren_base_type;//底层渲染器 ren_base_type ren_base(pixf); ren_base.clear( agg::rgba8(255,255,255) );//清除buffer背景色 typedef agg::renderer_scanline_aa_solid<ren_base_type> renderer_scanline_type;//高层渲染器 renderer_scanline_type ren_scanline(ren_base); //vertex source agg::ellipse ell(150,150, 80, 80); //coordinate conversion pipeline typedef agg::conv_contour<agg::ellipse> ell_cc_type; ell_cc_type ccell(ell); typedef agg::conv_stroke<agg::ellipse> ell_stroke_type; ell_stroke_type ell_stroke(ell); ell_stroke.width(1.5); agg::rasterizer_scanline_aa<> ras;//Polygon rasterizer, which including a clipper，将ell定点数据转换为scanline(由多个span组成) agg::scanline_u8 sl;//非封装扫描线容器,rasterizer use it to render the render_buffer for (i=0; i<5; ++i) { ell.init(150,150,80+10*i,80+10*i); ras.add_path(ell_stroke);//添加路径 ren_scanline.color( agg::rgba8(i*50,40,23) ); agg::render_scanlines( ras, sl, ren_scanline );//ras使用sl中的span渲染ren_scanline } } }; int agg_main(int argc, char* argv[]) { the_application app(agg::pix_format_bgr24, flip_y); app.caption("My AGG Demo"); if(app.init(300, 300, agg::window_resize )) { app.run(); } return 1; }
效果图如下：
