vpID); int GetXDim(ViewPortID vpID); …struct ViewPort { ViewPort(/**/): vpID_(CreateViewPt(/**/)) {/*RAII*/} ~ViewPort(){if (vpID_) FreeViewPt(vpID_);} opera6ons?struct ViewPort { ~~~~ ViewPort(ViewPort&& vp): vpID_(vp.vpID_) {vp.vpID_ = 0;} ~~~~ };struct ViewPort { ~~~~ ViewPort(ViewPort&& vp): vpID_(vp {vp.vpID_ = 0; /* Call OS to make a new ViewPort */} ~~~~ };struct ViewPort { ~~~~ ViewPort(ViewPort&& vp): vpID_(vp.vpID_) {vp.vpID_ = 0;}

Instrument expensive destructors • or explicitly release smart objects at the end of a scope bool Viewport::load_scene(const char* filename) { ZoneScoped; // ... std::shared_ptr new_scene; Instrument expensive destructors • or explicitly release smart objects at the end of a scope bool Viewport::load_scene(const char* filename) { ZoneScoped; // ... std::shared_ptr new_scene;

0, 0, 0 }, { 0, 1, 0 }); Matrix fov = FieldOfView(45, rect.AspectRatio(), 1, 100); Matrix view = Viewport(rect, 0, 100); Screen screen = world * (pov * fov * view); screen.PerspectiveDivide(); return

Instrument expensive destructors • or explicitly release smart objects at the end of a scope bool Viewport::load_scene(const char* filename) { ZoneScoped; // ... std::shared_ptr new_scene;

设定Document 长度。调用CView::DoPreparePrinting 以显示 【Print】对话框并产生打印机DC。 设定以DC 为准的Document 长度；配置GDI 资源 改变viewport 原点、剪截区、以及其它DC 属性。 列打印头、页尾等等 GDI 绘图动作 释放GDI 资源 图12-5 MFC 打印流程与我们的着力点 第 12 章 列印與預覽 683 以下是图12-5 rounding to nothing // Note: CScrollView::OnPaint() will have already adjusted the // viewport origin before calling OnDraw(), to reflect the // currently scrolled position. #0067 // Note: CScrollView::OnPaint() will have already adjusted the #0068 // viewport origin before calling OnDraw(), to reflect the #0069 // currently scrolled position. #0070