Reference nvgBeginFrame

Frames

Begin drawing a new frame. Calls to nanovg drawing API should be wrapped in nvgBeginFrame and nvgEndFrame. nvgBeginFrame defines the size of the window to render to in relation currently set viewport (i.e. glViewport on GL backends). Device pixel ration allows to control the rendering on Hi-DPI devices. For example, GLFW returns two dimension for an opened window: window size and frame buffer size. In that case you would set windowWidth and windowHeight to the window size devicePixelRatio to: frameBufferWidth / windowWidth.

procedure nvgBeginFrame(Ctx: PNVGcontext; WindowWidth, WindowHeight, DevicePixelRatio: Single);