h6. [[VideoOverlay]] h6(. » [[VideoOverlay SWI Calls|SWI Calls]] h6((. » VideoOverlay_RedrawWindow h2. VideoOverlay_RedrawWindow h5. (SWI &59CCA) |_<^{width:4em}. Entry |<^. | |<^. R0|<^. Overlay ID | |<^. R1|<^. Pointer to block from [[Wimp_RedrawWindow]] / [[Wimp_GetRectangle]] | |_<^{width:3em}. Exit |<^. | |- |<^. All registers preserved | h4. Use The owner of the window which an overlay is attached to must call this SWI for every redraw rectangle associated with the window. Taking into account the current clipping rectangle set by VideoOverlay_SetPosition, VideoOverlay will fill the corresponding screen pixels with the correct colour in order to allow the alpha blending / TCK hardware to operate correctly. For overlays which are composited directly into the framebuffer (e.g. software fallback for Basic overlays), this will trigger the rendering to take place. Whenever necessary, VideoOverlay will automatically call [[Wimp_ForceRedraw]] in order to request that relevant areas of the window are redrawn.