Programming for Palm OS/C/Off-screen windows

Be sure to focus on your offscreen window after all the events have been delivered for the start-up of your application. to create an offscreen window (and to remember the original window that your application started with) WinHandle offWin; WinHandle sysWin; Coord width = 160; Coord height = 160; WindowFormatType format = screenFormat; UInt16 error; offWin = WinCreateOffscreenWindow( width, height, format, &error); sysWin = WinGetDrawWindow(); to release an offscreen window Boolean eraseIt = false; if ( offWin != NULL) { WinDeleteWindow( offWin, eraseIt); } to focus on an offscreen window WinSetDrawWindow( offWin); After this invocation, functions such as WinEraseRectangle, WinDrawLine and so on will draw to the offscreen window. to blit your offscreen drawing to the original window WinHandle srcWin; WinHandle destWin; RectangleType r; Coord destX; Coord destY; WinDrawOperation mode; srcWin = offWin; destWin = sysWin; r.topLeft.x = 0; r.topLeft.y = 0; r.extent.x = 160; r.extent.y = 160; destX = 0; destY = 0; mode = winPaint; WinCopyRectangle( srcWin, destWin, &r, destX, destY, mode);