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# Qt/Embedded Environment Variables

Variable | Notes
--- | ---
`QWS_SW_CURSOR` | If defined, always use a software mouse cursor even when using an accelerated driver that supports a hardware cursor
`QWS_DISPLAY` | Defines the display type and framebuffer. Defaults to an unaccelerated Linux framebuffer driver on `/dev/fb0`. Valid drivers are QVFb, LinuxFb (unaccelerated Linux framebuffer), Transformed (for rotated displays), and VNC. Transformed displays have a special format: the specification should include a rotation as a multiple of 90 degrees given as Rot<x>, for instance Transformed:Rot90.
`QTDIR` | If defined this tells Qt/Embedded to where to find its fonts: fontdir should be in `$QTDIR/lib/fonts/`.
`QWS_SIZE` | If defined forces Qt/Embedded into a window of <width> x <height> size centred within the screen, e.g. 320x200
`QWS_NOMTRR` | If defined, don't use Memory Type Range Registers to define the framebuffer as write-combined on x86. Write-combining speeds up graphics output.
`QWS_USB_KEYBOARD` | If defined, instead of opening `/dev/tty`, open the USB low-level event device defined in `QWS_USB_KEYBOARD` (e.g. `/dev/input/event0`): this is useful if you want to run X and Qt/Embedded side by side on different framebuffers.
`QWS_MOUSE_PROTO` | Defined as <type>:<device>, e.g. `Microsoft:/dev/ttyS0`. If you want to use a USB mouse directly (separate from X) use `MouseMan:/dev/input/mouse0` or similar. Valid mouse protocls are Auto (automatically sense protocol), MouseMan, IntelliMouse, Microsoft, `QVfbMouse` (only useful with `QVfb`) and TPanel, an example touch panel driver.
`QWS_KEYBOARD` | Defines the keyboard type. Multiple keyboards can be handled at once; input will be read from all of them. Valid values: Buttons (an iPaq button device if `QT_QWS_IPAQ` is compiled), QVfbKeyboard (only useful with `QVfb`), and TTY (either a USB keyboard or `/dev/tty` depending if `QWS_USB_KEYBOARD` is defined)