103 lines
3.3 KiB
Text
103 lines
3.3 KiB
Text
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This file tells how to use gpm and X with a touch screen (this is
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being written as an addition to gpm 1.17.5 and currently the only
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supported touchscreen is the MicroTouch).
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USER INTERFACE
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--------------
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The decoder currently implemented in gpm is quite simple: it only
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supports mouse motion and button-1 events.
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When a user touches the screen, the decoder generates mouse motion
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events. Tapping on the screen generates button-press (as well as drag and
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release) events.
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A "tap" is a finger-down event generated quickly after a finger-up
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(half a secon at most). This means that you'll usually move the
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pointer to the desired position and then tap on it.
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Double-and triple clicks are easily generated by repeated tapping.
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Since tapping is usually accompanied by a small movement, the decoder
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will use the coordinates of the finger-up event for the button-press.
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Further dragging will be relative to the tapping position (i.e., the
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finger-up position). Moreover, the last coordinate pair received on
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finger-up is discarded, because it usually is slightly offset (due to
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the non-negligible area of the fingertip)
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GPM OPERATION
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-------------
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In order to run the touchscreen with gpm, you need to update the
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/dev/mouse symbolic link to point to the right serial port; then
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invoke gpm with a command line like
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gpm -t mtouch
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Unfortunately, there is currently no way to paste text. I think some
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modifier key should be eligible to this role but this would mean an
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in-depth modification to gpm. We have to discuss about it to make the
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right choice.
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Calibration
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-----------
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To calibrate the touchscreen, use the program "microtouch-setup" found
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in the source tree of gpm. The gpm daemon must already be running in
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order for the program to work flawlessly, as the program stops and
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restarts gpm internally (it depends on gpm for correct serial port
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initialization). "microtouch-setup" uses /dev/mouse to access the
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serial port, so /dev/mouse should point to a "ttyS" device.
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X OPERATION
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-----------
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In order to use the touchscreen in X, you should install in your
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system the "Summa" module, as modified by Frank Holtz (the driver is
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available from http://www.hof-berlin.de/tablet/tablet.html).
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Gpm must run in repeater mode, with a command line like:
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gpm -t mtouch -Rsumma
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, which instructs gpm to repeat packets according to the Summa protocol.
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Then, you need to add the following sections to your XF86config:
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Section "module"
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Load "xf86Summa.so"
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EndSection
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Section "Xinput"
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Subsection "SummaSketch"
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Port "/dev/gpmdata"
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DeviceName "touchscreen"
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Mode Absolute
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AlwaysCore
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EndSubSection
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EndSection
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Moreover, you should disable the "Pointer" section. I used a trick
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like this one:
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Section "Pointer"
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Protocol "MouseSystems"
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Device "/dev/fifo"
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EndSection
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Where /dev/fifo is just a plain unused fifo ("mknod /dev/fifo p")
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Calibration
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-----------
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To calibrate the touchscreen, use the program "microtouch-setup" found
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in the source tree of gpm (yes, it is the same program used for the
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text mode). The gpm daemon must already be running in order for the
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program to work flawlessly, as the program stops and restarts gpm
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internally (it depends on gpm for correct serial port
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initialization). "microtouch-setup" uses /dev/mouse to access the
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serial port, so /dev/mouse should point to a "ttyS" device.
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