PACKAGES += xserver-xorg-input-evdev xinput xinput-calibrator

define RPICONFIG +=

### Waveshare 4 Inch Display ###
hdmi_force_hotplug=1
dtparam=i2c_arm=on
dtparam=spi=on
enable_uart=1
dtoverlay=waveshare35a
# dtoverlay=ads7846,cs=1,penirq=25,penirq_pull=2,speed=50000,keep_vref_on=0,swapxy=0,pmax=255,xohms=150,xmin=200,xmax=3900,ymin=200,ymax=3900
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 430 320 60 6 0 0 0
hdmi_drive=2
display_rotate=0
endef

export display_wsLCD4_cfg display_wsLCD4_rotation

define display_wsLCD4_cfg :=
Section "InputClass"
	Identifier	"calibration"
	MatchProduct	"ADS7846 Touchscreen"
	Option	"Calibration"	"3950 172 3871 194"
	Option	"SwapAxes"	"1"
	Option	"EmulateThirdButton"	"1"
	Option	"EmulateThirdButtonTimeout"	"1000"
	Option	"EmulateThirdButtonMoveThreshold"	"300"

	# Identifier "evdev touchscreen catchall"
	# MatchIsTouchscreen "on"
	# Option  "Calibration"   "200 3950 250 4000"
	# MatchDevicePath "/dev/input/event*"
	# Driver "evdev"
EndSection
endef

define display_wsLCD4_rotation :=
# Keep touch matrix rotated in accordance with screen rotation
while sleep 3; do
  oldrotate="$${rotate}"
  rotate="$$(xrandr |grep primary)"
  rotate="$${rotate#*+0+0 }"
  rotate="$${rotate% (*}"

  [ "$${oldrotate}" = "$${rotate}" ] || case $$rotate in
    left)     xinput set-prop 'ADS7846 Touchscreen' 'Coordinate Transformation Matrix' 0 -1 1  1 0 0  0 0 1;;
    right)    xinput set-prop 'ADS7846 Touchscreen' 'Coordinate Transformation Matrix' 0 1 0  -1 0 1  0 0 1;;
    inverted) xinput set-prop 'ADS7846 Touchscreen' 'Coordinate Transformation Matrix' -1 0 1  0 -1 1  0 0 1;;
    *)        xinput set-prop 'ADS7846 Touchscreen' 'Coordinate Transformation Matrix' 1 0 0  0 1 0  0 0 1;;
  esac
done &
endef

.PHONY: _display_wsLCD4
_config: _display_wsLCD5 ${CFGROOT}/boot/waveshare35a.dtbo
_display_wsLCD4: ${CFGROOT} _copy _mount
	# Rough touch calibration
	mkdir -p "$${CFGROOT}/usr/share/X11/xorg.conf.d/"
	printf '%s\n' "$${display_wsLCD4_cfg}" >"$${CFGROOT}/usr/share/X11/xorg.conf.d/45-evdev.conf"
	# Resolution / Rotation stuff
	mkdir -p "$${CFGROOT}/etc/X11/Xsession.d/"
	printf 'xrandr --size 480x320\n' >"$${CFGROOT}/etc/X11/Xsession.d/10display_resolution"
	printf '%s\n' "$$display_wsLCD4_rotation" >"$${CFGROOT}/etc/X11/Xsession.d/20touch_rotation"
	# Correct DPI scaling, although application support is mediocre
	mkdir -p "$${CFGROOT}/etc/X11/Xresources/"
	printf 'Xft.dpi: 144\n' >"$${CFGROOT}/etc/X11/Xresources/dpi_resolution"
	# Workaround for applications that do not handle DPI scaling correctly
	-sed -i 's;^Exec=;Exec=env GDK_DPI_SCALE=.5 ;' \
	  $${CFGROOT}/usr/share/applications/chromium*.desktop \
	  $${CFGROOT}/usr/share/applications/firefox*.desktop \
	  $${CFGROOT}/usr/share/applications/exo-web-browser.desktop

${CFGROOT}/boot/waveshare35a.dtbo: modules/waveshare35a-overlay.dtb
	cp "$<" "$@"