libfprint/examples/sendvirtimg.py
Benjamin Berg 8cdeeeaaf1 examples: Add sendvirtimg.py script to send a print to virtual_imgdev
With this script it is possible to test libfprint/fprintd without any
hardware device. The image needs to be provides as a PNG with the alpha
channel storing the print data.

See the comment in the file on how the script can be used.
2019-06-12 17:48:39 +02:00

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2.2 KiB
Python
Executable file

#!/usr/bin/env python3
# This script can be used together with the virtual_imgdev to simulate an
# image based fingerprint reader.
#
# To use, set the FP_VIRTUAL_IMGDEV environment variable for both the
# libfprint using program (e.g. fprintd) and this script.
#
# Usually this would work by adding it into the systemd unit file. The
# best way of doing so is to create
# /etc/systemd/system/fprintd.service.d/fprintd-test.conf
#
# [Service]
# RuntimeDirectory=fprint
# Environment=FP_VIRTUAL_IMGDEV=/run/fprint/virtimg_sock
# Environment=G_MESSAGES_DEBUG=all
# ReadWritePaths=$RUNTIME_DIR
#
# After that run:
#
# systemctl daemon-reload
# systemctl restart fprintd.service
#
# You may also need to disable selinux.
#
# Then run this script with e.g.
# FP_VIRTUAL_IMGDEV=/run/fprint/virtimg_sock ./sendvirtimg.py prints/whorl.png
import cairo
import sys
import os
import socket
import struct
if len(sys.argv) == 2:
png = cairo.ImageSurface.create_from_png(sys.argv[1])
# Cairo wants 4 byte aligned rows, so just add a few pixel if necessary
w = png.get_width()
h = png.get_height()
w = (w + 3) // 4 * 4
h = (h + 3) // 4 * 4
img = cairo.ImageSurface(cairo.Format.A8, w, h)
cr = cairo.Context(img)
cr.set_source_rgba(1, 1, 1, 1)
cr.paint()
cr.set_source_rgba(0, 0, 0, 0)
cr.set_operator(cairo.OPERATOR_SOURCE)
cr.set_source_surface(png)
cr.paint()
else:
sys.stderr.write('You need to pass a PNG with an alpha channel!\n')
sys.exit(1)
def write_dbg_img():
dbg_img_rgb = cairo.ImageSurface(cairo.Format.RGB24, img.get_width(), img.get_height())
dbg_cr = cairo.Context(dbg_img_rgb)
dbg_cr.set_source_rgb(0, 0, 0)
dbg_cr.paint()
dbg_cr.set_source_rgb(1, 1, 1)
dbg_cr.mask_surface(img, 0, 0)
dbg_img_rgb.write_to_png('/tmp/test.png')
#write_dbg_img()
# Send image through socket
sockaddr = os.environ['FP_VIRTUAL_IMGDEV']
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
sock.connect(sockaddr)
mem = img.get_data()
mem = mem.tobytes()
assert len(mem) == img.get_width() * img.get_height()
encoded_img = struct.pack('ii', img.get_width(), img.get_height())
encoded_img += mem
sock.sendall(encoded_img)