xdotool comes to the rescue

In a previous post I explained how I implemented a method for adding my current location and the local time to my e-mail signature wherever I happen to be in the World, irrespective of the time on the laptop’s hardware clock and system clock. In that post I described how I created a keyboard shortcut using the Linux application AutoKey. Unfortunately AutoKey has not been updated for several years and no longer works properly in KDE Plasma 5 on my laptops. Therefore I decided to replace it with a KDE keyboard shortcut, and this is to explain how I did it.

First create a custom shortcut in KDE:

  1. ‘System Settings’ > ‘Shortcuts’ > ‘Custom Shortcuts’
  2. ‘Edit’ > ‘New’ > ‘Global Shortcut’ > ‘Command/URL’, and name the New Action ‘Insert current time’
  3. On the Comment pane for ‘Insert current time’, add the comment ‘Insert current time at specified location’ (without the quotes)
  4. On the Trigger pane, configure the shortcut to be Ctrl+Alt+Space
  5. On the Action pane, enter the Command/URL as ‘/home/fitzcarraldo/timezone_signature_GeoNames.sh‘ (without the quotes)
  6. Click ‘Apply’

Next modify the Bash script timezone_signature_GeoNames.sh so that it contains the following (obviously change the username and path to suit):

#!/bin/bash

place=$(kdialog --title "Current Location" --inputbox "Enter your location:")

placetime=$(perl /home/fitzcarraldo/now1.pl $place)

# xdotool does not output a space in a string, so we have to extract each field from the string
# and print each field individually, separated by a space character.

city=$(echo $placetime | awk -F "|" '{print $1}')
country=$(echo $placetime | awk -F "|" '{print $2}' | sed 's/[)(]//g')
region=$(echo $placetime | awk -F "|" '{print $4}')

datetime=$(/usr/bin/zdump $region | awk -F " " '{print $2" "$3" "$4" "$5" "$6" "$7}')
dayofweek=$(echo $datetime | awk -F " " '{print $1}')
month=$(echo $datetime | awk -F " " '{print $2}')
day=$(echo $datetime | awk -F " " '{print $3}')
time=$(echo $datetime | awk -F " " '{print $4}')
year=$(echo $datetime | awk -F " " '{print $5}')
timezone=$(echo $datetime | awk -F " " '{print $6}')

activewindow=$(xdotool getactivewindow)

xdotool type --window $activewindow "Sent from:"
for oneword in $city; do
    xdotool key --window $activewindow space
    sleep 0.1s
    xdotool type --window $activewindow --delay 100 $oneword
done
xdotool key --window $activewindow comma
for oneword in $country; do
    xdotool key --window $activewindow space
    sleep 0.1s
    xdotool type --window $activewindow --delay 100 $oneword
done
xdotool key --window $activewindow Return
xdotool type --window $activewindow "Local time now: "
xdotool type --window $activewindow $dayofweek
xdotool type --window $activewindow " "
xdotool type --window $activewindow $month
xdotool type --window $activewindow " "
xdotool type --window $activewindow $day
xdotool type --window $activewindow " "
xdotool type --window $activewindow $time
xdotool type --window $activewindow " "
xdotool type --window $activewindow $year
xdotool type --window $activewindow " "
if [ ${timezone:0:1} = "-" ]; then
    timezone="UTC-"${timezone#*-}
elif [ ${timezone:0:1} = "+" ]; then
    timezone="UTC+"${timezone#*+}
fi
xdotool type --window $activewindow $timezone
xdotool type --window $activewindow " "
xdotool key --window $activewindow Return
xdotool key --window $activewindow Return
echo

The Perl script now1.pl is listed in my my earlier post. Notice that the script timezone_signature_GeoNames.sh in my earlier post was much simpler. This was because the AutoKey shortcut took care of sending the text to the currently active window. Without AutoKey, I now had to do this myself in the script timezone_signature_GeoNames.sh, and the command xdotool came to the rescue. The developer explains what xdotool does as follows:

This tool lets you simulate keyboard input and mouse activity, move and resize windows, etc. It does this using X11’s XTEST extension and other Xlib functions.

Additionally, you can search for windows and move, resize, hide, and modify window properties like the title. If your window manager supports it, you can use xdotool to switch desktops, move windows between desktops, and change the number of desktops.

So I installed xdotool via the Gentoo package manager:

# emerge xdotool
# eix xdotool
[I] x11-misc/xdotool
     Available versions:  3.20150503.1-r1^t ~3.20160805.1^t {examples}
     Installed versions:  3.20150503.1-r1^t(22:51:30 02/04/17)(-examples)
     Homepage:            http://www.semicomplete.com/projects/xdotool/
     Description:         Simulate keyboard input and mouse activity, move and resize windows

Anyway, my Bash script using xdotool works a treat with Thunderbird (and KWrite, LibreOffice Writer, etc.). I used to experience a problem with certain characters, for example a colon was printed as a semi-colon (see the xdotool bug report xdotool writes the wrong case #121), but that no longer happens in my current KDE Plasma 5 installation:

Sent from: Galeão International Airport, Brazil
Local time now: Thu Jul 6 15:11:40 2017 UTC-03

What a useful tool xdotool is!

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Using the ClamAV daemon to scan files placed in my Downloads directory in Gentoo Linux

In a previous post I explained how to automatically detect files placed in my Downloads directory in Linux and scan them for viruses. The method I described in that post used clamscan, the command-line anti-virus scanner of ClamAV. Now, in addition ClamAV has a daemon (a program that runs continuously in the background), clamdscan, that you can enable. So I decided to switch to using clamdscan, as its response to downloaded files is much faster because the process waiting for new files to appear in ~/Downloads/ does not have to load clamscan from disk each time a new file arrives. Anyway, if you want to monitor a download directory in Gentoo Linux (running OpenRC) by using the ClamAV daemon — which will also download virus signature database updates automatically — then the procedure to set this up is given below.

1. Install clamav if it is not installed already:

root # emerge clamav

2. Add the service to the default runlevel:

root # rc-update add clamd default

The daemon will be launched automatically next time the computer boots.

3. The first download of the virus database has to be done manually:

root # freshclam

4. Start the daemon now:

root # rc-service clamd start

5. Create the Bash script ~/monitorDownloadsGUI with the following contents:

#!/bin/bash

DIR=$HOME/Downloads

# Get rid of old log file, if any
rm $HOME/virus-scan.log 2> /dev/null

IFS=$(echo -en "\n\b")

# Optionally, you can use shopt to avoid creating two processes due to the pipe
shopt -s lastpipe
inotifywait --quiet --monitor --event close_write,moved_to --recursive --format '%w%f' $DIR | while read FILE
# Added '--recursive' so that a directory copied into $DIR also triggers clamscan/clamdscan, although downloads
# from the Web would just be files, not directories.
do
     # Have to check file length is nonzero otherwise commands may be repeated
     if [ -s $FILE ]; then
          # Replace 'date >' with 'date >>' if you want to keep log file entries for previous scans.
          date > $HOME/virus-scan.log
          clamdscan --move=$HOME/virus-quarantine $FILE >> $HOME/virus-scan.log
          kdialog --title "Virus scan of $FILE" --msgbox "$(cat $HOME/virus-scan.log)"
     fi
done

Make it executable:

user $ chmod +x ~/monitorDownloadsGUI

6. Create the directory ~/virus-quarantine/ to store infected files pending investigation/deletion:

user $ mkdir ~/virus-quarantine

7. Install kdialog if it is not already installed:

root # emerge kdialog

8. Use ‘System Settings’ > ‘Startup and Shutdown’ > ‘Autostart’ to add the script ~/monitorDownloadsGUI to the list of script files that are automatically started each time you log in to KDE.

9. Log out then back in again, and you should see that everything is running as expected:

user $ rc-status | grep clam
 clamd                                                             [  started  ]

user $ ps -ef | grep clam | grep -v grep
clamav    1920     1  0 01:48 ?        00:00:00 /usr/sbin/clamd
clamav    1929     1  0 01:48 ?        00:00:00 /usr/bin/freshclam -d

user $ ps -ef | grep GUI | grep -v grep
fitzcarraldo      9143  8971  0 13:56 ?        00:00:00 /bin/bash /home/fitzcarraldo/.config/autostart-scripts/monitorDownloadsGUI.sh

10. To test, surf to http://www.eicar.org/85-0-Download.html and download one of the EICAR test files into your ~/Downloads/ directory. You should see a pop-up KDialog window with a message similar to the following:

Virus scan of /home/fitzcarraldo/Downloads/eicarcom2.zip — KDialog

Mon 27 Feb 14:05:26 GMT 2017
/home/fitzcarraldo/Downloads/eicarcom2.zip: Eicar-Test-Signature FOUND
/home/fitzcarraldo/Downloads/eicarcom2.zip: moved to ‘/home/fitzcarraldo/virus-quarantine/eicarcom2.zip’

———– SCAN SUMMARY ———–
Infected files: 1
Time: 0.001 sec (0 m 0 s)

Note that the above-mentioned pop-up window may be preceded by one or more pop-up windows with an error message. I’m using the Chrome browser at the moment, but you may get a similar message if you are using another browser. Here is an example:

Virus scan of /home/fitzcarraldo/Downloads/.com.google.Chrome.Uh3oGm — KDialog ?

Mon 27 Feb 14:16:30 GMT 2017
/home/fitzcarraldo/Downloads/.com.google.Chrome.Uh3oGm: Access denied. ERROR

———– SCAN SUMMARY ———–
Infected files: 0
Total errors: 1
Time: 0.000 sec (0 m 0 s)

Read the error message and click ‘OK’, as this is not an actual problem; it is inotifywait detecting temporary files in the ~/Downloads/ directory during the download process. With larger files sometimes several such messages are displayed, presumably because the file being downloaded is being opened and closed more than once during the downloading process. This issue does not occur if you copy or move a file into ~/Downloads/ from another directory in your installation; try it and see for yourself. Then you only get the one pop-up window with the scan result for the file you put in ~/Downloads/.

Also have a look in ~/virus-quarantine/ and you will see the EICAR test file in that directory. You can delete it if you want (it is not infected with a real virus, so does no harm).

In future be sure to read the messages in the pop-up windows before clicking ‘OK’, as they will inform you that an infected file has been moved to the quarantine directory.

That’s all there is to it. Very simple, and quite handy if you want to check quickly that files you download don’t have a malware payload. Just make sure you download all files into ~/Downloads/ or they will not be checked automatically. Also, if you are given e.g. a USB pen drive with a file on it, you can copy the file to ~/Downloads/ if you want it to be scanned for malware.

How to capture a screenshot of the SDDM greeter screen

In my previous post I explained how to capture a screenshot of the LightDM greeter screen. The procedure is essentially the same for the SDDM greeter screen; only the Bash script differs slightly. The procedure is given below.

  1. If they are not already installed, install the packages x11-apps/xwd and media-gfx/imagemagick.

  2. Create the Bash script ~/sddm-greeter-capture.sh containing the following:
    TMPXAUTHORITY=$(ls /var/run/sddm/*)
    sleep 30
    DISPLAY=:0 XAUTHORITY=/var/run/sddm/$TMPXAUTHORITY xwd -root > /tmp/greeter.xwd
    convert /tmp/greeter.xwd /home/fitzcarraldo/greeter.png
    

    Make sure you make it executable:

    user $ chmod +x sddm-greeter-capture.sh

  3. Log out of the Desktop Environment so that the SDDM greeter screen is displayed.

  4. Press Ctrl+Alt+F2 to switch to VT2.

  5. Log in to you user account and enter the following command (do not wait for it to complete):

    user $ sudo /home/fitzcarraldo/sddm-greeter-capture.sh

  6. As soon as you have pressed Enter for the above command, press Ctrl+Alt+F7 to switch back to VT7.

  7. Wait for at least 30 seconds to be sure the Bash script has made a snapshot of the SDDM greeter screen, then log in.

  8. You should now find the file ~/greeter.png containing a snapshot of your SDDM greeter screen.

If you install media-libs/netpbm instead of (or as well as) media-gfx/imagemagick then you can use a different command to convert in the Bash script:

TMPXAUTHORITY=$(ls /var/run/sddm/*)
sleep 30
#DISPLAY=:0 XAUTHORITY=/var/run/sddm/$TMPXAUTHORITY xwd -root | xwdtopnm | pnmtopng > /home/fitzcarraldo/greeter.png

The resulting PNG image looks equally good to my eyes.

How to capture a screenshot of the LightDM greeter screen

  1. If they are not already installed, install the packages x11-apps/xwd and media-gfx/imagemagick.

  2. Create the Bash script ~/lightdm-greeter-capture.sh containing the following:
    #!/bin/bash
    sleep 30
    DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/$DISPLAY xwd -root > /tmp/greeter.xwd
    convert /tmp/greeter.xwd /home/fitzcarraldo/greeter.png
    

    Make sure you make it executable:

    user $ chmod +x lightdm-greeter-capture.sh

  3. Log out of the Desktop Environment so that the LightDM greeter screen is displayed.

  4. Press Ctrl+Alt+F2 to switch to VT2.

  5. Log in to you user account and enter the following command (do not wait for it to complete):

    user $ sudo /home/fitzcarraldo/lightdm-greeter-capture.sh

  6. As soon as you have pressed Enter for the above command, press Ctrl+Alt+F7 to switch back to VT7.

  7. Wait for at least 30 seconds to be sure the Bash script has made a snapshot of the LightDM greeter screen, then log in.

  8. You should now find the file ~/greeter.png containing a snapshot of your LightDM greeter screen.

If you install media-libs/netpbm instead of (or as well as) media-gfx/imagemagick then you can use a different command to convert in the Bash script:

#!/bin/bash
sleep 30
DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/$DISPLAY xwd -root | xwdtopnm | pnmtopng > /home/fitzcarraldo/greeter.png

The resulting PNG image looks equally good to my eyes.

A long overdue update to Google Earth for Linux

Google has finally released Version 7.1.7.2600 of Google Earth for Linux, fixing various crashes and the infamous empty Panoramio window. The last version of Google Earth for Linux that worked properly ‘out of the box’ in Gentoo Linux for me was 5.2.1.1588, and that was several years ago.

The current version of Google Earth in the Portage main tree is 7.1.4.1529. That version does not display Panoramio photos in Gentoo Linux (Stable Branch) on my Clevo W230SS laptop (NVIDIA Optimus), and Version 7.1.4.1529 crashes at launch more often than not. So I was keen to try the new version. Below are the steps I followed to install Version 7.1.7.2600 in the Portage local overlay on the laptop. If you don’t already have a local overlay, see the Gentoo Wiki article Overlay/Local overlay. Don’t forget to copy the files directory and its contents from /usr/portage/sci-geosciences/googleearth/ to /usr/local/portage/sci-geosciences/googleearth/ as well.

1. Download the file google-earth-stable_current_amd64.deb from the Google Earth Web site (Download the latest version of Google Earth for PC, Mac or Linux).

2. Edit the file /etc/portage/package.use/googleearth and add the line:

=sci-geosciences/googleearth-7.1.7.2600 -bundled-libs

3. Edit the file /etc/portage/package.unmask/googleearth and add the line:

=sci-geosciences/googleearth-7.1.7.2600

4. Edit the file /etc/portage/package.accept_keywords/googleearth and add the line:

=sci-geosciences/googleearth-7.1.7.2600 ~amd64

5. Copy the downloaded binary package to the distfiles directory and rename the package:

root # cp /home/fitzcarraldo/Downloads/google-earth-stable_current_amd64.deb /usr/portage/distfiles/GoogleEarthLinux-7.1.7.2600_amd64.deb

6. Create an ebuild for the new version and generate a manifest:

root # cd /usr/local/portage/sci-geosciences/googleearth/
root # cp /usr/portage/sci-geosciences/googleearth/googleearth-7.1.4.1529.ebuild googleearth-7.1.7.2600.ebuild
root # ebuild googleearth-7.1.7.2600.ebuild manifest

7. Install Google Earth 7.1.7.2600:

root # emerge =googleearth-7.1.7.2600

The package was installed without any trouble:

root # eix -I googleearth
[I] sci-geosciences/googleearth
     Available versions:  {M}(~)7.1.4.1529^m {M}(~)7.1.7.2600^m[1] {+bundled-libs}
     Installed versions:  7.1.7.2600^m[1](00:02:27 02/10/16)(-bundled-libs)
     Homepage:            https://earth.google.com/
     Description:         A 3D interface to the planet

[1] "local_overlay" /usr/local/portage

Google Earth for Linux 7.1.7.2600 launches quickly and without trouble on this laptop, and Panoramio photos are indeed now visible again (finally!). The only issue is one I also came across over a year ago after hacking an earlier version of Google Earth for Linux: If you click on a photo icon and the Panoramio window that opens displays several thumbnails, clicking on a thumbnail results in a white Panoramio window without any photo and thumbnails. Apparently this only happens in KDE. Anyway, the work-around is to right-click on the desired thumbnail and select ‘Open in New Window’.

Completing PDF forms and adding your signature without having to print the form

A recent post in the Gentoo Forums made me interested to find out what is actually achievable with fillable PDF forms in Gentoo Linux and Windows 10 without being required to purchase a software licence, be it for personal or professional use, in order to be able to complete PDF forms (including forms that have automatically-updating bar codes).

Designing PDF Forms

It is possible to create PDF forms with LibreOffice, although LibreOffice cannot create a form containing bar codes that get updated automatically with the information entered in fields on the form. In order to create PDF forms that contain automatically-updating bar codes it is necessary to purchase Adobe Acrobat DC or Adobe LiveCycle Designer, which are Windows-only applications. As forms usually have several fields, 2D bar code symbologies are used in order to be able to encode the amount of data in a practical way. See the Adobe demonstration video Capture electronic data from printed forms.

Using PDF Forms

However, the enquiry in the above-mentioned forum thread was not about designing PDF forms, it was about being able to complete existing PDF forms (including forms that have automatically-updating bar codes, and including being able to add a written signature to the form without printing it out):

Hi,

I need to sign pdfs, and sometimes fill out pdf forms which also need to be signed. At the moment I get them, print them, sign them and scan them back in to return to the sender. I’d like to simplify that.

I know that on Windows and Mac OS your adobe software can sign the pdf, but I don’t even know how that works exactly.

It would be really neat if there were an app which could handle all that.

Oh yeah, another thing. Some forms (all?) when you fill them out and print them have a bar of machine-readable gobbledygook on the page which lets the recipient of a printed pdf scan the data back in with 100% accuracy. That would be neat too.

Thanks.

Although I have sometimes added my signature to a PDF form before printing it out — more on that later — I had never come across PDF forms with automatically-updating bar codes, so my curiosity was piqued. I decided to investigate if free applications could be used to complete PDF forms (including those with automatically-updating bar codes) and add a written signature. My investigations were carried out in Linux and Windows 10, and my findings are given below. In summary, I discovered that I could do all these things in Linux as well as in Windows 10, although in Linux I had to resort to running a Windows application under WINE if a PDF form contained automatically-updating bar codes. I did not bother trying the GNOME document viewer Evince, as I could find no evidence on the Web of it having the capability of updating bar codes automatically, and I use KDE.

For my tests I used the following four PDF forms I found on the Web:

  1. acrobat8_barcodedforms.pdf, an October 2006 PDF article from Adobe containing three sample form fields and an associated automatically-updating bar code (PDF417 symbology).
  2. barcode_field.pdf, a February 2013 sample PDF form with three fields and three associated bar codes of different symbologies (PDF417, Data Matrix and QR Code).
  3. PdfFormExample.pdf, a June 2013 sample PDF form created using LibreOffice (and therefore not containing automatically-updating bar codes).
  4. sample_barcoded_demo.pdf, a December 2005 sample PDF form from Adobe with an automatically-updating bar code (PDF417 symbology).

1. Windows 10

1.1 Acrobat Reader DC

This is the ubiquitous ‘free’ closed-source application you can download from Adobe.

Below are screenshots of the four sample PDF forms opened in Acrobat Reader DC…

1.1.1 I could enter text in the three fields in acrobat8_barcodedforms.pdf, and the bar code was updated accordingly:

Acrobat Reader DC - acrobat8_barcodedforms.pdf

Acrobat Reader DC - acrobat8_barcodedforms.pdf

I used my smartphone’s Barcode Scanner app to read the bar code on the hard-copy form printed by Acrobat Reader DC:

Text1Text2Text3I am able to change the text in these fields of this form to see how 2D barcodes work.

1.1.2 I could enter text in the three fields in barcode_field.pdf, but the three bar codes were not visible:

Acrobat Reader DC - acrobat8_barcodedforms.pdf

Acrobat Reader DC - barcode_field.pdf

1.1.3 I could enter text in the fields in PdfFormExample.pdf:

Acrobat Reader DC - PdfFormExample.pdf

Acrobat Reader DC - PdfFormExample.pdf

1.1.4 I could enter text in all fields of sample_barcoded_demo.pdf and the field contents were echoed in the box ‘Barcode Contents’ but the bar code itself was not visible:

Acrobat Reader DC - sample_barcoded_demo.pdf

Acrobat Reader DC - sample_barcoded_demo.pdf

So, in summary, Acrobat Reader DC is not a viable option if you have to deal with forms that include automatically-updating bar codes.

1.2 PDF-XChange Editor

This application from Canadian company Tracker Software Products supersedes their deprecated PDF-XChange Viewer and has additional features. Neither application is open-source, though. Some features only work fully if you purchase a software licence and enter the licence key. For example, if you add a signature to a PDF form (‘Document’ > ‘Signatures and Initials’) and then save it, DEMO stamps are added to the new PDF file (which still has editable fields). However, if you print the PDF form (either to a PDF file or to paper) then DEMO stamps are not added (but the new PDF file is not fillable/editable). Click on the two links below to view the sample PDF file PdfFormExample.pdf signed and saved to a new PDF file, and the sample PDF file PdfFormExample.pdf signed and printed to a new PDF file:

PdfFormExample_with_signature_added_then_Saved.pdf

PdfFormExample_with_signature_added_then_Printed_to_PDF.pdf

If you save them to disk and open them in PDF-XChange Editor, you will see the distinction.

As stated on the company’s Web site, the free application can be used for private and work purposes:

The FREE download of the PDF-XChange Editor may be used without limitation for Private, Commercial, Government and all uses, provided it is not: incorporated or distributed for profit/commercial gain with other software or media distribution of any type – without first gaining permission.

Below are screenshots of the four sample PDF forms opened in PDF-XChange Editor…

1.2.1 I could enter text in the three fields in acrobat8_barcodedforms.pdf, and the bar code was updated accordingly:

PDF-XChange Editor - acrobat8_barcodedforms.pdf

PDF-XChange Editor - acrobat8_barcodedforms.pdf

I used my smartphone’s Barcode Scanner app to read the bar code on the hard-copy form printed by PDF-XChange Editor:

Text1Text2Text3
I am able to change the text in these fields of this formto see how 2D barcodes work.

Notice that the layout of the encoded text is slightly different to the bar code generated by Adobe Acrobat Reader DC.

1.2.2 I could enter text in the three fields in barcode_field.pdf, and the three bar codes were visible:

PDF-XChange Editor - barcode_field.pdf

PDF-XChange Editor - barcode_field.pdf

I used my smartphone’s Barcode Scanner app to read the three bar codes on the hard-copy form printed by PDF-XChange Editor:

The PDF417 bar code was read as follows:

text_0:PDF417 barcode:I can enter text in these fields of this form and can see the three barcodes to the right of these fields in PDF-XChange Editor.

The Data Matrix bar code was read as follows:

text_1:Data Matrix barcode:
To change the barcode field to the right, type in this box. The barcode field to the right will reflect the contents of the text field as barcode after the text field lost the focus. To reset the contents of all barcode fields, cick the ‘Rset’ button.

Notice that the words ‘click’ and ‘Reset’ in the field were apparently not encoded correctly.

The QR Code bar code was read as a meaningless apparently random bunch of characters.

The PDF file and the three bar codes were generated on the fly by PHP code calling the pdflib library produced by the company PDFlib GmbH. I do not know how accurate this particular PDF file is, or how accurate is the Bar Code Scanner app on my smartphone.

1.2.3 I could enter text in the fields in PdfFormExample.pdf:

PDF-XChange Editor - PdfFormExample.pdf

PDF-XChange Editor - PdfFormExample.pdf

1.2.4 I could enter text in all fields of sample_barcoded_demo.pdf, and the field contents were echoed in the box ‘Barcode Contents’ and the bar code itself was visible:

PDF-XChange Editor - sample_barcoded_demo.pdf

PDF-XChange Editor - sample_barcoded_demo.pdf

I used my smartphone’s Barcode Scanner app to read the PDF417 bar code on the hard-copy form printed by PDF-XChange Editor:

Brian
S
Fitzgerald
Calle Fitzcarrald, 225
Iquitos

bsf@iquitos.nom.pe

So, in summary, PDF-XChange Editor appears to be a possible option in Windows 10, whether or not you have to deal with forms that include automatically-updating bar codes. I am quite impressed with the application.

2. Linux

2.1 Acrobat Reader 9

This is the free closed-source Linux application you can install via the Portage package manager (the package is app-text/acroread).

Below are screenshots of the four sample PDF forms opened in Acrobat Reader 9 for Linux.

2.1.1 I could enter text in the three fields in acrobat8_barcodedforms.pdf, and the bar code was updated accordingly:

Acrobat Reader 9 Linux - acrobat8_barcodedforms.pdf

Acrobat Reader 9 Linux - acrobat8_barcodedforms.pdf

I used my smartphone’s Barcode Scanner app to read the bar code on the hard-copy form printed by Acrobat Reader 9 for Linux:

Text1Text2Text3I am able to change the text in these fields of this form to see how 2D barcodes work.

2.1.2 I could enter text in the three fields in barcode_field.pdf, but the three bar codes were not visible:

Acrobat Reader 9 Linux - barcode_field.pdf

Acrobat Reader 9 Linux - barcode_field.pdf

2.1.3 I could enter text in the fields in PdfFormExample.pdf:

Acrobat Reader 9 Linux - PdfFormExample.pdf

Acrobat Reader 9 Linux - PdfFormExample.pdf

2.1.4 I could enter text in all fields of sample_barcoded_demo.pdf, and the field contents were echoed in the box ‘Barcode Contents’ but the bar code itself was not visible:

Acrobat Reader 9 Linux - sample_barcoded_demo.pdf

Acrobat Reader 9 Linux - sample_barcoded_demo.pdf

So, in summary, Acrobat Reader 9 for Linux is not a viable option if you have to deal with forms that include automatically-updating bar codes.

2.2 Okular

This is the well-known KDE document viewer application.

Below are screenshots of the four sample PDF forms opened in Okular.

2.2.1 I could enter text in the three fields in acrobat8_barcodedforms.pdf but the bar code was not visible:

Okular - acrobat8_barcodedforms.pdf

Okular - acrobat8_barcodedforms.pdf

2.2.2 I could enter text in the three fields in barcode_field.pdf but the three bar codes were not visible:

Okular - barcode_field.pdf

Okular - barcode_field.pdf

2.2.3 I could enter text in the fields in PdfFormExample.pdf:

Okular - PdfFormExample.pdf

Okular - PdfFormExample.pdf

2.2.4 I could enter text in all fields of sample_barcoded_demo.pdf but the field contents were not echoed in the box ‘Barcode Contents’ and the bar code itself was not visible:

Okular - sample_barcoded_demo.pdf

Okular - sample_barcoded_demo.pdf

So, in summary, Okular is not a viable option if you have to deal with forms that include automatically-updating bar codes. In fact, Okular was the worst of the bunch.

2.3 PDF-XChange Editor

To install this Windows application under WINE in Linux:

$ export WINEPREFIX=$HOME/.wine-pdfxve6
$ export WINEARCH="win32"
$ winecfg # Select Windows 10.
$ cd .wine-pdfxve6/drive_c/
$ # Copy downloaded installer to C: drive:
$ cp ~/Downloads/PDFXVE6.zip .
$ unzip PDFXVE6.zip
$ # Install PDF-XChange Editor:
$ wine PDFXVE6.exe

  • Click ‘Install’.
  • Click ‘Next’.
  • Select ‘I accept the terms in the License Agreement’ and click ‘Next’.
  • Click ‘Custom’.
  • Click ‘Browsers Plugins’ and select ‘Don’t install’. Click ‘Next’.
  • Leave ‘Create a Start Menu folder’ ticked. Untick ‘Create Desktop Icons.’ Untick ‘Set PDF-XChange Editor as default application for PDF files’. Untick ‘Set Printer “PDF-XChange Lite V6” As Default’. Click ‘Next’.
  • Select ‘Free Version’ and click ‘Next’.
  • Click ‘Install’.
  • Untick ‘Launch PDF-XChange Editor’ and click ‘Finish’.
  • Click ‘Close’.

KDE Plasma 5 then has an entry for PDF-XChange Editor in the Application Launcher under ‘Applications’ > ‘Wine’ > ‘Programs’ > ‘Tracker Software’. Alternatively, to launch PDF-XChange Editor from the command line, you should enter:

$ WINEPREFIX="$HOME/.wine-pdfxve6" && WINEARCH="win32" && wine $WINEPREFIX/drive_c/Program\ Files/Tracker\ Software/PDF\ Editor/PDFXEdit.exe

If you also want the Windows application running under WINE to be able to access PDF files on a NAS, i.e. to be able to open Samba shares, see my previous post How to enable a Windows application in WINE to access a Samba share on a NAS.

I will not bother showing screenshots of the four sample PDF files open in PDF-XChange Editor running under WINE in Linux, as the application’s behaviour is the same as in Windows (see the screenshots in sections 1.2.1 to 1.2.4 above). So, in summary, PDF-XChange Editor appears to be a viable option in Linux (albeit running under WINE), irrespective of whether or not you have to deal with forms that include automatically-updating bar codes.

3. Adding a signature to a soft copy of the PDF form

I am referring to a person’s written signature here, not to a digital signature. Rather than having to print the completed form on paper in order to sign it with a pen, then scan the fully-completed form in order to send it via e-mail, fax or whatever, many people wish to add their signature directly to the PDF form without having to print it. Below I explain the method I use to do this in both Linux and Windows.

3.1 Create a PNG file with your signature (one-time operation)

  1. Get a blank white piece of paper.
  2. Sign your name on the page.
  3. Scan the page with your scanner and save the image as a PNG file.
  4. Open the image with GIMP.
  5. Crop the image around the signature.
  6. Select ‘Layer’ > ‘Transparency’ > ‘Add Alpha Channel’.
  7. Select the Fuzzy Select Tool from the toolbox.
  8. Click on each white area and press the Delete key. Do this for the area around the signature and inside any loops. Obviously don’t click on the signature itself.
  9. Select ‘File’ > ‘Export’.
  10. Save the image as a PNG file.

3.2 Signing PDF documents

  1. Launch LibreOffice Draw and open the PDF file you wish to sign.
  2. Select ‘Insert’ > ‘Image…’ and select the PNG file of your signature. The image will be inserted.
  3. To move the signature around on the page, hover the mouse cursor over the image until the cursor changes to a red dot with four arrowheads, then click-and-hold to grab the image drag it.
  4. To reduce the size of the signature, hover the mouse cursor over the image until the cursor changes to a red dot with four arrowheads, then click and release. You will then see small blue ‘handles’ on the outline of the image. Hover the mouse cursor over a handle at one of the four corners of the image until the cursor changes to a Resize cursor. Click-and-hold and move the cursor to increase or decrease the size of the signature whilst maintaining the ratio of width to height.
  5. To save the completed and signed PDF form, select ‘File’ > ‘Export as PDF…’, click on ‘Export’ and give the file a name of your choice.

The new PDF file will contain all the information visible on the previous PDF file plus your written signature. However, unlike the original PDF file, you will not be able to modify any of the data. Therefore I recommend you retain a copy of the original PDF file before you added the signature, in case you wish to change any of field entries in future.

Note that the free PDF-XChange Editor can be used instead of LibreOffice Draw providing the PDF form is not secured or restricted, and providing you print it to a new PDF file using a virtual PDF printer driver. If the PDF form is secured or changes restricted, then use LibreOffice Draw as described above.

If you are using a PDF viewer that refuses to save your completed form as a PDF file after you have entered data in the fields (notice the message in the purple bar in the screenshots of Acrobat Reader 9 for Linux, for example), print the page to a PDF file instead by using the virtual PDF printer (‘Microsoft Print to PDF’ in Windows; CUPS ‘Virtual PDF Printer’ in Linux) at a resolution of e.g. 600 dpi (if possible). You should then be able to open that PDF file in LibreOffice Draw or PDF-XChange Editor to add your signature as explained above and print the signed form to a new PDF file.

Fixing all-white log-in screen when using the LightDM KDE greeter with Plasma 5 in Gentoo Linux

In a previous post I explained how I got LightDM to work on my Clevo W230SS laptop running KDE Plasma 5 in Gentoo Linux (Stable Branch). However, following a world update a few weeks later, the LightDM log-in screen (‘greeter’) became all white. Searching the Web showed me that this is a common problem with LightDM, although the cause appeared to be different in many other cases, as I could still see the password-entry box and the button to select the session.

To summarise what was already installed:

fitzcarraldo@clevow230ss ~ $ uname -a
Linux clevow230ss 3.18.11-gentoo #47 SMP Thu May 26 11:03:29 BST 2016 x86_64 Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz GenuineIntel GNU/Linux
fitzcarraldo@clevow230ss ~ $ eix -I plasma-meta
[I] kde-plasma/plasma-meta
     Available versions:  (5) 5.6.5 ~5.7.3
       {bluetooth +display-manager grub gtk +handbook mediacenter networkmanager pam plymouth pulseaudio +sddm sdk +wallpapers}
     Installed versions:  5.6.5(5)(12:28:08 26/07/16)(bluetooth display-manager gtk handbook networkmanager pam pulseaudio wallpapers -grub -mediacenter -plymouth -sddm -sdk)
     Homepage:            https://www.kde.org/workspaces/plasmadesktop/
     Description:         Merge this to pull in all Plasma 5 packages

fitzcarraldo@clevow230ss ~ $ eix -I lightdm
[I] x11-misc/lightdm
     Available versions:  1.10.5^t 1.16.7^t ~1.17.6^t ~1.18.1^t ~1.19.0^t ~1.19.3^t {audit +gnome +gtk +introspection kde qt4 qt5}
     Installed versions:  1.16.7^t(04:11:41 23/08/16)(introspection kde qt4 qt5 -audit -gnome -gtk)
     Homepage:            https://www.freedesktop.org/wiki/Software/LightDM
     Description:         A lightweight display manager

[I] x11-misc/lightdm-kde
     Available versions:  (4) 0.3.2.1-r1
       {aqua debug L10N="bs cs da de el es et fi fr ga gl hu it ja km lt mr nds nl pl pt pt-BR ro ru sk sl sv tr uk"}
     Installed versions:  0.3.2.1-r1(4)(01:13:13 12/07/16)(-aqua -debug L10N="pt-BR -bs -cs -da -de -el -es -et -fi -fr -ga -gl -hu -it -ja -km -lt -mr -nds -nl -pl -pt -ro -ru -sk -sl -sv -tr -uk")
     Homepage:            https://projects.kde.org/projects/playground/base/lightdm
     Description:         LightDM KDE greeter

Found 2 matches

And this is what I had previously configured:

fitzcarraldo@clevow230ss ~ $ grep -v ^# /etc/lightdm/lightdm.conf
[LightDM]

session-wrapper=/etc/lightdm/Xsession
[Seat:*]
greeter-session=lightdm-kde-greeter
session-wrapper=/etc/lightdm/Xsession
display-setup-script=/etc/X11/Sessions/plasma

[XDMCPServer]

[VNCServer]
fitzcarraldo@clevow230ss ~ $ cat /etc/X11/Sessions/plasma
#!/bin/bash
GPU=`eselect opengl list | grep \* | awk '{ print $2 }'`
if [ "$GPU" = "nvidia" ]; then
    xrandr --setprovideroutputsource modesetting NVIDIA-0
    xrandr --auto
fi

Now, given that I had installed the LightDM KDE Greeter, I would have expected there to be a default configuration file lightdm-kde-greeter.conf for it, but there was none:

fitzcarraldo@clevow230ss ~ $ ls /etc/lightdm/
Xsession  keys.conf  lightdm.conf  users.conf

So I created the file /etc/lightdm/lightdm-kde-greeter.conf with the following contents:

[greeter]
theme-name=classic

[greeter-settings]
Background=/home/fitzcarraldo/Pictures/Wallpaper/Linux/kde-1920x1080.jpg
BackgroundKeepAspectRatio=true
GreetMessage=Welcome to %hostname%

I downloaded a nice KDE wallpaper file from the Web, which I saved as /home/fitzcarraldo/Pictures/Wallpaper/Linux/kde-1920x1080.jpg, but you can save it anywhere you like and give it any name you want.

I found that the package manager had installed two themes, so I could have specified either:

fitzcarraldo@clevow230ss ~ $ ls /usr/share/apps/lightdm-kde-greeter/themes/
classic  userbar

Anyway, the outcome is that the LightDM login screen (greeter) is no longer white and displays a wallpaper of my choice. Mission accomplished.

Text too small in X Windows when using nvidia-drivers

In an earlier post titled ‘Switching between Intel and NVIDIA graphics processors on a laptop with NVIDIA Optimus hardware running Gentoo Linux‘ I described how I am able to switch between the closed-source NVIDIA video driver and the open-source Intel video driver on a Clevo W230SS laptop with NVIDIA Optimus hardware. This works nicely, but one thing had been niggling me for over a year: the size of the fonts in the Desktop Environment were much smaller when using the NVIDIA driver than when using the Intel driver. I could of course increase the font size via KDE’s ‘System Settings’ > ‘Font’ when using the NVIDIA driver, but then I would have to reduce the font size the same way when using the Intel driver. So I resolved to find a better way, and it turned out all I needed to do was add one line to the Monitor section in xorg.conf to specify the DPI (Dots Per Inch) for the X Screen when using the NVIDIA driver:

Section "Monitor"
    Identifier     "Monitor0"
    Option         "DPMS"
    Option         "DPI" "96 x 96"
EndSection

You can read more about this in the NVIDIA Accelerated Linux Graphics Driver README and Installation Guide, Appendix B. X Config Options.

As described in my earlier post, I run a script to copy a file I named xorg.conf.nvidia to xorg.conf when I want to use the NVIDIA driver, and another script to copy a file I named xorg.conf.intel to xorg.conf when I want to use the Intel driver. So all I needed to do was add the line Option "DPI" "96 x 96" to the Monitor section in the file xorg.conf.nvidia and run my script to switch to the NVIDIA driver. Problem finally solved.

Getting KDE Plasma 5 to work with the NVIDIA closed-source driver in Gentoo Linux

Up until a few days ago I had avoided migrating from KDE 4 to KDE Plasma 5, Frameworks 5 and Applications 5 — I’ll refer to the latter three package categories collectively as ‘KDE:5’ — on my main laptop, a Clevo W230SS with NVIDIA Optimus hardware and Gentoo Linux Stable Branch installed. My reluctance to migrate to KDE:5 was because of various problems I experience in KDE:5 on my Compal NBLB2 laptop, which has Gentoo Testing Branch installed (currently Plasma 5.7.1, which you would expect to be less buggy than Plasma 5.5.5 in the Gentoo Stable Branch).

Recently the maintainers of Gentoo’s KDE ebuilds removed some of the KDE 4 ebuilds and made some of the other ebuilds dependent on KDE:5. It became more complicated and convoluted to keep KDE 4 going, so I reluctantly threw in the towel and migrated to KDE:5 on my main laptop. I wish I could have kept KDE 4 on that machine, as KDE 4 worked extremely well (and looked great too).

My first problem after migrating was the infamous black screen in X Windows at start-up. Trying the various suggestions in the Gentoo Wiki did not help and, for the first time since I’ve owned the Clevo laptop, I was glad it has NVIDIA Optimus hardware as I was able to change from using nvidia-drivers to using xf86-video-intel, which got me to a usable Desktop after I switched desktop managers from SDDM (see the system log file error messages below) to LightDM.

Jul 17 04:32:37 clevow230ss sddm-helper[3245]: PAM unable to dlopen(/lib64/security/pam_systemd.so): /lib64/security/pam_systemd.so: cannot open shared object file: No such file or directory
Jul 17 04:32:37 clevow230ss sddm-helper[3245]: PAM adding faulty module: /lib64/security/pam_systemd.so

Although I had merged x11-misc/sddm with USE="-systemd" because my installation uses OpenRC, the above error messages made me suspect that something is wrong with the sddm-0.13.0-r3 ebuild, which is why I switched to LightDM.

However, using solely the Intel driver is not a long-term solution for me because DraftSight CAD software is slower with the Intel driver, so I was keen to get Plasma 5 working with the closed-source NVIDIA driver (I do not want to use Bumblebee).

I managed to get LightDM and Plasma 5 working with nvidia-drivers by doing the following:

  1. Merge x11-misc/lightdm.
  2. Re-merge kde-plasma/plasma-meta with USE="-sddm".
  3. Remove the x11-misc/sddm package and kde-plasma/sddm-kcm package by using the command ‘emerge --ask --depclean‘.
  4. Edit the file /etc/lightdm/lightdm.conf to add the line ‘greeter-session=lightdm-kde-greeter‘ as specified in Gentoo Wiki article LightDM.
  5. Edit the file /etc/lightdm/lightdm.conf to add the line ‘display-setup-script=/etc/X11/Sessions/plasma‘ (any file name would do).
  6. Create the above-mentioned Bash script /etc/X11/Sessions/plasma containing the following:
#!/bin/bash
GPU=`eselect opengl list | grep \* | awk '{ print $2 }'`
if [ "$GPU" = "nvidia" ]; then
    xrandr --setprovideroutputsource modesetting NVIDIA-0
    xrandr --auto
fi

I can now switch between the NVIDIA closed-source driver and the Intel open-source driver using the method described in an earlier post: Switching between Intel and NVIDIA graphics processors on a laptop with NVIDIA Optimus hardware running Gentoo Linux.

After updating Firefox for Linux, the folder icons in the bookmarks menu disappeared

Only a short post this time, but this problem has been annoying me for a few weeks. I use KDE 4.14 (kde-meta-4.14.3-r1) in Gentoo Linux on my main laptop, and recently upgraded Firefox to Version 46.0. The folder icons in Firefox’s bookmarks menu were no longer visible, although favicons were still visible in the bookmarks menu. The 2011 mozillaZine Forums thread After updating- ff4 bookmark folder icons disappeared [Linux] steered me in the right direction: I checked KDE 4’s ‘System Settings’ > ‘Application Appearance’ > ‘GTK’ and found that ‘Show icons in GTK menus’ was not ticked. I ticked this and clicked on ‘Apply’, and the problem was solved.