Questions[pencil](ubuntu)

I was looking for a UX design tool on Linux, so tried to install Pencil .

 dpkg -i Pencil_3.0.4_amd64.deb 
Selecting previously unselected package pencil.
(Reading database ... 291107 files and directories currently installed.)
Preparing to unpack Pencil_3.0.4_amd64.deb ...
Unpacking pencil (3.0.4-49) ...
Setting up pencil (3.0.4-49) ...
Processing triggers for gnome-menus (3.13.3-11ubuntu1.1) ...
Processing triggers for desktop-file-utils (0.23-1ubuntu3.18.04.2) ...
Processing triggers for mime-support (3.60ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...

I don't see any error, or it appear anywhere on the programs. It does not appear on the installed software either.

 dpkg -L pencil
/.
/opt
/opt/Pencil
/opt/Pencil/content_resources_200_percent.pak
/opt/Pencil/pencil
/opt/Pencil/views_resources_200_percent.pak
/opt/Pencil/icudtl.dat
/opt/Pencil/LICENSE.electron.txt
/opt/Pencil/blink_image_resources_200_percent.pak
/opt/Pencil/locales
/opt/Pencil/locales/sl.pak
/opt/Pencil/locales/cs.pak
/opt/Pencil/locales/fa.pak
/opt/Pencil/locales/ta.pak
/opt/Pencil/locales/gu.pak
/opt/Pencil/locales/nl.pak
/opt/Pencil/locales/id.pak
/opt/Pencil/locales/et.pak
/opt/Pencil/locales/ar.pak
/opt/Pencil/locales/am.pak
/opt/Pencil/locales/da.pak
/opt/Pencil/locales/fi.pak
/opt/Pencil/locales/lt.pak
/opt/Pencil/locales/en-GB.pak
/opt/Pencil/locales/it.pak
/opt/Pencil/locales/nb.pak
/opt/Pencil/locales/th.pak
/opt/Pencil/locales/sk.pak
/opt/Pencil/locales/ro.pak
/opt/Pencil/locales/hu.pak
/opt/Pencil/locales/sr.pak
/opt/Pencil/locales/mr.pak
/opt/Pencil/locales/fake-bidi.pak
/opt/Pencil/locales/zh-CN.pak
/opt/Pencil/locales/ko.pak
/opt/Pencil/locales/kn.pak
/opt/Pencil/locales/pl.pak
/opt/Pencil/locales/es.pak
/opt/Pencil/locales/ca.pak
/opt/Pencil/locales/vi.pak
/opt/Pencil/locales/he.pak
/opt/Pencil/locales/te.pak
/opt/Pencil/locales/pt-BR.pak
/opt/Pencil/locales/bn.pak
/opt/Pencil/locales/es-419.pak
/opt/Pencil/locales/en-US.pak
/opt/Pencil/locales/uk.pak
/opt/Pencil/locales/ml.pak
/opt/Pencil/locales/hr.pak
/opt/Pencil/locales/lv.pak
/opt/Pencil/locales/el.pak
/opt/Pencil/locales/ru.pak
/opt/Pencil/locales/hi.pak
/opt/Pencil/locales/de.pak
/opt/Pencil/locales/pt-PT.pak
/opt/Pencil/locales/ja.pak
/opt/Pencil/locales/ms.pak
/opt/Pencil/locales/sv.pak
/opt/Pencil/locales/fil.pak
/opt/Pencil/locales/zh-TW.pak
/opt/Pencil/locales/tr.pak
/opt/Pencil/locales/bg.pak
/opt/Pencil/locales/sw.pak
/opt/Pencil/locales/fr.pak
/opt/Pencil/snapshot_blob.bin
/opt/Pencil/libffmpeg.so
/opt/Pencil/resources
/opt/Pencil/resources/app.asar
/opt/Pencil/resources/app.asar.unpacked
/opt/Pencil/resources/app.asar.unpacked/node_modules
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/Typings
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/Typings/xelement.d.ts
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/LICENSE
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/package.json
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/xelement.sln
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/.vs
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/.vs/xelement
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/.vs/xelement/v14
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/.vs/xelement/v14/.suo
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/sampledata.xml
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/.npmignore
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/Index.js
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/lib
/opt/Pencil/resources/app.asar.unpacked/node_modules/xelement/lib/xelement.js
/opt/Pencil/resources/electron.asar
/opt/Pencil/content_shell.pak
/opt/Pencil/natives_blob.bin
/opt/Pencil/ui_resources_200_percent.pak
/opt/Pencil/libnode.so
/opt/Pencil/LICENSES.chromium.html
/usr
/usr/share
/usr/share/applications
/usr/share/applications/pencil.desktop
/usr/share/doc
/usr/share/doc/pencil
/usr/share/doc/pencil/changelog.gz
/usr/share/icons
/usr/share/icons/hicolor
/usr/share/icons/hicolor/48x48
/usr/share/icons/hicolor/48x48/apps
/usr/share/icons/hicolor/48x48/apps/pencil.png
/usr/share/icons/hicolor/32x32
/usr/share/icons/hicolor/32x32/apps
/usr/share/icons/hicolor/32x32/apps/pencil.png
/usr/share/icons/hicolor/64x64
/usr/share/icons/hicolor/64x64/apps
/usr/share/icons/hicolor/64x64/apps/pencil.png
/usr/share/icons/hicolor/24x24
/usr/share/icons/hicolor/24x24/apps
/usr/share/icons/hicolor/24x24/apps/pencil.png
/usr/share/icons/hicolor/16x16
/usr/share/icons/hicolor/16x16/apps
/usr/share/icons/hicolor/16x16/apps/pencil.png
/usr/share/icons/hicolor/96x96
/usr/share/icons/hicolor/96x96/apps
/usr/share/icons/hicolor/96x96/apps/pencil.png
/usr/share/icons/hicolor/128x128
/usr/share/icons/hicolor/128x128/apps
/usr/share/icons/hicolor/128x128/apps/pencil.png
/usr/share/icons/hicolor/256x256
/usr/share/icons/hicolor/256x256/apps
/usr/share/icons/hicolor/256x256/apps/pencil.png

What could be wrong here and how to fix it?

My system information is this:

inxi -Sxx 
System: Host: Milkybar-Computer Kernel: 4.15.0-46-generic i686 (32 bit gcc: 5.4.0) 
Desktop: Unity 7.4.5 (Gtk 3.18.9-1ubuntu3.3) dm: lightdm 
Distro: Ubuntu 16.04 xenial

I found pencil on Ubuntu software store, which was a buggy nightly build. So, I went ahead to its official site and downloaded its latest stable version using this link. It was in the form of '.Appimage' . So, I checked this:What is an "AppImage"? How do I install it? forum, and did accordingly. Terminal shows the following Screen:

milkybar@Milkybar-Computer:~/Downloads$ chmod a+x pencil2d-linux-i386-0.6.2.AppImage
milkybar@Milkybar-Computer:~/Downloads$ ./pencil2d-linux-i386-0.6.2.AppImage./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libgcc_s.so.1: version `GCC_7.0.0' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libQt5Gui.so.5)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libz.so.1: version `ZLIB_1.2.9' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libpng16.so.16)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libgcc_s.so.1: version `GCC_7.0.0' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libicui18n.so.60)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.27' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libpulsecommon-11.1.so)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.25' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libsystemd.so.0)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.27' not found (required by /tmp/.mount_pencilDbmznO/usr/bin/../lib/libsystemd.so.0)
milkybar@Milkybar-Computer:~/Downloads$ 

So, I installed GCC-7 from here Now, terminal shows:

milkybar@Milkybar-Computer:~/Downloads$ ./pencil2d-linux-i386-0.6.2.AppImage./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libz.so.1: version `ZLIB_1.2.9' not found (required by /tmp/.mount_pencilEkfHta/usr/bin/../lib/libpng16.so.16)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.27' not found (required by /tmp/.mount_pencilEkfHta/usr/bin/../lib/libpulsecommon-11.1.so)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.25' not found (required by /tmp/.mount_pencilEkfHta/usr/bin/../lib/libsystemd.so.0)
./pencil2d-linux-i386-0.6.2.AppImage: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.27' not found (required by /tmp/.mount_pencilEkfHta/usr/bin/../lib/libsystemd.so.0)

What do I do Now?

For some stupid reason whenever I start painting with pencil tool it simply doesn't act as expected at all. For example, I want to create a darkened shading effect on a base of one colour (skin colour in this case). Instead it draws a line with pale shade! Even worse, I cannot seem to draw other shades on other colours, like white - it just doesn't respond (although I can undo it, which still does nothing)! The fill tool still works properly.

Please help. everything worked fine with other projects, but on this picture it is just infuriating.

I downloaded Pencil from https://pencil.evolus.vn and installed the .deb file successfully but whenever I try to open the application nothing happens. it appears in the dock for a few moments but it won't open. is there something missing?!

I'm on ubuntu 18.4 (kernel version : 4.17)