Invisible text in QTextEdit

karlheinzreichel

Hmm.. according to your code:
When you do not set a text in the QTextEdit-Control (textEdit.setPlainText)
there will be no visible text in the control!

Alp Hancioglu

@karlheinzreichel I don't understand what you mean exactly but textEdit.append("some"); call doesn't display any text either. It moves the cursor but no text is shown.

karlheinzreichel

@Alp-Hancioglu
in your code above there is no append (or did I miss something ?)

Alp Hancioglu

@karlheinzreichel I tried the append call at some point but forgot to add it to the post. The issue seems much more bigger than QTextEdit though as there is also no text shown in VLC media player.

karlheinzreichel

As you build qt from scratch, the question :
Have you installed the libconfig libraries before ... ?

(probably not)

regards
karl-heinz

Alp Hancioglu

@karlheinzreichel I didn't explicitly install libconfig library myself. I don't know if other program installed it as prerequisite.
In order to build, I downloaded qt-everywhere-opensource-src-5.9.1.tar.xz file and extracted it.
Then called ./configure and make on bash.

karlheinzreichel

So I would reccomend to check the build requierments for QT
(see http://doc.qt.io/qt-5/linux-requirements.html)
before building the qt libs

regards
Karl-Heinz

jsulm

@Alp-Hancioglu Try to start your app with QT_DEBUG_PLUGINS environment variable set and check the output in the console. Looks like something is wrong with your system.

Alp Hancioglu

@jsulm I set the env variable and there are no errors listed. Just a bunch of plugin metadata loads. Should I look for something?

jsulm

@Alp-Hancioglu Are there any errors/warnings?

Alp Hancioglu

@jsulm There are no errors or warnings.

Alp Hancioglu

@karlheinzreichel I checked every package and its dev version listed in requirements list and they are all installed and at newest version so there is no need to install or upgrade any of them. Some packages don't have the exact same name on my machine: libfontconfig is listed as libfontconfig1 on mine, libfreetype is listed as libfreetype6 on mine but the descriptions match.
I built Qt a week ago so they were most probably at newest version at time of compilation so I don't think they are related to the issue I have.

jsulm

@Alp-Hancioglu If you execute configure script before building Qt you will get a summary what was found and enabled. You can execute configure again with -v parameter and see whether fontconfig was really enabled.

Alp Hancioglu

@jsulm Thanks for the continued support jsulm.

I used ./configure -v and saw that fontconfig is disabled in build options:

Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ no
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. no

Then I used ./configure -v -fontconfig to enable it but it didn't work with error:

ERROR: Feature 'fontconfig' was enabled, but the pre-condition '!config.win32 && !config.darwin && features.system-freetype && libs.fontconfig' failed.

Then I run following to make sure libfontconfig is installed:

sudo apt install libfontconfig1
[sudo] password for alp: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libfontconfig1 is already the newest version (2.11.94-0ubuntu1.1).
0 upgraded, 0 newly installed, 0 to remove and 39 not upgraded.

I also run ./configure -system-freetype -fontconfig but it doesn't make a difference with resulting errors:

ERROR: Feature 'system-freetype' was enabled, but the pre-condition 'features.freetype && libs.freetype' failed.

ERROR: Feature 'fontconfig' was enabled, but the pre-condition '!config.win32 && !config.darwin && features.system-freetype && libs.fontconfig' failed.

Make sure freetype is installed:

sudo apt install libfreetype6
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libfreetype6 is already the newest version (2.6.1-0.1ubuntu2.3).
0 upgraded, 0 newly installed, 0 to remove and 39 not upgraded.

jsulm

@Alp-Hancioglu You need to install the dev package for fontconfig. Something like libfontconfig1-dev.

Alp Hancioglu

@jsulm It is already installed:

sudo apt install libfontconfig1-dev
[sudo] password for alp: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libfontconfig1-dev is already the newest version (2.11.94-0ubuntu1.1).
0 upgraded, 0 newly installed, 0 to remove and 39 not upgraded.

I checked every dev package in the requirements list and they are all installed with newest versions

jsulm

@Alp-Hancioglu If you execute configure with -v you should get more output. Can you post it here?

Alp Hancioglu

I uninstalled Qt build with make uninstall and then fonts in VLC appeared. I am guessing Qt code in VLC was referencing Qt build libs in /usr/local/Qt-5.9.1/lib directory, which are deleted after uninstall, and this was causing the missing font in VLC. After uninstall VLC started referencing libs in /usr/lib/x86_64-linux-gnu/ which work and fonts appeared.

I tried compiling against headers and libs in qt-everywhere-opensource-src-5.9.1 directory, which is downloaded from qt website:

g++ -Wall -fPIC -c -g -I/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/include -I/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/include/QtWidgets main.cpp -o main.o
g++ -g -Wl,--trace main.o ext/printer.o -o main -L/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/lib -lQt5Gui -lQt5Core -lQt5Widgets
/usr/bin/ld: mode elf_x86_64
/usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/crt1.o
/usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/crti.o
/usr/lib/gcc/x86_64-linux-gnu/6/crtbegin.o
main.o
ext/printer.o
-lQt5Gui (/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/lib/libQt5Gui.so)
-lQt5Core (/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/lib/libQt5Core.so)
-lQt5Widgets (/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/lib/libQt5Widgets.so)
-lstdc++ (/usr/lib/gcc/x86_64-linux-gnu/6/libstdc++.so)
/lib/x86_64-linux-gnu/libm.so.6
/lib/x86_64-linux-gnu/libmvec.so.1
libgcc_s.so.1 (/usr/lib/gcc/x86_64-linux-gnu/6/libgcc_s.so.1)
/lib/x86_64-linux-gnu/libc.so.6
(/usr/lib/x86_64-linux-gnu/libc_nonshared.a)elf-init.oS
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
libgcc_s.so.1 (/usr/lib/gcc/x86_64-linux-gnu/6/libgcc_s.so.1)
/usr/lib/gcc/x86_64-linux-gnu/6/crtend.o
/usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/crtn.o

When I run with ./main following errors appear:

./main: /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5: version Qt_5' not found (required by ./main) ./main: /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5: version Qt_5' not found (required by ./main)
./main: /usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version Qt_5.9' not found (required by ./main) ./main: /usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version Qt_5' not found (required by ./main)

which makes me guess that libs in qt-everywhere-opensource-src-5.9.1 are empty and g++ references the libs in x86_64-linux-gnu which are not the latest version 5.9 as expected.

Alp Hancioglu

@jsulm I don't notice much difference with -v but here it is.

./configure -system-freetype -fontconfig -v

cd qtbase
/home/alp/Downloads/qt-everywhere-opensource-src-5.9.1/qtbase/configure -top-level -system-freetype -fontconfig -v
Creating qmake...
make: Nothing to be done for 'first'.
Command line: -system-freetype -fontconfig -v

Selecting Qt Edition.

Type 'c' if you want to use the Commercial Edition.
Type 'o' if you want to use the Open Source Edition.

Which edition of Qt do you want to use? o

This is the Qt Open Source Edition.

You are licensed to use this software under the terms of
the GNU Lesser General Public License (LGPL) version 3
or the GNU General Public License (GPL) version 2.

Type 'L' to view the GNU Lesser General Public License version 3 (LGPLv3).
Type 'G' to view the GNU General Public License version 2 (GPLv2).
Type 'y' to accept this license offer.
Type 'n' to decline this license offer.

Do you accept the terms of either license? y

Running configuration tests...
Done running configuration tests.

Configure summary:

Build type: linux-g++ (x86_64, CPU features: mmx sse sse2)
Configuration: use_gold_linker sse2 sse3 ssse3 sse4_1 sse4_2 avx avx2 avx512f avx512bw avx512cd avx512dq avx512er avx512ifma avx512pf avx512vbmi avx512vl compile_examples enable_new_dtags f16c largefile precompile_header shared rpath release c++11 c++14 c++1z concurrent dbus mremap reduce_exports reduce_relocations stl
Build options:
Mode ................................... release
Optimize release build for size ........ no
Building shared libraries .............. yes
Using C++ standard ..................... C++1z
Using gold linker ...................... yes
Using new DTAGS ........................ yes
Using precompiled headers .............. yes
Using LTCG ............................. no
Target compiler supports:
SSE .................................. SSE2 SSE3 SSSE3 SSE4.1 SSE4.2
AVX .................................. AVX AVX2 F16C
AVX512 ............................... F ER CD PF DQ BW VL IFMA VBMI
Build parts ............................ libs examples tools
Qt modules and options:
Qt Concurrent .......................... yes
Qt D-Bus ............................... yes
Qt D-Bus directly linked to libdbus .... no
Qt Gui ................................. yes
Qt Network ............................. yes
Qt Sql ................................. yes
Qt Testlib ............................. yes
Qt Widgets ............................. yes
Qt Xml ................................. yes
Support enabled for:
Using pkg-config ....................... yes
QML debugging .......................... yes
udev ................................... no
Using system zlib ...................... yes
Qt Core:
DoubleConversion ....................... yes
Using system DoubleConversion ........ no
GLib ................................... no
iconv .................................. yes
ICU .................................... no
Logging backends:
journald ............................. no
syslog ............................... no
slog2 ................................ no
Using system PCRE2 ..................... no
Qt Network:
getaddrinfo() .......................... yes
getifaddrs() ........................... yes
IPv6 ifname ............................ yes
libproxy ............................... no
OpenSSL ................................ no
Qt directly linked to OpenSSL ........ no
SCTP ................................... no
Use system proxies ..................... yes
Qt Gui:
Accessibility .......................... yes
FreeType ............................... yes
Using system FreeType ................ no
HarfBuzz ............................... yes
Using system HarfBuzz ................ no
Fontconfig ............................. no
Image formats:
GIF .................................. yes
ICO .................................. yes
JPEG ................................. yes
Using system libjpeg ............... no
PNG .................................. yes
Using system libpng ................ no
EGL .................................... no
OpenVG ................................. no
OpenGL:
Desktop OpenGL ....................... yes
OpenGL ES 2.0 ........................ no
OpenGL ES 3.0 ........................ no
OpenGL ES 3.1 ........................ no
Session Management ..................... yes
Features used by QPA backends:
evdev .................................. yes
libinput ............................... no
INTEGRITY HID .......................... no
mtdev .................................. no
tslib .................................. no
xkbcommon-evdev ........................ no
QPA backends:
DirectFB ............................... no
EGLFS .................................. no
LinuxFB ................................ yes
VNC .................................... yes
Mir client ............................. no
X11:
Using system-provided XCB libraries .. no
EGL on X11 ........................... no
Xinput2 .............................. no
XCB XKB .............................. yes
XLib ................................. yes
XCB render ........................... yes
XCB GLX .............................. yes
XCB Xlib ............................. yes
Using system-provided xkbcommon ...... no
Qt Widgets:
GTK+ ................................... no
Styles ................................. Fusion Windows
Qt PrintSupport:
CUPS ................................... no
Qt Sql:
DB2 (IBM) .............................. no
InterBase .............................. no
MySql .................................. no
OCI (Oracle) ........................... no
ODBC ................................... no
PostgreSQL ............................. no
SQLite2 ................................ no
SQLite ................................. yes
Using system provided SQLite ......... no
TDS (Sybase) ........................... no
Qt SerialBus:
Socket CAN ............................. yes
Socket CAN FD .......................... yes
QtXmlPatterns:
XML schema support ..................... yes
Qt QML:
QML interpreter ........................ yes
QML network support .................... yes
Qt Quick:
Direct3D 12 ............................ no
AnimatedImage item ..................... yes
Canvas item ............................ yes
Support for Qt Quick Designer .......... yes
Flipable item .......................... yes
GridView item .......................... yes
ListView item .......................... yes
Path support ........................... yes
PathView item .......................... yes
Positioner items ....................... yes
ShaderEffect item ...................... yes
Sprite item ............................ yes
Qt Gamepad:
SDL2 ................................... no
Qt 3D:
Assimp ................................. yes
System Assimp .......................... no
Output Qt3D Job traces ................. no
Output Qt3D GL traces .................. no
Qt 3D GeometryLoaders:
Autodesk FBX ........................... no
Qt Wayland Client ........................ no
Qt Wayland Compositor .................... no
Qt Bluetooth:
BlueZ .................................. no
BlueZ Low Energy ....................... no
Linux Crypto API ....................... no
Qt Sensors:
sensorfw ............................... no
Qt Multimedia:
ALSA ................................... no
GStreamer 1.0 .......................... no
GStreamer 0.10 ......................... no
Video for Linux ........................ yes
OpenAL ................................. no
PulseAudio ............................. no
Resource Policy (libresourceqt5) ....... no
Windows Audio Services ................. no
DirectShow ............................. no
Windows Media Foundation ............... no
Qt Quick Controls 2:
Styles ................................. Default Material Universal
Qt Quick Templates 2:
Hover support .......................... yes
Multi-touch support .................... yes
Qt Location:
Gypsy GPS Daemon ....................... no
WinRT Geolocation API .................. no
Qt WebEngine:
Embedded build ......................... no
Pepper Plugins ......................... yes
Printing and PDF ....................... yes
Proprietary Codecs ..................... no
Spellchecker ........................... yes
WebRTC ................................. yes
Using system ninja ..................... no
ALSA ................................... no
PulseAudio ............................. no
System libraries:
ICU .................................. no
libwebp and libwebpdemux ............. no
Opus ................................. no
ffmpeg ............................... no

Note: Also available for Linux: linux-clang linux-icc

Note: Disabling Linux Accessibility Bridge: D-Bus is missing.

Note: No wayland-egl support detected. Cross-toolkit compatibility disabled.

ERROR: Feature 'system-freetype' was enabled, but the pre-condition 'features.freetype && libs.freetype' failed.

ERROR: Feature 'fontconfig' was enabled, but the pre-condition '!config.win32 && !config.darwin && features.system-freetype && libs.fontconfig' failed.

jsulm

@Alp-Hancioglu said in Invisible text in QTextEdit:

Configure summary

There must be much more output before "Configure summary".
You should try it again from a clean state (you built before, so unzip source archive again).