QImage doesn't take in a JPG

Rapidrain

@jsulm the imageformats directory does (!) exist in the build. I found it last night. Now I wonder if I must include all of them in my compile and link statements, mention them in some manner.

My link command was :
g++ -Wl,-subsystem,windows -mthreads -o D:/Projects/FridgeMagnets3/bin/Debug/FridgeMagnets32d.exe obj/Debug/FridgeMagnets3d.o obj/Debug/MyLabeld.o obj/Debug/moc_MyLabeld.o obj/Debug/DragWidgetd.o obj/Debug/moc_DragWidgetd.o -LD:/Qt64/qt-install/lib -lglu32 -lopengl32 -lgdi32 -luser32 -lmingw32 -lqtmain -lQt5Widgets -lQt5Core -lQt5Gui

I copied the two files qjpeg.dll and qjpegd.dll into a directory imageformats and placed it next to the executable.
Then I changed the link command to :

g++ -Wl,-subsystem,windows -mthreads -o D:/Projects/FridgeMagnets3/bin/Debug/FridgeMagnets32d.exe obj/Debug/FridgeMagnets3d.o obj/Debug/MyLabeld.o obj/Debug/moc_MyLabeld.o obj/Debug/DragWidgetd.o obj/Debug/moc_DragWidgetd.o -LD:/Projects/FridgeMagnets3/imageformats -LD:/Qt64/qt-install/lib -lglu32 -lopengl32 -lgdi32 -luser32 -lmingw32 -lqtmain -lQt5Widgets -lQt5Core -lQt5Gui

Note that I added the imageformats directory as a source of libraries in the link command.

It didn't help though.

jsulm

@Rapidrain Sure it exists, but does it contain the JPEG plug-in? It should be named like libqjpeg.so
You do not have to add any of them to your compile/link config!
When deploying your app later you just need to make sure you deploy all needed plug-ins as well. See http://doc.qt.io/qt-5/linux-deployment.html

Rapidrain

@jsulm there is qjpeg.dll in the imageformats directory but ....
libqjpeg.so is nowhere on my computers.
I have used Qt for years and have countless versions here.
I have never seed libqjpeg.so

jsulm

@Rapidrain Sorry forgot that you're on Windows. qjpeg.dll is what you need.
Try to start your app with QT_DEBUG_PLUGINS environment variable set to 1 (you can add it in QtCreator Run settings of your project).

Rapidrain

@jsulm said in QImage doesn't take in a JPG:

QT_DEBUG_PLUGINS

I'm not using QtCreator

jsulm

@Rapidrain When do it wherever you're developing. If you start your app from a terminal:

QT_DEBUG_PLUGINS=1 && ./my_app

Rapidrain

@jsulm said in QImage doesn't take in a JPG:

QT_DEBUG_PLUGINS=1 && ./my_app

I tried what you suggested, it doesn't help.

jsulm

@Rapidrain Sorry, again forgot that you're on Windows:

set QT_DEBUG_PLUGINS=1
./my_app

Rapidrain

@jsulm said in QImage doesn't take in a JPG:

QT_DEBUG_PLUGINS=1

guess what?
It doesn't help.
Can you suggest a chain of options I must add to g++ when compiling and linking this code?

jsulm

@Rapidrain said in QImage doesn't take in a JPG:

Can you suggest a chain of options I must add to g++ when compiling and linking this code?

As I said before: there is no need to add any options to compiler/linker. The plug-ins are automatically loaded at runtime when needed. You either have some issues with your JPEG plug-in or with the picture you're trying to display. See http://doc.qt.io/qt-5/debug.html
After setting QT_DEBUG_PLUGINS your app should actually output a lot of text. Do you test a debug build?

Rapidrain

@jsulm , What exactly do you mean "do you test a debug build" ???

jsulm

@Rapidrain Did you build your app in debug or release mode?

Rapidrain

@Rapidrain After setting QT_DEBUG_PLUGINS your app should actually output a lot of text. Do you test a debug build?

the statement "set QT_DEBUG_PLUGINS=1" is not a communication with my app. It is a communication with the Windows Operating System. Why should my app output a "lot of text" ?? It hasn't even started yet.

Rapidrain

@jsulm I am building it at the moment in Debug mode

jsulm

@Rapidrain said in QImage doesn't take in a JPG:

It is a communication with the Windows Operating System

wrong, it just sets an environment variable - Windows does not care about it at all. Qt checks this variable at runtime and if it is set it prints debug output while loading plug-ins. That's how environment variable work.

You can see which variables are set executing "set" command on Windows.

Rapidrain

@jsulm so when I set a windows environment variable to a value, I am not communicating with the Windows OS in any way??

jsulm

@Rapidrain It depends on what you mean if you say "Windows OS"? Do you mean Windows NT kernel? Then no, you do not communicate with it. If you consider the shell as part of the OS then you are interacting with the OS, but not communicating as the OS does not care about variables you set - it just sets a variable to a value that's it.

SGaist

Hi,

From the image you posted, your jpeg plugin files are not located in the correct sub-folder.

Charlie_Hdz

@Rapidrain

Any external image should be allocated in Resources.

Please create a resource file in your project. In the resource view... add a prefix "/", and then insert your image.

In your code, use something like the example below, rather that the absolute path.

m_pBackButton->setIcon(QIcon(":/Resources/cancelButton.jpg"));

Thank you.

Rapidrain

It's working with jpegs now. I had reference to a non-existant directory in the link statement.
Sorry Charlie, but doing it with this resources dance makes it all too complicated. Doing baby steps here.
Maybe later.

It wasn't the jpeg plugins.