Dynamically created buttons and connecting signal to slot

[Kris Revi]

@JonB ooh noo... lambda in C++ is a pain compared to python version :|

btw i'll switch to the new connect()

[JonB]

@Kris-Revi
I have just appended some reference links for the lambda stuff to my previous post.

[Kris Revi]

@JonB so i got it working

connect(button, &QPushButton::clicked, [=]() { selectedImageDisplay("./Matrix Images/32 x 32/" + filename); });

having 1 problem tho

void MainWindow::selectedImageDisplay(QString img)
{
    imageObject = new QImage();           // Make a new imageObject
    imageObject->load(img);          // Load the image from path

    QJsonArray RGB565;
    for(int y = 0; y < imageObject->height(); y++) {
        const quint16 *line = reinterpret_cast<const quint16*>(imageObject->constScanLine(y));
        for(int x = 0; x < imageObject->width(); x++)
            RGB565 << *(line++);
    }

    socket.sendCommandStrip(QString("pixArt"), RGB565);
}

when it gets sent to the Matrix the pixels are out of order and the colors are way off for some reason :S can you spot why? cause i cant :S

[JonB]

@Kris-Revi
I believe you got that loop-packing code from @Bonnie in another thread, so he can come and sort it out ;-)

While you wait for him/inspiration, do some debugging yourself: look at the first so-many byte values sent, compare against the values of those received, is there a difference-pattern? Do you even end up with same number received as sent? Your problem might be in retrieving them, packing/unpacking them, or JSONifying them.

[P.S. You had a QSignalMapper earlier: if you're going to go down lambda route (much more powerful) you can probably get rid of that.]

[Kris Revi]

@JonB that's true! i googled and got som sugestion for my problem but yea! :) removed now!

[Kris Revi]

@JonB i fixed it! so i mentioned that the colors was off and pixel order so i thought why not just try

*imageObject = imageObject->convertToFormat(QImage::Format_RGB16);

and that was the problem :) even if i saved the image as RGB16 upen uploading it and converting it it was not saved as RGB16 apparently

[Christian Ehrlicher]

@Kris-Revi said in Dynamically created buttons and connecting signal to slot:

imageObject = new QImage();

You leak this image object. Better create it on the stack.

[Kris Revi]

@Christian-Ehrlicher leak? stack what now?

[JonB]

@Kris-Revi
"leak" means the memory used by your new QImage() is never returned to the pool. Either delete it at the end, or @Christian-Ehrlicher is suggesting easiest is make it a QImage imageObject; variable here, which means it is on the "stack" (instead of the "heap" for newed objects). Then it gets thrown away at end of the method for sure.

[Kris Revi]

@JonB so make a QImage imageObject; not imageObject = new QImage() ?,

[mrjj]

@Kris-Revi
Yes exactly.