QLabel snap to ScrollBar

jsulm

@Mikeeeeee said in QLabel snap to ScrollBar:

How do I know the visible coordinates of an Image?

What do you mean?
What are "visible coordinates" and relative to what do you want to have them?
Do you mean you want to know which part of displayed image is visible?

Mikeeeeee

Yes. For example, I see the Central 50% of the image? How do I know I'm seeing an image from 25% to 75%?

Mikeeeeee

Partially solve. But regardless of the scrollbar state, pageStep() returns a single value

qDebug()<<scrollArea->horizontalScrollBar()->value()
<<scrollArea->horizontalScrollBar()->maximum()
<<scrollArea->horizontalScrollBar()->minimum()
<<scrollArea->horizontalScrollBar()->pageStep();

mrjj

@Mikeeeeee said in QLabel snap to ScrollBar:

pageStep

But it is a single step value. how much to scroll for a page.
What do you need it for ?

Mikeeeeee

I wanted to know the width of the scroll and scrollbar and calculate the visible part.

Mikeeeeee

Need to know the size of the scroll and its position and determine.
Scroll size = (widget size/picture size)/zoom

Mikeeeeee

How can I remove the menu bar? If I remove createActions(); from the constructor, the program does not start.

mrjj

Hi
If i do
// createActions();
it starts fine.
Please provide more details.

Mikeeeeee

The compiler writes that the program closed abnormally. Debagger says he received a signal from the operating system: SIGSEGV , destination: Segmentation fault

Mikeeeeee

If you want, I can send you the project

mrjj

hi
I think its something else than createActions();
Use the debugger to find the line where it crashes.

Mikeeeeee

error in qaction.cpp

void QAction::setEnabled(bool b)
{
    Q_D(QAction);
    if (b == d->enabled && b != d->forceDisabled)
        return;
    d->forceDisabled = !b;
    if (b && (!d->visible || (d->group && !d->group->isEnabled())))
        return;
    QAPP_CHECK("setEnabled");
    d->enabled = b;
#ifndef QT_NO_SHORTCUT
    d->setShortcutEnabled(b, qApp->d_func()->shortcutMap);  //here
#endif
    d->sendDataChanged();
}

Mikeeeeee

This post is deleted!

Mikeeeeee

I commented out all QAction and the program starts, but the picture at start is not loaded. But you need to change the zoom level to display the picture. Please tell me how to fix it.

mrjj

@Mikeeeeee

hi
I think it would be better to call
createActions();
and simply do

menuBar()->hide();

so its not shown.

That way you dont get issues with dangling pointers in the program.

Mikeeeeee

@mrjj said in QLabel snap to ScrollBar:

menuBar()->hide();

it works, thank you!