keepaspectratio problem

[iswaryasenthilkumar]

am having multiple images each having different aspect ratio am going to display each images one after another for every 10 seconds. the probelm is the images are replacing for every 10 seconds i dont get proper images because images are dfferent in size,and also its showing previous images if current images are small in size i dont get idea to display without replacing.
my codes are below

QImage ImageToLoad;
ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
QLabel *label = new QLabel(this);
label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
label->show();

QImage ImageToLoad;
ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
QLabel *label = new QLabel(this);
label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
label->show();

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i need if the previous displayed images are big and if the current images are small while displaying i should not see previous image while current image displaying
Please guide me to rectify this problem
Thanks in advance

[anda_skoa]

Your code does not show how you delete the label of the previous image.

Which brings us to the question: why do you have a new label for each image if you want to only show one at a time?

Cheers,
_

[iswaryasenthilkumar]

when am keeping single label for each images my program has stopped not executing,,as you said now am checking to delete previous label

Your code does not show how you delete the label of the previous image.

Which brings us to the question: why do you have a new label for each image if you want to only show one at a time?

Cheers,
_

[anda_skoa]

when am keeping single label for each images my program has stopped not executing

What does that mean?
That should work without any problem.

Cheers,
_

[iswaryasenthilkumar]

i declared Qlabel *label in widget.h ,,i used this label to upload images using pixmap but my program stopped i getting this message
" this program unexpectedly finished"

[yeye_olive]

i declared Qlabel *label in widget.h ,,i used this label to upload images using pixmap but my program stopped i getting this message
" this program unexpectedly finished"

The reason for that is most likely completely orthogonal to the choice between 1 or many instances of QLabel. Have you run the code through a debugger? What results did you get? Please post the non-working code.

[iswaryasenthilkumar]

i getting same error olive

The program has unexpectedly finished.

The program has unexpectedly finished.

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my code below

void Widget::displayimages()
{
 
    ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
    label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
    label->show();
 
}

void Widget::displayimages()
{
  
    ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
    label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
    label->show();

}

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as per anda_skoa said i used label->deletelater to delete label while am using in code i cant able to see images.how to delete previous images please give me suggestion for this

The reason for that is most likely completely orthogonal to the choice between 1 or many instances of QLabel. Have you run the code through a debugger? What results did you get? Please post the non-working code.

[wysota]

as per anda_skoa said i used label->deletelater to delete label while am using in code i cant able to see images.how to delete previous images please give me suggestion for this

If you delete the label then it is not valid anymore so if you try to access it afterwards, your program crashes.

[iswaryasenthilkumar]

my problem is i can able to see the previous images if current image was small ,i want to display like slideshow as per imagesaspect ratio,i should not see the previous images while current images are displaying

If you delete the label then it is not valid anymore so if you try to access it afterwards, your program crashes.

[wysota]

Again, reuse an existing label instead of creating a new one for each image.

[iswaryasenthilkumar]

i cant see the images

Widget.h
QLabel *label;

Widget.h
QLabel *label;

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widget.cpp
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
  label = new QLabel(this);
}

widget.cpp
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
  label = new QLabel(this);
}

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void Widget::displayimages()
    {
 
    ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
    label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
    label->show();
 
    }

void Widget::displayimages()
    {
     
    ImageToLoad.load(dir.absoluteFilePath(dirList.value(localimage)));
    label->setPixmap(QPixmap::fromImage(ImageToLoad.scaled( 1025,1025,Qt::KeepAspectRatio)));
    label->show();
     
    }

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[/code]
as you said i reusing the label bt i cant see the images

Again, reuse an existing label instead of creating a new one for each image.

[yeye_olive]

I once solved a similar problem: display images with various aspect ratios centered in a widget, change the image without completely messing up the layout. I vaguely remember -- but I may have overlooked something, and/or the situation might have changed since then -- that QLabel on its own was not the ideal solution. I ended up implementing two perfectly working solutions:

1. a custom widget which would scale, position, and paint the image like I needed;
2. a general-purpose layout manager that would scale and position the widgets inside it while respecting their preferred aspect ratio, in which I would put a QLabel displaying the image.

Solution 1 is faster to implement, but also less reusable.

[anda_skoa]

i declared Qlabel *label in widget.h ,,i used this label to upload images using pixmap but my program stopped i getting this message
" this program unexpectedly finished"

Are you actually creating an instance for this pointer?
You code snippet in the first posting looks like you are creating a local instance, not using the member.

Cheers,
_

[iswaryasenthilkumar]

can you give some example i know am doing wrong please give some example how to rectify this problem

Are you actually creating an instance for this pointer?
You code snippet in the first posting looks like you are creating a local instance, not using the member.

Cheers,
_

[anda_skoa]

You latest code snippet looks reasonably OK, though the label is not part of any layout.
Why don't you just add the label in designer instead of adding it later on in code?

Cheers,
_

[iswaryasenthilkumar]

my task is want to create label through code,,and also i rectified the problem,thank you so much
my code

widget.cpp
    Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
    {
    label = new QLabel;
    }

widget.cpp
    Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
    {
    label = new QLabel;
    }

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but some issues in there,,first 3 images are displayed in one label after again new label arrising in that few images displaying in this label i cant able to see my images like slideshow..whats wrong in my code

You latest code snippet looks reasonably OK, though the label is not part of any layout.
Why don't you just add the label in designer instead of adding it later on in code?

Cheers,
_

[wysota]

Which code?

[iswaryasenthilkumar]

nw my code executing ,,using single label to display multiple images,,but my label was not fit to widget,how to fit my label to widget,,??

[wysota]

Put it in a layout.

[yeye_olive]

nw my code executing ,,using single label to display multiple images,,but my label was not fit to widget,how to fit my label to widget,,??

That is what layout managers are for. anda_skoa already remarked in this thread that you created QLabel without putting them in layouts.