Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Have you tried following <a href="http://doc.qt.io/qt-5/qtwidgets-widgets-imageviewer-example.html" rel="nofollow">Qt's scroll area example</a>? If you're using a QLabel to display your image, then the use of QScrollArea is pretty much the standard way of achieving what you want. You use it like so (from the example):</p> <pre><code> imageLabel = new QLabel; imageLabel-&gt;setBackgroundRole(QPalette::Base); imageLabel-&gt;setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored); imageLabel-&gt;setScaledContents(true); scrollArea = new QScrollArea; scrollArea-&gt;setBackgroundRole(QPalette::Dark); scrollArea-&gt;setWidget(imageLabel); setCentralWidget(scrollArea); </code></pre> <p>Then zooming is handled like so:</p> <pre><code> void ImageViewer::zoomIn() { scaleImage(1.25); } void ImageViewer::zoomOut() { scaleImage(0.8); } void ImageViewer::scaleImage(double factor) { Q_ASSERT(imageLabel-&gt;pixmap()); scaleFactor *= factor; imageLabel-&gt;resize(scaleFactor * imageLabel-&gt;pixmap()-&gt;size()); adjustScrollBar(scrollArea-&gt;horizontalScrollBar(), factor); adjustScrollBar(scrollArea-&gt;verticalScrollBar(), factor); zoomInAct-&gt;setEnabled(scaleFactor &lt; 3.0); zoomOutAct-&gt;setEnabled(scaleFactor &gt; 0.333); } void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor) { scrollBar-&gt;setValue(int(factor * scrollBar-&gt;value() + ((factor - 1) * scrollBar-&gt;pageStep()/2))); } </code></pre> <p>You can, of course, get a better idea of what's going on by looking at the example, but that's the gist of it. I think perhaps the adjustScrollBar() function might be the most helpful thing for you.</p> <p>Your last comment on the original post is correct, the QScrollArea doesn't magically notice the change in size of its contents. Look at how the example uses adjustScrollBar() to compensate for this fact.</p>
    singulars
    1. This table or related slice is empty.
    1. POQLabel showing an image inside a QScrollArea
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USAndreas Haferburg
    1. USEli Hooten
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COIn fact, this Qt example is the one I'm using to do my application. I have those functions implemented. The bars don't appear. The only difference is that, in XML version, I you can't implement scrollArea->setWidget(imageLabel) and setCentralWidget(scrollArea) sentences. I guess the first one is like dragging the imageLabel inside the scrollarea. I tried the second one, and the application crushes.
      singulars
      1. PO
      1. USMark Green
    2. COWell, I detected the error, but I don't know why is that: scrollArea->horizontalScrollBar()->setValue() doesn't do anything. The value passed to setValue is negative or positive, always different, but the value of both scrollbars is still 0. Always! :(
      singulars
      1. PO
      1. USMark Green
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload