QLabel showing an image inside a QScrollArea
image, qlabel, qscrollarea, qt, scrollbar
Solution
I know this is an old post - but in case you or anyone is still having a problem, it might help to set `QScrollArea::widgetResizable` to false.
At least, when I tried a similar thing, my vertical scrollbar was always disabled (even though I set the size of the scrollable widget to have a height larger than the viewport) until I set this to false.
When it's true, I think it updates the size of the scrollable widget, thus the scrollbars should not be needed. This allows you to do what it does in the example I guess, and implement a stretch-to-fit function. (actually what I'm trying to do is fit to width, with just a vertical scroll bar)
Problem
I've successfully implemented a Image Viewer (for DICOM) in Qt. I can see the image and I can zoom in and out correctly. Now, I want to see scroll bars if the image is too big to show when I zoom in. I've used the UI. I placed a QScrollArea. Inside, the QLabel. The verticalScrollBarPolicy is ScrollBarAsNeeded. The horizontalScrollBarPolicy is ScrollBarAsNeeded. The problem is: it doesn't work. I zoom in, but no scrollbar appears. Second try: using a layout inside the QScrollArea. So now there's a QWidget between the QScrollArea and the QLabel: a horizontal layout. Opened the same image, now I can see a vertical scroll bar on the right. The image is streched from left to right. When I zoom the image gets its correct proportion. BUT... I zoom out and the scroll bar is the same, even if I can see the whole image. The horizontal scroll bar never appears. Resizing the QLabel doesn't seem to affect. But if I resize the QScrollArea (resizing the main window) the horizontal scroll bar appears. I've been checking some numbers: In the QScrollArea - Its size changes: below 599 width (why this number? I can't see it anywhere) the horizontal bar appears. - sizeHint() always returns the same values: 33x41 In the QLabel - The dimensions change, but that doesn't affect. - sizeHint() always returns the same values: 560x1558 Here is the code in XML from the UI designer: ``` <widget class="QWidget" name="centralWidget"> <property name="autoFillBackground"> <bool>false</bool> </property> <layout class="QVBoxLayout" name="verticalLayout"> <property name="margin"> <number>0</number> </property> <item> <widget class="QScrollArea" name="scrollArea"> <property name="widgetResizable"> <bool>true</bool> </property> <property name="alignment"> <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignTop</set> </property> <widget class="QWidget" name="scrollAreaWidgetContents"> <property name="geometry"> <rect> <x>0</x> <y>0</y> <width>637</width> <height>649</height> </rect> </property> <layout class="QHBoxLayout" name="horizontalLayout_2"> <item> <widget class="QLabel" name="miImagen"> <property name="sizePolicy"> <sizepolicy hsizetype="Preferred" vsizetype="Preferred"> <horstretch>0</horstretch> <verstretch>0</verstretch> </sizepolicy> </property> <property name="autoFillBackground"> <bool>true</bool> </property> <property name="scaledContents"> <bool>true</bool> </property> <property name="alignment"> <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignTop</set> </property> </widget> </item> </layout> </widget> </widget> </item> </layout> </widget> ``` What am I missing? Thank you.