How do I remove white border around QScrollArea?
I’m trying to edit the source of an app called qcomicbook ( http://qcomicbook.linux-projects.net/ ), to remove an annoying 1px white border which persists in full-screen mode.
First I tried changing the background of the main window black, but it had no effect. Here is the newly compiled app against the designer preview:
I tried also setting some border and margin style information but the white border remained, so I looked at the cpp source, searched the Qt docs, and made a few simple edits, but they had no effect.
At first I thought this would be a quick cosmetic fix, but now I assume the developer could not find the cause.
He has this inside PageViewBase.cpp:
- PageViewBase::PageViewBase(QWidget *parent, int physicalPages, const ViewProperties &props)
- : QScrollArea(parent)
- , m_physicalPages(physicalPages)
- , props(props)
- , smallcursor(NULL)
- context_menu = new QMenu(this);
- connect(&this->props, SIGNAL(changed()), this, SLOT(propsChanged()));
This inside ContinuousPageView.cpp:
- ContinuousPageView::ContinuousPageView(QWidget *parent, int physicalPages, const ViewProperties& props)
- : PageViewBase(parent, physicalPages, props)
- , m_firstVisible(-1)
- , m_firstVisibleOffset(0)
- , m_y1pos(NULL)
- , m_y2pos(NULL)
- // w->setColor(QPalette::Background, Qt::black);
- // adding above line didn't work
- m_layout = new QVBoxLayout(w);
- m_layout->setContentsMargins(0, 0, 0, 0);
- // changing above line didn't change anything
- // track scrollbar range changes to restore its relative position
- connect(verticalScrollBar(), SIGNAL(rangeChanged(int, int)), this, SLOT(scrollbarRangeChanged(int, int)));
And this inside ComicMainWindow.cpp:
- void ComicMainWindow::setupComicImageView()
- const int n = (sink != NULL ? sink->numOfImages() : 0);
- if (view)
- const ViewProperties props;
- if (cfg->continuousScrolling())
- view = new ContinuousPageView(this, n, props);
- view = new SimplePageView(this, n, props);
- connect(actionPageTop, SIGNAL(triggered(bool)), view, SLOT(scrollToTop()));
Well, I’m not sure that’s the only one. QFrame is a QWidget with a border, so I guess that any widget that’d like to be surrounded by a border, can descend directly from QFrame.
Anyway, it’s really strange that your border does not disappear. If you place a QScrollArea on a QWidget with Qt Designer, you can test it by yourself and it works (are you sure it’s a QScrollArea???)
I can just think about two causes:
a) a particular stylesheet is present, and it draws a border. In this case, you should remove it there.
b) it has a custom paint event. It shouldn’t be so difficult to remove any suspicious drawRect inside that method.