I am trying to control multiple items animation by using QGraphicsItemAnimation. For my understanding of QGraphicsItemAnimation, i shall have a QTimeline and several QGraphicsItems which control by QGraphicsItemAnimation.
At first, i did not use the QGraphicsItemAnimation, but only QTimeline, and connect QTimeline and QGraphicsItem.
Like this:
connect(timeLine, SIGNAL(valueChanged(qreal)), graphicsItem, SLOT(scale(qreal)));
void GraphicsItem::scale(qreal value)
{
setTransform(QTransform()
.translate(mZoomFactor.x(), mZoomFactor.y())
.scale(value + 1, value + 1)
.translate(-mZoomFactor.x(), -mZoomFactor.y()));
}
But using this way make the animation look like lose frame.
So i referred the Qt example, however QGraphicsItemAnimation do not provide such function like setTransformAt() or setOpacityAt(). Is there any Qt example for complex animation?
Related
I'm a student programmer currently developing an application for work using Qt4. I am building an equation editor and I'm having issues attempting to highlight a string within my QTextEdit field. I have a function that parses through the QTextEdit string and returns an a start and end integer of where an error is located. My original strategy was to use HTML tags at these two points to highlight the error. Unfortunately there appears to be an issue with html tagging and the equation syntax.
What I think I need is a strategy that relies on Qt's library to set a background color between these two indices. I began looking a QSyntaxHighlighter; however I think that this is more for highlighting using a predefined set of laws and not for just grabbing up anything between a & b and setting the background color. If I can use syntax highlighter please provide me with and example or reference as I have already read through the documentation and didn't find anything.
Thanks for any help in advance!
P.S. Just to emphasize on the html compatibility issues; html becomes problematic due to multiple < and > signs used.
You can use QTextCursor and QTextCharFormat for it:
QTextEdit *edit = new QTextEdit;
...
int begin = ...
int end = ...
...
QTextCharFormat fmt;
fmt.setBackground(Qt::yellow);
QTextCursor cursor(edit->document());
cursor.setPosition(begin, QTextCursor::MoveAnchor);
cursor.setPosition(end, QTextCursor::KeepAnchor);
cursor.setCharFormat(fmt);
Is there a way to find out the filename of a QPixmap? My intention was to test which pixmap is currently set.
I've tried Squish to find out any properties, but I've get only access to some stuff like width, height etc
I assume that while you writing a test you already know which image you want to see. You can convert QPixmap to QImage and check if it contains the same image as expected:
bool same = QImage(filename) == pixmap.toImage();
It's not efficient but should be ok for testing purposes.
I try to test drag&drop with simple sequince: mousePress + mouseMove + mouseRelease. But it's not work.
I investigate qtest source and found, that move event tested through main dispatcher processEvent(). Also I found some bugs in qt bug-tracker: 1, 2
So, I think, that it's not possible to test drag&drop under latest stable Qt4. Have anybody success story with this?
I have had no luck simulating drag and drop via the QTest mouse functions, and digia says
they're not adding that functionality to QT4. I implemented drag/drop testing via a method similar to the one suggested in the above link:
create your mime_data, something like:
mime_data = widget_model.mimeData(indexes)
or
mime_data = QMimeData()
mime_data.setText(widget.text())
then use a function like this to drop the data:
def dropOnto(self, widget, mime_data):
action = Qt.CopyAction|Qt.MoveAction
pt = widget.rect().center()
drag_drop = QDropEvent(pt, action, mime_data, Qt.LeftButton, Qt.NoModifier)
drag_drop.acceptProposedAction()
widget.dropEvent(drag_drop)
mouseMoveEvent() handler starts and blocks at QDrag.exec(). In order to simulate the drop, you have to schedule it e.g. with QTimer:
def complete_qdrag_exec():
QTest.mouseMove(drop_target)
QTest.qWait(50)
QTest.mouseClick(drop_target, Qt.MouseButton.LeftButton)
QTimer.singleShot(1000, complete_qdrag_exec)
QTest.mousePress(drag_source, Qt.MouseButton.LeftButton, Qt.KeyboardModifier.NoModifier, QPoint(10, 10))
QTest.mouseMove(drag_source, QPoint(50, 50)) # Ensure distance sufficient for DND start threshol
I have a GUI application whose main part is a QPlainTextEdit. It is used to display a log of the application, and as such the associated text grows line by line ad infinitum.
As the application is intended to run very long, I need to limit the memory that will be allocated for this log. Therefore I want to have some maxNumLines or maxNumCharacters parameter that will make sure the history will be truncated when reached, i.e. the head lines will be removed as new lines are appended (a.k.a. log rotation).
To achieve this I found the functions
// get the associated text
QString toPlainText () const
// set the associated text
void setPlainText ( const QString & text )
Therefore something like this untested code would probably do the trick:
QString &tmp = pte.toPlainText();
while (tmp.size() > maxNumCharacters) {
// remove lines from the head of the string until the desired size is reached
// removes nothing if "\n" could not be found
tmp.remove(0, tmp.indexOf("\n")+1);
}
pte.setPlainText( tmp );
Is this the way to go to remove the first line(s) from the QPlainTextEdit? Are there probably other Qt Text GUI elements that would better fit to this task (set a maximum number of lines and truncate at the head of the list), e.g. somehow display a QStringList in which I could store the lines (s.t. I could easily erase(0))?
Or does the QPlainTextEdit eventually implement such upper bound for the size of the associated QString after all?
Apparantly the property maximumBlockCount is exactly what I need:
If you want to limit the total number of paragraphs in a QPlainTextEdit, as it is for example useful in a log viewer, then you can use the maximumBlockCount property. The combination of setMaximumBlockCount() and appendPlainText() turns QPlainTextEdit into an efficient viewer for log text.
For reference:
http://doc.qt.io/qt-5/qplaintextedit.html#maximumBlockCount-prop
I had exactly the same problem a months back, and I ended up using a QListView. Although using the model/view/delegate architecture is a bit more fiddly, it scales much better in the long run. For example once the basic architecture is in place, adding a filter that displays only error or warning entries becomes trivial, or creating a delegate so that the background of error entries are painted red is also straightforward.
I have some code creating a QTabWidget from Python using PyQt4. I want to get a 'throbber' animated gif in the tab. The /only way/ I have found how to do this is the following convoluted method.
tabBar = self.tabReports.tabBar()
lbl = QtGui.QLabel(self.tabReports)
movie = QtGui.QMovie(os.path.join(self.basedir, "images\\throbber.gif"))
lbl.setMovie(movie)
QtCore.QObject.connect(movie, QtCore.SIGNAL("frameChanged(int)"), lambda i: movie.jumpToFrame(i))
movie.start()
log.debug("valid = %s"%(movie.isValid()))
tabBar.setTabButton(idxtab, QtGui.QTabBar.LeftSide, lbl)
The debugging call always returns true, but the throbber sometimes works, sometimes is blank, and sometimes has a large ugly delay between frames. In particular, I can't help but think connecting the frameChanged signal from the movie to a function that simply calls jumpToFrame on the same movie is not correct.
Even more distressing, if I simply drop the lambda (That is, make the line say QtCore.QObject.connect(movie, QtCore.SIGNAL("frameChanged(int)"), movie.jumpToFrame) it never renders even the first frame.
So, what am I doing wrong?
PS: I realize .tabBar() is a protected member, but I assumed (apparently correctly) that PyQt unprotects protected members :). I'm new to Qt, and i'd rather not subclass QTabWidget if I can help it.
I believe the problem with the code I initially posted was that the QMovie didn't have a parent, and thus scoping issues allowed the underlying C++ issue to be destroyed. It is also possible I had had threading issues - threading.thread and QThread do not play nice together. The working code I have now is below - no messing with signals nor slots needed.
def animateTab(self, tab_widget, enable):
tw = tab_widget
tabBar = tw.tabBar()
if enable:
lbl = QtGui.QLabel(tw)
movie = QtGui.QMovie("images\\throbber.gif"), parent=lbl)
movie.setScaledSize(QtCore.QSize(16, 16))
lbl.setMovie(movie)
movie.start()
else:
lbl = QtGui.QLabel(tw)
lbl.setMinimumSize(QtCore.QSize(16, 16))
tabBar.setTabButton(tab_section.index, QtGui.QTabBar.LeftSide, lbl)
I faced the same problem and this posting helped to make it work:
http://www.daniweb.com/forums/printthread.php?t=191210&pp=40
For me this seems to make the difference: QMovie("image.gif", QByteArray(), self)