@kumararajas said in QWebView - On Click CPU Performance:

Thank you @Konstantin-Tokarev This explanation means a lot. This helps us to understand that we are using older version of Qt WebKit and which is not really efficient.
At this moment of time, we don't have a plan to update to the latest version. We will have to find a work around in the application to manage the situation.

Does it mean that you cannot change any bits of software in your system and you are limited to workarounds on the side of web page? If so, it's really sad situation.

If you are able to change software, you are strongly adviced to use QtWebKit 2.3.4, or at least give it a try.

@kumararajas said in QWebView - On Click CPU Performance:

@Konstantin-Tokarev Yes, we have been trying to understand who consumes the lot of CPU and why. When I did profiling using gprof/perf tools, I can find out that which function in my application consumes a lot, but that does not root in to the framework, which is webkit. Do you recommend any method which I can profile the framework side as well?

Don't use gprof. This tool claims to measure time spent in functions, but in fact measures totally different thing. And, as you've already discovered, it can only profile code which was rebuilt with -pg flag.

As for perf, it is decent tool. On older systems oprofile can be used. Make sure that your QtWebKit library is not stripped

And even if we find issues in the framework, at this moment we are not in a position to upgrade the system. So we will identify the work around and live with it ( Already found couple of work around solution, which I will be sharing it in a while here )

I have no idea what do you mean here, and I don't really want to be in your shoes. (/me once had to reverse engineer and then binary patch 3rd party kernel driver with no source code, but at least there were no problems with updating target system)

Reason for asking such question is,
Someone might have faced similar problem and might have the ready solution. Instead of I spending lot of time in exploring, researching, debugging, etc, I could post it here to know if someone knows about it. However, in parallel to posting this question, I have been doing things in parallel if in case I don't get the answer. For this post, you being a legend on webkit, you have mentioned that it could be a problem of webkit version that we use, which makes sense and unveils the root cause.

I'm far from being legend, and there may be other reasons of high CPU consumptions, maybe several factors at once. It can be that WebKit just doesn't have enough memory to process page, and system is thrashing (you'll see high sys usage in top then).

When I touch the report, does Qt Web Kit renders the whole web page again?

If you are not using QWebSettings::TiledBackingStoreEnabled and are not using accelerated composting on QGLWidget viewport, and are not using QWebPage::setPreferredContentsSize, then QtWebKit definitely reners whole page again after scroll. It doesn't redraw old pixel, but it performs whole rendering procedure with QPainter being clipped to update region. It may easily be a bottleneck if page is complex

@Johnx8664 Learning Qt4 at this point would be a waste of your time. Like @SGaist said it's long past it's end of life. Qt5 is 12 major releases into it's life cycle now and 5 years old now.

I would grab a book on Qt5, or I find it's pretty easy to learn Qt just from the docs that come with it. If you know C++ well (and you should if you are tackling Qt), then you should be fine learning from the Qt Assistant docs. There are a lot of examples and tutorials in there as well.

@Devopia53
it works! , Thanks alot

@Thanos

thanks for your feedback.

So please mark this topic as SOLVED now.

Don't @ the moderators unless you have an issue requiring moderation.

Depending on the content of your line edit, you can use toLatin1() or toUtf8() rather than making these two conversions.

Hi
I just keep a pointer to the "white lines" and adjust if i move yellow.

class ColorItem : public QGraphicsItem { .. ConnectorLine* line = nullptr; .. protected: QVariant itemChange(GraphicsItemChange change, const QVariant& value) override { if (change == ItemPositionChange && scene()) { if (line) { line->adjust(); } } return QGraphicsItem::itemChange(change, value); } private: QColor color; };

line->Adjust() alters its endpoints. You could just adjust it directly here.

@srikanth
https://stackoverflow.com/questions/19575747/error-lnk2038-mismatch-detected-for-msc-ver-value-1600-doesnt-match-valu

and others like https://stackoverflow.com/questions/14692019/linking-error-because-of-different-versions-msvc-and-qt-libraries

@ShivaHaze
@ShivaHaze said in 'evaluateJavaScript()' doesn't return any value. (content position on page wanted):

You are a god to me - Thanks so much!

I think you might have meant "good" rather than "god" ;-)

I am very pleased this approach has worked for you. It is potentially useful for me to know for my own work one day. Had I realized you had not tried the "delay" principle earlier, we would have got there quicker.

The actual implementation of the delay loop is "naughty". It will mean that your application is "running busily" (i.e. using CPU time, potentially blocking other applications) for most of 1 second. If an expert here looks at it, please don't shout at me! Like I said, I got it from elsewhere as "quick & dirty". For your purposes it's probably fine, and we achieved it without you having to do slots & signals which you were not keen on learning at this stage.

If you feel like you want to improve/experiment, in the same stackoverflow thread have a look at https://stackoverflow.com/a/3756341/489865, leveraging QWaitCondition, whose description sounds like it should have the same effect without the "busy blocking":

class SleepSimulator{ QMutex localMutex; QWaitCondition sleepSimulator; public: SleepSimulator::SleepSimulator() { localMutex.lock(); } void sleep(unsigned long sleepMS) { sleepSimulator.wait(&localMutex, sleepMS); } void CancelSleep() { sleepSimulator.wakeAll(); } };

Certainly I would try it. If you copied that class into your code, you would call it (I assume) via:

SleepSimulator* sleep = new SleepSimulator(); sleep->sleep(1000); delete sleep;

Now I think you can get down to the real coding you want to do for your application! Best of luck.

@raven-worx

Great, it works.

Actually I did try setting QTabWidget setAutoFillBackground(True) previously, but it didn't work.
Now I tried set VGroupBox setAutoFillBackground(True), then the color changed to light grey which is the exact default color I need.

Thanks so much, raven-worx.

It would be nice to say what self and event are. I'm guessing a QGraphicsItem and a parameter of QGraphicsSceneMouseEvent? Is that right?

If so then event.pos() and event.scenePos() are not exchangeable. The first one is cursor position in item's coordinates and the second one cursor position in scene coordinates. They are the same only when item is placed at (0,0). If item is moved they will differ. It's important to note that these values are what they were at the time the event took place, which might be different from the "current" values for item (this is a good thing). For example if you move your mouse fast and there are a lot of events generated the cursor position in these events will be a little behind the actual current position of the cursor before they "catch up".

As for self.scenePos() - this is the position of the item in the scene. This is the point relative to which the event.pos() is calculated. It is not necessary the top left of the bounding rect. It can be placed anywhere using 'setTransformOriginPoint()'. It is often set to the center of the item. For example if you have a bunch of draggable circles a center is probably more convenient than a top left corner. For vertical bars on a chart the origin might be placed at the middle bottom of a bar etc.

@Asperamanca

No, I didn't set these two flags ItemClipsToShape, ItemClipsChildrenToShape.

Then I tried setting only one flag ItemClipsToShape, and both of ItemClipsToShape, ItemClipsChildrenToShape. For each, it still check if the point is in the boundingrect() firstly, and then check the shape() which means if point is not in boundingrect(), it wouldn't bother to check shape().

So now my solution is still enlarging the boundingrect() area.

You're welcome !

Since you have it working now, please mark that thread as solved using the "Topic Tools" button so that other forum users may know a solution has been found :)

@joeQ As it turns out, I just tried the opposite. I had one newed Message Box for everything. In the place that had the funny location, I made a separate newed Message Box and it ended up in the correct place - the middle of its parent.

@DougyDrumz Open the dialog without this information. Then in a separate thread (so you don't lock things up) get the info you need and populate the dialog once the info is available.

The way I would do that is just show a loading widget of some sort while it loads the info, then once loaded, show the real widgets on the dialog. You can use QStackedWidget to make this easy.

Another way is don't use dialogs. Modern applications rarely use them any more, except for things like File->Open.

@DougyDrumz said in Can't Cancel Progress Dialog.:

OK. I found it. I was being dumb! I have two flavors of Progress Dialogs. One is inside an App, and the other is standalone, meant to be called form a script. I was looking at the one in the App when I should have been looking at the other one. The standalone one doesn't have have a cancel slot.

Good !

:D
I haven't had much time to test if the bug exists in Qt5. I'll check it out and update the topic accordingly. If the bug is still there, of course, I will submit the fix.

Thanks for your time.

Hi
Just as a note.
No (dropdown) menus I have ever used can be triggered by right clicking. ( some offer properties this way)
so can I ask why you need that?

difference between exec() and show(),
Only QDialog have exec() Qwidgets have show.
When you call show on a Dialog, it becomes visible but do not
wait for input.
example mainw::func() { MyDialog *dia=new MyDialog(this); dia->show(); int a=0; // this code is run the moment dialog is shown on screen, } using exec() mainw::func() { MyDialog dia; dia.exec(); int a=0; // this code is run only after dialog is dismissed. }

The version of dialog where u call show() could be called floating so when user click ok
it should emit signal that something should happen. ( to maiwindow )

The exec() version will report back the result ok/cancel/closed at once.

learn when to use QObject, QWidget, QFrame
QWidget is often used if making own widget. QFrame is used if you just need something to draw
a frame. If you use Designer you can check out the Widgets that are available.
QDialog is useful for any type of windows that pop ups up or open via a menu.

I have to set anything inside Register.
Yes, Register should be able to give the data back.
the widgets inside are private so you need a function to return the data.
You might also need to call
http://doc.qt.io/qt-5/qdialog.html#accept
in your Register buttons clicked slot.

Why Qt 4.8.6 and not the latest Qt 4.8.7 ?
I've compiled Qt 4.8.7 with VS2010, VS2013 and VS2015, in 32 and 64 bits, here's my steps:
https://github.com/sandym/qt-patches/tree/master/windows/qt-4.8.7

@sachin786

it print garbage for hex[ ]......

What do you expect to be printed exactly? The data is binary so any of the elements that can't be displayed will be printed as gibberish ... 0x01, 0x00 are non-printable characters, so you'd see (depending on the platform) squares or other strange symbols, this doesn't necessarily mean the data is corrupted, only that it's interpreted in a erroneous way.

I figured it out. You can't call the connect statement for the doubleClick signal until the QListView is in scope.

@DougyDrumz
Easy peasy ... no one seems to want to answer my questions though. ;)
Happy coding!

Hi,

IIRC, that's part of the GNOME Human Interface Guidelines so there's no much you can do from a Qt point of view.

Let me tone down this discussion by saying that the original reason for my question has disappeared. I misunderstood how QPrinter worked. I thought I would need the string versions of the QPrintDialog enums to pass on to lp. Turns out QPrinter does what I need to do automatically and I don't need to call lp. Thanks for the lively discussion though.

Good !

Since you have it working now please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)

Hi and welcome to devnet,

Did you double check the that sudo apt-get install qtcreator ran successfully ?

Hi,

You have to port the CMakeLists.txt for Qt 5. You have the CMake Manual in Qt's documentation to help you get started.

Hi,

You can try implementing a QStyledDelegateItem and paint only the icon.

Hope it helps

Which border are you referring to ?

Can you post an image of how you would like your QTabBar to look exactly ?

@DougyDrumz
Well it would be nice if one could just grab and drag to size them.
maybe in 6.5 :)

Did you generate the Xcode project using qmake ?

The problem is solved,

The problem was caused by the difference between Qt SDK compiler and application compiler !

I recompiled the src of qt sdk with the compiler used to my program and now it work !
thanx,

One alternative might be to implement a QAbstractTextDocumentLayout