Re: [Interest] To QML or not to QML...
Jason wrote on Wednesday, 7 March 2012 6:01 AM > My own experiments in QML have leave me to believe that aside from it's > limitations (there are many) that most everything "visual" and not classically > widget-oriented is made substantially easier. > If it's 'hard" in QML you're probably doing it wrong, unless it's a QML > limitation. Hi Jason, I have some problems with the QAbstractTreeView: - I want each tree item to visually own its children - eg, when an item is selected the background of all its children changes as well. - I want to change the drop indicator to provide more options. I assume changing the widget would be too tedious. I'm deciding whether to starting the project in QML or GraphicsView. Can you elaborate on the limitations that you have found in QML? That might save me grief later on. Thanks! Tony. ___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
Re: [Interest] To QML or not to QML...
My own experiments in QML have leave me to believe that aside from it's limitations (there are many) that most everything "visual" and not classically widget-oriented is made substantially easier. If it's 'hard" in QML you're probably doing it wrong, unless it's a QML limitation. - Original Message - From: BRM To: Interests Qt Cc: Sent: Tuesday, March 6, 2012 12:26 PM Subject: Re: [Interest] To QML or not to QML... > From: Preet >On Mon, Mar 5, 2012 at 12:54 PM, Jason H wrote: >> It is my understanding that the major differences between 4 and 5 are that 5 >> assumes (and requires) a hardware GL implementation (scenegraph), where 4 >> does not. > >I was under the impression that the legacy QtQuick 1 stuff would be >available in Qt5 as is with software rasterization under the existing >'QDeclarative' classes/module. The QtQuick 2 stuff all seems to be >under the 'QQuick' module. Yes, there's a bunch of renaming going on, and such from what I can tell on the development list; but I haven't paid too much attention to the QML side of things. >>In terms of your coding, his largely comes down to the import >> statements that are used. >> From: BRM >> To: Interests Qt >> Sent: Monday, March 5, 2012 12:39 PM >> Subject: [Interest] To QML or not to QML... >> >> I'm working on an application that presently uses Qt 4.7 for a front-end to >> a larger system. One of its main tasks is to display data in the system >> which requires rendering up to around a thousand or so points and overlaying >> a template of the ideal against the actual. Presently it does all the work >> in a custom QWidget class and implements the drawing in >> QWidget::paintEvent(QPaintEvent *event). However, I am getting ready to do a >> major rewrite of this functionality - namely I want to add some text labels, >> values, and lines for some of the measurements related to it, and am trying >> to determine the best possible path of two that are available. >> >> No matter what I do, there will be some major rework to my application as >> things are just changing a lot to do the new functionality I am seeking >> (can't be helped). >> >> The below are the options I am aware of: >> >> >> 1. Rework the painting to be done to a QImage/QPixMap/etc, and then use >> QGraphScene to display the data, do the overlays, etc. >> 2. Use QML (Qt Quick 1) similar to #1 >> 3. Use QML (Qt Quick 1) similar to present operation >> >> My main requirements are that I need to be able to update at least a few >> times a second (typically 3-5 times a second; possibly higher), and adding >> the new text with lines and numbers for the measurements. >> >> >> As I have not yet touched QML, and there are many on this list who have, >> what you recommend? >> Would it be worth trying to do this in QML - either #2 or #3 - or should I >> just stick to #1? >> >> For those involved with Qt5, will there likely be big changes in the >> functionality in moving this to Qt5 when the time comes? I understand (from >> the development list) that QML1 is generally easy to port to QML2 but that >> it depends on what you do with QML; am I likely to run into a big issue in >> the port given what I need to do? > >It's not clear why you want to move to QML... is it because you want >to draw stuff (text and other graph elements) in QML directly (and >think this might be easier)? If your current app is setup using >'form-style' widgets and has a traditional desktop GUI, then it might >be a lot of additional effort to move it to QML. > >There's this QML canvas project: >http://qt.gitorious.org/qt-labs/qmlcanvas, that might make it easier >for you to draw your graph. But really this depends on the complexity >of what you're trying to do. There are also projects like Qwt: >http://qwt.sourceforge.net/, which use widget-based Qt to draw >complicated graphs. My main reason for thinking about whether or not to use QML is two fold: 1. I am about to embark on something that no matter what I do is going to be complicated. Perhaps QML can make it simpler; I don't know. 2. (The bigger reason) Qt is moving towards QML. Since #1 has to be done any way, if QML will meet the need, why not move to it now instead of later? > From: Sivan Greenberg >To: BRM >Cc: Interests Qt >Sent: Tuesday, March 6, 2012 6:21 AM >Subject: Re: [Interest] To QML or not to QML... > >Hello! > >On Mon, Mar 5, 2012 at 7:39 PM, BRM wrote: >> >> As I have not yet touched QML, and there are many on this list who have,
Re: [Interest] To QML or not to QML...
> From: Preet >On Mon, Mar 5, 2012 at 12:54 PM, Jason H wrote: >> It is my understanding that the major differences between 4 and 5 are that 5 >> assumes (and requires) a hardware GL implementation (scenegraph), where 4 >> does not. > >I was under the impression that the legacy QtQuick 1 stuff would be >available in Qt5 as is with software rasterization under the existing >'QDeclarative' classes/module. The QtQuick 2 stuff all seems to be >under the 'QQuick' module. Yes, there's a bunch of renaming going on, and such from what I can tell on the development list; but I haven't paid too much attention to the QML side of things. >>In terms of your coding, his largely comes down to the import >> statements that are used. >> From: BRM >> To: Interests Qt >> Sent: Monday, March 5, 2012 12:39 PM >> Subject: [Interest] To QML or not to QML... >> >> I'm working on an application that presently uses Qt 4.7 for a front-end to >> a larger system. One of its main tasks is to display data in the system >> which requires rendering up to around a thousand or so points and overlaying >> a template of the ideal against the actual. Presently it does all the work >> in a custom QWidget class and implements the drawing in >> QWidget::paintEvent(QPaintEvent *event). However, I am getting ready to do a >> major rewrite of this functionality - namely I want to add some text labels, >> values, and lines for some of the measurements related to it, and am trying >> to determine the best possible path of two that are available. >> >> No matter what I do, there will be some major rework to my application as >> things are just changing a lot to do the new functionality I am seeking >> (can't be helped). >> >> The below are the options I am aware of: >> >> >> 1. Rework the painting to be done to a QImage/QPixMap/etc, and then use >> QGraphScene to display the data, do the overlays, etc. >> 2. Use QML (Qt Quick 1) similar to #1 >> 3. Use QML (Qt Quick 1) similar to present operation >> >> My main requirements are that I need to be able to update at least a few >> times a second (typically 3-5 times a second; possibly higher), and adding >> the new text with lines and numbers for the measurements. >> >> >> As I have not yet touched QML, and there are many on this list who have, >> what you recommend? >> Would it be worth trying to do this in QML - either #2 or #3 - or should I >> just stick to #1? >> >> For those involved with Qt5, will there likely be big changes in the >> functionality in moving this to Qt5 when the time comes? I understand (from >> the development list) that QML1 is generally easy to port to QML2 but that >> it depends on what you do with QML; am I likely to run into a big issue in >> the port given what I need to do? > >It's not clear why you want to move to QML... is it because you want >to draw stuff (text and other graph elements) in QML directly (and >think this might be easier)? If your current app is setup using >'form-style' widgets and has a traditional desktop GUI, then it might >be a lot of additional effort to move it to QML. > >There's this QML canvas project: >http://qt.gitorious.org/qt-labs/qmlcanvas, that might make it easier >for you to draw your graph. But really this depends on the complexity >of what you're trying to do. There are also projects like Qwt: >http://qwt.sourceforge.net/, which use widget-based Qt to draw >complicated graphs. My main reason for thinking about whether or not to use QML is two fold: 1. I am about to embark on something that no matter what I do is going to be complicated. Perhaps QML can make it simpler; I don't know. 2. (The bigger reason) Qt is moving towards QML. Since #1 has to be done any way, if QML will meet the need, why not move to it now instead of later? > From: Sivan Greenberg >To: BRM >Cc: Interests Qt >Sent: Tuesday, March 6, 2012 6:21 AM >Subject: Re: [Interest] To QML or not to QML... > >Hello! > >On Mon, Mar 5, 2012 at 7:39 PM, BRM wrote: >> >> As I have not yet touched QML, and there are many on this list who have, >> what you recommend? >> Would it be worth trying to do this in QML - either #2 or #3 - or should I >> just stick to #1? >> > >You could try and use pure QML (e.g. have QML elements of a Point and >rest of your entities) abstraction and do a test run if speed is >what's important in populating thousands of items. > >I would guess that drawing inside a QML View will behave and have the >same constraints as drawing inside
Re: [Interest] To QML or not to QML...
Hello! On Mon, Mar 5, 2012 at 7:39 PM, BRM wrote: > > As I have not yet touched QML, and there are many on this list who have, what > you recommend? > Would it be worth trying to do this in QML - either #2 or #3 - or should I > just stick to #1? > You could try and use pure QML (e.g. have QML elements of a Point and rest of your entities) abstraction and do a test run if speed is what's important in populating thousands of items. I would guess that drawing inside a QML View will behave and have the same constraints as drawing inside a QWidget, perhaps with some performance difference depending on the complexity of your drawing if you stick to high level item (complex shapes as custom elements themselves) but if you implement it yourself you might need to re-implement a translation layer from highlevel -> geomtric shapes -> back to low level drawing and and profiling and perfecting your QML should prove much more beneficial. QML abstraction will give you the enormous (in my experience) benefit of close to effortless reusable components, and making the "drawing" process close to 'code-free' , real nicety when you add more overlays and detail perhaps in the future, or base more advanced display items on what you already have, or use this overlaying and layers in many other apps you might want to develop further (again, in *my* experience, with less hassle than using QWidget code) , and be able to use QML's cool fluidity and relatively easy to achieve display and device scaling and fit, and.. and... (well you got it, I love QML ;). Eventually, I've seen people here make their QML become very performant with the suitable know how and I'm sure you could find help if you run into issues. The important thing is to try and experiment with your data set before you invest into switching technologies, a good approach to follow before any major rewrite! Hope this helps, -Sivan ___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
Re: [Interest] To QML or not to QML...
On Mon, Mar 5, 2012 at 12:54 PM, Jason H wrote: > It is my understanding that the major differences between 4 and 5 are that 5 > assumes (and requires) a hardware GL implementation (scenegraph), where 4 > does not. I was under the impression that the legacy QtQuick 1 stuff would be available in Qt5 as is with software rasterization under the existing 'QDeclarative' classes/module. The QtQuick 2 stuff all seems to be under the 'QQuick' module. In terms of your coding, his largely comes down to the import > statements that are used. > > > > > From: BRM > To: Interests Qt > Sent: Monday, March 5, 2012 12:39 PM > Subject: [Interest] To QML or not to QML... > > I'm working on an application that presently uses Qt 4.7 for a front-end to > a larger system. One of its main tasks is to display data in the system > which requires rendering up to around a thousand or so points and overlaying > a template of the ideal against the actual. Presently it does all the work > in a custom QWidget class and implements the drawing in > QWidget::paintEvent(QPaintEvent *event). However, I am getting ready to do a > major rewrite of this functionality - namely I want to add some text labels, > values, and lines for some of the measurements related to it, and am trying > to determine the best possible path of two that are available. > > No matter what I do, there will be some major rework to my application as > things are just changing a lot to do the new functionality I am seeking > (can't be helped). > > The below are the options I am aware of: > > > 1. Rework the painting to be done to a QImage/QPixMap/etc, and then use > QGraphScene to display the data, do the overlays, etc. > 2. Use QML (Qt Quick 1) similar to #1 > 3. Use QML (Qt Quick 1) similar to present operation > > My main requirements are that I need to be able to update at least a few > times a second (typically 3-5 times a second; possibly higher), and adding > the new text with lines and numbers for the measurements. > > > As I have not yet touched QML, and there are many on this list who have, > what you recommend? > Would it be worth trying to do this in QML - either #2 or #3 - or should I > just stick to #1? > > For those involved with Qt5, will there likely be big changes in the > functionality in moving this to Qt5 when the time comes? I understand (from > the development list) that QML1 is generally easy to port to QML2 but that > it depends on what you do with QML; am I likely to run into a big issue in > the port given what I need to do? It's not clear why you want to move to QML... is it because you want to draw stuff (text and other graph elements) in QML directly (and think this might be easier)? If your current app is setup using 'form-style' widgets and has a traditional desktop GUI, then it might be a lot of additional effort to move it to QML. There's this QML canvas project: http://qt.gitorious.org/qt-labs/qmlcanvas, that might make it easier for you to draw your graph. But really this depends on the complexity of what you're trying to do. There are also projects like Qwt: http://qwt.sourceforge.net/, which use widget-based Qt to draw complicated graphs. Regards, Preet > > TIA, > > Ben > ___ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest > > > > ___ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest > ___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
Re: [Interest] To QML or not to QML...
It is my understanding that the major differences between 4 and 5 are that 5 assumes (and requires) a hardware GL implementation (scenegraph), where 4 does not. In terms of your coding, his largely comes down to the import statements that are used. From: BRM To: Interests Qt Sent: Monday, March 5, 2012 12:39 PM Subject: [Interest] To QML or not to QML... I'm working on an application that presently uses Qt 4.7 for a front-end to a larger system. One of its main tasks is to display data in the system which requires rendering up to around a thousand or so points and overlaying a template of the ideal against the actual. Presently it does all the work in a custom QWidget class and implements the drawing in QWidget::paintEvent(QPaintEvent *event). However, I am getting ready to do a major rewrite of this functionality - namely I want to add some text labels, values, and lines for some of the measurements related to it, and am trying to determine the best possible path of two that are available. No matter what I do, there will be some major rework to my application as things are just changing a lot to do the new functionality I am seeking (can't be helped). The below are the options I am aware of: 1. Rework the painting to be done to a QImage/QPixMap/etc, and then use QGraphScene to display the data, do the overlays, etc. 2. Use QML (Qt Quick 1) similar to #1 3. Use QML (Qt Quick 1) similar to present operation My main requirements are that I need to be able to update at least a few times a second (typically 3-5 times a second; possibly higher), and adding the new text with lines and numbers for the measurements. As I have not yet touched QML, and there are many on this list who have, what you recommend? Would it be worth trying to do this in QML - either #2 or #3 - or should I just stick to #1? For those involved with Qt5, will there likely be big changes in the functionality in moving this to Qt5 when the time comes? I understand (from the development list) that QML1 is generally easy to port to QML2 but that it depends on what you do with QML; am I likely to run into a big issue in the port given what I need to do? TIA, Ben ___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
[Interest] To QML or not to QML...
I'm working on an application that presently uses Qt 4.7 for a front-end to a larger system. One of its main tasks is to display data in the system which requires rendering up to around a thousand or so points and overlaying a template of the ideal against the actual. Presently it does all the work in a custom QWidget class and implements the drawing in QWidget::paintEvent(QPaintEvent *event). However, I am getting ready to do a major rewrite of this functionality - namely I want to add some text labels, values, and lines for some of the measurements related to it, and am trying to determine the best possible path of two that are available. No matter what I do, there will be some major rework to my application as things are just changing a lot to do the new functionality I am seeking (can't be helped). The below are the options I am aware of: 1. Rework the painting to be done to a QImage/QPixMap/etc, and then use QGraphScene to display the data, do the overlays, etc. 2. Use QML (Qt Quick 1) similar to #1 3. Use QML (Qt Quick 1) similar to present operation My main requirements are that I need to be able to update at least a few times a second (typically 3-5 times a second; possibly higher), and adding the new text with lines and numbers for the measurements. As I have not yet touched QML, and there are many on this list who have, what you recommend? Would it be worth trying to do this in QML - either #2 or #3 - or should I just stick to #1? For those involved with Qt5, will there likely be big changes in the functionality in moving this to Qt5 when the time comes? I understand (from the development list) that QML1 is generally easy to port to QML2 but that it depends on what you do with QML; am I likely to run into a big issue in the port given what I need to do? TIA, Ben ___ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
