The Qt Quick 2 Spectrogram example demonstrates how to show a polar and cartesian spectrograms and how to utilize orthographic projection to show them in 2D. Spectrogram is simply a surface graph with a range gradient used to emphasize the different values.
Typically spectrograms are shown with two dimensional surfaces, which we simulate with a top down orthographic view of the graph. To enforce the 2D effect, we disable the graph rotation via mouse or touch when in the orthographic mode. The focus in this example is on showing how to display spectrograms, so the basic functionality is not explained.
To run the example from Qt Creatoropen the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example. To create a 2D spectrogram, we define a Surface3D item:. The key properties for enabling the 2D effect are orthoProjection and scene. We remove the perspective by enabling orthographic projection for the graph, and then we eliminate the Y-dimension by viewing the graph directly from above:.
Since this viewpoint causes the horizontal axis grid to be mostly obscured by the surface, we also specify that the horizontal grid should be drawn on top of the graph:. Depending on the data, it is sometimes more natural to use a polar graph instead of a cartesian one. Qt Data Visualization supports this via polar property. In this example we provide a button to switch between polar and cartesian modes:. In the polar mode, the X-axis is converted into the angular polar axis, and the Z-axis is converted into the radial polar axis.
The surface points are recalculated according to new axes. The radial axis labels are drawn outside the graph by default, but in this example we want to draw them right next to the 0 degree angular axis inside the graph, so we define only a tiny offset for them:. To enforce the 2D effect, graph rotation via user input is disabled when in orthographic mode. We do this by specifying a new input handler:. When the projection mode changes, we adjust the value of the rotationEnabled property of the customInputHandler to control the rotation.
Example project code. Documentation contributions included herein are the copyrights of their respective owners.Right click on the root entry of your project in the left sidebar and choose Add Existing Files In the appearing file dialog, select the qcustomplot. If this is done, your project structure and.
If you are using Qt version 5. This makes sure the printsupport and widgets is not added when using older Qt versions. The project is now ready to use QCustomPlot. Place a regular QWidget on your form in the desired location. Right click on it and hit Promote to In the appearing dialog, enter QCustomPlot in the input field next to Promoted class name. The input next to Header file should automatically fill with the correct qcustomplot. You won't see any immediate visual changes in QtCreator or QtDesignerbut while running the application, you will see an empty plot with axes and grid lines.
Linking aborts with "Undefined reference to QPrinter Using a shared library means to not include the. The sharedlib package in the download section provides two projects that demonstrate this: one compiles the shared QCustomPlot library and the other uses the shared library. This should quickly get you started using QCustomPlot as a shared library. The QCustomPlot. Just extract the whole package to a new directory, navigate inside the example directories and run qmake; make.
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Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I am hoping to create a program that draws a lattice of hexagons that the user can rotate and shear, as well as pan around and zoom in and out of. It will eventually be a MIDI controller.
Which type of project would be better for this, and why? Note: Qt Widgets have been replaced with QML Widgets; this answer responds to the question as asked, which is now strictly a historical question about the old Qt Widgets. Qt Quick is a declarative, smartphone-style user interface with support for a lot of the cool animation transitions that are common in smartphone apps. Quick is also a good choice for rapidly developing a prototype. Qt Widget is the traditional desktop-oriented UI model.
Right now pre-Qt5Qt Quick support for desktop system features is lacking but improving. There's not as much support for menus, toolbars, dialogs, and other standard desktop behaviors in Quick, while Widget supports those elements extremely well.
Do you want your app to look and feel native on desktop and tablet platforms, or are you building a simple application around your own custom UI widget? As Mat said, if Qt Quick supports the features you want, that will probably be your fastest approach. If you want to build full-featured desktop versions, Qt Widget is probably your best bet. Widgets are good for the very basic stuff, but I once you need to create something that is a bit more fancy, widgets will fall short very soon.
Qml is simply way more flexible, you can anchor items wherever you want instead of using the limited layout system of widgets. There are almost no platform-dependency flaws while widgets are full of these. And the property binding system makes it so damn easy to keep your ui in sync with your model. This is seven years after the question was first posted As such, Qt Widgets could be considered low-level compared to Qt Quick.
But this implies that in the long run, a Qt Widgets project will run faster and have better performance. That said, it is often used for desktop development. Qt Quick caters more to mobile development although it can still be used in desktop development. It has ready-to-use popupsanimationstabs and layouts, flickablesdrawersand the usual controls; all ubiquitous in mobile development.
Both have ui files which work with QtDesigner, providing a high-level view for setting layouts and creating interfaces. In Qt Quick, extensions are. In Qt Widgets, they are. If you're completely new to programming, I suggest having a look at Qt Quick first.
Personally, I think Qt Quick has a gentler learning curve and is easier to work with to accomplish myriads of projects. It's called "Qt Quick " for a reason. Don't look down on Qt Widgets though, they have some nice modules that outdo QtQuick. They use signals and slots. In the end, even if you're mainly using Qt Widgets, you might want to look at Qt Quick as it offers a high-level declarative language to work with and allows you to set things up more quickly.
The update will force the Item to re-paint by calling the paint method. This is how I think things work:. But if I call the paint method instead of update I get a compile error, because QDeclarativeItem::paint is virtual. Yeah it is not supposed to be called by user. It is called when a re-paint is requested using update.
But since QGraphicsProxyWidget is in picture here the re-implementing paint is not required. Have you tried to call addFlow from the QML? This will ensure that the addFlow is called when the FlowGrafik Item is ready.
The weird thing is that whatever I write in the constructor of FlowGrafik gets displayed perfectly. I even tried to delete all internal objects of FlowGrafik in the addFlow function, like QGraphicsProxyWidget and customPlotand I created new ones, but the results are the same.
Chillax Did you check by adding the code which changes plot values same as addFlow inside refresh? We are getting really close! Unfortunately the results are the same, but I found out that the paint method never gets called! I didn't see the "paint" at the application output.
Any ideas on how to move on? Chillax As said earlier to call paint you need to call update. I see "refresh" at the application output, but I don't see "paint".
The question is why doesn't update call paint? Chillax It should actually. But it didn't help to hide it before the update and then show it again. I saved the pixmap to a jpg file, and it looks just as I expect it to look like.
Can you think of a better solution for displaying my QCustomPlot Qwidget? I am pretty sure this is possibe in QML, and it shouldn't be this hard.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I am using Qwt now for two years.
I like its object oriented classes, which makes it very easy to adapt the plots and functionality. These days QCustomPlot is becoming more and more popular and competes with Qwt. Of course I did compare the APIs. However I am interested in the testimonies of experienced users from both libraries.
What is convenient? What not? Are there any pitfalls? I wouldn't call myself "experienced", as I used Qwt only for a few months, and QCustomPlot for a few weeks. That being said, my impressions are:. There's also another important difference between QCustomPlot and Qwt - licensing.
I can't compare both libraries since I only use QCustomPlot for a year now but I believe my comment may be useful to other nevertheless. If LGPL-ish license is required, there may not be a free of charge option depends on the consideration of the author.
Given the quality and usability of the library, the donation my company gave in exchange for the LGPL license agreement was not undue. When Plotting lots of points. What i noticed is: while dragging, Qwt only drags the plot area and after dropping it draw on the area.
Also, Qwt provide raw buffer option that can be managed externally. Qwt can be made much more good looking just after changing it background to white, antialiased enabled and grids. Learn more. Ask Question. Asked 7 years, 5 months ago. Active 5 years, 3 months ago. Viewed 18k times. Active Oldest Votes. That being said, my impressions are: QCustomPlot seems to be more actively developed at present.Qt C++ 05 Real Time Plotting with QCustomPlot
Last release was in August whereas last release of Qwt dates back to Subjectively, its interface seems more 'aligned' with Qt framework. Qwt, on the other hand, seems more mature and featureful. For instance, current release of QCustomPlot has no straightforward way to set the colour background for the axis rectangle only setting background to a user-supplied pixmap is supported.
Another example - Qwt has special classes and methods to facilitate plotting and zooming in-out the curves with a very large number of points. I found nothing like that in QCustomPlot.
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Mikhail Kagalenko Mikhail Kagalenko 1 1 silver badge 6 6 bronze badges. Qwt is actually licensed under the "Qwt License" which, while based on the LGPL, seems to include an advertising clause which may actually make it incompatible with the GPL. When doing so the application has to indicate somehow f.
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I have a problem with my Makefile. I downloaded opensource Qt project. Hence, when I try to compile it I got a message:" error: No rule to make target needed by stop. So when I replace relative paths to absolute it works, another case it got me with the error above. System is Linux. I would use QtCreator, opening the project and then adding one of the misplaced sources let say the first you see in.
The IDE should place it with the correct relative path, as appropriate per your folder choice. After that cut'n'paste the path prefix all over the remaining places. Anyway, path prefixes should be relative to the directory where you find the. One reason for this issue is because you have removed a file which you no longer need but forgot remove from res. Learn more. Qt project, no rule to make target needed by Ask Question.
For plotting, you need a 3rd-party library because Qt doesn't have its own plotting functions. I found that QCustomPlot is also used to plot graphs. You'll have to ask someone who has used both Qwt and QCustomPlot before though -- I have never used them. Yout Qt version had been built without the opengl module. If you want to use an OpenGL plot canvas you need to rebuild Qt with this module - but usually you are not intersted in this feature and you can simply disable this feature for Qwt: edit qwtconfig.
QCustomPlot doesn't require installing. The simplest mode of operation is to just include the qcustomplot. Of course, you can also compile a dynamic library from it, if you'd like. A new website is in progress with much more support material. Just download the QCustomPlot. In there, you'll find the. Copy them to your local project directory, and add them to your project.
In QtCreator, right click on the root project icon in the top left sidebar, select "Add Existing Files Then just include "qcustomplot. Have a look at the webpage, it's pretty well explained there.
The examples project should also help alot in getting started that's also in the download package. Compile Qwt : Create visual studio project and copy only the header files and cpp files to the project and just compile. You can get the Qtw dll and libs.
QCustomPlot : does not have that much performance when it comes to adding real time data. They have few doxygen generated documents, but they will be of little help.
Basics of plotting with QCustomPlot
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Hi, For plotting, you need a 3rd-party library because Qt doesn't have its own plotting functions. QCustomPlot is also a 3rd party solution and not part of the official Qt release. Try reading their documentation to see what's different. At first Itried to install qwt in my system.