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To create a scene with geometrical items, see QGraphicsScene 's documentation. To visualize a scene, you start by constructing a QGraphicsView object, passing the address of the scene you want to visualize to QGraphicsView 's constructor.

Alternatively, you can call setScene to set the scene at a later point. After you call showthe view will by default scroll to the center of the scene and display any items that are visible at this point.

qgraphicsview tutorial

For example:. You can explicitly scroll to any position on the scene by using the scroll bars, or by calling centerOn. By passing a point to centerOnQGraphicsView will scroll its viewport to ensure that the point is centered in the view.

An overload is provided for scrolling to a QGraphicsItemin which case QGraphicsView will see to that the center of the item is centered in the view. If all you want is to ensure that a certain area is visible, but not necessarily centered, you can call ensureVisible instead. QGraphicsView can be used to visualize a whole scene, or only parts of it.

The visualized area is by default detected automatically when the view is displayed for the first time by calling QGraphicsScene::itemsBoundingRect. To set the visualized area rectangle yourself, you can call setSceneRect. This will adjust the scroll bars' ranges appropriately. QGraphicsView visualizes the scene by calling render.

By default, the items are drawn onto the viewport by using a regular QPainterand using default render hints. You can access this widget by calling viewportor you can replace it by calling setViewport. QGraphicsView takes ownership of the viewport widget. QGraphicsView supports affine transformations, using QTransform. You can either pass a matrix to setTransformor you can call one of the convenience functions rotatescaletranslate or shear.

The most two common transformations are scaling, which is used to implement zooming, and rotation. QGraphicsView keeps the center of the view fixed during a transformation. Because of the scene alignment setAligmenttranslating the view will have no visual impact. You can interact with the items on the scene by using the mouse and keyboard.

QGraphicsView translates the mouse and key events into scene events, events that inherit QGraphicsSceneEvent, and forward them to the visualized scene. In the end, it's the individual item that handles the events and reacts to them.

For example, if you click on a selectable item, the item will typically let the scene know that it has been selected, and it will also redraw itself to display a selection rectangle.

Similiary, if you click and drag the mouse to move a movable item, it's the item that handles the mouse moves and moves itself. Item interaction is enabled by default, and you can toggle it by calling setInteractive. You can also provide your own custom scene interaction, by creating a subclass of QGraphicsViewand reimplementing the mouse and key event handlers. To simplify how you programmatically interact with items in the view, QGraphicsView provides the mapping functions mapToScene and mapFromSceneand the item accessors items and itemAt.

These functions allow you to map points, rectangles, polygons and paths between view coordinates and scene coordinates, and to find items on the scene using view coordinates. This enum describes the flags that you can set for a QGraphicsView 's cache mode.

This enum describes the default action for the view when pressing and dragging the mouse over the viewport. This enum describes flags that you can enable to improve rendering performance in QGraphicsView. By default, none of these flags are set.

Note that setting a flag usually imposes a side effect, and this effect can vary between paint devices and platforms. It stores an OR combination of OptimizationFlag values. This enums describe the possible anchors that QGraphicsView can use when the user resizes the view or when the view is transformed.

See also resizeAnchor and transformationAnchor. This enum describes how QGraphicsView updates its viewport when the scene contents change or are exposed.Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you may not be able to execute some actions. Please download a browser that supports JavaScript, or enable it if it's disabled i.

I want to use Box2D with qgraphicsview items. I converted box2d cmake project to qmake pro file and added to my project tree. I googled a lot but there are tutorials for QML, not qgraphicsview.

I found this post. I want to create a top-down project. Then moving balls in first frame. But they don't hit the walls and go outside.

I can post source code if needed. If not what is the best way to implement physics of colliding and bouncing balls that would also react to gravity? Qt Forum. Only users with topic management privileges can see it. I don't know how to map box2d rectangles to qgraphicsitems so I can't see the boxes : Thanks. Reply Quote 0 1 Reply Last reply. I join the question. Is there any example using Box2d in Qt5 that would run multiplatform? However, I'm not aware of an implementation for the graphics view framework.

QGraphics Basic Example

Reply Quote 1 1 Reply Last reply. Loading More Posts 3 Posts. Reply Reply as topic.Items or widgets? QGraphicsItem or QWidget? Which should I choose? Can you do everything with both?

You can write a games board widget, or a games board scene. An audio spectrum widget, or an audio spectrum item. Is QWidget faster? It can be, especially for simple widgets, and if you do everything right and have the time to spend. Will Graphics View save me time? Maybe the task you're trying to solve is a perfect match for Graphics View, and as you go along implementing it, you implement zooming and scrolling and right there I'd like to double-click to open a line edit - pushbutton box but Where do I put it?

Who is its parent? What do I do when the user scrolls the view? Install event filters? Embedding a widget inside a QGraphicsScene Have you ever invested time and energy on creating the world's finest widget, and then wanted to use it with Graphics View?

So what do you do? With either approach, what you want is to end up with something like this, graphics items and widgets dancing together as if nothing had happened:. I myself and several other Trolls've spent some time researching this topic.

It's not trivial; most solutions to embedding widgets into a scene end up with several serious drawbacks.Thursday January 19, by Andy Nichols nezticle Comments. There was a time when the Qt Graphics View Framework was seen as the solution to create modern user interfaces with Qt. I did give the same talk in webinar format though which you can view here.

After each time giving the talk, I got many questions about the Graphics View framework, which I was quite harsh on.

My conclusion was that users should avoid QGraphicsView for new applications and instead use Qt Quick. This proved to be a controversial claim because Graphics View is used in many applications shipping today. Prophetic comment on a post about Qt Scene Graph. Qt Quick and its Scenegraph API can do most of what Graphics View could do and much more, but there are still features that got left behind:.

qgraphicsview tutorial

Because all items in Graphics View can live in a shared QGraphicsScene, it is possible to have more than one QGraphicsView widget each of which could display different views of the shared scene.

This is quite difficult to replicate in Qt Quick 2 because each view would need to create its own copy of the scene. A cool as the feature seems, in practice it was not used so much by customers. The feature was also less practical on mobile and embedded platforms where only one view would be used per screen. This proved to be an unfortunate design decision because it also limited opportunities for optimization.

It makes the code really complex and optimization hard. If you need to show the same scene multiple ways when migrating to Qt Quick, then you will need to separate the data you would like to visualize from the scene defined in QML. Populate each Qt Quick scene with only the data present in the view of your logical scene. This is more complicated but does provide more flexibility in how you store the state of your shared scene.

I concede that it was easier to do in QGraphicsView. This is both a blessing and a curse. When Qt Quick 2 was released with Qt 5. This minimum requirement did not fit everyone's needs, and the solution was to keep Qt Quick 1 around for those customers.

In Qt 4 QPainter had a couple of different graphics systems backends that could be used. This meant that if you were rendering with QPainter you could either choose to do so in software rasteror with the GPU opengl. In general this would improve the rendering performance of Graphics View.

However, under the hood QPainter is generating loads of state changes and rendering the scene back to front leading to a poor use of the GPU. This is a large reason why the Qt Quick Scenegraph exists. Qt Quick as of 5. This is a neat feature and became a customer favorite shortly after its debut. The intention was to enable users to reuse controls that already existed.

For simple widgets like QPushButton and QSlider the cost in extra memory usage and proxying was worth it for the convenience gained. However users did not stop there and would place complex widget hierarchies into their scenes like their entire QMainWindow or QDialog. What was convenient for customers was also problematic for performance.

QWidgets can not be embedded into a Graphics View scene directly.To create a scene with geometrical items, see QGraphicsScene 's documentation. To visualize a scene, you start by constructing a QGraphicsView object, passing the address of the scene you want to visualize to QGraphicsView's constructor.

Alternatively, you can call setScene to set the scene at a later point. After you call showthe view will by default scroll to the center of the scene and display any items that are visible at this point.

For example:. You can explicitly scroll to any position on the scene by using the scroll bars, or by calling centerOn. By passing a point to centerOnQGraphicsView will scroll its viewport to ensure that the point is centered in the view. An overload is provided for scrolling to a QGraphicsItemin which case QGraphicsView will see to that the center of the item is centered in the view.

If all you want is to ensure that a certain area is visible, but not necessarily centered, you can call ensureVisible instead. QGraphicsView can be used to visualize a whole scene, or only parts of it. The visualized area is by default detected automatically when the view is displayed for the first time by calling QGraphicsScene::itemsBoundingRect. To set the visualized area rectangle yourself, you can call setSceneRect.

This will adjust the scroll bars' ranges appropriately. QGraphicsView visualizes the scene by calling render. By default, the items are drawn onto the viewport by using a regular QPainterand using default render hints. You can access this widget by calling viewportor you can replace it by calling setViewport. QGraphicsView takes ownership of the viewport widget.

qgraphicsview tutorial

QGraphicsView supports affine transformations, using QTransform. You can either pass a matrix to setTransformor you can call one of the convenience functions rotatescaletranslate or shear. The most two common transformations are scaling, which is used to implement zooming, and rotation.

QGraphicsView keeps the center of the view fixed during a transformation. Because of the scene alignment setAligmenttranslating the view will have no visual impact. You can interact with the items on the scene by using the mouse and keyboard.

QGraphicsView translates the mouse and key events into scene events, events that inherit QGraphicsSceneEvent, and forward them to the visualized scene.

In the end, it's the individual item that handles the events and reacts to them. For example, if you click on a selectable item, the item will typically let the scene know that it has been selected, and it will also redraw itself to display a selection rectangle. Similiary, if you click and drag the mouse to move a movable item, it's the item that handles the mouse moves and moves itself. Item interaction is enabled by default, and you can toggle it by calling setInteractive. You can also provide your own custom scene interaction, by creating a subclass of QGraphicsView, and reimplementing the mouse and key event handlers.

To simplify how you programmatically interact with items in the view, QGraphicsView provides the mapping functions mapToScene and mapFromSceneand the item accessors items and itemAt.Inherited by: QDeclarativeView. The PySide. QGraphicsView class provides a widget for displaying the contents of a PySide.

Qt Documentation Snapshots

QGraphicsView visualizes the contents of a PySide. QGraphicsScene in a scrollable viewport. To create a scene with geometrical items, see PySide. To visualize a scene, you start by constructing a PySide. QGraphicsView object, passing the address of the scene you want to visualize to PySide.

Alternatively, you can call PySide. After you call PySide. For example:. You can explicitly scroll to any position on the scene by using the scroll bars, or by calling PySide. By passing a point to PySide. QGraphicsView will scroll its viewport to ensure that the point is centered in the view.

An overload is provided for scrolling to a PySide. QGraphicsItemin which case PySide. QGraphicsView will see to that the center of the item is centered in the view. If all you want is to ensure that a certain area is visible, but not necessarily centered, you can call PySide.

QGraphicsView can be used to visualize a whole scene, or only parts of it. The visualized area is by default detected automatically when the view is displayed for the first time by calling QGraphicsScene. To set the visualized area rectangle yourself, you can call PySide. QGraphicsView visualizes the scene by calling PySide. By default, the items are drawn onto the viewport by using a regular PySide. QPainterand using default render hints. To change the default render hints that PySide.

QGraphicsView passes to PySide. QPainter when painting items, you can call PySide. By default, PySide. QGraphicsView provides a regular PySide. QWidget for the viewport widget. You can access this widget by calling PySide. QGraphicsView takes ownership of the viewport widget. QGraphicsView supports affine transformations, using PySide.

You can either pass a matrix to PySide. The most two common transformations are scaling, which is used to implement zooming, and rotation. QGraphicsView keeps the center of the view fixed during a transformation. You can interact with the items on the scene by using the mouse and keyboard. QGraphicsView translates the mouse and key events into scene events, events that inherit PySide.

QGraphicsSceneEvent, and forward them to the visualized scene.

QGraphicsView Class

For example, if you click on a selectable item, the item will typically let the scene know that it has been selected, and it will also redraw itself to display a selection rectangle.QGraphics can be used to organize complicated scenes of visual objects into a framework that makes them easier to handle. QGraphicsItems are the basic visual items that exist in the scene. You can also make your own items by inheriting QGraphicsItem. These items are then put into a QGraphicsScene which is basically the world you are planning to look at.

The items can move within the scene which is like having them move in the world you are looking at.

qgraphicsview tutorial

The items positioning and orientation is handled by transformation matrices called QTransforms. Qt has nice functions built in so you usually do not need to work with the QTransforms directly, instead you call functions such as rotate or scale which create the proper transforms for you. The scene is then viewed by the perspective defined in the QGraphicsView again with QTransformswhich is the piece you would put into a widget in you UI.

In the following example there is a very simple scene with just one item a pixmapwhich is put into a scene and displayed in a view. By turning on the DragMode flag the scene can be panned around with the mouse and by using the scale and rotate functions it can be scaled in and out with the scroll on the mouse and rotated with the arrow keys. Qt Pan, zoom, and rotate with QGraphicsView. Example QGraphics can be used to organize complicated scenes of visual objects into a framework that makes them easier to handle.

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