Qgraphicsscene move item. wrote on last edited by #2.

Qgraphicsscene move item Returns the current scene for the item, or nullptr if the item is not stored in a scene. 文章浏览阅读1. Now it seems that QGraphicsScene::mousemoveEvent is not called when I move the mouse. The class serves as a container for QGraphicsItems. You can add QGraphicsItem objects (like rectangles, ellipses, If they are set paths or transformations that have regular intervals (i. However, I can get it to work if I press the left mouse button and move it while holding the button. Please Help! Thanks! 1 Reply Last reply . I can't find any function to return me the rectangle of my current screen, i searched in all QGraphicsScene and QGraphicsView functions. 1k次。本文详细介绍了Qt中的图形视图框架，包括QGraphicsScene、QGraphicsItem和QGraphicsView的用法。QGraphicsScene负责管理图形项，提供事件管理和无变换渲染；QGraphicsItem是所有图形项的基础，支持自定义几何、碰撞检测和绘画；QGraphicsView是观察场景的窗口，可缩放、旋转。 If all of the selected items move together, then when item1 moves, it checks whether item2 is also currently selected (thereby, it also moves) with item1->scene()->selectedItems()->indexOf(item2). I think the problem has to do with the parent of the widget. e. I want to improve this by only showing the handles when the item is selected. When I rotate a Qgraphicspixmapitem in it, it appears to move also. Actually, the Qt Documentation on QGraphicsItem provides an example which exactly solves the problem of limiting the movement of items to the scene rect:. until now everything works I have this widget that I would like to add to my qgraphicsscene but it isn't working exactly how I want it to. In that operation, you get the current style, and use QStyle::drawControl to draw a button. width() / 2. 0; I am new to Qt in general and QGraphicsView in particular. All QGraphicsScene ‘s item location algorithms are of an order close to logarithmic complexity, by making use of binary search. – I am trying to move a QGraphicsPixmapItem but I have a little problem. What's the correct way to move the item ? 1 Reply Last reply . I am using QMainWindow and QFrames to organize content of window and I can add items, but can't move the items. I instantiate QGraphicsEllipseItem into a QGraphicsScene and I use HoverEnterEvent and HoverLeaveEvent to change mouseMoveEvent sends the necessary information to handle the hover event of the items but 简述 在图形视图框架中，QGraphicsScene 提供一个快速的接口，用于管理大量 item，QGraphicsItem 是场景中 item 的基类。 图形视图提供了一些典型形状的标准 item，当 这个类翻译了好久，实在是成员函数太多了，分享出来，希望对大家有用，多多支持哦~~ 详细介绍 QGraphicsItem类是视图框架的一部分，是在一个QGraphicsScene中最基本的图形类，它为绘制你 自己的item提供了一个轻量 Missing or Incorrect Item Painting. However, this is not dynamic and has limitations. QRectF QGraphicsItem:: sceneBoundingRect const. 2) Double click the item, which deletes the item - you'll need to handle double clicks, and hit-testing the QGraphicsItems, you'll have to implement After a careful read of the documentation, my conclusion is that it is not possible to move outside the scene. At best, I can get the rectangle to 文章浏览阅读1. 1 Reply Last reply . scene. As soon as I get rid of the mouse event functions, I can normally select and move my objects on the scene. I'm trying to add items to qgraphicsscene, and move them later. The problem is, only one of the items receives a mouse move event in that case. Returns the bounding rect of this item in scene coordinates, by combining sceneTransform() with boundingRect(). Since 4. If they do, then you've dropped one onto the other. sceneRect和setSceneRect函数可用于获取和设置视图中场景的可视化区域。显然，该值不必与QGraphicsScene类的sceneRect相同。; centerOn函数可用于确保特定点或项目 I have one QGraphicsScene as the main scene with several movable QGraphicsItems in it and another QGraphicsScene on top of the main scene as an overlay. So you can If I want this item to be moveable, I can call its function setFlag(QGraphicsItem::ItemIsMovable). Specifically, the coordinates of setScale() changes the size of the item, not the view scale of the scene. While the item is beeing updated (lasts a few seconds) i want to move the whole Scene and reset the movement after the item is fully updated. Previously when I had not inherited QGraphicsScene but only made an object of QGraphicsScene, the above two items were movable in the scene. Even if asking the item for its position seems only to Unfortunately, QGraphicsItem is a base class of all graphics items usable inside QGraphicsScene, and, as most "item-like" objects in Qt, is not derived from QWidget or QObject. 2. I want to be able to call addR on the other hand moves the rectangle inside the item and does not move the item itself. QtGui. moveBy(150,0); This moves your circle So when you first added the item, whatever the item's position is, it will be used as the top-left of the displayed scene. scrollbars, zoom+other buttons - I want to make it Now, When ever I click on one rect_item from the item list in QgraphicsScene, I want to print that item. I though it would be as simple as: A Binary Space Partitioning tree is applied. QGraphicsScene::clear removes and deletes items. One way is to iterate through these 1000 items and call setPos for each one ! I think this will block user interface. If i uncomment QGraphicsScene::mousePressEvent(event); Otherwise, it sounds like it's best to implement both selection and move completely in your own class, and no longer call base class events. When a QGraphicsView receives a QMouseEvent, it translates it to a QGraphicsSceneMouseEvent. I want one more thing - get notifications when user has finished moving the object. QGraphicsScene is part of the Graphics View Framework. In this case, you have a pointer to the item, so if you call QGraphicsScene::removeItem, it will remove it from the scene and you can then delete the item. If they are set paths or transformations that have regular intervals (i. Moreover, they can only be parented to another QGraphicsItem (apart from being owned by QGraphicsScene. This is very smooth and is what I would like to achieve. QGraphicsScene class provides a surface for managing a large number of 2D graphical items. Stack Overflow. , scenes where most items do not move). circle. The event is then forwarded to the QGraphicsScene associated with the view. No index is 场景类 — QGraphicsScene. // c Skip to main content. Hello, I made an application using the Qt and c++, I'm using QGraphicsView to display a map consist of different map tiles added to QGraphicsScene as QGraphicsItem. Improve this question. e. setRect(150,-0,200,200 The value 150 in the four lines do nothing. My goal is to be able to add the widget to the scene and pics = self. there are two models and two views. class Item : public QGraphicsItem { public: void setSharedPos(Position *pos) { sharedPosition = pos; } //implement the paint() function //its beeing called by the scene void paint() { //set the shared position here setPos(sharedPos); The only hitch with this is that you need some way of giving the actual animation "instructions" to the individual graphics items. So my questions are: How do I access a QPixmap item once I have added it to a QGraphicsView via a QGraphicsScene. How to move QGraphicsScene by dragging with mouse? QtWS: Super Early Bird Tickets Available! But this doesn't work in my program, the scene just goes back every time I move the mouse (pressed) to the point where I first clicked on the scene (I don't really understynd that too). So your item is actually moved, but the scene is shown with an offset. If the event is not handled by the scene, the view may use it, e. ItemIsSelectable" and "QGraphicsItem. Just use it as-is, and set the item's QGraphicsItem::ItemIsMovable flag. 8k次，点赞2次，收藏5次。这一次，简介一下GraphicsItem的移动。代码如下："""QGraphicsItem 的基本缩放By Linyoubiao2020-03-17"""from PyQt5. Qt's QGraphicsScene provides some nice functionality out of box: user can select objects and move them around. I add it to the scene with "addItem" I am attempting to properly constrain the movement of a QGraphicsItem (specifically QGraphicsRectItem) without changing the native behavior to function as a scrollbar on the X-axis. Solution Double-check item positions and transformations. 0. QtWidgets import (QApplication, QGraphicsView, QGraphicsScene, QGraphicsIte_pyqt setcachemode Where the this pointer refers to a QGraphicsScene. In both cases, I Note that the item's geometry is provided in item coordinates, and its // Create a line of length 100 QGraphicsItem * anotherLine = addLine(0,0, 100, 100); // move it to where I want it to be within the scene anotherLine->setPos(50,50); So if I am adding 所有 QGraphicsScene 's item location algorithms are of an order close to logarithmic complexity, by making use of binary search. PySide. The models are the QGraphicsScene and a standard QStandardItemModel, whereas the views are a QListView and a QGraphicsView. To add or move an item to a scene, call QGraphicsScene::addItem(). If you can't move the item with the mouse, Hi. QGraphicsView lets you move items out of the box, you don't need to add code for that. I want to move all of these 1000 items to new position. The PySide. QGraphicsScene::NoIndex-1 Use QGraphicsItem::setPos on the item group as a whole to move it collectively. In some cases, when you left click and hold while on an item or widget, that item or widget will grab the mouse, so it can track mouse moves even as they leave that respective item. Instead, you can create your own QGraphicsRectItem decendant, and reimplement the paint operation. So it looks like it's at (0, 0). Now the item can be clicked on and moved around in What I want to know is if there is a way move the polygon the same way it moves when you turn on the "QGraphicsItem. The only reason for reimplementation of When the mouse is dragging, I change the scrollbars depending on the QMouseEvent x and y. NoIndex. I'd like to use QGraphicsItemGroup because in this way each disk can access the position of the other. How to get updated values of items on scene after mouseMoveEvent Qt/C++ - Lesson 023. This will give you a graphics item that looks exactly like any button on your system, but that you can manipulate in the same way as any other graphics item. Follow edited Oct 25, 2019 at 14:07. That all seems to work but the positions that are reported seem to be relative to the old position of the item. Then I define "l2" as a QGraphicsItem "lnk" and define pen, isSelectable and isMovable. A complete example is provided in this answer. The Z value decides the stacking order of sibling items. qxoz. But scene hold old position of items, not updated after item move. To make the objects movable, I use the flag ItemIsMovable which unfortunately doesn't seem to work inside a QGraphicsItemGroup The following My goal is to move the content of the item with mouseMoveEvent. But now how to check which of the three objects caused mouse event. It is used together with PySide. But if you have more than one item in the scene, it changes the relation between items. All QGraphicsScene's item location algorithms are of an order close to logarithmic complexity, by making use of binary search. The overlay scene is exactly the same size as the user's display, whereas the main scene is much bigger, so it needs to be scrolled up and down automatically. Solution Use QGraphicsScene::setSceneRect to set the scene's bounding QGraphicsScene 提供了一种方便而强大的方式来管理和显示图形项，通过与 QGraphicsView 结合，可以实现复杂的图形视图应用。 合理使用场景边界、图形项和事件处理方法，可以实现高效的图形项管理和交互。在实际应用中，结合自定义图形项、动画效果和碰撞检测，可以实现更加丰富和动态的图形视图 You can query item position from anywhere, just cycle through all items in the scene and check if they are instances of Node, then get their pos(). Since the whole movement logic (including selections) is already implemented by QGraphicsScene, I'm not sure what I have a QGraphicsScene containing some simple objects (in this simplified example circles) that I want to change into other objects (here squares) when selected. On the release of the mouse button, check if the bounding rects of the items intersect with QRect::contains(const QRectF). Currently I'm able to select, drag and scale rectangles using handles. QGraphicsScene类提供了处理多个图形项（QGraphicsItem）所需的几乎所有方法。其主要作用是作 My goal is to write a software that displays two movable disks that live inside the same QGraphicsItemGroup. Say there are 3 object of this subclass in which I am implementing mouse events. And when you move it . items() for i in pics: i. QGraphicsScene. 场景分为3层：分别是背景层、图形项层、前景层。我们绘制的图形item都是放在图形项层的：. All gists Back to GitHub Sign in Sign up << "Custom item left clicked with alt key. A Binary Space Partitioning tree is applied. Now as you an see on the picture attached, I have three lines where I am putting QGraphicsItems. "; // resize the item: double radius = boundingRect(). In my code i define a QGraphicView with a scene as QGraphicsScene. Skip to content. In general, mouse events are first delivered to the QGraphicsView (on QWidget level), then forwareded to the QGraphicsScene, then translated into QGraphics*-Event types, and then QGraphicsScene简介 QGraphicsScene是图形视图框架的组成部分。它提供了一个用于管理大量2D图元的表面(Surface)。QGraphicsScene作为QGraphicsItem的容器，与QGraphicsView一起使用，以可视化2D曲面上的图元，例如线条、矩形、文本以及自定义图元。 I'm trying to create a subclass of QUndoCommand that represents a movement of one or more QGraphicsItem. , for the DragMode. Then I create a line "l2" with QLineF. In addition, QGraphicsItem ‘s collision detection mechanisms use boundingRect() to provide an efficient You have to choose if the top and left resizing only change the rectangle of the item, or its position. I set the child item's ItemIsMovable flag and when I try to move the child item, the parent item does not move, only child item moves. For now I tried overriding the mouseMoveEvent of QGraphicsScene and emit a signal to PPI-Class containintg the QGraphicsScene Objet. 作者：丶布布文章预览： 图形视图框架的介绍 视图类—QGraphicsView 场景类—QGraphicsScene 图元类—QGraphicsItem 总结 图形视图框架的介绍在Qt框架内的许多模块，类和子框架下，有一块专门用于简化图形处理的工具，称为图形视图框架。它包含许多类，几乎所有的类都以QGraphics开头，并且所有这些类都可 My QGraphicsScene is very large (10k X 10K), so the QGraphicsView cannot show it entirely, there are scroll bars. sierdzio Moderators. Remember: the rectangle of QGraphicsRectItem is always expressed in local coordinates: an item created with 100, 100, 50, 50 will appear the same as one created with 0, 0, 50, 50 and then moved at 100, 100, but they are not the same. QGraphicsScene bases its item index on boundingRect(), and QGraphicsView uses it both for culling invisible items, and for determining the area that needs to be recomposed when drawing overlapping items. I have figured out that this has something to do with the QGraphicsView adjusting to keep the scene in view. For a one item scene, it's effectively the same. The thing is more or less everything is working for me, I can detect where I clicked and so on, but when I try to move the objects what I have on QGraphicsScene, I have to double click them to select them, and then can I only move them. (Keep in mind QGraphicsItemGroup inherits QGraphicsItem) – Osama Kawish. So if you create QVector of QGraphicsItem once, and the code from your question (with adding and clearing scene) is called many times, you delete items many times what leads to crash. The default Z value is zero. Q Offline. I can detect Skip to main content. I am making a timeline widget based on Qt's amazing Graphics View framework. I'm trying to understand how to use QGraphicsScene and QGraphicsView and I am testing item placement with QGraphicsRectItem. addItem(&circle); circle. cpp. I added these items to a custom graphics scene and the move operation works perfectly for me. . 文章浏览阅读2k次。前言之前被一个问题给难住了，就是在场景中没有触发mousePressEvent，却进入了mouseMoveEvent。解决方法：因为我自定义了QGraphicsScene，然后在自定义场景的构造函数中像场景中添加了QWidget中元素，导致了scene中一些相关item不出现，以及场景中没有触发mousePressEvent，却进入 The boundingRect() function has many different purposes. g. The main task is to I have a QGraphicsView and a QGraphicsScene connected like this: graphicsScene->setSceneRect(this-> Can anyone explain how I would move the pixmap to the corner of the scene/view ( const QGraphicsItem * item, ) The way that QGraphicsScene and QGraphicsView interact is that you can have a single scene with at least I try to understand, how to move/transform graphic items inside a QGraphicsScene. QGraphicsScene is part of the Graphics I want to move the QPushButton or kind of QWidget in QGraphicsView for example QListWidet, auto *item = new QGraphicsRectItem(0, 0, 75, 40); auto *proxy = new QGraphicsProxyWidget Move QGraphicsView top left to a certain point in The QGraphicsScene class provides a surface for managing a large number of 2D graphical items. Also, if you're setting the ItemIsMovable flag, you should call the base class implementation of mouseMoveEvent, otherwise if you move the item on your own that flag is completely useless. Now, I have made them movable with the ItemIsMovable flag, but I only want each item to be movable on the X axis (from left to right). I'm trying to extend my Qt knowledge to QGraphicsView by implementing a diagram-ish application. 9. After removing an item from a scene, unless it is parented to another You're seeking a lot of answers, Not so much how to handle QGraphicsItem or QGraphicsScene. change every second), all you need to do is reimplement the objects void QGraphicsItem::advance ( int phase ) method, making sure that you perform the changes Multiselection works but i can't drag items any more. You only need to add code to handle the items in detail, like what to do when selecting an item or what happens if you move the item. QVariant Component::itemChange(GraphicsItemChange change, [Qt5] QGraphics图形视图框架概述(Item、Scene和View)，在Qt框架内的许多模块，类和子框架下，有一块专门用于简化图形处理的工具，称为**图形视图框架** QGraphicsView类是 Qt 窗口小部件类，可以将其放置在窗口上以显示QGraphicsScene QGraphicsScene scene; QGraphicsEllipseItem circle; scene. So I subclassed QGraphicsEllipseItem and QObject and overrode the itemChange method to trigger a signal. . It is used together with QGraphicsView for visualizing graphical items, such as lines, rectangles, text, or even custom items, on a 2D surface. updateBarierMap method get positions of QGraphicsPolygonItem`s and generate grid map. I also add some waypoints as QGraphicsItem to my map with zValue of 2 so they display on top of my tiles, also I add these way points to a list so I can use them later . S Offline. Qt QGraphicsScene click, select, move, resize, delete QGraphicsItems - QGraphicsSceneTest. In other words rectangle coordinates are relative to the item origin point, not to 0,0 I tried as u suggested. Solution Ensure that the item's paint method is implemented correctly. No index is I have around 1000 graphics item in my QGraphicsScene. QGraphicsScene::NoIndex -1 No index is applied. The purpose is to have the ruler aware of the current mouse position. However, one can manually set the limits of the scene to something bigger than the actual scene. Currently, you can move them in every direction. Moving QGraphicsItem on QGraphicsScene with mouse help. In tutorials I have found authors use QDialog and QgraphicsView as the only widget. The HandleItems are children to a ManipulatorItem which in turn scales a DiagramItem of choice. Adding, moving and removing items is logarithmic. 1) Right click an added item, create a context menu, and then use scene->removeItem(addedItem); here. 244k 19 19 gold badges 199 199 silver badges 278 278 bronze badges. change every second), all you need to do is reimplement the objects void QGraphicsItem::advance ( QGraphicsScene::mousePressEvent(event); if(!event->isAccepted()) {if(event->button() == Qt::LeftButton) {// add a custom item to the scene: QPointF pt = event->scenePos(); So, if you move a QGraphicsItem it's event itemChange(GraphicsItemChange change, const QVariant &value), is called (change == ItemPositionHasChanged). If the result is -1 , it means that item2 is not selected, hence, it is not moving and the arrow shape needs to be updated; otherwise, move the arrow along with Yes, I know QGraphicsScene::selectedItems ? Why ? :) In my case it's better to use setSelectionArea(), to set the path to my Selection rectangle ! I create the scene and I have put some actions to take place when the user clicks on a scene item. eyllanesc. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company You can now move it and wait for the mouse release. I am trying to overwrite the QGraphicsScene mouseEvent() function to accomplish the same movement with press-and-release-once (pick item), move (without holding press), press-and-release-twice (drop item). How to stop a middle mouse click from deselecting items in a QGraphicsScene without blocking it from items in the scene? 3. If several items are moved at once (by selecting them first), this should be represented as a single command within the QUndoStack. QGraphicScene takes ownership of Item when addItem is called. class Position { QPoinfF pos; } Then you can add that class to your item. python; pyqt; qgraphicsview; qgraphicsscene; Share. Let's say that you make an application that will In other words, take the item with the mouse and exercise his moving to another place graphic -Создать подкласс QGraphicsScene -Переопределить mousePress/Move/Release Hi, II'm trying to move a GraphicsItem on a GraphicsScene using moveBy()Function but nothing moves on the screen , may someone help me to achieve this ? Thanks in advance here is the Programmcode i tried to write : ----- class Container: public QGraphicsRectItem { public: Container(QGraphicsItem* parent=0, intx, int y); A Binary Space Partitioning tree is applied. If not, then animate the graphics item back to the previously stored position. "; // add the item to the selection: setSelected(true); Graphics View框架结构”三元素“：场景类（QGraphicsScene）、视图类（QGraphicsView）和图元类（QGraphicsItem）。场景类提供管理位于其中的图元容器，视图类显示场景中的图元，场景可以通过多个视图表现。主要 概述 QgraphicsScene类为管理大量的2D图形item提供了一个管理界面，做为item的容器，它配合使用QgraphicsView使用来观察items,例如线，矩形，文本或者自定义的items， QgraphicsScene提供了方便的函数来让你高效的找到items的位置，或者决定在scene上哪个item可以看到，配合QgraphicsView窗口，你可以让可见scene，或者 Probably QGraphicsItem is freed twice. An item with a higher Z value will always be drawn on top of another item with a lower Z value. setPos(100,100) However, it doesn't make a difference, and even if it did, it would be awkward to have to search for it with a "for in". New positions don't relate to each other and all of them should be done at the same time. What you could do is to create a new class. I tried overriding the mouseMoveEvent function, but then I need to re-write the behavior for the rectangle in both the X and Y directions. The easiest solution is to set a big enough scene at the beginning as suggested here. if (event ->button () == Qt::RightButton) rightMousePressed = true; QGraphicsScene::mousePressEvent(event); if(!event->isAccepted()) {if(event->button() == Qt::LeftButton) {// add a custom item to the scene: QPointF pt = event The QGraphicsScene class forms the root of a scene graph, a hierarchical structure of graphical items. More specifically I'd like to have parent objects which don't draw themselves, they are drawn by their child objects, and under various circumstances, but in particular when the parent objects are I'm creating some graphic data displaying widget in Qt4 and I was tempted to use the QGraphicsScene for it, create QGraphicsItems for the data items etc. Incorrect Item Positioning. Warning: The suggested solutions won't work for multiply selected items. Solution Verify that the item's visibility and opacity are set appropriately. wrote on last edited by #2. This approach is best for static scenes (i. All gists Back to GitHub Sign in Sign up << "Custom item left clicked with shift key. Adding an item is simple, you can just call the QGraphicsScene function addItem, which takes a QGraphicsItem*. Select and move events do not work in QGraphicsScene. However, I wanted to add some layer of controls (eg. When I press on the item and move, the reference point changes to the topleft, and I want to move the item using the reference point in the center. I have removed the scroll bars because I don't need them and I want parts of the scene to go out of view without the You can use QGraphicsItem::setZValue ( qreal z ) to set the Z-value of the item. So you can set it to a higher value to bring it on top : item->setZValue(1); From QGraphicsItem::mouseMoveEvent method call QGraphicsScene::updateBarierMap. QGraphicsScene::NoIndex-1: No index is The default mouseEvent function in QGraphicsScene allows to move the Item by press-and-hold, move, and release. About; Products OverflowAI; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; I have a QGraphicsEllipseItem that I want to be movable and triggering signals on moving. There are lower level events, like mouse move, press, release, but I'd not like to reimplement the functionality that is already there (moving the In QGraphicsScene::mousemoveEvent, I call mouseMoveEvent of the ruler widget explicitly. In addition to containing the item, scene, and screen coordinates of the event (as I am trying to move my item The only way this works is if I iterate through all my items and check the mouse position: class Item : public QGraphicsItem { Item() Use a regular QGraphicsView and QGraphicsScene and add an Item object to the scene. Is there something I am missing out on. ItemIsMovable" flags and move the item manually. QGraphicsView for visualizing graphical items, such as lines, rectangles, text, or even custom items, on a 2D surface. No index is applied. QGraphicsView::setTransform() should be used if you want to keep the item's relationship to the scene and other items. cbwwdm eopr mjrsbk uceub ihgmxomd asppmu sbwn ihiyr nsra igm vpekny xbcqhi yvp hftdj byiih