I would like to display a callout on a QChart with a QBarSeries displayed.
I'm struggling in how to convert the position of my mouse to the qchart coordinate frame, so that I can use it as Anchor in my callout.
I would like to set it during my
MainWindow::barSeriesHovered(bool status, int index, QBarSet *barset){}
event.
I managed to do it using following code:
auto point = QCursor::pos();
point = myChartView->mapFromGlobal(point);
auto pointF = myChartView->mapToScene(point);
pointF = myChartView->chart()->mapFromScene(point);
pointF = myChartView->chart()->mapToValue(point,myChartView->chart()->series().at(0));
myCallout->setAnchor(pointF);
maybe not the most efficient use, but yes, it works
Another drawback is, that it always appears at the border of a bar, and does not move with your mouse cursor while you move around inside the bar, but yes, it works
Related
We are developing a macOS application whose GUI is relying on Qt.
At startup, we want to show() the QMainWindow at a specific location on the currently active screen (with multi screen systems in mind).
Is there a way to get the QScreen representing the currently active screen?
From our test, QGuiApplication::primaryScreen() is the first screen (which is consistent with the name), but we cannot find an equivalent for the active screen.
Qt5 provides functionality to do so, the QWindow::setScreen method sets the screen on which the window should be shown.
Any widget provides access to this pointer via QWidget::windowHandle():
QWidget * widget = new QWidget();
auto screens = qApp->screens();
// compute the index
widget->windowHandle()->setScreen(screens[index]);
widget->showFullScreen();
To get the screen number, you can use the mouse position and assume that the screen with the mouse is the one with the current focus:
QPoint globalCursorPos = QCursor::pos();
int mouseScreen = qApp->desktop()->screenNumber(globalCursorPos);
So the final code can be something like that:
QWidget * widget = new QWidget();
const auto globalCursorPos = QCursor::pos();
const auto mouseScreen = qApp->desktop()->screenNumber(globalCursorPos);
widget->windowHandle()->setScreen(qApp->screens()[mouseScreen]);
widget->showFullScreen();
Windows
If this approach does not fit your needs, you will need to perform some OS calls.
For instance, on Windows, you can use MonitorFromWindow:
HMONITOR active_monitor_number = MonitorFromWindow(GetActiveWindow(), MONITOR_DEFAULTTONEAREST);
If you need more information about the screen, you can use Qt or GetMonitorInfo.
I am not a Mac OS X developer, but it may exist a similar API
I did it in the following way:
#if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
QPoint topLeft = QPoint(0, 0);
QScreen* currentScreen = QGuiApplication::screenAt(QCursor::pos());
if (nullptr != currentScreen) {
topLeft = currentScreen->geometry().topLeft();
}
#else
QPoint topLeft =
qApp->desktop()
->screenGeometry(qApp->desktop()->screenNumber(QCursor::pos()))
.topLeft();
#endif
someWidget->move(mapFromGlobal(topLeft) + QPoint(offset, offset));
Note that, sometimes, you may get nullptr for currentScreen (in my case if primary screen is at the bottom and mouse pos at the bottom or left edge on the primary screen).
I wanted to have an online monitoring system that could tell where the shape is currently, but am getting very weird coordinates of the item, also the dimensions of it get higher by 1 each time I create new one and drag it.
Initial position (map size is 751 by 751, checked by outputting to qDebug(), scene bound to yellow space) :
Dragging it to the left top corner.
As you can see in the beginning it was on (200;200), but after dragging it is on (-201;-196). After deleting it and creating new shape on the same position with the same properties, new shape can't be seen because it is outside of the map, which suggests that edits don't show correct data.
Here is the code of updating the edits:
void CallableGraphicsRectItem::mouseReleaseEvent(QGraphicsSceneMouseEvent* event)
{
QGraphicsRectItem::mouseReleaseEvent(event);
ptr->updateEdits(this);
}
Here is what I managed to cut down into updateEdits():
void MainWindow::updateEdits(QAbstractGraphicsShapeItem* item)
{
//stuff not related to scene
auto posReal = item->scenePos();
auto pos = posReal.toPoint();
//create QString from coordinates
QString coordinate;
coordinate.setNum(pos.x());
ui->leftXEdit->setText(coordinate);
coordinate.setNum(pos.y());
ui->upperYEdit->setText(coordinate);
//get width and height for rect, radius for circle
auto boundingRectReal = item->sceneBoundingRect();
auto boundingRect = boundingRectReal.toRect();
ui->widthEdit->setText(QString::number(boundingRect.width()));
//disables height edit for circles, not really relevant
if (!items[currentShapeIndex].isRect)
{
ui->heightEdit->setDisabled(true);
}
else
{
ui->heightEdit->setDisabled(false);
ui->heightEdit->setText(QString::number(boundingRect.height()));
}
}
Here is how I anchor the QGraphicsScene to the left top corner of the yellow area:
scene->setSceneRect(0, 0, mapSize.width() - 20, mapSize.height() - 20);
ui->graphicsView->setScene(scene);
How can I report the right data to the edits?
You're better off overriding the itemChange method and using the ItemPositionHasChanged notification. You have to set the ItemSendsGeometryChanges flag on the item so that it receives these notifications.
I'm not sure that your item's final position has been set when you're still in the mouseReleaseEvent method. Tracking it in itemChange will ensure that the data is valid, and this kind of thing is what it's for.
Also, note that "pos" is in the item's parent coordinates, and "boundingRect" is in the item's coordinate space. You should use "scenePos" and "sceneBoundingRect" if you want to be sure you're using scene coordinates. If the item doesn't have a parent, then "pos" and "scenePos" will return the same values, but "boundingRect" and "sceneBoundingRect" will generally differ.
First of all, I'd like to mention that I found that related post How to get the mouse position on the screen in Qt? but it "just didn't work" for me. I made some tests, and the results didn't work as I expected, so I decided to make a new post to talk about the test I made and to find an alternative solution.
That's the code I used to make the test:
QScreen *screen0 = QApplication::screens().at(0);
QScreen *screen1 = QApplication::screens().at(1);
printf("screen0 %s \n", screen0->name().toStdString().c_str());
printf("screen1 %s \n", screen1->name().toStdString().c_str());
// Position on first screen.
QPoint pos0 = QCursor::pos(screen0);
// Position on second screen.
QPoint pos1 = QCursor::pos(screen1);
printf("pos 0: %d, %d \n", pos0.x(), pos0.y());
printf("pos 1: %d, %d \n", pos1.x(), pos1.y());
// Get position without screen.
QPoint pos = QCursor::pos();
printf("pos: %d, %d \n", pos.x(), pos.y());
What I was expecting, is that only one screen would return a valid position, since the cursor is only at one screen, not on both. But it's not the case, the both positions (pos0 and pos1) has the exactly same value, as we can see on the output:
screen0 DVI-D-0
screen1 HDMI-0
pos 0: 1904, 1178
pos 1: 1904, 1178
pos: 1904, 1178
Since the both positions has the same values, I can't know at which screen is the cursor. I don't know if that's a normal behavior or a bug, since the documentation doesn't say what happens when the screen argument isn't the screen where the mouse is.
My idea, is to open/launch an application (executed by a Qt daemon that must detect the selected screen) to the screen where the mouse is. I know that with libX11 it's possible, because I did it in the past, but I need to work with Qt 5, and I can't figure out how to do detect the selected screen with Qt.
I also made other tests, using QApplication and QDesktopWidget classes with no luck.
That's really weird. As a workaround, you could try this:
QPoint globalCursorPos = QCursor::pos();
int mouseScreen = qApp->desktop()->screenNumber(globalCursorPos);
Now you know which screen the cursor is in. Then you could find the cursor position within that screen doing this:
QRect mouseScreenGeometry = qApp->desktop()->screen(mouseScreen)->geometry();
QPoint localCursorPos = globalCursorPos - mouseScreenGeometry.topLeft();
This may seem like a trivial solution, but on my KDE it works (I ran into the same problems originally).
If you want to determine the local mouse coordinates with respect to a widget (this will be in device pixels and relative to the top left corner of the widget I believe) you can use
QWidget::mapFromGlobal(QCursor::pos());
i.e. call this->mapFromGlobal.
To figure out on which screen you are, you can iterate throught QGuiApplication::screens() and check whether the cursor fits in the geometry of the screen.
Here is a more complex example to compute the native cursor position (note the additional work needed to work with High DPI screens):
QPoint getNativeCursorPosition()
{
QPoint pos = cursorPosToNative(QCursor::pos());
// Cursor positions from Qt are calculated in a strange way, the offset to
// the origin of the current screen is in device-independent pixels while
// the origin itself is native!
for (QScreen *screen : QGuiApplication::screens()) {
QRect screenRect = screen->geometry();
if (screenRect.contains(pos)) {
QPoint origin = screenRect.topLeft();
return origin + (pos - origin) * screen->devicePixelRatio();
}
}
// should not happen, but try to find a good fallback.
return pos * qApp->devicePixelRatio();
}
This may work for you?
It did for me
QDesktopWidget *widget = QApplication::desktop();
QPosition globalCursorPosition = widget->cursor().pos();
Sice it seems that it can't be done with Qt (at least with my system configuration, and it seems that also in Windows) I decided to use the libX11 to make that implementation, which works like charm.
It's not an ideal solution because I wanted to only use Qt, but it works.
With QML you can use the properties of the Screen QML Type:
Screen.virtualX : The x coordinate of the screen within the virtual desktop.
Screen.virtualY : The y coordinate of the screen within the virtual desktop.
import QtQuick 2.6
import QtQuick.Window 2.2
console.log("Pos x : " + Screen.virtualX )
console.log("Pos y : " + Screen.virtualY )
This work with single screen as well multi-monitor systems.
I recently ran into a similar problem on Qt 5.15 + Windows + mixed DPI and needed this work around within a QWindow object.
QScreen* primaryScreen = QGuiApplication::primaryScreen();
QScreen* thisScreen = screen();
qreal primaryDPR = primaryScreen->devicePixelRatio();
qreal thisDPR = thisScreen->devicePixelRatio();
qreal scale = thisDPR / primaryDPR;
QPoint pos = scale * QCursor::pos();
I'm unsure if this works on other platforms.
The title says it pretty much all:
I have two screens, and each time I create a QDialog it appears in the same screen as its parent.
How can I make it appear in a different screen? Or should I use a different type of top-level widget?
The code I use to create the dialog is:
QDialog my_dialog = new QDialog(this,
Qt::WindowMaximizeButtonHint |
Qt::WindowCloseButtonHint);
...
EDIT:
I have also tried using the QDesktopWidget which gives me a QScreen object that refers to the second screen. But then I don't find how to instruct the QDialog to use that QScreen (setting it as the parent doesn't work).
It is bad, that you edit your question without reading comments :(
// Your screen geometry:
QRect buildScreenGeometry()
{
auto desktop = QApplication::desktop();
QRect virtualRect;
const auto n = desktop->screenCount();
for ( auto i = 0; i < n; i++ )
virtualRect |= desktop->screenGeometry(i);
return virtualRect;
}
// Moving
auto dlg = new QDialog( someParent );
auto newPoint = QPoint( 2000, 0 ); // point on another screen
auto realPos = someParent->mapFromGlobal( newPoint );
dlg->move( realPos );
That's all.
UPDATE:
You should understand, that there are only ONE screen area with COMMON coordinate system, that contains ALL screens.
For example, you have 2 monitors with 800x600 resolution. First (main) monitor is standing left, and second standing right. In this case, coordinate system, that is available for your application is 1600x600. So, if your widget has 100x100 top-left position, on a first monitor, and you want to move it to another, you should call move(900x100); // 900 == screen1.width() + dialog.pos().x(). Then your widget will have 100x100 position on second monitor.
You should read Qt documentation.
You can use move on your QDialog, but be aware that move will set the QDialog position relative to it's parent.
You can get the Main Window's screen position and use that to setup the QDialog position. Just know that you're not guaranteed to have 2 screens on the end user machine.
For more information on move see: http://doc.qt.io/qt-5/application-windows.html#window-geometry
In my application I need to return the relative mouse position from an SDL_Surface, the problem is the mouse position that gets returned is relative to the SDL window and not the SDL_Surface. I guess my question is what is the easiest / most effective way of doing this. Any questions just ask. Thanks.
EDIT: Sorry I should have explained better, I have SDL_Surface* Surf_Display; on Surf_display there is an Image say its 1000 x 1000, So in order to see the image on a 600 x 600 window I have a camera that I can move around ( really its the surface that moves not the camera ) for instance to look right of the image I move the surface -1 left if that makes sense. So my problem is when I click my mouse on a part of the surface(image) my mouse returns the position that the mouse compared to where the cursor is in the window, what i'm wanting is so that it returns the position of the cursor compared to where it is on the surface(image)
I hope that better explains the situation. Thanks again
Just add(or subtract, depending on how you look at it) the offset to the mouse coordinates. So you're drawing the surface something like this:
SDL_Rect dest_rect = { -camera.x, -camera.y };
SDL_BlitSurface(image_surface, NULL, screen_surface, &dest_rect);
I don't know if you're using event based mouse handling, or if you're using SDL_GetMouseState, but either way, you would simply add camera.x and camera.y to the mouse position, for example:
int x, y;
SDL_GetMouseState(&x, &y);
x += camera.x;
y += camera.y;