C++ (Cpp) pointAfterScale Examples

Example #1

File: PlotView.cpp Project: UIKit0/discover

/**
  * Zoom the view in and out.
  */
void PlotView::wheelEvent(QWheelEvent* event) {

    // Get the position of the mouse before scaling, in scene coords
    QPointF pointBeforeScale(mapToScene(event->pos()));

    // Get the original screen centerpoint
    QPointF screenCenter = GetCenter(); //CurrentCenterPoint; //(visRect.center());

    // Scale the view ie. do the zoom
    double scaleFactor = 1.25; // How fast we zoom
    if (event->delta() > 0) {
        // Zoom in
        scale(scaleFactor, scaleFactor);
    }
    else {
        // Zooming out
        scale(1.0 / scaleFactor, 1.0 / scaleFactor);
    }

    // Get the position after scaling, in scene coords
    QPointF pointAfterScale(mapToScene(event->pos()));

    // Get the offset of how the screen moved
    QPointF offset = pointBeforeScale - pointAfterScale;

    // Adjust to the new center for correct zooming
    QPointF newCenter = screenCenter + offset;
    SetCenter(newCenter);
}

Example #2

File: umlview.cpp Project: Nephos/umbrello

/**
 * Zoom the view in and out.
 */
void UMLView::wheelEvent(QWheelEvent* event)
{
    // get the position of the mouse before scaling, in scene coords
    QPointF pointBeforeScale(mapToScene(event->pos()));

    // get the original screen centerpoint
    QPointF screenCenter = center();

    // scale the view ie. do the zoom
    double scaleFactor = 1.15;
    if (event->delta() > 0) {
        // zoom in
        if (currentZoom() < 500) {
            scale(scaleFactor, scaleFactor);
        }
    } else {
        // zooming out
        if (currentZoom() > 10) {
            scale(1.0 / scaleFactor, 1.0 / scaleFactor);
        }
    }

    // get the position after scaling, in scene coords
    QPointF pointAfterScale(mapToScene(event->pos()));

    // get the offset of how the screen moved
    QPointF offset = pointBeforeScale - pointAfterScale;

    // adjust to the new center for correct zooming
    QPointF newCenter = screenCenter + offset;
    setCenter(newCenter);

    DEBUG(DBG_SRC) << "currentZoom=" << currentZoom();
    UMLApp::app()->slotZoomSliderMoved(currentZoom());
}

Example #3

File: mygraphicsview.cpp Project: quimnuss/superannotator

void MyGraphicsView::scale(double factor)
{
    //Get the position of the mouse before scaling, in scene coords
    QPointF pointBeforeScale(mapToScene( mLastMouseMovePt ));

    //Get the original screen centerpoint
    QPointF screenCenter = GetCenter(); //CurrentCenterPoint; //(visRect.center());

    double tempScale = factor;
    tempScale *= mScaleFactor;

    if ( tempScale > mZoomMax )
        tempScale = mZoomMax;
    if (tempScale < mZoomMin)
        tempScale = mZoomMin;

    factor = tempScale / mScaleFactor;

    mScaleFactor = tempScale;

    //Scale the view ie. do the zoom
    QGraphicsView::scale(factor, factor);

    //Get the position after scaling, in scene coords
    QPointF pointAfterScale(mapToScene( mLastMouseMovePt ));

    //Get the offset of how the screen moved
    QPointF offset = pointBeforeScale - pointAfterScale;

    //Adjust to the new center for correct zooming
    QPointF newCenter = screenCenter + offset;
    SetCenter(newCenter);
}