Error while initializing the Object in Qt

[Meera Hadid]

Re: Calling an object from another class

I want an object of qMRMLSliceControllerWidget in qMRMLSliceWidget.

1. In the header file I declared the object (qMRMLSliceControllerWidget* scw_temp1;) and in the .cxx file I initialized the object
   (scw_temp1 = new qMRMLSliceControllerWidget(q)).
   error:
2. I even tried creating a static Get() method in qMRMLSliceControllerWidget which return object of this class, even then I am getting errors.
   

[mrjj]

Hi

Are you sure you are using the right types?
The first error seems to say cannot make an A into B.
SlideWidget versus SlideControllerWidget

But for test :
if you make a

in qMRMLSliceWidget.cpp

void test () {
qMRMLSliceControllerWidget test;
}

will it accept it ?

Ofc with the right include etc.

if still no. Then you might have a circular include where
qMRMLSliceWidget includes qMRMLSliceControllerWidget and reverse.

[Meera Hadid]

I tried using test() method:

I have a doubt even in test() method we are just declaring the object right, we are not initializing. My doubt is how to initialize the object.
For accessing the widgets in qMRMLSliceControllerWidget I will have to create its object right? or is there any other method.

[JonB]

@Meera-Hadid said in Error while initializing the Object in Qt:

I tried using test() method

The error message indicates that, whatever code you have written, you are attempting to access a variable named test when you say you declared a method named test().

[Meera Hadid]

using test object i tried calling the spinBox in qMRMLSliceControllerWidget
code:

qMRMLSliceControllerWidgetPrivate* qMRMLSliceWidget::test() {
    qMRMLSliceControllerWidgetPrivate* test;
    return test;
}

test_obj = qMRMLSliceWidget::test();
  this->ControllerLayout = new QVBoxLayout(q);
  this->ControllerLayout->setSpacing(2);
  QMargins cmargins = this->ControllerLayout->contentsMargins();
  cmargins.setTop(0);
  cmargins.setBottom(0);
  cmargins.setLeft(0);
  cmargins.setRight(0);
  this->ControllerLayout->setContentsMargins(cmargins);
  
  this->ControllerLayout->addWidget(test_obj->spinBox);
  q->setLayout(this->ControllerLayout);

[mrjj]

@Meera-Hadid

Hi

we should not name both object and function test. sorry my bad, too little coffe :)

I meant

void test () {
qMRMLSliceControllerWidget mySC;
}

it was just to see if it does know the type without errors.

Well its just a local variable so it is initialized as such. ( even there is no new )

It seems it does know the type and does not complain about it ? , correct ?

So this seems to be fine so you should be able to create
a qMRMLSliceWidget in qMRMLSliceWidget.

I think what ever the q is you are giving it
new qMRMLSliceControllerWidget(q)) <<<< i think its not what it wants

hence the error in the picture

[mrjj]

@Meera-Hadid
Hi
the code you just posted will crash :)
Its dangling pointer.

qMRMLSliceControllerWidgetPrivate* qMRMLSliceWidget::test() {
qMRMLSliceControllerWidgetPrivate* test; <<<<< dangling pointer !
return test;
}

so that will not work 100%

it must be
qMRMLSliceControllerWidgetPrivate* qMRMLSliceWidget::test() {
qMRMLSliceControllerWidgetPrivate* test = new qMRMLSliceControllerWidgetPrivate( what ever it wants)
return test;
}

ps. why you go from qMRMLSliceControllerWidget to
qMRMLSliceControllerWidgetPrivate `?
the private type seems its called that as one should not use it outside class ?

[Meera Hadid]

Basically the spinBox is defined in qMRMLSliceControllerWidgetPrivate but it is a public variable. For better understanding

qMRMLSliceControllerWidget_p.h:

#ifndef __qMRMLSliceControllerWidget_p_h
#define __qMRMLSliceControllerWidget_p_h
// CTK includes
#include <ctkPimpl.h>
#include <ctkVTKObject.h>

// qMRML includes
#include "qMRMLSliceControllerWidget.h"
#include "qMRMLViewControllerBar_p.h"
#include "ui_qMRMLSliceControllerWidget.h"

// MRMLLogic includes
#include <vtkMRMLSliceLogic.h>

// VTK includes
#include <vtkAlgorithmOutput.h>
#include <vtkCollection.h>
#include <vtkImageData.h>
#include <vtkSmartPointer.h>
#include <vtkWeakPointer.h>

class ctkSignalMapper;
class ctkDoubleSpinBox;
class ctkVTKSliceView;
class QSpinBox;
class qMRMLSliderWidget;
class vtkMRMLSliceNode;
class vtkObject;
class vtkMRMLSegmentationDisplayNode;

//-----------------------------------------------------------------------------
struct QMRML_WIDGETS_EXPORT qMRMLOrientation
{
  QString Prefix;
  QString ToolTip;
};

//-----------------------------------------------------------------------------
class QMRML_WIDGETS_EXPORT qMRMLSliceControllerWidgetPrivate
  : public qMRMLViewControllerBarPrivate
  , public Ui_qMRMLSliceControllerWidget
{
  Q_OBJECT
  QVTK_OBJECT
  Q_DECLARE_PUBLIC(qMRMLSliceControllerWidget);

public:
  typedef qMRMLSliceControllerWidgetPrivate Self;
  typedef qMRMLViewControllerBarPrivate Superclass;
  qMRMLSliceControllerWidgetPrivate(qMRMLSliceControllerWidget& object);
  ~qMRMLSliceControllerWidgetPrivate() override;

  void init() override;
  void setColor(QColor color) override;

  void setupLinkedOptionsMenu();
  void setupReformatOptionsMenu();
  void setupLightboxMenu();
  void setupCompositingMenu();
  void setupSliceSpacingMenu();
  void setupSliceModelMenu();
  void setupSegmentationMenu();
  void setupLabelMapMenu();
  void setupMoreOptionsMenu();
  void setupOrientationMarkerMenu();
  void setupRulerMenu();

  qMRMLOrientation mrmlOrientation(const QString& name);

  vtkSmartPointer<vtkCollection> saveNodesForUndo(const QString& nodeTypes);

  void enableLayerWidgets();

  vtkMRMLSliceLogic* compositeNodeLogic(vtkMRMLSliceCompositeNode* node);
  vtkMRMLSliceLogic* sliceNodeLogic(vtkMRMLSliceNode* node);

  void setForegroundInterpolation(vtkMRMLSliceLogic* logic, bool interpolate);
  void setBackgroundInterpolation(vtkMRMLSliceLogic* logic, bool interpolate);

  /// Create a list of orientation containing the regular presets and also
  /// the "Reformat" string if sliceToRAS is different one of the preset.
  static void updateSliceOrientationSelector(
      vtkMRMLSliceNode* sliceNode, QComboBox *sliceOrientationSelector);

  //static qMRMLSliceControllerWidgetPrivate* Get();

public slots:
  /// Update widget state when the scene is modified
  void updateFromMRMLScene();

  /// Update widget state using the associated MRML slice node
  void updateWidgetFromMRMLSliceNode();

  /// Update widget state using the associated MRML slice composite node
  void updateWidgetFromMRMLSliceCompositeNode();

  /// Called after a foreground layer volume node is selected
  /// using the associated qMRMLNodeComboBox
  void onForegroundLayerNodeSelected(vtkMRMLNode* node);

  /// Called after a background layer volume node is selected
  /// using the associated qMRMLNodeComboBox
  void onBackgroundLayerNodeSelected(vtkMRMLNode* node);

  /// Called after a label layer volume node is selected
  /// using the associated qMRMLNodeComboBox
  void onLabelMapNodeSelected(vtkMRMLNode* node);

  /// Called after a segmentation node is selected in the combobox
  void onSegmentationNodeSelected(vtkMRMLNode* node);

  /// Called after the currently selected segmentation node's display
  /// option is modified
  void onSegmentationNodeDisplayModifiedEvent(vtkObject* nodeObject);
  /// Called when segment visibility is changed from the segment combobox
  void onSegmentVisibilitySelectionChanged(QStringList selectedSegmentIDs);
  /// Update segmentation outline/fill button
  void updateSegmentationOutlineFillButton();
  /// Utility function to get the display node of the current segmentation
  vtkMRMLSegmentationDisplayNode* currentSegmentationDisplayNode();

  void updateFromForegroundDisplayNode(vtkObject* displayNode);
  void updateFromBackgroundDisplayNode(vtkObject* displayNode);

  void updateFromForegroundVolumeNode(vtkObject* volumeNode);
  void updateFromBackgroundVolumeNode(vtkObject* volumeNode);

  /// Called after the SliceLogic is modified
  void onSliceLogicModifiedEvent();

  void applyCustomLightbox();

protected:
  void setupPopupUi() override;
  virtual void setMRMLSliceNodeInternal(vtkMRMLSliceNode* sliceNode);
  void setMRMLSliceCompositeNodeInternal(vtkMRMLSliceCompositeNode* sliceComposite);

public:
  vtkMRMLSliceNode*                   MRMLSliceNode;
  vtkMRMLSliceCompositeNode*          MRMLSliceCompositeNode;
  vtkSmartPointer<vtkMRMLSliceLogic>  SliceLogic;
  vtkCollection*                      SliceLogics;
  vtkWeakPointer<vtkAlgorithmOutput>  ImageDataConnection;
  QHash<QString, qMRMLOrientation>    SliceOrientationToDescription;
  QString                             SliceViewName;
  QButtonGroup*                       ControllerButtonGroup;

  QToolButton*                        FitToWindowToolButton;
  qMRMLSliderWidget*                  SliceOffsetSlider;
 ctkDoubleSpinBox*                   spinBox;
  double                              LastLabelMapOpacity;
  double                              LastForegroundOpacity;
  double                              LastBackgroundOpacity;
  QMenu*                              LightboxMenu;
  QMenu*                              CompositingMenu;
  QMenu*                              SliceSpacingMenu;
  QMenu*                              SliceModelMenu;
  QMenu*                              SegmentationMenu;
  QMenu*                              LabelMapMenu;
  QMenu*                              OrientationMarkerMenu;
  QMenu*                              RulerMenu;

  ctkDoubleSpinBox*                   SliceSpacingSpinBox;
  ctkDoubleSpinBox*                   SliceFOVSpinBox;
  QSpinBox*                           LightBoxRowsSpinBox;
  QSpinBox*                           LightBoxColumnsSpinBox;

  ctkDoubleSpinBox*                   SliceModelFOVXSpinBox;
  ctkDoubleSpinBox*                   SliceModelFOVYSpinBox;

  ctkDoubleSpinBox*                   SliceModelOriginXSpinBox;
  ctkDoubleSpinBox*                   SliceModelOriginYSpinBox;

  QSpinBox*                           SliceModelDimensionXSpinBox;
  QSpinBox*                           SliceModelDimensionYSpinBox;

  QSize                               ViewSize;

  ctkSignalMapper*                    OrientationMarkerTypesMapper;
  ctkSignalMapper*                    OrientationMarkerSizesMapper;

  ctkSignalMapper*                    RulerTypesMapper;
  ctkSignalMapper*                    RulerColorMapper;
};

#endif

[Meera Hadid]

qMRMLSliceControllerWidget.cxx:

void qMRMLSliceControllerWidgetPrivate::init()
{
  Q_Q(qMRMLSliceControllerWidget);

  this->Superclass::init();
  this->FitToWindowToolButton = new QToolButton(q);
  this->FitToWindowToolButton->setObjectName("FitToWindowToolButton");
  //this->FitToWindowToolButton->setToolTip(tr("Adjust the Slice Viewer's field of view to match the extent of lowest non-None volume layer (bg, then fg, then label)."));
  //QIcon fitToWindowIcon(":/Icons/SlicesFitToWindow.png");
  //this->FitToWindowToolButton->setIcon(fitToWindowIcon);
  this->FitToWindowToolButton->setAutoRaise(true);
  this->FitToWindowToolButton->setDefaultAction(this->actionFit_to_window);
  this->FitToWindowToolButton->setFixedSize(15, 15);
  this->BarLayout->insertWidget(2, this->FitToWindowToolButton);
  //Hide FitToWindowToolButton from the Barlayout
  this->FitToWindowToolButton->hide();


  this->SliceOffsetSlider = new qMRMLSliderWidget(q);
  this->SliceOffsetSlider->setObjectName("SliceOffsetSlider");
  this->SliceOffsetSlider->setTracking(false);
  this->SliceOffsetSlider->setToolTip(qMRMLSliceControllerWidget::tr("Slice distance from RAS origin"));
  this->SliceOffsetSlider->setQuantity("length");
  this->SliceOffsetSlider->setUnitAwareProperties(
    qMRMLSliderWidget::Suffix|qMRMLSliderWidget::Precision|qMRMLSliderWidget::Scaling);
  this->SliceOffsetSlider->spinBox()->setDecimalsOption(
    ctkDoubleSpinBox::DecimalsByShortcuts |
    ctkDoubleSpinBox::DecimalsByKey |
    ctkDoubleSpinBox::DecimalsAsMin );

  //this->SliceOffsetSlider->spinBox()->setParent(this->PopupWidget);
  spinBox = this->SliceOffsetSlider->spinBox();
  spinBox->setFrame(false);
  spinBox->spinBox()->setButtonSymbols(QAbstractSpinBox::NoButtons);
  spinBox->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
  int targetHeight = spinBox->parentWidget()->layout()->sizeHint().height();//setSizeConstraint(QLayout::SetMinimumSize);
  int fontHeight = spinBox->fontMetrics().height();
  qreal heightRatio = static_cast<qreal>(targetHeight - 2) / fontHeight;
  if (heightRatio  < 1.)
    {
    QFont stretchedFont(spinBox->font());
    stretchedFont.setPointSizeF(stretchedFont.pointSizeF() * heightRatio);
    spinBox->setFont(stretchedFont);
    }

  // Connect Slice offset slider
  this->connect(this->SliceOffsetSlider, SIGNAL(valueChanged(double)),
                q, SLOT(setSliceOffsetValue(double)), Qt::QueuedConnection);
  this->connect(this->SliceOffsetSlider, SIGNAL(valueIsChanging(double)),
                q, SLOT(trackSliceOffsetValue(double)), Qt::QueuedConnection);
  this->connect(q, SIGNAL(mrmlSceneChanged(vtkMRMLScene*)),
                this->SliceOffsetSlider, SLOT(setMRMLScene(vtkMRMLScene*)));
  this->BarLayout->addWidget(this->SliceOffsetSlider);
  this->SliceOffsetSlider->hide();
  this->BarLayout->addWidget(this->spinBox);

  //spinBox->hide();
  // Move the spinbox in the popup instead of having it in the slider bar
  //dynamic_cast<QGridLayout*>(this->PopupWidget->layout())->addWidget(
  //  this->SliceOffsetSlider->spinBox(), 0, 0, 1, 2);

  // Hide all buttons by default
  this->MoreButton->setChecked(false);

  vtkNew<vtkMRMLSliceLogic> defaultLogic;
  q->setSliceLogic(defaultLogic.GetPointer());

  q->setSliceViewName("Red");
}

i want to use this spinBox in qMRMLSliceWidget

[Meera Hadid]

and the qMRMLSliceControllerWidget constructor is

qMRMLSliceControllerWidgetPrivate::qMRMLSliceControllerWidgetPrivate(qMRMLSliceControllerWidget& object)
  : Superclass(object)
{
  this->SliceLogic = nullptr;
  this->MRMLSliceNode = nullptr;
  this->MRMLSliceCompositeNode = nullptr;
  this->SliceLogics = nullptr;

  this->ControllerButtonGroup = nullptr;
  qMRMLOrientation axialOrientation = {qMRMLSliceControllerWidget::tr("Axial:"), qMRMLSliceControllerWidget::tr("I <-----> S")};
  qMRMLOrientation sagittalOrientation = {qMRMLSliceControllerWidget::tr("Sagittal:"), qMRMLSliceControllerWidget::tr("L <-----> R")};
  qMRMLOrientation coronalOrientation = {qMRMLSliceControllerWidget::tr("Coronal:"), qMRMLSliceControllerWidget::tr("P <-----> A")};
  qMRMLOrientation obliqueOrientation = {"", qMRMLSliceControllerWidget::tr("Oblique")};

  this->SliceOrientationToDescription["Axial"] = axialOrientation;
  this->SliceOrientationToDescription["Sagittal"] = sagittalOrientation;
  this->SliceOrientationToDescription["Coronal"] = coronalOrientation;
  this->SliceOrientationToDescription["Reformat"] = obliqueOrientation;

  this->LastLabelMapOpacity = 1.;
  this->LastForegroundOpacity = 1.;
  this->LastBackgroundOpacity = 1.;

  this->FitToWindowToolButton = nullptr;
  this->SliceOffsetSlider = nullptr;
  this->spinBox = nullptr;
  
  this->LightboxMenu = nullptr;
  this->CompositingMenu = nullptr;
  this->SliceSpacingMenu = nullptr;
  this->SliceModelMenu = nullptr;
  this->SegmentationMenu = nullptr;
  this->LabelMapMenu = nullptr;
  this->OrientationMarkerMenu = nullptr;
  this->RulerMenu = nullptr;

  this->SliceSpacingSpinBox = nullptr;
  this->SliceFOVSpinBox = nullptr;
  this->LightBoxRowsSpinBox = nullptr;
  this->LightBoxColumnsSpinBox = nullptr;

  this->SliceModelFOVXSpinBox = nullptr;
  this->SliceModelFOVYSpinBox = nullptr;

  this->SliceModelOriginXSpinBox = nullptr;
  this->SliceModelOriginYSpinBox = nullptr;

  this->SliceModelDimensionXSpinBox = nullptr;
  this->SliceModelDimensionYSpinBox = nullptr;
}

i want to place this spinBox in qMRMLSliceWidget, is there any method for doing this?

[mrjj]

@Meera-Hadid
Do you mean its
ctkDoubleSpinBox* spinBox; ?

well its public so i guess you can.

it sems to be allocated / assigned in
qMRMLSliceControllerWidgetPrivate::init()
....
spinBox = this->SliceOffsetSlider->spinBox();

but im still not sure what that "q" is that it seems to use for constructor.

[Meera Hadid]

I Have a QToolButton in the first UI I don't want to display it over there but the functionalities/actions of the button are initialized in the first.cxx file. So when I create an object of the first class in the second class and try adding the button in a widget of the second class does the button get transferred?

QToolButton code in qMRMLSLiceControllerWidget.cxx:

this->FitToWindowToolButton = new QToolButton(q);
this->FitToWindowToolButton->setObjectName("FitToWindowToolButton");
this->FitToWindowToolButton->setAutoRaise(true);
this->FitToWindowToolButton->setDefaultAction(this->actionFit_to_window);
this->FitToWindowToolButton->setFixedSize(15, 15);

QObject::connect(this->actionFit_to_window, SIGNAL(triggered()),
               q, SLOT(fitSliceToBackground()));

Object of qMRMLSLiceControllerWidget in qMRMLSliceWidget: initialization in qMRMLSliceWidget_p.h:

qMRMLSliceControllerWidget* scw;

declaration in qMRMLSliceWidget.cxx:

scw = new qMRMLSliceControllerWidget(q);

when I create an object like this in my App I don't know for what reason 0.00 is getting displayed

[Coleman Jeffrey]

Thank you and everyone, I also had the same problem.
Thanks