Why the image

[Geng.Y]

I wanna load an image of 256*256 and put it in the center of widget, but no matter how I change the size of the window, only part of the image showed. What's wrong about that? Wish you could help me with this!

//imagewarping.h

#ifndef IMAGEWARPING_H
#define IMAGEWARPING_H

#include <QtWidgets/QMainWindow>
#include "ui_imagewarping.h"
#include "warpwidget.h"

class ImageWarping : public QMainWindow
{
	Q_OBJECT

public:
	ImageWarping(QWidget *parent = 0);
	~ImageWarping();

	void Init();

private:
	Ui::ImageWarpingClass ui;

	QMenu *menu_file;
	QMenu *menu_edit;
	QToolBar *toolbar_file;
	QToolBar *toolbar_edit;
	QAction *action_open;
	QAction *action_save;
	QAction *action_warp;
	QAction *action_delete;

	WarpWidget *warp_widegt;
};

#endif // IMAGEWARPING_H

//imagewarping.cpp

#include "imagewarping.h"

ImageWarping::ImageWarping(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	Init();
}

ImageWarping::~ImageWarping()
{

}

void ImageWarping::Init()
{
	action_open = new QAction(QIcon("open.png"),tr("Open"),this);
	action_save = new QAction(QIcon("save.png"),tr("Save"),this);
	action_warp = new QAction(QIcon("warp.jpg"),tr("Warp"),this);
	action_delete = new QAction(QIcon("delete.jpg"),tr("Delete"),this);

	menu_file = menuBar()->addMenu(tr("&File"));
	menu_file->setStatusTip(tr("file menu"));
	menu_file->addAction(action_open);
	menu_file->addAction(action_save);

	menu_edit = menuBar()->addMenu(tr("&Edit"));
	menu_edit->setStatusTip(tr("Edit"));
	menu_edit->addAction(action_warp);
	menu_edit->addAction(action_delete);

	toolbar_file = addToolBar(tr("File"));
	toolbar_file->addAction(action_open);
	toolbar_file->addSeparator();
	toolbar_file->addAction(action_save);
	

	toolbar_edit = addToolBar(tr("Warping"));
	toolbar_edit->addAction(action_warp);
	toolbar_edit->addSeparator();
	toolbar_edit->addAction(action_delete);

	warp_widegt = new WarpWidget();
	setCentralWidget(warp_widegt);

	connect(action_open,&QAction::triggered,warp_widegt,&WarpWidget::Open);
	connect(action_save,&QAction::triggered,warp_widegt,&WarpWidget::Save);
	connect(action_warp,&QAction::triggered,warp_widegt,&WarpWidget::Warp);
	connect(action_delete,&QAction::triggered,warp_widegt,&WarpWidget::Delete);

}

//warpwidget.h

#ifndef WARPWIDGET_H
#define WARPWIDGET_H

#include <QWidget>
#include <QImage>
#include <QPainter>
#include <QFileDialog>
#include <QMouseEvent>
#include <vector>
#include <math.h>
#include <iostream>
#include "ui_warpwidget.h"
#include "Line.h"

using namespace std;

class WarpWidget : public QWidget
{
	Q_OBJECT

public:
	WarpWidget(QWidget *parent = 0);
	~WarpWidget();

	void paintEvent(QPaintEvent *);
	void mousePressEvent(QMouseEvent *event);
	void mouseMoveEvent(QMouseEvent *event);
	void mouseReleaseEvent(QMouseEvent *event);

	void Open();
	void Save();
	void Warp();
	void Reset();
	void Delete();

	double Di_func(QPoint p,QPoint pi);
	double Delta(QPoint p,QPoint pi);
	double Wi_func(QPoint p,QPoint pi);
	QPoint Fi_fun(QPoint p,int i);
	QPoint F_Func(QPoint p);

private:
	Ui::WarpWidget ui;

	bool draw_status;

	QImage *ptr_image;
	QImage *ptr_image_backup;

	QPoint m_StartPoint;
	QPoint m_EndPoint;
	double u;
	vector<Line*> line_array;
};

#endif // WARPWIDGET_H

//warpwidget.cpp

#include "warpwidget.h"

WarpWidget::WarpWidget(QWidget *parent)
	: QWidget(parent)
{
	ui.setupUi(this);

	ptr_image = new QImage();
	ptr_image_backup = new QImage();

	draw_status = false;
}

WarpWidget::~WarpWidget()
{
	for (int i=0;i<line_array.size();i++)
	{
		if (line_array[i])
		{
			delete line_array[i];
			line_array[i] = NULL;
		}
	}
}

void WarpWidget::Open()
{
	QString fileName = QFileDialog::getOpenFileName(this,tr("Read Image"),".",tr("Image(*.bmp *.png *.jpg)"));

	if (!fileName.isEmpty())
	{
		ptr_image->load(fileName);
		ptr_image_backup->load(fileName);
	}

	update();
}

void WarpWidget::Save()
{
	QString fileName = QFileDialog::getSaveFileName(this,tr("Save Image"),".",tr("Image(*.bmp,*.png,*.jpg)"));
}

void WarpWidget::Warp()
{

}

void WarpWidget::Reset()
{
	*ptr_image = *ptr_image_backup;

	update();
}

void WarpWidget::Delete()
{
	if (!line_array.empty())
	{
		line_array.pop_back();
	}
	
}

void WarpWidget::mousePressEvent(QMouseEvent *event)
{
	if (Qt::LeftButton == event->button())
	{
		draw_status = true;

		m_StartPoint = m_EndPoint = event->pos();
	}
}

void WarpWidget::mouseMoveEvent(QMouseEvent *event)
{
	if (draw_status)
	{
		m_EndPoint = event->pos();
	}
}

void WarpWidget::mouseReleaseEvent(QMouseEvent *event)
{
	Line *current_line = NULL;
	current_line = new Line(m_StartPoint,m_EndPoint);
	line_array.push_back(current_line);
	draw_status = false;
}

void WarpWidget::paintEvent(QPaintEvent *)
{
	QPen pen;
	QPainter painter(this);
	painter.begin(this);

	painter.setBrush(Qt::lightGray);
	QRect back_rect(0,0,width(),height());
	painter.drawRect(back_rect);
        //*Put the image in the center of the widget*
	QRect image_rect((width()-ptr_image->width()/2),(height()-ptr_image->height())/2,width(),height());
	QRect source(0,0,100,100);
	painter.drawImage(image_rect,*ptr_image);
	

	pen.setWidth(5);	
	pen.setColor(Qt::darkCyan);
	painter.setPen(pen);

	for (int i=0;i<line_array.size();i++)
	{
		line_array[i]->Draw(painter);
	}

	if (draw_status)
	{	
		painter.drawLine(m_StartPoint,m_EndPoint);
	}

	painter.end();

	update();
}

double WarpWidget::Di_func(QPoint p,QPoint pi)
{
	return ((p.rx()-pi.rx())*(p.rx()-pi.rx())+(p.ry()-pi.ry())*(p.ry()-pi.ry()));
}

double WarpWidget::Delta(QPoint p,QPoint pi)
{
	return pow(1/Di_func(p,pi),u/2.0);
}

double WarpWidget::Wi_func(QPoint p,QPoint pi)
{
	double sum = 0;
	if (p == pi)
	{
		return 1;
	}
	else
	{
		for (int i=0;i<line_array.size();i++)
		{
			sum += Delta(p,line_array[i]->getStartPoint());
		}
		return Delta(p,pi)/sum;
	}
}

QPoint WarpWidget::Fi_fun(QPoint p,int i)
{
	QPoint result = line_array[i]->getEndPoint();

	result.rx() += p.rx() - line_array[i]->getEndPoint().rx();
	result.ry() += p.ry() - line_array[i]->getEndPoint().ry();

	return result;
}

QPoint WarpWidget::F_Func(QPoint p)
{
	QPoint result(0,0);
	for (int i=0;i<line_array.size();i++)
	{
		result.rx() += Wi_func(p,line_array[i]->getStartPoint()) * Fi_fun(p,i).rx();
		result.ry() += Wi_func(p,line_array[i]->getStartPoint()) * Fi_fun(p,i).ry();
	}

	return result;
}

[Vinod Kuntoji]

@Geng.Y said in Why the image:

WarpWidget

warp_widegt = new WarpWidget();
QHBoxLayout* hbox = new QHBoxLayout(this);
hbox->addWidget(warp_widegt);
this->centreWidget()->setLayout( hbox );
setCentralWidget( centreWidget() );

[Geng.Y]

There seems to be another mistake here.

[Vinod Kuntoji]

@Geng.Y

warp_widegt = new WarpWidget();
QHBoxLayout* hbox = new QHBoxLayout(this);
hbox->addWidget(warp_widegt);
QWidget* centreWidget = new QWidget();
centreWidget->setLayout( hbox );
setCentralWidget( centreWidget );

[Geng.Y]

It still doesn't work. Thank you！

[Vinod Kuntoji]

@Geng-Y ,

Have you tried setAlignment?

[Geng.Y]

Not yet. I'm new to Qt, but I'll try!

[raven-worx]

@Geng.Y said in Why the image:

QRect image_rect((width()-ptr_image->width()/2),(height()-ptr_image->height())/2,width(),height());
QRect source(0,0,100,100);
painter.drawImage(image_rect,*ptr_image);

Try this instead:

int x = (width()-ptr_image->width()) / 2;
int y = (height()-ptr_image->height())/2;
painter.drawImage( QPoint(x,y),*ptr_image );

at least you have a misplaced ) in your code.

[Geng.Y]

@raven-worx Thank you very much, and I find that I've neglected ()!