HPPA/HPPA/ImageViewer.cpp

#include "stdafx.h"
#include <iostream>

#include <QWheelEvent>
#include <QPoint>

#include "ImageViewer.h"


#define VIEW_CENTER viewport()->rect().center()
#define VIEW_WIDTH  viewport()->rect().width()
#define VIEW_HEIGHT viewport()->rect().height()


ImageViewer::ImageViewer(QWidget* pParent) :QGraphicsView(pParent)
{
	setRenderHint(QPainter::Antialiasing);
	setRenderHint(QPainter::SmoothPixmapTransform);
	setDragMode(QGraphicsView::ScrollHandDrag);

	// 关键点：不使用 Qt 默认的 anchor，而是自己控制
	setTransformationAnchor(QGraphicsView::NoAnchor);
	setResizeAnchor(QGraphicsView::NoAnchor);

	m_qtGraphicsScene = new QGraphicsScene(this);
	this->setScene(m_qtGraphicsScene);
	m_qtGraphicsScene->setSceneRect(-1e6, -1e6, 2e6, 2e6);

	m_framNumberLabel = new QLabel(this);
	m_framNumberLabel->setAlignment(Qt::AlignHCenter);
	m_framNumberLabel->setAlignment(Qt::AlignVCenter);

	QFont ft;
	ft.setPointSize(14);
	m_framNumberLabel->setFont(ft);
	m_framNumberLabel->setText("0");


	m_GraphicsPixmapItemHandle = nullptr;

	m_scale = 1.0;
	m_zoomDelta = 0.1;
	m_translateSpeed = 1.0;
	m_bMouseTranslate = false;


	setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
	setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
	setFrameShape(QFrame::NoFrame);
}

ImageViewer::~ImageViewer()
{

}

void ImageViewer::DisplayFrameNumber(int frameNumber)
{
	m_framNumberLabel->setText(QString::number(frameNumber));
	m_framNumberLabel->adjustSize();
}

void ImageViewer::SetImage(QPixmap *image)
{
	if (!HasImage())
	{
		m_GraphicsPixmapItemHandle = m_qtGraphicsScene->addPixmap(*image);
	}
	else
	{
		m_GraphicsPixmapItemHandle->setPixmap(*image);
	}
	ensureSceneVisible();
}

void ImageViewer::ensureSceneVisible()
{
	resetTransform();

	auto view_rect = viewport()->rect();
	auto scene_rect = this->scene()->itemsBoundingRect();

	double x_ratio = view_rect.width() / scene_rect.width();
	double y_ratio = view_rect.height() / scene_rect.height();
	double scale_factor = std::min(x_ratio, y_ratio) * 0.9;

	scale(scale_factor, scale_factor);
	m_scale *= scale_factor;

	centerOn(scene_rect.center());
}

bool ImageViewer::HasImage()
{
	if (m_GraphicsPixmapItemHandle == nullptr)
	{
		return false;
	}
	else
	{
		return true;
	}
}

void ImageViewer::wheelEvent(QWheelEvent *event)
{
	//qDebug() << "---------------+++++++++++++++++++++++++++++++++++++++++++++++++++ ";
	//if (true)//HasImage()
	//{
	//	//围绕鼠标点放大：https://blog.csdn.net/GoForwardToStep/article/details/77035287?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-3.channel_param&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-3.channel_param
	//	// 获取当前鼠标相对于view的位置;
	//	QPointF cursorPoint = event->pos();
	//	// 获取当前鼠标相对于scene的位置;
	//	QPointF scenePos = this->mapToScene(QPoint(cursorPoint.x(), cursorPoint.y()));

	//	// 获取view的宽高;
	//	qreal viewWidth = this->viewport()->width();
	//	qreal viewHeight = this->viewport()->height();

	//	// 获取当前鼠标位置相当于view大小的横纵比例;
	//	qreal hScale = cursorPoint.x() / viewWidth;
	//	qreal vScale = cursorPoint.y() / viewHeight;


	//	// 滚轮的滚动量
	//	QPoint scrollAmount = event->angleDelta();
	//	// 正值表示滚轮远离使用者放大负值表示朝向使用者缩小
	//	scrollAmount.y() > 0 ? zoomIn() : zoomOut();


	//	// 将scene坐标转换为放大缩小后的坐标;
	//	QPointF viewPoint = this->matrix().map(scenePos);
	//	// 通过滚动条控制view放大缩小后的展示scene的位置;
	//	horizontalScrollBar()->setValue(int(viewPoint.x() - viewWidth * hScale));
	//	verticalScrollBar()->setValue(int(viewPoint.y() - viewHeight * vScale));
	//}

	if (HasImage())
	{
		QPointF oldPos = mapToScene(event->pos());

		QPoint scrollAmount = event->angleDelta();
		scrollAmount.y() > 0 ? zoomIn() : zoomOut();

		QPointF newPos = mapToScene(event->pos());

		QPointF delta = newPos - oldPos;
		translate(delta.x(), delta.y());
	}

	//QGraphicsView::wheelEvent(event);//？？？？？？？？？？？？？？？？
}

void ImageViewer::scaling(qreal scaleFactor)
{
	//qDebug() << this->sceneRect();
	scale(scaleFactor, scaleFactor);
}

void ImageViewer::mousePressEvent(QMouseEvent *event)
{
	if (event->button()==Qt::LeftButton)
	{
		m_bMouseTranslate = true;
		m_lastMousePos = event->pos();

		//qDebug() << mapToScene(m_lastMousePos);

		emit leftMouseButtonPressed(mapToScene(m_lastMousePos).x(), mapToScene(m_lastMousePos).y());
	}
	

	//If you do not perform all the necessary work in your implementation of the virtual function, you may need to call the base class's implementation.
	QGraphicsView::mousePressEvent(event);
}

void ImageViewer::mouseMoveEvent(QMouseEvent *event)
{
	if (m_bMouseTranslate){
		QPointF mouseDelta = mapToScene(event->pos()) - mapToScene(m_lastMousePos);
		translate(mouseDelta.x(),mouseDelta.y());
	}

	m_lastMousePos = event->pos();
	QGraphicsView::mousePressEvent(event);
}

void ImageViewer::mouseReleaseEvent(QMouseEvent *event)
{
	m_bMouseTranslate = false;
	QGraphicsView::mouseReleaseEvent(event);
}

void ImageViewer::mouseDoubleClickEvent(QMouseEvent *event)
{
	QGraphicsView::mouseDoubleClickEvent(event);
}

void ImageViewer::zoomIn()
{
	zoom(1 + m_zoomDelta);
}

void ImageViewer::zoomOut()
{
	zoom(1 - m_zoomDelta);
}

void ImageViewer::zoom(float scaleFactor)
{
	// 防止过小或过大
	qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();
	if (factor < 0.07 || factor > 100)
		return;

	scale(scaleFactor, scaleFactor);
	m_scale *= scaleFactor;
}

void ImageViewer::setTranslateSpeed(qreal speed)
{
	// 建议速度范围
	Q_ASSERT_X(speed >= 0.0 && speed <= 2.0,
		"InteractiveView::setTranslateSpeed", "Speed should be in range [0.0, 2.0].");
	m_translateSpeed = speed;
}

qreal ImageViewer::translateSpeed() const
{
	return m_translateSpeed;
}

void ImageViewer::setZoomDelta(qreal delta)
{
	// 建议增量范围
	Q_ASSERT_X(delta >= 0.0 && delta <= 1.0,
		"InteractiveView::setZoomDelta", "Delta should be in range [0.0, 1.0].");
	m_zoomDelta = delta;
}

qreal ImageViewer::zoomDelta() const
{
	return m_zoomDelta;
}