Qt OpenCV 旋转图片

展示效果：

代码很简单，copy可以直接使用

代码如下：

RotationWgt.h

#pragma once

#include <QBoxLayout>
#include <QLabel>
#include <QSlider>
#include <QWidget>

class RotationWgt : public QWidget {
  Q_OBJECT
public:
  RotationWgt();
  ~RotationWgt();
  void initUI();
  QLabel *m_lblImg;
  QSlider *m_slider;
public slots:
  void slot_valueChange(int value);
};

RotationWgt.cpp

#include "RotationWgt.h"
#include <QDebug>
#include <QImage>
#include <opencv2/core.hpp>
#include <opencv2/opencv.hpp>
cv::Mat mat;
RotationWgt::RotationWgt() {
  setFixedSize(900, 800);
  initUI();
}

RotationWgt::~RotationWgt() {}

void RotationWgt::initUI() {
  QVBoxLayout *mainV = new QVBoxLayout();

  mat = cv::imread("D:/opencv/code/source/aa.jpg");
  QImage img(mat.data, mat.cols, mat.rows, mat.step, QImage::Format_RGB888);

  m_lblImg = new QLabel();
  m_lblImg->setPixmap(QPixmap::fromImage(img));
  m_slider = new QSlider();
  m_slider->setRange(0, 180);
  m_slider->setValue(0);
  m_slider->setOrientation(Qt::Horizontal);
  m_slider->setFixedWidth(400);
  connect(m_slider, &QSlider::valueChanged, this,
          &RotationWgt::slot_valueChange);

  mainV->addWidget(m_lblImg, 0, Qt::AlignHCenter);
  mainV->addStretch();
  mainV->addWidget(m_slider, 0, Qt::AlignHCenter);
  mainV->addStretch();

  setLayout(mainV);
}

void RotationWgt::slot_valueChange(int value) {
  // 定义旋转中心
  cv::Point2f center(mat.cols / 2, mat.rows / 2);
  // 获取旋转矩阵
  cv::Mat rotationMatrix = cv::getRotationMatrix2D(center, value, 1);
  //旋转图像
  cv::Mat rotatedImage;
  cv::warpAffine(mat, rotatedImage, rotationMatrix, mat.size());
  QImage img(rotatedImage.data, rotatedImage.cols, rotatedImage.rows,
             rotatedImage.step, QImage::Format_RGB888);
  m_lblImg->setPixmap(QPixmap::fromImage(img));
}