Add imageCropper

QWidgetDemo.pro

@@ -1,6 +1,7 @@
 TEMPLATE = subdirs
 #定义了ordered表示子项目按照添加的顺序来编译
 CONFIG  += ordered
+SUBDIRS += imagecropper     #图片裁剪
 SUBDIRS += lightbutton      #高亮按钮控件
 SUBDIRS += movewidget       #通用控件移动类
 SUBDIRS += flatui           #模仿flatui类

imagecropper/base/imagecropperdialog.h

@@ -0,0 +1,99 @@
+#ifndef IMAGECROPPER_H
+#define IMAGECROPPER_H
+
+#include <QWidget>
+#include <QDialog>
+#include <QPainter>
+#include <QLabel>
+#include <QPixmap>
+#include <QString>
+#include <QMessageBox>
+#include <QHBoxLayout>
+#include <QVBoxLayout>
+#include <QPushButton>
+
+#include "imagecropperlabel.h"
+
+/*******************************************************
+ *  Loacl private class, which do image-cropping
+ *  Used in class ImageCropper
+*******************************************************/
+class ImageCropperDialogPrivate : public QDialog
+{
+    Q_OBJECT
+public:
+    ImageCropperDialogPrivate(const QPixmap &imageIn, QPixmap &outputImage,
+                              int windowWidth, int windowHeight,
+                              CropperShape shape, QSize cropperSize = QSize())
+        : QDialog(nullptr)
+        , outputImage(outputImage)
+    {
+        this->setAttribute(Qt::WA_DeleteOnClose, true);
+        this->setWindowTitle("Image Cropper");
+        this->setMouseTracking(true);
+        this->setModal(true);
+
+        imageLabel = new ImageCropperLabel(windowWidth, windowHeight, this);
+        imageLabel->setCropper(shape, cropperSize);
+        imageLabel->setOutputShape(OutputShape::RECT);
+        imageLabel->setOriginalImage(imageIn);
+        imageLabel->enableOpacity(true);
+
+        QHBoxLayout *btnLayout = new QHBoxLayout();
+        btnOk = new QPushButton("OK", this);
+        btnCancel = new QPushButton("Cancel", this);
+        btnLayout->addStretch();
+        btnLayout->addWidget(btnOk);
+        btnLayout->addWidget(btnCancel);
+
+        QVBoxLayout *mainLayout = new QVBoxLayout(this);
+        mainLayout->addWidget(imageLabel);
+        mainLayout->addLayout(btnLayout);
+
+        connect(btnOk, &QPushButton::clicked, this, [this]() {
+            this->outputImage = this->imageLabel->getCroppedImage();
+            this->close();
+        });
+        connect(btnCancel, &QPushButton::clicked, this, [this]() {
+            this->outputImage = QPixmap();
+            this->close();
+        });
+    }
+
+private:
+    ImageCropperLabel *imageLabel;
+    QPushButton *btnOk;
+    QPushButton *btnCancel;
+    QPixmap &outputImage;
+};
+
+/*******************************************************************
+ *  class ImageCropperDialog
+ *      create a instane of class ImageCropperDialogPrivate
+ *      and get cropped image from the instance(after closing)
+********************************************************************/
+class ImageCropperDialog : QObject
+{
+public:
+    static QPixmap getCroppedImage(const QString &filename, int windowWidth, int windowHeight,
+                                   CropperShape cropperShape, QSize crooperSize = QSize())
+    {
+        QPixmap inputImage;
+        QPixmap outputImage;
+
+        if (!inputImage.load(filename)) {
+            QMessageBox::critical(nullptr, "Error", "Load image failed!", QMessageBox::Ok);
+            return outputImage;
+        }
+
+        ImageCropperDialogPrivate *imageCropperDo =
+            new ImageCropperDialogPrivate(inputImage, outputImage,
+                                          windowWidth, windowHeight,
+                                          cropperShape, crooperSize);
+        imageCropperDo->exec();
+
+        return outputImage;
+    }
+};
+
+#endif // IMAGECROPPER_H

imagecropper/base/imagecropperlabel.cpp

@@ -0,0 +1,714 @@
+#include "imagecropperlabel.h"
+
+#include <QPainter>
+#include <QPainterPath>
+#include <QMouseEvent>
+#include <QDebug>
+#include <QBitmap>
+
+ImageCropperLabel::ImageCropperLabel(int width, int height, QWidget* parent) :
+         QLabel(parent)
+{
+    this->setFixedSize(width, height);
+    this->setAlignment(Qt::AlignCenter);
+    this->setMouseTracking(true);
+
+    borderPen.setWidth(1);
+    borderPen.setColor(Qt::white);
+    borderPen.setDashPattern(QVector<qreal>() << 3 << 3 << 3 << 3);
+}
+
+void ImageCropperLabel::setOriginalImage(const QPixmap &pixmap) {
+    originalImage = pixmap;
+
+    int imgWidth = pixmap.width();
+    int imgHeight = pixmap.height();
+    int labelWidth = this->width();
+    int labelHeight = this->height();
+    int imgWidthInLabel;
+    int imgHeightInLabel;
+
+    if (imgWidth * labelHeight < imgHeight * labelWidth) {
+        scaledRate = labelHeight / double(imgHeight);
+        imgHeightInLabel = labelHeight;
+        imgWidthInLabel = int(scaledRate * imgWidth);
+        imageRect.setRect((labelWidth - imgWidthInLabel) / 2, 0,
+                          imgWidthInLabel, imgHeightInLabel);
+    }
+    else {
+        scaledRate = labelWidth / double(imgWidth);
+        imgWidthInLabel = labelWidth;
+        imgHeightInLabel = int(scaledRate * imgHeight);
+        imageRect.setRect(0, (labelHeight - imgHeightInLabel) / 2,
+                          imgWidthInLabel, imgHeightInLabel);
+    }
+
+    tempImage = originalImage.scaled(imgWidthInLabel, imgHeightInLabel,
+                                     Qt::KeepAspectRatio, Qt::SmoothTransformation);
+    this->setPixmap(tempImage);
+
+    if (cropperShape >= CropperShape::FIXED_RECT) {
+        cropperRect.setWidth(int(cropperRect_.width() * scaledRate));
+        cropperRect.setHeight(int(cropperRect_.height() * scaledRate));
+    }
+    resetCropperPos();
+}
+
+
+/*****************************************
+ * set cropper's shape (and size)
+*****************************************/
+void ImageCropperLabel::setRectCropper() {
+    cropperShape = CropperShape::RECT;
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setSquareCropper() {
+    cropperShape = CropperShape::SQUARE;
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setEllipseCropper() {
+    cropperShape = CropperShape::ELLIPSE;
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setCircleCropper() {
+    cropperShape = CropperShape::CIRCLE;
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setFixedRectCropper(QSize size) {
+    cropperShape = CropperShape::FIXED_RECT;
+    cropperRect_.setSize(size);
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setFixedEllipseCropper(QSize size) {
+    cropperShape = CropperShape::FIXED_ELLIPSE;
+    cropperRect_.setSize(size);
+    resetCropperPos();
+}
+
+// not recommended
+void ImageCropperLabel::setCropper(CropperShape shape, QSize size) {
+    cropperShape = shape;
+    cropperRect_.setSize(size);
+    resetCropperPos();
+}
+
+/*****************************************************************************
+     * Set cropper's fixed size
+    *****************************************************************************/
+void ImageCropperLabel::setCropperFixedSize(int fixedWidth, int fixedHeight) {
+    cropperRect_.setSize(QSize(fixedWidth, fixedHeight));
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setCropperFixedWidth(int fixedWidth) {
+    cropperRect_.setWidth(fixedWidth);
+    resetCropperPos();
+}
+
+void ImageCropperLabel::setCropperFixedHeight(int fixedHeight) {
+    cropperRect_.setHeight(fixedHeight);
+    resetCropperPos();
+}
+
+/**********************************************
+ * Move cropper to the center of the image
+ * And resize to default
+**********************************************/
+void ImageCropperLabel::resetCropperPos() {
+    int labelWidth = this->width();
+    int labelHeight = this->height();
+
+    if (cropperShape == CropperShape::FIXED_RECT || cropperShape == CropperShape::FIXED_ELLIPSE) {
+        cropperRect.setWidth(int(cropperRect_.width() * scaledRate));
+        cropperRect.setHeight(int(cropperRect_.height() * scaledRate));
+    }
+
+    switch (cropperShape) {
+        case CropperShape::UNDEFINED:
+            break;
+        case CropperShape::FIXED_RECT:
+        case CropperShape::FIXED_ELLIPSE: {
+            cropperRect.setRect((labelWidth - cropperRect.width()) / 2,
+                             (labelHeight - cropperRect.height()) / 2,
+                             cropperRect.width(), cropperRect.height());
+            break;
+        }
+        case CropperShape::RECT:
+        case CropperShape::SQUARE:
+        case CropperShape::ELLIPSE:
+        case CropperShape::CIRCLE: {
+            int imgWidth = tempImage.width();
+            int imgHeight = tempImage.height();
+            int edge = int((imgWidth > imgHeight ? imgHeight : imgWidth) * 3 / 4.0);
+            cropperRect.setRect((labelWidth - edge) / 2, (labelHeight - edge) / 2, edge, edge);
+            break;
+        }
+    }
+}
+
+QPixmap ImageCropperLabel::getCroppedImage() {
+    return getCroppedImage(this->outputShape);
+}
+
+QPixmap ImageCropperLabel::getCroppedImage(OutputShape shape) {
+    int startX = int((cropperRect.left() - imageRect.left()) / scaledRate);
+    int startY = int((cropperRect.top() - imageRect.top()) / scaledRate);
+    int croppedWidth = int(cropperRect.width() / scaledRate);
+    int croppedHeight = int(cropperRect.height() / scaledRate);
+
+    QPixmap resultImage(croppedWidth, croppedHeight);
+    resultImage = originalImage.copy(startX, startY, croppedWidth, croppedHeight);
+
+    // Set ellipse mask (cut to ellipse shape)
+    if (shape == OutputShape::ELLIPSE) {
+        QSize size(croppedWidth, croppedHeight);
+        QBitmap mask(size);
+        QPainter painter(&mask);
+        painter.setRenderHint(QPainter::Antialiasing);
+        painter.setRenderHint(QPainter::SmoothPixmapTransform);
+        painter.fillRect(0, 0, size.width(), size.height(), Qt::white);
+        painter.setBrush(QColor(0, 0, 0));
+        painter.drawRoundRect(0, 0, size.width(), size.height(), 99, 99);
+        resultImage.setMask(mask);
+    }
+
+    return resultImage;
+}
+
+
+void ImageCropperLabel::paintEvent(QPaintEvent *event) {
+    // Draw original image
+    QLabel::paintEvent(event);
+
+    // Draw cropper and set some effects
+    switch (cropperShape) {
+        case CropperShape::UNDEFINED:
+            break;
+        case CropperShape::FIXED_RECT:
+            drawRectOpacity();
+            break;
+        case CropperShape::FIXED_ELLIPSE:
+            drawEllipseOpacity();
+            break;
+        case CropperShape::RECT:
+            drawRectOpacity();
+            drawSquareEdge(!ONLY_FOUR_CORNERS);
+            break;
+        case CropperShape::SQUARE:
+            drawRectOpacity();
+            drawSquareEdge(ONLY_FOUR_CORNERS);
+            break;
+        case CropperShape::ELLIPSE:
+            drawEllipseOpacity();
+            drawSquareEdge(!ONLY_FOUR_CORNERS);
+            break;
+        case CropperShape::CIRCLE:
+            drawEllipseOpacity();
+            drawSquareEdge(ONLY_FOUR_CORNERS);
+            break;
+    }
+
+    // Draw cropper rect
+    if (isShowRectBorder) {
+        QPainter painter(this);
+        painter.setPen(borderPen);
+        painter.drawRect(cropperRect);
+    }
+}
+
+void ImageCropperLabel::drawSquareEdge(bool onlyFourCorners) {
+    if (!isShowDragSquare)
+        return;
+
+    // Four corners
+    drawFillRect(cropperRect.topLeft(), dragSquareEdge, dragSquareColor);
+    drawFillRect(cropperRect.topRight(), dragSquareEdge, dragSquareColor);
+    drawFillRect(cropperRect.bottomLeft(), dragSquareEdge, dragSquareColor);
+    drawFillRect(cropperRect.bottomRight(), dragSquareEdge, dragSquareColor);
+
+    // Four edges
+    if (!onlyFourCorners) {
+        int centralX = cropperRect.left() + cropperRect.width() / 2;
+        int centralY = cropperRect.top() + cropperRect.height() / 2;
+        drawFillRect(QPoint(cropperRect.left(), centralY), dragSquareEdge, dragSquareColor);
+        drawFillRect(QPoint(centralX, cropperRect.top()), dragSquareEdge, dragSquareColor);
+        drawFillRect(QPoint(cropperRect.right(), centralY), dragSquareEdge, dragSquareColor);
+        drawFillRect(QPoint(centralX, cropperRect.bottom()), dragSquareEdge, dragSquareColor);
+    }
+}
+
+void ImageCropperLabel::drawFillRect(QPoint centralPoint, int edge, QColor color) {
+    QRect rect(centralPoint.x() - edge / 2, centralPoint.y() - edge / 2, edge, edge);
+    QPainter painter(this);
+    painter.fillRect(rect, color);
+}
+
+// Opacity effect
+void ImageCropperLabel::drawOpacity(const QPainterPath& path) {
+    QPainter painterOpac(this);
+    painterOpac.setOpacity(opacity);
+    painterOpac.fillPath(path, QBrush(Qt::black));
+}
+
+void ImageCropperLabel::drawRectOpacity() {
+    if (isShowOpacityEffect) {
+        QPainterPath p1, p2, p;
+        p1.addRect(imageRect);
+        p2.addRect(cropperRect);
+        p = p1.subtracted(p2);
+        drawOpacity(p);
+    }
+}
+
+void ImageCropperLabel::drawEllipseOpacity() {
+    if (isShowOpacityEffect) {
+        QPainterPath p1, p2, p;
+        p1.addRect(imageRect);
+        p2.addEllipse(cropperRect);
+        p = p1.subtracted(p2);
+        drawOpacity(p);
+    }
+}
+
+bool ImageCropperLabel::isPosNearDragSquare(const QPoint& pt1, const QPoint& pt2) {
+    return abs(pt1.x() - pt2.x()) * 2 <= dragSquareEdge
+           && abs(pt1.y() - pt2.y()) * 2 <= dragSquareEdge;
+}
+
+int ImageCropperLabel::getPosInCropperRect(const QPoint &pt) {
+    if (isPosNearDragSquare(pt, QPoint(cropperRect.right(), cropperRect.center().y())))
+        return RECT_RIGHT;
+    if (isPosNearDragSquare(pt, cropperRect.bottomRight()))
+        return RECT_BOTTOM_RIGHT;
+    if (isPosNearDragSquare(pt, QPoint(cropperRect.center().x(), cropperRect.bottom())))
+        return RECT_BOTTOM;
+    if (isPosNearDragSquare(pt, cropperRect.bottomLeft()))
+        return RECT_BOTTOM_LEFT;
+    if (isPosNearDragSquare(pt, QPoint(cropperRect.left(), cropperRect.center().y())))
+        return RECT_LEFT;
+    if (isPosNearDragSquare(pt, cropperRect.topLeft()))
+        return RECT_TOP_LEFT;
+    if (isPosNearDragSquare(pt, QPoint(cropperRect.center().x(), cropperRect.top())))
+        return RECT_TOP;
+    if (isPosNearDragSquare(pt, cropperRect.topRight()))
+        return RECT_TOP_RIGHT;
+    if (cropperRect.contains(pt, true))
+        return RECT_INSIDE;
+    return RECT_OUTSIZD;
+}
+
+/*************************************************
+ *
+ *  Change mouse cursor type
+ *      Arrow, SizeHor, SizeVer, etc...
+ *
+*************************************************/
+
+void ImageCropperLabel::changeCursor() {
+    switch (cursorPosInCropperRect) {
+        case RECT_OUTSIZD:
+            setCursor(Qt::ArrowCursor);
+            break;
+        case RECT_BOTTOM_RIGHT: {
+            switch (cropperShape) {
+            case CropperShape::SQUARE:
+            case CropperShape::CIRCLE:
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeFDiagCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_RIGHT: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeHorCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_BOTTOM: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeVerCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_BOTTOM_LEFT: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+            case CropperShape::SQUARE:
+            case CropperShape::CIRCLE:
+                setCursor(Qt::SizeBDiagCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_LEFT: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeHorCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_TOP_LEFT: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+            case CropperShape::SQUARE:
+            case CropperShape::CIRCLE:
+                setCursor(Qt::SizeFDiagCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_TOP: {
+            switch (cropperShape) {
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeVerCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_TOP_RIGHT: {
+            switch (cropperShape) {
+            case CropperShape::SQUARE:
+            case CropperShape::CIRCLE:
+            case CropperShape::RECT:
+            case CropperShape::ELLIPSE:
+                setCursor(Qt::SizeBDiagCursor);
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+        case RECT_INSIDE: {
+            setCursor(Qt::SizeAllCursor);
+            break;
+        }
+    }
+}
+
+/*****************************************************
+ *
+ *  Mouse Events
+ *
+*****************************************************/
+
+void ImageCropperLabel::mousePressEvent(QMouseEvent *e) {
+    currPos = lastPos = e->pos();
+    isLButtonPressed = true;
+}
+
+void ImageCropperLabel::mouseMoveEvent(QMouseEvent *e) {
+    currPos = e->pos();
+    if (!isCursorPosCalculated) {
+        cursorPosInCropperRect = getPosInCropperRect(currPos);
+        changeCursor();
+    }
+
+    if (!isLButtonPressed)
+        return;
+    if (!imageRect.contains(currPos))
+        return;
+
+    isCursorPosCalculated = true;
+
+    int xOffset = currPos.x() - lastPos.x();
+    int yOffset = currPos.y() - lastPos.y();
+    lastPos = currPos;
+
+    int disX = 0;
+    int disY = 0;
+
+    // Move cropper
+    switch (cursorPosInCropperRect) {
+        case RECT_OUTSIZD:
+            break;
+        case RECT_BOTTOM_RIGHT: {
+            disX = currPos.x() - cropperRect.left();
+            disY = currPos.y() - cropperRect.top();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                    break;
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    setCursor(Qt::SizeFDiagCursor);
+                    if (disX >= cropperMinimumWidth && disY >= cropperMinimumHeight) {
+                        if (disX > disY && cropperRect.top() + disX <= imageRect.bottom()) {
+                            cropperRect.setRight(currPos.x());
+                            cropperRect.setBottom(cropperRect.top() + disX);
+                            emit croppedImageChanged();
+                        }
+                        else if (disX <= disY && cropperRect.left() + disY <= imageRect.right()) {
+                            cropperRect.setBottom(currPos.y());
+                            cropperRect.setRight(cropperRect.left() + disY);
+                            emit croppedImageChanged();
+                        }
+                    }
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    setCursor(Qt::SizeFDiagCursor);
+                    if (disX >= cropperMinimumWidth) {
+                        cropperRect.setRight(currPos.x());
+                        emit croppedImageChanged();
+                    }
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setBottom(currPos.y());
+                        emit croppedImageChanged();
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_RIGHT: {
+            disX = currPos.x() - cropperRect.left();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disX >= cropperMinimumWidth) {
+                        cropperRect.setRight(currPos.x());
+                        emit croppedImageChanged();
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_BOTTOM: {
+            disY = currPos.y() - cropperRect.top();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setBottom(cropperRect.bottom() + yOffset);
+                        emit croppedImageChanged();
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_BOTTOM_LEFT: {
+            disX = cropperRect.right() - currPos.x();
+            disY = currPos.y() - cropperRect.top();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                    break;
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disX >= cropperMinimumWidth) {
+                        cropperRect.setLeft(currPos.x());
+                        emit croppedImageChanged();
+                    }
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setBottom(currPos.y());
+                        emit croppedImageChanged();
+                    }
+                    break;
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    if (disX >= cropperMinimumWidth && disY >= cropperMinimumHeight) {
+                        if (disX > disY && cropperRect.top() + disX <= imageRect.bottom()) {
+                            cropperRect.setLeft(currPos.x());
+                            cropperRect.setBottom(cropperRect.top() + disX);
+                            emit croppedImageChanged();
+                        }
+                        else if (disX <= disY && cropperRect.right() - disY >= imageRect.left()) {
+                            cropperRect.setBottom(currPos.y());
+                            cropperRect.setLeft(cropperRect.right() - disY);
+                            emit croppedImageChanged();
+                        }
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_LEFT: {
+            disX = cropperRect.right() - currPos.x();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disX >= cropperMinimumHeight) {
+                        cropperRect.setLeft(cropperRect.left() + xOffset);
+                        emit croppedImageChanged();
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_TOP_LEFT: {
+            disX = cropperRect.right() - currPos.x();
+            disY = cropperRect.bottom() - currPos.y();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disX >= cropperMinimumWidth) {
+                        cropperRect.setLeft(currPos.x());
+                        emit croppedImageChanged();
+                    }
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setTop(currPos.y());
+                        emit croppedImageChanged();
+                    }
+                    break;
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    if (disX >= cropperMinimumWidth && disY >= cropperMinimumHeight) {
+                        if (disX > disY && cropperRect.bottom() - disX >= imageRect.top()) {
+                            cropperRect.setLeft(currPos.x());
+                            cropperRect.setTop(cropperRect.bottom() - disX);
+                            emit croppedImageChanged();
+                        }
+                        else if (disX <= disY && cropperRect.right() - disY >= imageRect.left()) {
+                            cropperRect.setTop(currPos.y());
+                            cropperRect.setLeft(cropperRect.right() - disY);
+                            emit croppedImageChanged();
+                        }
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_TOP: {
+            disY = cropperRect.bottom() - currPos.y();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setTop(cropperRect.top() + yOffset);
+                        emit croppedImageChanged();
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_TOP_RIGHT: {
+            disX = currPos.x() - cropperRect.left();
+            disY = cropperRect.bottom() - currPos.y();
+            switch (cropperShape) {
+                case CropperShape::UNDEFINED:
+                case CropperShape::FIXED_RECT:
+                case CropperShape::FIXED_ELLIPSE:
+                    break;
+                case CropperShape::RECT:
+                case CropperShape::ELLIPSE:
+                    if (disX >= cropperMinimumWidth) {
+                        cropperRect.setRight(currPos.x());
+                        emit croppedImageChanged();
+                    }
+                    if (disY >= cropperMinimumHeight) {
+                        cropperRect.setTop(currPos.y());
+                        emit croppedImageChanged();
+                    }
+                    break;
+                case CropperShape::SQUARE:
+                case CropperShape::CIRCLE:
+                    if (disX >= cropperMinimumWidth && disY >= cropperMinimumHeight) {
+                        if (disX < disY && cropperRect.left() + disY <= imageRect.right()) {
+                            cropperRect.setTop(currPos.y());
+                            cropperRect.setRight(cropperRect.left() + disY);
+                            emit croppedImageChanged();
+                        }
+                        else if (disX >= disY && cropperRect.bottom() - disX >= imageRect.top()) {
+                            cropperRect.setRight(currPos.x());
+                            cropperRect.setTop(cropperRect.bottom() - disX);
+                            emit croppedImageChanged();
+                        }
+                    }
+                    break;
+            }
+            break;
+        }
+        case RECT_INSIDE: {
+            // Make sure the cropperRect is entirely inside the imageRecct
+            if (xOffset > 0) {
+                if (cropperRect.right() + xOffset > imageRect.right())
+                    xOffset = 0;
+            }
+            else if (xOffset < 0) {
+                if (cropperRect.left() + xOffset < imageRect.left())
+                    xOffset = 0;
+            }
+            if (yOffset > 0) {
+                if (cropperRect.bottom() + yOffset > imageRect.bottom())
+                    yOffset = 0;
+            }
+            else if (yOffset < 0) {
+                if (cropperRect.top() + yOffset < imageRect.top())
+                    yOffset = 0;
+            }
+            cropperRect.moveTo(cropperRect.left() + xOffset, cropperRect.top() + yOffset);
+            emit croppedImageChanged();
+        }
+        break;
+    }
+
+    repaint();
+}
+
+void ImageCropperLabel::mouseReleaseEvent(QMouseEvent *) {
+    isLButtonPressed = false;
+    isCursorPosCalculated = false;
+    setCursor(Qt::ArrowCursor);
+}
+

imagecropper/base/imagecropperlabel.h

@@ -0,0 +1,168 @@
+#ifndef IMAGECROPPERLABEL_H
+#define IMAGECROPPERLABEL_H
+
+#include <QLabel>
+#include <QPixmap>
+#include <QPen>
+
+enum class CropperShape {
+    UNDEFINED = 0,
+    RECT = 1,
+    SQUARE = 2,
+    FIXED_RECT = 3,
+    ELLIPSE = 4,
+    CIRCLE = 5,
+    FIXED_ELLIPSE = 6
+};
+
+enum class OutputShape {
+    RECT = 0,
+    ELLIPSE = 1
+};
+
+enum class SizeType {
+    fixedSize = 0,
+    fitToMaxWidth = 1,
+    fitToMaxHeight = 2,
+    fitToMaxWidthHeight = 3,
+};
+
+class ImageCropperLabel : public QLabel
+{
+    Q_OBJECT
+public:
+    ImageCropperLabel(int width, int height, QWidget *parent);
+
+    void setOriginalImage(const QPixmap &pixmap);
+    void setOutputShape(OutputShape shape) { outputShape = shape; }
+    QPixmap getCroppedImage();
+    QPixmap getCroppedImage(OutputShape shape);
+
+    /*****************************************
+     * Set cropper's shape
+    *****************************************/
+    void setRectCropper();
+    void setSquareCropper();
+    void setEllipseCropper();
+    void setCircleCropper();
+    void setFixedRectCropper(QSize size);
+    void setFixedEllipseCropper(QSize size);
+    void setCropper(CropperShape shape, QSize size); // not recommended
+
+    /*****************************************************************************
+     * Set cropper's fixed size
+    *****************************************************************************/
+    void setCropperFixedSize(int fixedWidth, int fixedHeight);
+    void setCropperFixedWidth(int fixedWidht);
+    void setCropperFixedHeight(int fixedHeight);
+
+    /*****************************************************************************
+     * Set cropper's minimum size
+     * default: the twice of minimum of the edge lenght of drag square
+    *****************************************************************************/
+    void setCropperMinimumSize(int minWidth, int minHeight)
+    {
+        cropperMinimumWidth = minWidth;
+        cropperMinimumHeight = minHeight;
+    }
+    void setCropperMinimumWidth(int minWidth) { cropperMinimumWidth = minWidth; }
+    void setCropperMinimumHeight(int minHeight) { cropperMinimumHeight = minHeight; }
+
+    /*************************************************
+     * Set the size, color, visibility of rectangular border
+    *************************************************/
+    void setShowRectBorder(bool show) { isShowRectBorder = show; }
+    QPen getBorderPen() { return borderPen; }
+    void setBorderPen(const QPen &pen) { borderPen = pen; }
+
+    /*************************************************
+     * Set the size, color of drag square
+    *************************************************/
+    void setShowDragSquare(bool show) { isShowDragSquare = show; }
+    void setDragSquareEdge(int edge) { dragSquareEdge = (edge >= 3 ? edge : 3); }
+    void setDragSquareColor(const QColor &color) { dragSquareColor = color; }
+
+    /*****************************************
+     *  Opacity Effect
+    *****************************************/
+    void enableOpacity(bool b = true) { isShowOpacityEffect = b; }
+    void setOpacity(double newOpacity) { opacity = newOpacity; }
+
+signals:
+    void croppedImageChanged();
+
+protected:
+    /*****************************************
+     * Event
+    *****************************************/
+    virtual void paintEvent(QPaintEvent *event) override;
+    virtual void mousePressEvent(QMouseEvent *e) override;
+    virtual void mouseMoveEvent(QMouseEvent *e) override;
+    virtual void mouseReleaseEvent(QMouseEvent *e) override;
+
+private:
+    /***************************************
+     * Draw shapes
+    ***************************************/
+    void drawFillRect(QPoint centralPoint, int edge, QColor color);
+    void drawRectOpacity();
+    void drawEllipseOpacity();
+    void drawOpacity(const QPainterPath &path); // shadow effect
+    void drawSquareEdge(bool onlyFourCorners);
+
+    /***************************************
+     * Other utility methods
+    ***************************************/
+    int getPosInCropperRect(const QPoint &pt);
+    bool isPosNearDragSquare(const QPoint &pt1, const QPoint &pt2);
+    void resetCropperPos();
+    void changeCursor();
+
+    enum {
+        RECT_OUTSIZD = 0,
+        RECT_INSIDE = 1,
+        RECT_TOP_LEFT,
+        RECT_TOP,
+        RECT_TOP_RIGHT,
+        RECT_RIGHT,
+        RECT_BOTTOM_RIGHT,
+        RECT_BOTTOM,
+        RECT_BOTTOM_LEFT,
+        RECT_LEFT
+    };
+
+    const bool ONLY_FOUR_CORNERS = true;
+
+private:
+    QPixmap originalImage;
+    QPixmap tempImage;
+
+    bool isShowRectBorder = true;
+    QPen borderPen;
+
+    CropperShape cropperShape = CropperShape::UNDEFINED;
+    OutputShape outputShape = OutputShape::RECT;
+
+    QRect imageRect; // the whole image area in the label (not real size)
+    QRect cropperRect; // a rectangle frame to choose image area (not real size)
+    QRect cropperRect_; // cropper rect (real size)
+    double scaledRate = 1.0;
+
+    bool isLButtonPressed = false;
+    bool isCursorPosCalculated = false;
+    int cursorPosInCropperRect = RECT_OUTSIZD;
+    QPoint lastPos;
+    QPoint currPos;
+
+    bool isShowDragSquare = true;
+    int dragSquareEdge = 8;
+    QColor dragSquareColor = Qt::white;
+
+    int cropperMinimumWidth = dragSquareEdge * 2;
+    int cropperMinimumHeight = dragSquareEdge * 2;
+
+    bool isShowOpacityEffect = false;
+    double opacity = 0.6;
+};
+
+#endif // IMAGECROPPERLABEL_H

imagecropper/example/imagecropperdemo.cpp

@@ -0,0 +1,415 @@
+#include "imagecropperdemo.h"
+#include <QFormLayout>
+#include <QColorDialog>
+#include <QVBoxLayout>
+#include <QFileDialog>
+#include <QMessageBox>
+
+ImageCropperDemo::ImageCropperDemo(QWidget* parent) :
+    QDialog(parent)
+{
+    setupLayout();
+    init();
+
+    this->setAttribute(Qt::WA_DeleteOnClose, true);
+    this->setWindowTitle("Image Cropper Demo");
+}
+
+
+void ImageCropperDemo::setupLayout() {
+    imgCropperLabel = new ImageCropperLabel(600, 500, this);
+    imgCropperLabel->setFrameStyle(1);
+
+    comboOutputShape = new QComboBox(this);
+    comboCropperShape = new QComboBox(this);
+
+    labelPreviewImage = new QLabel(this);
+
+    editOriginalImagePath = new QLineEdit(this);
+    btnChooseOriginalImagePath = new QPushButton(this);
+    QHBoxLayout* hOriginalImagePathLayout = new QHBoxLayout();
+    hOriginalImagePathLayout->addWidget(editOriginalImagePath);
+    hOriginalImagePathLayout->addWidget(btnChooseOriginalImagePath);
+
+    editCropperFixedWidth = new QLineEdit(this);
+    editCropperFixedHeight = new QLineEdit(this);
+    QHBoxLayout* hCropperFixedSizeLayout = new QHBoxLayout();
+    hCropperFixedSizeLayout->addWidget(editCropperFixedWidth);
+    hCropperFixedSizeLayout->addWidget(editCropperFixedHeight);
+
+    editCropperMinWidth = new QLineEdit("8", this);
+    editCropperMinHeight = new QLineEdit("8", this);
+    QHBoxLayout* hCropperMinSizeLayout = new QHBoxLayout();
+    hCropperMinSizeLayout->addWidget(editCropperMinWidth);
+    hCropperMinSizeLayout->addWidget(editCropperMinHeight);
+
+    checkEnableOpacity = new QCheckBox(this);
+    sliderOpacity = new QSlider(Qt::Horizontal, this);
+
+    checkShowDragSquare = new QCheckBox(this);
+    editDragSquareEdge = new QLineEdit("8", this);
+    checkShowRectBorder = new QCheckBox(this);
+
+    labelRectBorderColor = new QLabel(this);
+    btnChooseRectBorderCorlor = new QPushButton(this);
+    QHBoxLayout* hRectBorderColorLayout = new QHBoxLayout();
+    hRectBorderColorLayout->addWidget(labelRectBorderColor);
+    hRectBorderColorLayout->addWidget(btnChooseRectBorderCorlor);
+
+    labelDragSquareColor = new QLabel(this);
+    btnChooseDragSquareColor = new QPushButton(this);
+    QHBoxLayout* hDragSquareColorLayout = new QHBoxLayout();
+    hDragSquareColorLayout->addWidget(labelDragSquareColor);
+    hDragSquareColorLayout->addWidget(btnChooseDragSquareColor);
+
+    QFormLayout* formLayout1 = new QFormLayout();
+    formLayout1->addRow(new QLabel("Preview:"), labelPreviewImage);
+    formLayout1->addRow(new QLabel("OriginalImage:", this), hOriginalImagePathLayout);
+    formLayout1->addRow(new QLabel("OutputShape:", this), comboOutputShape);
+    formLayout1->addRow(new QLabel("CropperShape:", this), comboCropperShape);
+    formLayout1->addRow(new QLabel("FixedSize:", this), hCropperFixedSizeLayout);
+    formLayout1->addRow(new QLabel("MinimumSize:", this), hCropperMinSizeLayout);
+
+    QFormLayout* formLayout2 = new QFormLayout();
+    formLayout2->addRow(new QLabel("EnableOpacity:", this), checkEnableOpacity);
+    formLayout2->addRow(new QLabel("Opacity:", this), sliderOpacity);
+
+    QFormLayout* formLayout3 = new QFormLayout();
+    formLayout3->addRow(new QLabel("ShowDragSquare:", this), checkShowDragSquare);
+    formLayout3->addRow(new QLabel("DragSquareEdge:", this), editDragSquareEdge);
+    formLayout3->addRow(new QLabel("DragSquareColor:", this), hDragSquareColorLayout);
+
+    QFormLayout* formLayout4 = new QFormLayout();
+    formLayout4->addRow(new QLabel("ShowRectBorder:", this), checkShowRectBorder);
+    formLayout4->addRow(new QLabel("RectBorderColor:", this), hRectBorderColorLayout);
+
+    btnSavePreview = new QPushButton("Save", this);
+    btnQuit = new QPushButton("Quit", this);
+    QHBoxLayout* btnLayout = new QHBoxLayout();
+    btnLayout->addStretch();
+    btnLayout->addWidget(btnSavePreview);
+    btnLayout->addStretch();
+    btnLayout->addWidget(btnQuit);
+    btnLayout->addStretch();
+
+    QVBoxLayout* vLayout = new QVBoxLayout();
+    vLayout->addLayout(formLayout1);
+    vLayout->addStretch();
+    vLayout->addLayout(formLayout2);
+    vLayout->addStretch();
+    vLayout->addLayout(formLayout3);
+    vLayout->addStretch();
+    vLayout->addLayout(formLayout4);
+    vLayout->addStretch();
+    vLayout->addLayout(btnLayout);
+
+    mainLayout = new QHBoxLayout(this);
+    mainLayout->addWidget(imgCropperLabel);
+    mainLayout->addLayout(vLayout);
+}
+
+void ImageCropperDemo::init() {
+    imgCropperLabel->setRectCropper();
+    editCropperFixedWidth->setEnabled(false);
+    editCropperFixedHeight->setEnabled(false);
+
+    labelPreviewImage->setFixedSize(96, 96);
+    labelPreviewImage->setAlignment(Qt::AlignCenter);
+    labelPreviewImage->setFrameStyle(QFrame::Panel | QFrame::Sunken);
+    connect(imgCropperLabel, &ImageCropperLabel::croppedImageChanged,
+            this, &ImageCropperDemo::onUpdatePreview);
+
+    btnChooseOriginalImagePath->setIcon(QIcon("res/select-file.ico"));
+    btnChooseOriginalImagePath->setFixedWidth(30);
+    connect(btnChooseOriginalImagePath, &QPushButton::clicked,
+            this, &ImageCropperDemo::onChooseOriginalImage);
+
+    comboOutputShape->addItem("Rect/Square");
+    comboOutputShape->addItem("Ellipse/Circle");
+    connect(comboOutputShape, SIGNAL(currentIndexChanged(int)),
+            this, SLOT(onOutputShapeChanged(int)));
+
+    comboCropperShape->addItem("Rect");
+    comboCropperShape->addItem("Square");
+    comboCropperShape->addItem("FixedRect");
+    comboCropperShape->addItem("Ellipse");
+    comboCropperShape->addItem("Circle");
+    comboCropperShape->addItem("FixedEllipse");
+    connect(comboCropperShape, SIGNAL(currentIndexChanged(int)),
+            this, SLOT(onCropperShapeChanged(int)));
+
+    connect(editCropperFixedWidth, &QLineEdit::textChanged,
+            this, &ImageCropperDemo::onFixedWidthChanged);
+    connect(editCropperFixedHeight, &QLineEdit::textChanged,
+            this, &ImageCropperDemo::onFixedHeightChanged);
+    connect(editCropperMinWidth, &QLineEdit::textChanged,
+            this, &ImageCropperDemo::onMinWidthChanged);
+    connect(editCropperMinHeight, &QLineEdit::textChanged,
+            this, &ImageCropperDemo::onMinHeightChanged);
+
+    checkEnableOpacity->setCheckState(Qt::Checked);
+    imgCropperLabel->enableOpacity(true);
+    connect(checkEnableOpacity, &QCheckBox::stateChanged,
+            this, &ImageCropperDemo::onEnableOpacityChanged);
+
+    checkShowDragSquare->setCheckState(Qt::Checked);
+    imgCropperLabel->setShowDragSquare(true);
+    connect(checkShowDragSquare, &QCheckBox::stateChanged,
+            this, &ImageCropperDemo::onShowDragSquareChanged);
+    connect(editDragSquareEdge, &QLineEdit::textChanged,
+            this, &ImageCropperDemo::onDragSquareEdgeChanged);
+
+    sliderOpacity->setRange(0, 100);
+    sliderOpacity->setValue(60);
+    connect(sliderOpacity, &QSlider::valueChanged,
+            this, &ImageCropperDemo::onOpacityChanged);
+
+    checkShowRectBorder->setCheckState(Qt::Checked);
+    connect(checkShowRectBorder, &QCheckBox::stateChanged,
+            this, &ImageCropperDemo::onShowRectBorder);
+
+    setLabelColor(labelRectBorderColor, Qt::white);
+    btnChooseRectBorderCorlor->setIcon(QIcon("res/color-palette.ico"));
+    btnChooseRectBorderCorlor->setFixedWidth(40);
+    connect(btnChooseRectBorderCorlor, &QPushButton::clicked,
+            this, &ImageCropperDemo::onChooseRectBorderColor);
+
+    setLabelColor(labelDragSquareColor, Qt::white);
+    btnChooseDragSquareColor->setIcon(QIcon("res/color-palette.ico"));
+    btnChooseDragSquareColor->setFixedWidth(40);
+    connect(btnChooseDragSquareColor, &QPushButton::clicked,
+            this, &ImageCropperDemo::onChooseDragSquareColor);
+
+    connect(btnSavePreview, &QPushButton::clicked,
+            this, &ImageCropperDemo::onSaveCroppedImage);
+    connect(btnQuit, &QPushButton::clicked,
+            this, &ImageCropperDemo::close);
+
+    imgCropperLabel->update();
+}
+
+
+/*****************************************************************************
+ *
+ *    slots
+ *
+*****************************************************************************/
+
+void ImageCropperDemo::onChooseOriginalImage() {
+    QString filename = QFileDialog::getOpenFileName(this, "Select a picture", "",
+                                                    "picture (*.jpg *.png *.bmp)");
+    if (filename.isNull())
+        return;
+
+    QPixmap pixmap;
+    if (!pixmap.load(filename)) {
+        QMessageBox::critical(this, "Error", "Load image failed", QMessageBox::Ok);
+        return;
+    }
+
+    editOriginalImagePath->setText(filename);
+    imgCropperLabel->setOriginalImage(pixmap);
+    imgCropperLabel->update();
+    onUpdatePreview();
+    labelPreviewImage->setFrameStyle(0);
+}
+
+void ImageCropperDemo::onOutputShapeChanged(int idx) {
+    // Output: Rectangular
+    if (idx == 0)
+        imgCropperLabel->setOutputShape(OutputShape::RECT);
+    else
+        imgCropperLabel->setOutputShape(OutputShape::ELLIPSE);
+    onUpdatePreview();
+}
+
+void ImageCropperDemo::onCropperShapeChanged(int idx) {
+    switch (CropperShape(idx + 1)) {
+    case CropperShape::RECT: {
+        imgCropperLabel->setRectCropper();
+        editCropperFixedWidth->setEnabled(false);
+        editCropperFixedHeight->setEnabled(false);
+        editCropperMinWidth->setEnabled(true);
+        editCropperMinHeight->setEnabled(true);
+        checkShowDragSquare->setEnabled(true);
+        editDragSquareEdge->setEnabled(true);
+        btnChooseDragSquareColor->setEnabled(true);
+        break;
+    }
+    case CropperShape::SQUARE: {
+        imgCropperLabel->setSquareCropper();
+        editCropperFixedWidth->setEnabled(false);
+        editCropperFixedHeight->setEnabled(false);
+        editCropperMinWidth->setEnabled(true);
+        editCropperMinHeight->setEnabled(true);
+        checkShowDragSquare->setEnabled(true);
+        editDragSquareEdge->setEnabled(true);
+        btnChooseDragSquareColor->setEnabled(true);
+        break;
+    }
+    case CropperShape::FIXED_RECT: {
+        imgCropperLabel->setFixedRectCropper(QSize(64, 64));
+        editCropperFixedWidth->setEnabled(true);
+        editCropperFixedHeight->setEnabled(true);
+        editCropperMinWidth->setEnabled(false);
+        editCropperMinHeight->setEnabled(false);
+        editCropperFixedWidth->setText("64");
+        editCropperFixedHeight->setText("64");
+        checkShowDragSquare->setEnabled(false);
+        editDragSquareEdge->setEnabled(false);
+        btnChooseDragSquareColor->setEnabled(false);
+        break;
+    }
+    case CropperShape::ELLIPSE: {
+        imgCropperLabel->setEllipseCropper();
+        editCropperFixedWidth->setEnabled(false);
+        editCropperFixedHeight->setEnabled(false);
+        editCropperMinWidth->setEnabled(true);
+        editCropperMinHeight->setEnabled(true);
+        checkShowDragSquare->setEnabled(true);
+        editDragSquareEdge->setEnabled(true);
+        btnChooseDragSquareColor->setEnabled(true);
+        break;
+    }
+    case CropperShape::CIRCLE: {
+        imgCropperLabel->setCircleCropper();
+        editCropperFixedWidth->setEnabled(false);
+        editCropperFixedHeight->setEnabled(false);
+        editCropperMinWidth->setEnabled(true);
+        editCropperMinHeight->setEnabled(true);
+        checkShowDragSquare->setEnabled(true);
+        editDragSquareEdge->setEnabled(true);
+        btnChooseDragSquareColor->setEnabled(true);
+        break;
+    }
+    case CropperShape::FIXED_ELLIPSE:
+        imgCropperLabel->setFixedEllipseCropper(QSize(64, 64));
+        editCropperFixedWidth->setEnabled(true);
+        editCropperFixedHeight->setEnabled(true);
+        editCropperMinWidth->setEnabled(false);
+        editCropperMinHeight->setEnabled(false);
+        editCropperFixedWidth->setText("64");
+        editCropperFixedHeight->setText("64");
+        checkShowDragSquare->setEnabled(false);
+        editDragSquareEdge->setEnabled(false);
+        btnChooseDragSquareColor->setEnabled(false);
+        break;
+    case CropperShape::UNDEFINED:
+        break;
+    }
+
+    imgCropperLabel->update();
+    onUpdatePreview();
+}
+
+void ImageCropperDemo::onEnableOpacityChanged(int state) {
+    if (state == Qt::Checked) {
+        sliderOpacity->setEnabled(true);
+        imgCropperLabel->enableOpacity(true);
+    }
+    else {
+        sliderOpacity->setEnabled(false);
+        imgCropperLabel->enableOpacity(false);
+    }
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onShowDragSquareChanged(int state) {
+    if (state == Qt::Checked) {
+        editDragSquareEdge->setEnabled(true);
+        btnChooseDragSquareColor->setEnabled(true);
+        imgCropperLabel->setShowDragSquare(true);
+    }
+    else {
+        editDragSquareEdge->setEnabled(false);
+        btnChooseDragSquareColor->setEnabled(false);
+        imgCropperLabel->setShowDragSquare(false);
+    }
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onDragSquareEdgeChanged(QString edge) {
+    imgCropperLabel->setDragSquareEdge(edge.toInt());
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onOpacityChanged(int val) {
+    imgCropperLabel->setOpacity(val / 100.0);
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onFixedWidthChanged(QString width) {
+    imgCropperLabel->setCropperFixedWidth(width.toInt());
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onFixedHeightChanged(QString height) {
+    imgCropperLabel->setCropperFixedHeight(height.toInt());
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onMinWidthChanged(QString width) {
+    imgCropperLabel->setCropperMinimumWidth(width.toInt());
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onMinHeightChanged(QString height) {
+    imgCropperLabel->setMinimumHeight(height.toInt());
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onShowRectBorder(int state) {
+    if (state == Qt::Checked) {
+        btnChooseRectBorderCorlor->setEnabled(true);
+        imgCropperLabel->setShowRectBorder(true);
+    }
+    else {
+        btnChooseRectBorderCorlor->setEnabled(false);
+        imgCropperLabel->setShowRectBorder(false);
+    }
+    imgCropperLabel->update();
+}
+
+void ImageCropperDemo::onChooseRectBorderColor() {
+    QColor color = QColorDialog::getColor(imgCropperLabel->getBorderPen().color(), this);
+    if (color.isValid()) {
+        setLabelColor(labelRectBorderColor, color);
+        QPen pen = imgCropperLabel->getBorderPen();
+        pen.setColor(color);
+        imgCropperLabel->setBorderPen(pen);
+        imgCropperLabel->update();
+    }
+}
+
+void ImageCropperDemo::onChooseDragSquareColor() {
+    QColor color = QColorDialog::getColor(Qt::white, this);
+    if (color.isValid()) {
+        setLabelColor(labelDragSquareColor, color);
+        imgCropperLabel->setDragSquareColor(color);
+        imgCropperLabel->update();
+    }
+}
+
+void ImageCropperDemo::onUpdatePreview() {
+    QPixmap preview = imgCropperLabel->getCroppedImage();
+    preview = preview.scaled(labelPreviewImage->width(), labelPreviewImage->height(),
+                             Qt::KeepAspectRatio, Qt::SmoothTransformation);
+    labelPreviewImage->setPixmap(preview);
+}
+
+void ImageCropperDemo::onSaveCroppedImage() {
+    const QPixmap* pixmap = labelPreviewImage->pixmap();
+    if (!pixmap) {
+        QMessageBox::information(this, "Error", "There is no cropped image to save.", QMessageBox::Ok);
+        return ;
+    }
+
+    QString filename = QFileDialog::getSaveFileName(this, "Save cropped image", "", "picture (*.png)");
+    if (!filename.isNull()) {
+        if (imgCropperLabel->getCroppedImage().save(filename, "PNG"))
+            QMessageBox::information(this, "Prompt", "Saved successfully", QMessageBox::Ok);
+        else
+            QMessageBox::information(this, "Error", "Save image failed!", QMessageBox::Ok);
+    }
+}
+

imagecropper/example/imagecropperdemo.h

@@ -0,0 +1,85 @@
+#ifndef TESTIMAGECROPPERLABEL_H
+#define TESTIMAGECROPPERLABEL_H
+
+#include <QObject>
+#include <QDialog>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QComboBox>
+#include <QLineEdit>
+#include <QCheckBox>
+#include <QPushButton>
+#include <QSlider>
+
+#include "../base/imagecropperlabel.h"
+
+class ImageCropperDemo : public QDialog
+{
+    Q_OBJECT
+public:
+    ImageCropperDemo(QWidget* parent = nullptr);
+
+    void setupLayout();
+
+    void init();
+
+public slots:
+    void onOutputShapeChanged(int idx);
+    void onCropperShapeChanged(int idx);
+    void onEnableOpacityChanged(int state);
+    void onShowDragSquareChanged(int state);
+    void onDragSquareEdgeChanged(QString edge);
+    void onOpacityChanged(int val);
+    void onFixedWidthChanged(QString width);
+    void onFixedHeightChanged(QString height);
+    void onMinWidthChanged(QString width);
+    void onMinHeightChanged(QString height);
+    void onShowRectBorder(int state);
+    void onChooseRectBorderColor();
+    void onChooseDragSquareColor();
+
+    void onChooseOriginalImage();
+    void onUpdatePreview();
+    void onSaveCroppedImage();
+
+private:
+    void setLabelColor(QLabel* label, QColor color) {
+        QPixmap pixmap(QSize(80, 25));
+        pixmap.fill(color);
+        label->setPixmap(pixmap);
+    }
+
+private:
+    ImageCropperLabel* imgCropperLabel;
+    QHBoxLayout* mainLayout;
+
+    QLabel* labelPreviewImage;
+
+    QComboBox* comboOutputShape;
+    QComboBox* comboCropperShape;
+
+    QLineEdit* editOriginalImagePath;
+    QPushButton* btnChooseOriginalImagePath;
+
+    QLineEdit* editCropperFixedWidth;
+    QLineEdit* editCropperFixedHeight;
+    QLineEdit* editCropperMinWidth;
+    QLineEdit* editCropperMinHeight;
+
+    QCheckBox* checkShowDragSquare;
+    QCheckBox* checkEnableOpacity;
+    QSlider* sliderOpacity;
+    QLineEdit* editDragSquareEdge;
+
+    QCheckBox* checkShowRectBorder;
+    QLabel* labelRectBorderColor;
+    QPushButton* btnChooseRectBorderCorlor;
+
+    QLabel* labelDragSquareColor;
+    QPushButton* btnChooseDragSquareColor;
+
+    QPushButton* btnSavePreview;
+    QPushButton* btnQuit;
+};
+
+#endif // TESTIMAGECROPPERLABEL_H

imagecropper/example/main.cpp

@@ -0,0 +1,11 @@
+#include "mainwindow.h"
+
+#include <QApplication>
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+    MainWindow w;
+    w.show();
+    return a.exec();
+}

imagecropper/example/mainwindow.cpp

@@ -0,0 +1,62 @@
+#include "mainwindow.h"
+#include "imagecropperdemo.h"
+
+#include "../base/imagecropperdialog.h"
+
+#include <QHBoxLayout>
+#include <QVBoxLayout>
+#include <QFileDialog>
+
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+{
+    setupLayout();
+}
+
+MainWindow::~MainWindow()
+{
+}
+
+void MainWindow::setupLayout() {
+    QWidget* centralWidget = new QWidget(this);
+
+    btnCustomCrop = new QPushButton("Custom Crop", centralWidget);
+    btnSimpleCrop = new QPushButton("Simple Crop", centralWidget);
+
+    QVBoxLayout* mainLayout = new QVBoxLayout(centralWidget);
+    mainLayout->addWidget(btnCustomCrop);
+    mainLayout->addWidget(btnSimpleCrop);
+    this->setCentralWidget(centralWidget);
+
+    connect(btnCustomCrop, &QPushButton::clicked, this, &MainWindow::onCustomCrop);
+    connect(btnSimpleCrop, &QPushButton::clicked, this, &MainWindow::onSimpleCrop);
+}
+
+void MainWindow::onCustomCrop() {
+    ImageCropperDemo* dialog = new ImageCropperDemo(this);
+    dialog->show();
+}
+
+void MainWindow::onSimpleCrop() {
+    QMessageBox::information(this, "Prompt", "Please select a picture", QMessageBox::Ok);
+    QString filename = QFileDialog::getOpenFileName(this, "Select image", "", "image (*.png *.jpg)");
+    if (filename.isNull())
+        return;
+
+    //                                   *********
+    //                                    *******
+    //                                     *****
+    //                                      ***
+    //                                       *
+    QPixmap image = ImageCropperDialog::getCroppedImage(filename, 600, 400, CropperShape::CIRCLE);
+    if (image.isNull())
+        return;
+
+    QDialog* dialog = new QDialog(nullptr);
+    dialog->setAttribute(Qt::WA_DeleteOnClose, true);
+    QLabel* label = new QLabel(dialog);
+    label->setFixedSize(image.size());
+    label->setPixmap(image);
+    dialog->exec();
+}

imagecropper/example/mainwindow.h

@@ -0,0 +1,26 @@
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+#include <QPushButton>
+
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    MainWindow(QWidget *parent = nullptr);
+    ~MainWindow();
+
+public slots:
+    void onCustomCrop();
+    void onSimpleCrop();
+
+private:
+    void setupLayout();
+
+private:
+    QPushButton* btnCustomCrop;
+    QPushButton* btnSimpleCrop;
+};
+#endif // MAINWINDOW_H

imagecropper/imagecropper.pro

@@ -0,0 +1,33 @@
+QT       += core gui
+
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
+
+CONFIG += c++11
+
+# The following define makes your compiler emit warnings if you use
+# any Qt feature that has been marked deprecated (the exact warnings
+# depend on your compiler). Please consult the documentation of the
+# deprecated API in order to know how to port your code away from it.
+DEFINES += QT_DEPRECATED_WARNINGS
+
+# You can also make your code fail to compile if it uses deprecated APIs.
+# In order to do so, uncomment the following line.
+# You can also select to disable deprecated APIs only up to a certain version of Qt.
+#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
+
+SOURCES += \
+    base/imagecropperlabel.cpp \
+    example/imagecropperdemo.cpp \
+    example/main.cpp \
+    example/mainwindow.cpp
+
+HEADERS += \
+    base/imagecropperdialog.h \
+    base/imagecropperlabel.h \
+    example/imagecropperdemo.h \
+    example/mainwindow.h
+
+# Default rules for deployment.
+qnx: target.path = /tmp/$${TARGET}/bin
+else: unix:!android: target.path = /opt/$${TARGET}/bin
+!isEmpty(target.path): INSTALLS += target