229 lines
7.3 KiB
C++
229 lines
7.3 KiB
C++
#include "dialogs/ImageCropDialog.h"
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#include <QBoxLayout>
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#include <QDialogButtonBox>
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#include <QLabel>
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#include <QMouseEvent>
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#include <QPainter>
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#include <QPushButton>
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#include <QImageReader>
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#include <QtMath>
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class ImageCropDialog::CropView final : public QWidget {
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public:
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explicit CropView(QWidget* parent = nullptr)
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: QWidget(parent) {
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setMouseTracking(true);
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setMinimumSize(480, 320);
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}
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void setImage(const QImage& img) {
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m_image = img;
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m_selection = {};
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updateGeometry();
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update();
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}
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bool hasSelection() const { return !m_selection.isNull() && m_selection.width() > 0 && m_selection.height() > 0; }
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QRect selectionInImagePixels() const {
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if (m_image.isNull() || !hasSelection()) {
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return {};
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}
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const auto map = viewToImageTransform();
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// selection 是 view 坐标；映射到 image 像素坐标
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const QRectF selF = QRectF(m_selection).normalized();
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bool invertible = false;
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const QTransform inv = map.inverted(&invertible);
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if (!invertible) {
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return {};
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}
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const QPointF topLeftImg = inv.map(selF.topLeft());
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const QPointF bottomRightImg = inv.map(selF.bottomRight());
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// 使用 floor/ceil，避免因为取整导致宽高变 0
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const int left = qFloor(std::min(topLeftImg.x(), bottomRightImg.x()));
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const int top = qFloor(std::min(topLeftImg.y(), bottomRightImg.y()));
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const int right = qCeil(std::max(topLeftImg.x(), bottomRightImg.x()));
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const int bottom = qCeil(std::max(topLeftImg.y(), bottomRightImg.y()));
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QRect r(QPoint(left, top), QPoint(right, bottom));
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r = r.normalized().intersected(QRect(0, 0, m_image.width(), m_image.height()));
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return r;
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}
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void resetSelection() {
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m_selection = {};
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update();
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}
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protected:
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void paintEvent(QPaintEvent*) override {
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QPainter p(this);
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p.fillRect(rect(), palette().window());
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if (m_image.isNull()) {
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p.setPen(palette().text().color());
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p.drawText(rect(), Qt::AlignCenter, QStringLiteral("无法加载图片"));
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return;
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}
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const auto map = viewToImageTransform();
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p.setRenderHint(QPainter::SmoothPixmapTransform, true);
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p.setTransform(map);
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p.drawImage(QPoint(0, 0), m_image);
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p.resetTransform();
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if (hasSelection()) {
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// 避免 CompositionMode_Clear 在某些平台/样式下表现异常：
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// 用“围绕选区画四块遮罩”的方式实现高亮裁剪区域。
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const QRect sel = m_selection.normalized().intersected(rect());
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const QColor shade(0, 0, 0, 120);
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// 上
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p.fillRect(QRect(0, 0, width(), sel.top()), shade);
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// 下
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p.fillRect(QRect(0, sel.bottom(), width(), height() - sel.bottom()), shade);
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// 左
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p.fillRect(QRect(0, sel.top(), sel.left(), sel.height()), shade);
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// 右
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p.fillRect(QRect(sel.right(), sel.top(), width() - sel.right(), sel.height()), shade);
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p.setPen(QPen(QColor(255, 255, 255, 220), 2));
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p.drawRect(sel);
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}
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}
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void mousePressEvent(QMouseEvent* e) override {
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if (m_image.isNull() || e->button() != Qt::LeftButton) {
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return;
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}
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m_dragging = true;
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m_anchor = e->position().toPoint();
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m_selection = QRect(m_anchor, m_anchor);
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update();
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}
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void mouseMoveEvent(QMouseEvent* e) override {
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if (!m_dragging) {
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return;
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}
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const QPoint cur = e->position().toPoint();
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m_selection = QRect(m_anchor, cur).normalized();
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update();
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}
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void mouseReleaseEvent(QMouseEvent* e) override {
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if (e->button() != Qt::LeftButton) {
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return;
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}
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m_dragging = false;
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update();
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}
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private:
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QTransform viewToImageTransform() const {
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// 让图片按比例 fit 到 view 中居中显示
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const QSizeF viewSize = size();
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const QSizeF imgSize = m_image.size();
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const qreal sx = viewSize.width() / imgSize.width();
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const qreal sy = viewSize.height() / imgSize.height();
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const qreal s = std::min(sx, sy);
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const qreal drawW = imgSize.width() * s;
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const qreal drawH = imgSize.height() * s;
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const qreal offsetX = (viewSize.width() - drawW) / 2.0;
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const qreal offsetY = (viewSize.height() - drawH) / 2.0;
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QTransform t;
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t.translate(offsetX, offsetY);
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t.scale(s, s);
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return t;
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}
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private:
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QImage m_image;
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bool m_dragging = false;
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QPoint m_anchor;
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QRect m_selection;
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};
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ImageCropDialog::ImageCropDialog(const QString& imagePath, QWidget* parent)
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: QDialog(parent),
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m_imagePath(imagePath) {
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setWindowTitle(QStringLiteral("裁剪图片"));
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setModal(true);
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resize(900, 600);
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loadImageOrClose();
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rebuildUi();
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}
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void ImageCropDialog::loadImageOrClose() {
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// Qt 默认的 image allocation limit 较小（常见为 256MB），超大分辨率图会被拒绝。
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// 这里用 QImageReader 并提高 limit；同时对极端大图按像素数上限自动缩放，避免 OOM。
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#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
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QImageReader::setAllocationLimit(1024); // MB
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#endif
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QImageReader reader(m_imagePath);
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reader.setAutoTransform(true);
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const QSize sz = reader.size();
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if (sz.isValid()) {
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constexpr qint64 kMaxPixels = 120LL * 1000LL * 1000LL; // 120MP
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const qint64 pixels = qint64(sz.width()) * qint64(sz.height());
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if (pixels > kMaxPixels) {
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const double s = std::sqrt(double(kMaxPixels) / std::max<double>(1.0, double(pixels)));
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const int nw = std::max(1, int(std::lround(sz.width() * s)));
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const int nh = std::max(1, int(std::lround(sz.height() * s)));
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reader.setScaledSize(QSize(nw, nh));
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}
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}
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m_image = reader.read();
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if (m_image.isNull()) {
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reject();
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}
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}
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void ImageCropDialog::rebuildUi() {
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auto* root = new QVBoxLayout(this);
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auto* hint = new QLabel(QStringLiteral("拖拽选择裁剪区域（不选则使用整张图）。"), this);
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root->addWidget(hint);
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m_view = new CropView(this);
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m_view->setImage(m_image);
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root->addWidget(m_view, 1);
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auto* buttons = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, this);
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m_okButton = buttons->button(QDialogButtonBox::Ok);
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auto* resetBtn = new QPushButton(QStringLiteral("重置选择"), this);
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buttons->addButton(resetBtn, QDialogButtonBox::ActionRole);
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connect(resetBtn, &QPushButton::clicked, this, &ImageCropDialog::onReset);
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connect(buttons, &QDialogButtonBox::accepted, this, &ImageCropDialog::onOk);
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connect(buttons, &QDialogButtonBox::rejected, this, &ImageCropDialog::reject);
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root->addWidget(buttons);
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}
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bool ImageCropDialog::hasValidSelection() const {
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return m_view && m_view->hasSelection();
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}
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QRect ImageCropDialog::selectedRectInImagePixels() const {
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if (!m_view) {
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return {};
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}
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return m_view->selectionInImagePixels();
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}
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void ImageCropDialog::onReset() {
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if (m_view) {
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m_view->resetSelection();
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}
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}
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void ImageCropDialog::onOk() {
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accept();
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}
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