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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#include "gestures.h"
#include <QPainter>
#include <QPainterPath>
#include <QRectF>
#include <QWidget>
namespace {
qreal swipeDirectionAngle(QSwipeGesture::SwipeDirection d)
{
switch (d) {
case QSwipeGesture::NoDirection:
case QSwipeGesture::Right:
break;
case QSwipeGesture::Left:
return 180;
case QSwipeGesture::Up:
return 90;
case QSwipeGesture::Down:
return 270;
}
return 0;
}
// Draws an arrow assuming a mathematical coordinate system, Y axis pointing
// upwards, angle counterclockwise (that is, 45' is pointing up/right).
void drawArrow(const QPointF ¢er, qreal length, qreal angleDegrees,
const QColor &color, int arrowSize, QPainter &painter)
{
painter.save();
painter.translate(center); // Transform center to (0,0) rotate and draw arrow pointing right.
painter.rotate(-angleDegrees);
QPen pen = painter.pen();
pen.setColor(color);
pen.setWidth(2);
painter.setPen(pen);
const QPointF endPoint(length, 0);
painter.drawLine(QPointF(0, 0), endPoint);
painter.drawLine(endPoint, endPoint + QPoint(-arrowSize, -arrowSize));
painter.drawLine(endPoint, endPoint + QPoint(-arrowSize, arrowSize));
painter.restore();
}
} // namespace
Gesture::Gesture(const QWidget *w, const QGesture *source)
: m_type(source->gestureType())
, m_hotSpot(w->mapFromGlobal(source->hotSpot().toPoint()))
, m_hasHotSpot(source->hasHotSpot())
{
}
QPointF Gesture::drawHotSpot(const QRectF &rect, QPainter &painter) const
{
const QPointF h = m_hasHotSpot ? m_hotSpot : rect.center();
painter.drawEllipse(h, 15, 15);
return h;
}
Gesture *Gesture::fromQGesture(const QWidget *w, const QGesture *source)
{
Gesture *result = nullptr;
switch (source->gestureType()) {
case Qt::TapGesture:
case Qt::TapAndHoldGesture:
case Qt::PanGesture:
result = new PanGesture(w, static_cast<const QPanGesture *>(source));
break;
case Qt::PinchGesture:
case Qt::CustomGesture:
case Qt::LastGestureType:
break;
case Qt::SwipeGesture:
result = new SwipeGesture(w, static_cast<const QSwipeGesture *>(source));
break;
}
return result;
}
PanGesture::PanGesture(const QWidget *w, const QPanGesture *source)
: Gesture(w, source), m_offset(source->offset())
{
}
void PanGesture::draw(const QRectF &rect, QPainter &painter) const
{
const QPointF hotSpot = drawHotSpot(rect, painter);
painter.drawLine(hotSpot, hotSpot + m_offset);
}
SwipeGesture::SwipeGesture(const QWidget *w, const QSwipeGesture *source)
: Gesture(w, source)
, m_horizontal(source->horizontalDirection())
, m_vertical(source->verticalDirection())
, m_angle(source->swipeAngle())
{
}
void SwipeGesture::draw(const QRectF &rect, QPainter &painter) const
{
enum { arrowLength = 50, arrowHeadSize = 10 };
const QPointF hotSpot = drawHotSpot(rect, painter);
drawArrow(hotSpot, arrowLength, swipeDirectionAngle(m_horizontal), Qt::red, arrowHeadSize, painter);
drawArrow(hotSpot, arrowLength, swipeDirectionAngle(m_vertical), Qt::green, arrowHeadSize, painter);
drawArrow(hotSpot, arrowLength, m_angle, Qt::blue, arrowHeadSize, painter);
}