qwheelarea.cpp 5.68 KiB
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#include "qwheelarea_p.h"
QT_BEGIN_NAMESPACE
// On Mac OS X, the scrolling speed in Safari is roughly 2.5 times faster
// than in TextEdit (the native app). The former is using high-resolution
// pixel-based delta values as they are, which is fine for a typical web
// content, whereas the latter evidently makes scrolling slower to make it
// feel natural and more precise for typical document type of content.
// => we'll compromise between the two for now, and pick an arbitrary value
//    to make the pixel-based scrolling speed something between the two
static const qreal pixelDeltaAdjustment = 0.5;
// The default scroll speed for typical angle-based mouse wheels. The value
// comes originally from QTextEdit, which sets 20px steps by default.
static const qreal defaultScrollSpeed = 20.0;
QWheelArea::QWheelArea(QQuickItem *parent)
    : QQuickItem(parent),
      m_horizontalMinimumValue(0),
      m_horizontalMaximumValue(0),
      m_verticalMinimumValue(0),
      m_verticalMaximumValue(0),
      m_horizontalValue(0),
      m_verticalValue(0),
      m_verticalDelta(0),
      m_horizontalDelta(0),
      m_scrollSpeed(defaultScrollSpeed)
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} QWheelArea::~QWheelArea() { } void QWheelArea::wheelEvent(QWheelEvent *we) { QPoint numPixels = we->pixelDelta(); QPoint numDegrees = we->angleDelta() / 8; if (!numPixels.isNull()) { setHorizontalDelta(numPixels.x() * pixelDeltaAdjustment); setVerticalDelta(numPixels.y() * pixelDeltaAdjustment); } else if (!numDegrees.isNull()) { setHorizontalDelta(numDegrees.x() / 15.0 * m_scrollSpeed); setVerticalDelta(numDegrees.y() / 15.0 * m_scrollSpeed); } we->accept(); } void QWheelArea::setHorizontalMinimumValue(qreal value) { m_horizontalMinimumValue = value; } qreal QWheelArea::horizontalMinimumValue() const { return m_horizontalMinimumValue; } void QWheelArea::setHorizontalMaximumValue(qreal value) { m_horizontalMaximumValue = value; } qreal QWheelArea::horizontalMaximumValue() const { return m_horizontalMaximumValue; } void QWheelArea::setVerticalMinimumValue(qreal value) { m_verticalMinimumValue = value; } qreal QWheelArea::verticalMinimumValue() const { return m_verticalMinimumValue; } void QWheelArea::setVerticalMaximumValue(qreal value) { m_verticalMaximumValue = value; } qreal QWheelArea::verticalMaximumValue() const { return m_verticalMaximumValue; } void QWheelArea::setHorizontalValue(qreal value) { value = qBound<qreal>(m_horizontalMinimumValue, value, m_horizontalMaximumValue); if (value != m_horizontalValue) { m_horizontalValue = value;
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emit horizontalValueChanged(); } } qreal QWheelArea::horizontalValue() const { return m_horizontalValue; } void QWheelArea::setVerticalValue(qreal value) { value = qBound<qreal>(m_verticalMinimumValue, value, m_verticalMaximumValue); if (value != m_verticalValue) { m_verticalValue = value; emit verticalValueChanged(); } } qreal QWheelArea::verticalValue() const { return m_verticalValue; } void QWheelArea::setVerticalDelta(qreal value) { m_verticalDelta = value; setVerticalValue(m_verticalValue - m_verticalDelta); emit verticalWheelMoved(); } qreal QWheelArea::verticalDelta() const { return m_verticalDelta; } void QWheelArea::setHorizontalDelta(qreal value) { m_horizontalDelta = value; setHorizontalValue(m_horizontalValue - m_horizontalDelta); emit horizontalWheelMoved(); } qreal QWheelArea::horizontalDelta() const { return m_horizontalDelta; } void QWheelArea::setScrollSpeed(qreal value) { if (value != m_scrollSpeed) { m_scrollSpeed = value; emit scrollSpeedChanged(); } } qreal QWheelArea::scrollSpeed() const { return m_scrollSpeed; } QT_END_NAMESPACE