From 879f56327e5d41564ae010a2ab98a02c76396d0e Mon Sep 17 00:00:00 2001
From: J-P Nurmi <jpnurmi@digia.com>
Date: Wed, 20 Feb 2013 15:47:58 +0100
Subject: [PATCH] WheelArea: adjust wheel scrolling speed
Use (slightly adjusted) pixel values on systems that provide
platforms that support high-resolution pixel-based delta values,
such as Mac OS X, and set a reasonable default scrolling speed
(20px) for typical angle based mouse wheels.
Change-Id: I3ff7b3dfcb31fbc83c25188078f82cf5416ea355
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
---
src/private/qwheelarea.cpp | 33 ++++++++++++++++++++++++++-------
1 file changed, 26 insertions(+), 7 deletions(-)
diff --git a/src/private/qwheelarea.cpp b/src/private/qwheelarea.cpp
index eb06f31f6..db3b51714 100644
--- a/src/private/qwheelarea.cpp
+++ b/src/private/qwheelarea.cpp
@@ -43,6 +43,19 @@
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),
@@ -53,7 +66,7 @@ QWheelArea::QWheelArea(QQuickItem *parent)
m_verticalValue(0),
m_verticalDelta(0),
m_horizontalDelta(0),
- m_scrollSpeed(1.0)
+ m_scrollSpeed(defaultScrollSpeed)
{
}
@@ -65,11 +78,17 @@ QWheelArea::~QWheelArea()
void QWheelArea::wheelEvent(QWheelEvent *we)
{
- if (we->orientation() == Qt::Vertical) {
- setVerticalDelta(we->delta());
- } else {
- setHorizontalDelta(we->delta());
+ 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();
}
@@ -145,7 +164,7 @@ qreal QWheelArea::verticalValue() const
void QWheelArea::setVerticalDelta(qreal value)
{
- m_verticalDelta = m_scrollSpeed * value / 15;
+ m_verticalDelta = value;
setVerticalValue(m_verticalValue - m_verticalDelta);
emit verticalWheelMoved();
@@ -158,7 +177,7 @@ qreal QWheelArea::verticalDelta() const
void QWheelArea::setHorizontalDelta(qreal value)
{
- m_horizontalDelta = value / 15;
+ m_horizontalDelta = value;
setHorizontalValue(m_horizontalValue - m_horizontalDelta);
emit horizontalWheelMoved();
--
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