From 9440519bc8140c16fb40ae961c9cffd31c4902ee Mon Sep 17 00:00:00 2001
From: laserpants <johannes@isomorphic.co>
Date: Fri, 25 Mar 2016 23:30:28 +0300
Subject: [PATCH] fix handle positioning

---
 components/slider.cpp | 51 ++++++++++++++++++++++++-------------------
 components/slider.h   | 10 ++++++---
 2 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/components/slider.cpp b/components/slider.cpp
index ed0f499..64e1062 100644
--- a/components/slider.cpp
+++ b/components/slider.cpp
@@ -13,12 +13,6 @@ Handle::~Handle()
 {
 }
 
-void Handle::setPosition(const QPoint &pos)
-{
-    _position = pos;
-    refreshGeometry();
-}
-
 void Handle::refreshGeometry()
 {
     QWidget *container = parentWidget();
@@ -31,13 +25,6 @@ void Handle::refreshGeometry()
     update();
 }
 
-bool Handle::event(QEvent *event)
-{
-    qDebug() << event;
-
-    return QWidget::event(event);
-}
-
 void Handle::paintEvent(QPaintEvent *event)
 {
     QPainter painter(this);
@@ -52,22 +39,17 @@ void Handle::paintEvent(QPaintEvent *event)
 
 void Handle::mousePressEvent(QMouseEvent *event)
 {
-    _eventPos = event->globalPos();
-    _offset = pos();
-}
-
-void Handle::mouseReleaseEvent(QMouseEvent *event)
-{
-    Q_UNUSED(event)
+    _offset = pos() - event->globalPos();
 }
 
 void Handle::mouseMoveEvent(QMouseEvent *event)
 {
-    setPosition(_offset + event->globalPos() - _eventPos);
+    setPosition(_offset + event->globalPos());
 }
 
 Slider::Slider(QWidget *parent)
     : QWidget(parent),
+      _drag(false),
       _handle(new Handle(this)),
       _orientation(Qt::Horizontal)
 {
@@ -98,17 +80,40 @@ void Slider::paintEvent(QPaintEvent *event)
     QWidget::paintEvent(event);
 }
 
+
 void Slider::mousePressEvent(QMouseEvent *event)
 {
     const QSize s = _handle->sizeHint();
-    _handle->setPosition(event->pos() - QPoint(s.width()/2, s.height()/2));
+    const QPoint p = event->pos();
+    const QPoint newPos = p - QPoint(s.width()/2, s.height()/2);
 
+    if (Qt::Horizontal == _orientation ? touchesRail(p.y(), height()/2) : touchesRail(p.x(), width()/2)) {
+        _handle->setPosition(newPos);
+        _handle->setOffset(newPos - event->globalPos());
+        _drag = true;
+    } else {
+        _drag = false;
+    }
     QWidget::mousePressEvent(event);
 }
 
+void Slider::mouseMoveEvent(QMouseEvent *event)
+{
+    if (_drag) {
+        _handle->setPosition(_handle->offset() + event->globalPos());
+    }
+    QWidget::mouseMoveEvent(event);
+}
+
 void Slider::resizeEvent(QResizeEvent *event)
 {
     _handle->refreshGeometry();
-
     QWidget::resizeEvent(event);
 }
+
+
+bool Slider::touchesRail(int p, int x) const
+{
+    return (p >= x-2 && p < x+2);
+}
+
diff --git a/components/slider.h b/components/slider.h
index fdf2ea8..4dad01b 100644
--- a/components/slider.h
+++ b/components/slider.h
@@ -15,15 +15,15 @@ public:
     ~Handle();
 
     inline QSize sizeHint() const { return QSize(16, 16); }
+    inline void setPosition(const QPoint &pos) { _position = pos; refreshGeometry(); }
     inline const QPoint &position() const { return _position; }
-    inline void setPosition(const QPoint &pos);
+    inline void setOffset(const QPoint &offset) { _offset = offset; update(); }
+    inline const QPoint &offset() const { return _offset; }
     void refreshGeometry();
 
 protected:
-    bool event(QEvent *event);
     void paintEvent(QPaintEvent *event);
     void mousePressEvent(QMouseEvent *event);
-    void mouseReleaseEvent(QMouseEvent *event);
     void mouseMoveEvent(QMouseEvent *event);
 
 private:
@@ -47,9 +47,13 @@ public:
 protected:
     void paintEvent(QPaintEvent *event);
     void mousePressEvent(QMouseEvent *event);
+    void mouseMoveEvent(QMouseEvent *event);
     void resizeEvent(QResizeEvent *event);
 
 private:
+    bool touchesRail(int p, int x) const;
+
+    bool            _drag;
     Handle   *const _handle;
     Qt::Orientation _orientation;
 };