Developer Documentation
QtGraphicsButton.cc
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50 
51 
52 //=============================================================================
53 //
54 // CLASS QtGraphicsButton - IMPLEMENTATION
55 //
56 //=============================================================================
57 
58 //== INCLUDES =================================================================
59 
60 #include <QPainter>
61 #include <QGraphicsSceneMouseEvent>
62 
63 #include "QtGraphicsButton.hh"
64 
65 //== IMPLEMENTATION ==========================================================
66 
67 QtGraphicsButton::QtGraphicsButton (const QImage &_image, QGraphicsItem *_parent, int _width, int _height) :
68  QGraphicsItem (_parent),
69  checkable_(false),
70  checked_(false),
71  pressed_(false),
72  over_(false),
73  width_(_width),
74  height_(_height)
75 {
76  if (width_ <= 0)
77  width_ = _image.width ();
78  if (height_ <= 0)
79  height_ = _image.height ();
80 
81  // scale image to button dimensions
82  QImage i = _image.scaled (width_, height_, Qt::IgnoreAspectRatio, Qt::SmoothTransformation).convertToFormat (QImage::Format_ARGB32);
83 
84  checkedPix_ = QPixmap::fromImage (i);
85 
86  // generate black/white and transparent images for the other button states
87  QImage normal (width_, height_, QImage::Format_ARGB32);
88  QImage over (width_, height_, QImage::Format_ARGB32);
89 
90  for (int x = 0; x < width_; x++)
91  for (int y = 0; y < height_; y++)
92  {
93  QRgb pix = i.pixel (x, y);
94  over.setPixel (x, y, qRgba (qRed (pix), qGreen (pix), qBlue (pix), qAlpha (pix) * 0.5));
95  normal.setPixel (x, y, qRgba (qGray (pix), qGray (pix), qGray (pix), qAlpha (pix) * 0.3));
96  }
97  overPix_ = QPixmap::fromImage (over);
98  normalPix_ = QPixmap::fromImage (normal);
99 
100  setAcceptHoverEvents (true);
101 }
102 
103 //-----------------------------------------------------------------------------
104 
106 {
107  return QRectF (QPointF(0, 0), QSizeF (width_, height_));
108 }
109 
110 //-----------------------------------------------------------------------------
111 
112 void QtGraphicsButton::paint (QPainter *_painter, const QStyleOptionGraphicsItem *, QWidget *)
113 {
114  _painter->setClipping (false);
115  if (pressed_ || checked_)
116  _painter->drawPixmap (0, 0, checkedPix_);
117  else if (over_)
118  _painter->drawPixmap (0, 0, overPix_);
119  else
120  _painter->drawPixmap (0, 0, normalPix_);
121 }
122 
123 //-----------------------------------------------------------------------------
124 
126 {
127  checkable_ = _value;
128 }
129 
130 //-----------------------------------------------------------------------------
131 
133 {
134  checked_ = _value;
135 }
136 
137 //-----------------------------------------------------------------------------
138 
140 {
141  return checked_;
142 }
143 
144 //-----------------------------------------------------------------------------
145 
146 void QtGraphicsButton::hoverEnterEvent (QGraphicsSceneHoverEvent *)
147 {
148  over_ = true;
149  update ();
150 }
151 
152 //-----------------------------------------------------------------------------
153 
154 void QtGraphicsButton::hoverLeaveEvent (QGraphicsSceneHoverEvent *)
155 {
156  over_ = false;
157  update ();
158 }
159 
160 //-----------------------------------------------------------------------------
161 
162 void QtGraphicsButton::mousePressEvent ( QGraphicsSceneMouseEvent *_event)
163 {
164  _event->accept ();
165  pressed_ = true;
166  if (checkable_)
167  checked_ = !checked_;
168  update ();
169 
170  emit pressed ();
171 }
172 
173 //-----------------------------------------------------------------------------
174 
175 void QtGraphicsButton::mouseReleaseEvent (QGraphicsSceneMouseEvent *_event)
176 {
177  _event->accept ();
178  pressed_ = false;
179  update ();
180 }
181 
182 //-----------------------------------------------------------------------------
183 
184 QVariant QtGraphicsButton::itemChange (GraphicsItemChange _change, const QVariant &_value)
185 {
186  // reset state if button was hidden
187  if (_change == QGraphicsItem::ItemVisibleHasChanged)
188  {
189  pressed_ = false;
190  over_ = false;
191  }
192  return QGraphicsItem::itemChange (_change, _value);
193 }
194 
195 //=============================================================================
bool checkable_
button state
virtual void hoverEnterEvent(QGraphicsSceneHoverEvent *_event)
event tracking
virtual QRectF boundingRect() const
returns the bounding rect
QtGraphicsButton(const QImage &_image, QGraphicsItem *_parent=0, int _width=-1, int _height=-1)
virtual void paint(QPainter *_painter, const QStyleOptionGraphicsItem *_option, QWidget *_widget=0)
paints the button
bool isChecked() const
returns button checked state
void pressed()
signals a button press
void setCheckable(bool _value)
makes the button checkable
QPixmap normalPix_
pixmaps for different button states
int width_
button size
void setChecked(bool _value)
sets button checked state