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Documentation/Source/eric5.Graphics.AssociationItem.html
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| 1 <?xml version="1.0" encoding="utf-8"?> | |
| 2 <!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Strict//EN' | |
| 3 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd'> | |
| 4 <html><head> | |
| 5 <title>eric5.Graphics.AssociationItem</title> | |
| 6 <style> | |
| 7 b'body {\n background:white;\n margin: 0em 1em 10em 1em;\n color: black;\n}\n\nh1 { color: white; background: #4FA4FF; }\nh2 { color: white; background: #4FA4FF; }\nh3 { color: white; background: #00557F; }\nh4 { color: white; background: #00557F; }\n \na { color: #AA5500; }\n' | |
| 8 </style> | |
| 9 </head> | |
| 10 <body><a NAME="top" ID="top"></a> | |
| 11 <h1>eric5.Graphics.AssociationItem</h1> | |
| 12 <p> | |
| 13 Module implementing a graphics item for an association between two items. | |
| 14 </p> | |
| 15 <h3>Global Attributes</h3> | |
| 16 <table> | |
| 17 <tr><td>Center</td></tr><tr><td>East</td></tr><tr><td>Generalisation</td></tr><tr><td>Imports</td></tr><tr><td>NoRegion</td></tr><tr><td>Normal</td></tr><tr><td>North</td></tr><tr><td>NorthEast</td></tr><tr><td>NorthWest</td></tr><tr><td>South</td></tr><tr><td>SouthEast</td></tr><tr><td>SouthWest</td></tr><tr><td>West</td></tr> | |
| 18 </table> | |
| 19 <h3>Classes</h3> | |
| 20 <table> | |
| 21 <tr> | |
| 22 <td><a href="#AssociationItem">AssociationItem</a></td> | |
| 23 <td>Class implementing a graphics item for an association between two items.</td> | |
| 24 </tr> | |
| 25 </table> | |
| 26 <h3>Functions</h3> | |
| 27 <table> | |
| 28 <tr><td>None</td></tr> | |
| 29 </table> | |
| 30 <hr /><hr /> | |
| 31 <a NAME="AssociationItem" ID="AssociationItem"></a> | |
| 32 <h2>AssociationItem</h2> | |
| 33 <p> | |
| 34 Class implementing a graphics item for an association between two items. | |
| 35 </p><p> | |
| 36 The association is drawn as an arrow starting at the first items and | |
| 37 ending at the second. | |
| 38 </p> | |
| 39 <h3>Derived from</h3> | |
| 40 E4ArrowItem | |
| 41 <h3>Class Attributes</h3> | |
| 42 <table> | |
| 43 <tr><td>None</td></tr> | |
| 44 </table> | |
| 45 <h3>Methods</h3> | |
| 46 <table> | |
| 47 <tr> | |
| 48 <td><a href="#AssociationItem.__init__">AssociationItem</a></td> | |
| 49 <td>Constructor</td> | |
| 50 </tr><tr> | |
| 51 <td><a href="#AssociationItem.__calculateEndingPoints_center">__calculateEndingPoints_center</a></td> | |
| 52 <td>Private method to calculate the ending points of the association item.</td> | |
| 53 </tr><tr> | |
| 54 <td><a href="#AssociationItem.__calculateEndingPoints_rectangle">__calculateEndingPoints_rectangle</a></td> | |
| 55 <td>Private method to calculate the ending points of the association item.</td> | |
| 56 </tr><tr> | |
| 57 <td><a href="#AssociationItem.__findIntersection">__findIntersection</a></td> | |
| 58 <td>Method to calculate the intersection point of two lines.</td> | |
| 59 </tr><tr> | |
| 60 <td><a href="#AssociationItem.__findPointRegion">__findPointRegion</a></td> | |
| 61 <td>Private method to find out, which region of rectangle rect contains the point (PosX, PosY) and returns the region number.</td> | |
| 62 </tr><tr> | |
| 63 <td><a href="#AssociationItem.__findRectIntersectionPoint">__findRectIntersectionPoint</a></td> | |
| 64 <td>Private method to find the intersetion point of a line with a rectangle.</td> | |
| 65 </tr><tr> | |
| 66 <td><a href="#AssociationItem.__mapRectFromItem">__mapRectFromItem</a></td> | |
| 67 <td>Private method to map item's rectangle to this item's coordinate system.</td> | |
| 68 </tr><tr> | |
| 69 <td><a href="#AssociationItem.__updateEndPoint">__updateEndPoint</a></td> | |
| 70 <td>Private method to update an endpoint.</td> | |
| 71 </tr><tr> | |
| 72 <td><a href="#AssociationItem.unassociate">unassociate</a></td> | |
| 73 <td>Public method to unassociate from the widgets.</td> | |
| 74 </tr><tr> | |
| 75 <td><a href="#AssociationItem.widgetMoved">widgetMoved</a></td> | |
| 76 <td>Public method to recalculate the association after a widget was moved.</td> | |
| 77 </tr> | |
| 78 </table> | |
| 79 <a NAME="AssociationItem.__init__" ID="AssociationItem.__init__"></a> | |
| 80 <h4>AssociationItem (Constructor)</h4> | |
| 81 <b>AssociationItem</b>(<i>itemA, itemB, type = Normal, parent = None</i>) | |
| 82 <p> | |
| 83 Constructor | |
| 84 </p><dl> | |
| 85 <dt><i>itemA</i></dt> | |
| 86 <dd> | |
| 87 first widget of the association | |
| 88 </dd><dt><i>itemB</i></dt> | |
| 89 <dd> | |
| 90 second widget of the association | |
| 91 </dd><dt><i>type</i></dt> | |
| 92 <dd> | |
| 93 type of the association. This must be one of | |
| 94 <ul> | |
| 95 <li>Normal (default)</li> | |
| 96 <li>Generalisation</li> | |
| 97 <li>Imports</li> | |
| 98 </ul> | |
| 99 </dd><dt><i>parent=</i></dt> | |
| 100 <dd> | |
| 101 reference to the parent object (QGraphicsItem) | |
| 102 </dd> | |
| 103 </dl><a NAME="AssociationItem.__calculateEndingPoints_center" ID="AssociationItem.__calculateEndingPoints_center"></a> | |
| 104 <h4>AssociationItem.__calculateEndingPoints_center</h4> | |
| 105 <b>__calculateEndingPoints_center</b>(<i></i>) | |
| 106 <p> | |
| 107 Private method to calculate the ending points of the association item. | |
| 108 </p><p> | |
| 109 The ending points are calculated from the centers of the | |
| 110 two associated items. | |
| 111 </p><a NAME="AssociationItem.__calculateEndingPoints_rectangle" ID="AssociationItem.__calculateEndingPoints_rectangle"></a> | |
| 112 <h4>AssociationItem.__calculateEndingPoints_rectangle</h4> | |
| 113 <b>__calculateEndingPoints_rectangle</b>(<i></i>) | |
| 114 <p> | |
| 115 Private method to calculate the ending points of the association item. | |
| 116 </p><p> | |
| 117 The ending points are calculated by the following method. | |
| 118 </p><p> | |
| 119 For each item the diagram is divided in four Regions by its diagonals | |
| 120 as indicated below | |
| 121 <pre> | |
| 122 \ Region 2 / | |
| 123 \ / | |
| 124 |--------| | |
| 125 | \ / | | |
| 126 | \ / | | |
| 127 | \/ | | |
| 128 Region 1 | /\ | Region 3 | |
| 129 | / \ | | |
| 130 | / \ | | |
| 131 |--------| | |
| 132 / \ | |
| 133 / Region 4 \ | |
| 134 </pre> | |
| 135 </p><p> | |
| 136 Each diagonal is defined by two corners of the bounding rectangle | |
| 137 </p><p> | |
| 138 To calculate the start point we have to find out in which | |
| 139 region (defined by itemA's diagonals) is itemB's TopLeft corner | |
| 140 (lets call it region M). After that the start point will be | |
| 141 the middle point of rectangle's side contained in region M. | |
| 142 </p><p> | |
| 143 To calculate the end point we repeat the above but in the opposite direction | |
| 144 (from itemB to itemA) | |
| 145 </p><a NAME="AssociationItem.__findIntersection" ID="AssociationItem.__findIntersection"></a> | |
| 146 <h4>AssociationItem.__findIntersection</h4> | |
| 147 <b>__findIntersection</b>(<i>p1, p2, p3, p4</i>) | |
| 148 <p> | |
| 149 Method to calculate the intersection point of two lines. | |
| 150 </p><p> | |
| 151 The first line is determined by the points p1 and p2, the second | |
| 152 line by p3 and p4. If the intersection point is not contained in | |
| 153 the segment p1p2, then it returns (-1.0, -1.0). | |
| 154 </p><p> | |
| 155 For the function's internal calculations remember:<br /> | |
| 156 QT coordinates start with the point (0,0) as the topleft corner | |
| 157 and x-values increase from left to right and y-values increase | |
| 158 from top to bottom; it means the visible area is quadrant I in | |
| 159 the regular XY coordinate system | |
| 160 </p><p> | |
| 161 <pre> | |
| 162 Quadrant II | Quadrant I | |
| 163 -----------------|----------------- | |
| 164 Quadrant III | Quadrant IV | |
| 165 </pre> | |
| 166 </p><p> | |
| 167 In order for the linear function calculations to work in this method | |
| 168 we must switch x and y values (x values become y values and viceversa) | |
| 169 </p><dl> | |
| 170 <dt><i>p1</i></dt> | |
| 171 <dd> | |
| 172 first point of first line (QPointF) | |
| 173 </dd><dt><i>p2</i></dt> | |
| 174 <dd> | |
| 175 second point of first line (QPointF) | |
| 176 </dd><dt><i>p3</i></dt> | |
| 177 <dd> | |
| 178 first point of second line (QPointF) | |
| 179 </dd><dt><i>p4</i></dt> | |
| 180 <dd> | |
| 181 second point of second line (QPointF) | |
| 182 </dd> | |
| 183 </dl><dl> | |
| 184 <dt>Returns:</dt> | |
| 185 <dd> | |
| 186 the intersection point (QPointF) | |
| 187 </dd> | |
| 188 </dl><a NAME="AssociationItem.__findPointRegion" ID="AssociationItem.__findPointRegion"></a> | |
| 189 <h4>AssociationItem.__findPointRegion</h4> | |
| 190 <b>__findPointRegion</b>(<i>rect, posX, posY</i>) | |
| 191 <p> | |
| 192 Private method to find out, which region of rectangle rect contains the point | |
| 193 (PosX, PosY) and returns the region number. | |
| 194 </p><dl> | |
| 195 <dt><i>rect</i></dt> | |
| 196 <dd> | |
| 197 rectangle to calculate the region for (QRectF) | |
| 198 </dd><dt><i>posX</i></dt> | |
| 199 <dd> | |
| 200 x position of point (float) | |
| 201 </dd><dt><i>posY</i></dt> | |
| 202 <dd> | |
| 203 y position of point (float) | |
| 204 </dd> | |
| 205 </dl><dl> | |
| 206 <dt>Returns:</dt> | |
| 207 <dd> | |
| 208 the calculated region number<br /> | |
| 209 West = Region 1<br /> | |
| 210 North = Region 2<br /> | |
| 211 East = Region 3<br /> | |
| 212 South = Region 4<br /> | |
| 213 NorthWest = On diagonal 2 between Region 1 and 2<br /> | |
| 214 NorthEast = On diagonal 1 between Region 2 and 3<br /> | |
| 215 SouthEast = On diagonal 2 between Region 3 and 4<br /> | |
| 216 SouthWest = On diagonal 1 between Region4 and 1<br /> | |
| 217 Center = On diagonal 1 and On diagonal 2 (the center)<br /> | |
| 218 </dd> | |
| 219 </dl><a NAME="AssociationItem.__findRectIntersectionPoint" ID="AssociationItem.__findRectIntersectionPoint"></a> | |
| 220 <h4>AssociationItem.__findRectIntersectionPoint</h4> | |
| 221 <b>__findRectIntersectionPoint</b>(<i>item, p1, p2</i>) | |
| 222 <p> | |
| 223 Private method to find the intersetion point of a line with a rectangle. | |
| 224 </p><dl> | |
| 225 <dt><i>item</i></dt> | |
| 226 <dd> | |
| 227 item to check against | |
| 228 </dd><dt><i>p1</i></dt> | |
| 229 <dd> | |
| 230 first point of the line (QPointF) | |
| 231 </dd><dt><i>p2</i></dt> | |
| 232 <dd> | |
| 233 second point of the line (QPointF) | |
| 234 </dd> | |
| 235 </dl><dl> | |
| 236 <dt>Returns:</dt> | |
| 237 <dd> | |
| 238 the intersection point (QPointF) | |
| 239 </dd> | |
| 240 </dl><a NAME="AssociationItem.__mapRectFromItem" ID="AssociationItem.__mapRectFromItem"></a> | |
| 241 <h4>AssociationItem.__mapRectFromItem</h4> | |
| 242 <b>__mapRectFromItem</b>(<i>item</i>) | |
| 243 <p> | |
| 244 Private method to map item's rectangle to this item's coordinate system. | |
| 245 </p><dl> | |
| 246 <dt><i>item</i></dt> | |
| 247 <dd> | |
| 248 reference to the item to be mapped (QGraphicsRectItem) | |
| 249 </dd> | |
| 250 </dl><dl> | |
| 251 <dt>Returns:</dt> | |
| 252 <dd> | |
| 253 item's rectangle in local coordinates (QRectF) | |
| 254 </dd> | |
| 255 </dl><a NAME="AssociationItem.__updateEndPoint" ID="AssociationItem.__updateEndPoint"></a> | |
| 256 <h4>AssociationItem.__updateEndPoint</h4> | |
| 257 <b>__updateEndPoint</b>(<i>region, isWidgetA</i>) | |
| 258 <p> | |
| 259 Private method to update an endpoint. | |
| 260 </p><dl> | |
| 261 <dt><i>region</i></dt> | |
| 262 <dd> | |
| 263 the region for the endpoint (integer) | |
| 264 </dd><dt><i>isWidgetA</i></dt> | |
| 265 <dd> | |
| 266 flag indicating update for itemA is done (boolean) | |
| 267 </dd> | |
| 268 </dl><a NAME="AssociationItem.unassociate" ID="AssociationItem.unassociate"></a> | |
| 269 <h4>AssociationItem.unassociate</h4> | |
| 270 <b>unassociate</b>(<i></i>) | |
| 271 <p> | |
| 272 Public method to unassociate from the widgets. | |
| 273 </p><a NAME="AssociationItem.widgetMoved" ID="AssociationItem.widgetMoved"></a> | |
| 274 <h4>AssociationItem.widgetMoved</h4> | |
| 275 <b>widgetMoved</b>(<i></i>) | |
| 276 <p> | |
| 277 Public method to recalculate the association after a widget was moved. | |
| 278 </p> | |
| 279 <div align="right"><a href="#top">Up</a></div> | |
| 280 <hr /> | |
| 281 </body></html> |
