library.pyjamas.dnd.DNDHelper

35 """ 36 DNDHelper is a singleton drag and drop agent. 37 38 It acts as dragging/dropping agent for platforms that do not support html5 39 drag and drop. 40 """ 41

42 - def __init__(self):

43 self.dropTargets = [] 44 self.dragging = NOT_DRAGGING 45 self.dragBusy = False 46 self._currentTargetElement = None 47 self.previousDropTarget = None 48 self.draggingImage = None 49 self.origMouseX = 0 50 self.origMouseY = 0 51 self.currentDragOperation = 'none' 52 self.data = None 53 self.returnTimer = Timer(notify=self.onReturningWidget) 54 self.mouseEvent = None 55 self.dragDataStore = None

56

57 - def setCurrentTargetElement(self, element):

58 if self._currentTargetElement is not None: 59 if not DOM.compare(self._currentTargetElement, element): 60 # leave_event = self.makeDragEvent(self.mouseEvent, 'dragleave', 61 # self.currentTargetElement) 62 self.fireDNDEvent('dragleave', self.currentTargetElement, 63 self.currentDropWidget) 64 # self.currentDropWidget.onDragLeave(leave_event) 65 # self.finalize(leave_event) 66 self._currentTargetElement = element

67

68 - def getCurrentTargetElement(self):

69 return self._currentTargetElement

70 71 currentTargetElement = property(getCurrentTargetElement, 72 setCurrentTargetElement) 73

74 - def getElement(self):

75 """ 76 ie6 GlassWidget impl needs this 77 """ 78 return self.dragWidget.getElement()

79

80 - def updateDropEffect(self, dataTransfer, event_type):

81 """ 82 http://dev.w3.org/html5/spec/dnd.html#dragevent 83 """ 84 # default for dragstart, drag, dragleave 85 dropEffect='none' 86 87 if event_type in ['dragover', 'dragenter']: 88 ea = dataTransfer.getEffectAllowed() 89 if ea == 'none': 90 dropEffect = 'none' 91 elif ea.startswith('copy') or ea == 'all': 92 dropEffect = 'copy' 93 elif ea.startswith('link'): 94 dropEffect = 'link' 95 elif ea == 'move': 96 dropEffect = 'move' 97 else: 98 dropEffect = 'copy' 99 elif event_type in ['drop', 'dragend']: 100 dropEffect = self.currentDragOperation 101 dataTransfer.dropEffect = dropEffect

102

103 - def updateDragOperation(self, event):

104 """ 105 http://dev.w3.org/html5/spec/dnd.html 106 """ 107 dataTransfer = event.dataTransfer 108 ea = dataTransfer.effectAllowed 109 de = dataTransfer.dropEffect 110 if (de == 'copy' and ea in 111 ['uninitialized', 'copy','copyLink', 'copyMove', 'all']): 112 self.currentDragOperation = 'copy' 113 elif (de == 'link' and ea in 114 ['uninitialized', 'link', 'copyLink', 'linkMove', 'all']): 115 self.currentDragOperation = 'link' 116 elif (de == 'move' and ea in 117 ['uninitialized', 'move', 'copyMove', 'linkMove', 'all']): 118 self.currentDragOperation = 'move' 119 else: 120 self.currentDragOperation = 'none'

121

122 - def updateAllowedEffects(self, drag_event):

123 dt = drag_event.dataTransfer 124 self.dragDataStore.allowed_effects_state = dt.effectAllowed

125

126 - def registerTarget(self, target):

127 """ 128 Rather than searching the entire document for drop target widgets and 129 maybe drop targets within widgets, this implementation holds a list of 130 widgets and searches only within this list for potential drop targets. 131 """ 132 if not target in self.dropTargets: 133 self.dropTargets.append(target)

134

135 - def unregisterTarget(self, target):

136 """ 137 I dont know why, but a widget may no longer want to be registered 138 as a drop target. 139 """ 140 while target in self.dropTargets: 141 self.dropTargets.remove(target)

142 143

144 - def setDragImage(self, element, x, y):

145 position_absolute = DOM.getStyleAttribute(element, 146 'position') == 'absolute' 147 if position_absolute: 148 self.dragLeftOffset = x + DOM.getAbsoluteLeft( 149 element.offsetParent) 150 self.dragTopOffset = y + DOM.getAbsoluteTop( 151 element.offsetParent) 152 else: 153 self.dragLeftOffset = x 154 self.dragTopOffset = y 155 if element.tagName.lower().endswith('img'): 156 src = DOM.getAttribute(element,'src') 157 element = DOM.createElement('img') 158 DOM.setAttribute(element, 'src', src) 159 if not self.draggingImage: 160 self.createDraggingImage(element) 161 else: 162 self.draggingImage.setImage(element)

163

164 - def addFeedbackElement(self, element):

165 """ 166 This is called from DataTransfer 167 """ 168 if self.draggingImage: 169 self.draggingImage.addElement(element) 170 else: 171 self.createDraggingImage(element)

172

173 - def createDraggingImage(self, element):

174 self.draggingImage = DraggingWidget(element) 175 return self.draggingImage

176

177 - def setDragImageLocation(self, x, y):

178 """ 179 Move the dragging image around. 180 """ 181 elt_top = y - self.dragTopOffset 182 elt_left = x - self.dragLeftOffset 183 # if self.absParent: 184 # ap = self.absParent 185 # elt_top -= int(self.absTop) 186 # elt_left -= int(self.absLeft) 187 188 self.draggingImage.setStyleAttribute('top', elt_top ) 189 self.draggingImage.setStyleAttribute('left', elt_left)

190

191 - def getAbsoluteLeft(self):

192 """ 193 GlassWidget wants this 194 """ 195 # return 0 196 # if self.absParent: 197 # return self.absParent.getAbsoluteLeft() 198 return self.dragWidget.getAbsoluteLeft()

199 #return self.origLeft 200

201 - def getAbsoluteTop(self):

202 """ 203 GlassWidget wants this 204 """ 205 # return 0 206 # if self.absParent: 207 # return self.absParent.getAbsoluteTop() 208 return self.dragWidget.getAbsoluteTop()

209 #return self.origTop

210 - def makeDragEvent(self, event, type, target=None):

211 dt = DataTransfer(self.dragDataStore) 212 self.updateDropEffect(dt, type) 213 drag_event = DragEvent(event, type, dt, target) 214 return drag_event

215

216 - def finalize(self, event):

217 self.dragDataStore.allowed_effects_state = \ 218 event.dataTransfer.effectAllowed 219 if event.type in ['dragstart', 'drop']: 220 self.dragDataStore.setMode(PROTECTED) 221 event.dataTransfer.dataStore = None

222

223 - def fireDNDEvent(self, name, target, widget):

224 if name == 'dragstart': 225 self.dragDataStore.setMode(READ_WRITE) 226 elif name == 'drop': 227 self.dragDataStore.setMode(READ_ONLY) 228 event = self.makeDragEvent(self.mouseEvent, name, target) 229 widget.onBrowserEvent(event) 230 self.finalize(event) 231 return event

232

233 - def initFeedbackImage(self):

234 ds = self.dragDataStore 235 x = 0 236 y = 0 237 if ds.bitmap is not None: 238 if ds.hotspot_coordinate is not None: 239 offset = ds.hotspot_coordinate 240 x = offset[0] 241 y = offset[1] 242 self.setDragImage(ds.bitmap, x, y) 243 return 244 if self.dragDataStore.elements: 245 for element in self.dragDataStore.elements: 246 self.addFeedbackElement(element)

247 248

249 - def onMouseMove(self, sender, x, y):

250 event = DOM.eventGetCurrentEvent() 251 self.mouseEvent = event 252 button = DOM.eventGetButton(event) 253 if not button == Event.BUTTON_LEFT: 254 return 255 ## The following commented code lets the native dnd happen in IE. sucks. 256 ## But it may enable dragging our widgets out of IE into other apps. 257 # else: 258 # try: 259 # self.dragWidget.getElement().dragDrop() 260 # return 261 # except: 262 # pass 263 264 # Adjust x and y to absolute coordinates. 265 x, y = eventCoordinates(event) 266 267 if self.dragging == DRAGGING_NO_MOVEMENT_YET: 268 self.origMouseX = x 269 self.origMouseY = y 270 self.currentDragOperation = 'none' 271 fromElement = self.dragWidget.getElement() 272 # Is the widget itself draggable? 273 try: 274 draggable = fromElement.draggable 275 except: 276 draggable = False 277 # if not, find the draggable element at (x, y) in the widget 278 if not draggable: 279 fromElement = findDraggable(sender.getElement(), 280 self.origMouseX, self.origMouseY) 281 # Nothing draggable found. return. 282 if fromElement is None: 283 self.dragging = NOT_DRAGGING 284 return 285 # Get the location for the dragging widget 286 287 #self.absParent = None 288 289 #self.absParent = self.dragWidget.getParent() 290 #self.absLeft = DOM.getStyleAttribute(fromElement, 'left') 291 292 #print self.absLeft 293 #self.absTop = DOM.getStyleAttribute(fromElement, 'top') 294 #print self.absTop 295 #self.origTop = DOM.getAbsoluteTop(fromElement) + parent.getAbsoluteTop() 296 #self.origLeft = DOM.getAbsoluteLeft(fromElement) + parent.getAbsoluteLeft() 297 self.origTop = DOM.getAbsoluteTop(fromElement) 298 self.origLeft = DOM.getAbsoluteLeft(fromElement) 299 #self.glassTop = DOM.getAbsoluteTop(fromElement.offsetParent) 300 #self.glassLeft = DOM.getAbsoluteTop(fromElement.offsetParent) 301 position_absolute = DOM.getStyleAttribute(fromElement, 302 'position') == 'absolute' 303 if position_absolute: 304 self.dragLeftOffset = (self.origMouseX - 305 DOM.getAbsoluteLeft(fromElement.offsetParent)) 306 self.dragTopOffset = (self.origMouseY - 307 DOM.getAbsoluteTop(fromElement.offsetParent)) 308 else: 309 self.dragLeftOffset = self.origMouseX - self.origLeft 310 self.dragTopOffset = self.origMouseY - self.origTop 311 312 # self.setDragImage(fromElement, 313 # self.origMouseX - self.origLeft, 314 # self.origMouseY - self.origTop) 315 self.dragDataStore.elements = [fromElement] 316 dragStartEvent = self.fireDNDEvent('dragstart', None, 317 self.dragWidget) 318 if not isCanceled(dragStartEvent): 319 self.initFeedbackImage() 320 RootPanel().add(self.draggingImage) 321 self.setDragImageLocation(x, y) 322 self.dragging = ACTIVELY_DRAGGING 323 GlassWidget.show(self) 324 elif self.dragging == ACTIVELY_DRAGGING: 325 try: 326 doc().selection.empty() 327 except: 328 wnd().getSelection().removeAllRanges() 329 330 self.setDragImageLocation(x, y) 331 332 # If we are still working on the previous iteration, or if we have 333 # done this recently, we'll wait for the next event. 334 if self.dragBusy or time.time() - self.drag_time < 0.25: 335 return 336 337 self.doDrag(event, x, y) 338 self.drag_time = time.time()

339 340 341

342 - def doDrag(self, event, x, y):

343 self.dragBusy = True 344 #self.dragDataStore.dropEffect = 'none' 345 drag_event = self.fireDNDEvent('drag', None, self.dragWidget) 346 # drag event was not canceled 347 if not isCanceled(drag_event): 348 target = None 349 widget = None 350 # Find the most specific element under the cursor and the widget 351 # with the drop listener for it. 352 for widget in self.dropTargets: 353 target = getElementUnderMouse(widget, x, y) 354 if target is not None: 355 break 356 if target: 357 drop_widget = widget 358 drop_element = target 359 if (not self.currentTargetElement or 360 not DOM.compare(drop_element, self.currentTargetElement)): 361 # enter_event = self.makeDragEvent(event,'dragenter', 362 # drop_element) 363 enter_event = self.fireDNDEvent('dragenter', drop_element, 364 drop_widget) 365 # drop_widget.onDragEnter(enter_event) 366 # self.finalize(enter_event) 367 if isCanceled(enter_event): 368 self.currentTargetElement = drop_element 369 self.currentDropWidget = drop_widget 370 371 if self.currentTargetElement is not None: 372 # disable dropping if over event is not canceled 373 # over_event = self.makeDragEvent(event, 'dragover', 374 # drop_element) 375 over_event = self.fireDNDEvent('dragover', drop_element, 376 self.currentDropWidget) 377 # self.currentDropWidget.onDragOver(over_event) 378 # self.finalize(over_event) 379 if isCanceled(over_event): 380 self.updateDragOperation(over_event) 381 else: 382 self.currentDragOperation = 'none' 383 self.draggingImage.updateCursor(self.currentDragOperation) 384 else: 385 self.currentTargetElement = None 386 387 else: 388 self.currentDragOperation = 'none' 389 self.dragBusy = False

390

391 - def onMouseDown(self, sender, x, y):

392 self.dragWidget = sender 393 event = DOM.eventGetCurrentEvent() 394 self.mouseEvent = event 395 button = DOM.eventGetButton(event) 396 if button != Event.BUTTON_LEFT: 397 return 398 # x, y = eventCoordinates(event) 399 # self.origMouseX = x 400 # self.origMouseY = y 401 self.dragging = DRAGGING_NO_MOVEMENT_YET 402 self.drag_time = time.time() 403 self.dragDataStore = DragDataStore()

404

405 - def onMouseUp(self, sender, x, y):

406 # event = DOM.eventGetCurrentEvent() 407 self.dragging = NOT_DRAGGING 408 if self.draggingImage: 409 GlassWidget.hide() 410 if (self.currentDragOperation == 'none' 411 or not self.currentTargetElement): 412 if self.currentTargetElement: 413 # leave_event = self.makeDragEvent(event, 'dragleave', 414 # self.currentTargetElement) 415 self.fireDNDEvent('dragleave', self.currentTargetElement, 416 self.currentDropWidget) 417 # self.currentDropWidget.onDragLeave(leave_event) 418 # self.finalize(leave_event) 419 else: 420 self.currentDragOperation = 'none' 421 self.returnDrag() 422 else: 423 # self.dragDataStore.mode = READ_ONLY 424 # drop_event = self.makeDragEvent(event, 'drop', 425 # self.currentTargetElement) 426 drop_event = self.fireDNDEvent('drop', self.currentTargetElement, 427 self.currentDropWidget) 428 #self.dropEffect = self.currentDragOperation 429 # self.currentDropWidget.onDrop(drop_event) 430 # self.finalize(drop_event) 431 if isCanceled(drop_event): 432 self.currentDragOperation = drop_event.dataTransfer.dropEffect 433 else: 434 self.currentDragOperation = 'none' 435 self.zapDragImage() 436 437 #self.dropEffect = self.currentDragOperation 438 self.fireDNDEvent('dragend', None, self.dragWidget)

439 # dragEnd_event = self.makeDragEvent(event, 'dragend') 440 441 # self.dragWidget.onDragEnd(dragEnd_event) 442 # self.finalize(dragEnd_event) 443

444 - def zapDragImage(self):

445 RootPanel().remove(self.draggingImage) 446 self.draggingImage = None

447

448 - def returnDrag(self):

449 self.moveItemTo(self.draggingImage,self.origLeft, self.origTop)

450

451 - def returnXY(self, start, destination, count):

452 start_x, start_y = start 453 destination_x, destination_y = destination 454 diff_x = (start_x - destination_x) / count 455 diff_y = (start_y - destination_y) / count 456 while (abs(start_x - destination_x) > 10 457 or abs(start_y - destination_y) > 10): 458 start_x -= diff_x 459 start_y -= diff_y 460 yield start_x, start_y 461 raise StopIteration

462

463 - def onReturningWidget(self, timer):

464 try: 465 next_loc = self.return_iterator.next() 466 except StopIteration: 467 self.zapDragImage() 468 return 469 x, y = next_loc 470 self.draggingImage.setStyleAttribute('top', str(y)) 471 self.draggingImage.setStyleAttribute('left', str(x)) 472 self.returnTimer.schedule(50)

473

474 - def moveItemTo(self, widget, x, y):

475 self.returnWidget = widget 476 returnWidgetDestination = x, y 477 widgetStart = widget.getAbsoluteLeft(), widget.getAbsoluteTop() 478 self.return_iterator = self.returnXY(widgetStart, 479 returnWidgetDestination, 10) 480 self.returnTimer.schedule(50)

481

482 - def onMouseEnter(self, sender):

483 pass

484

485 - def onMouseLeave(self, sender):

486 if self.dragging == DRAGGING_NO_MOVEMENT_YET: 487 self.dragging = NOT_DRAGGING

488

489 - def onMouseGlassEnter(self, sender):

490 pass

491

492 - def onMouseGlassLeave(self, sender):

493 pass

Source Code for Module library.pyjamas.dnd.DNDHelper