QGIS » QGIS Application

+1

very interesting patch!

Martin, do you have time to review this patch?

Applied in 8f32f25a (SVN r12835) with several modifications:

• plugin layers are subclassed from QgsPluginLayer and not directly from QgsMapLayer for convenience
• each plugin layer type has its unique name used in QgsPluginLayerRegistry - instead of dynamically assigned IDs
• layer creator has been enhanced to return the unique layer type name and to be able to open layer's properties dialog (and renamed to QgsPluginLayerType as it's not just a creator)
• simplified creation of plugin layers: for the unique type name the registry returns instance of the layer
• when the plugin layer type is removed from registry, layer of that type are removed automatically

I've modified also the sample plugin to reflect my changes.

Sample plugin from the example:

LAYER_TYPE = "sample" 

class [[SamplePluginLayer]](QgsPluginLayer):
  def +init+(self, width=None):
    [[QgsPluginLayer]].+init+(self, LAYER_TYPE, "Sample plugin layer")

    self.width = width if width is not None else 256
    self.setValid(True)

  def draw(self, rendererContext):
    painter = rendererContext.painter()
    painter.setPen(Qt.red)
    painter.drawRect(32, 32, self.width, 128)
    return True

  def readXml(self, node):
    self.width = node.toElement().attribute("width", "256").toInt()r0
    return True

  def writeXml(self, node, doc):
    element = node.toElement()
    # write plugin layer type to project (essential to be read from project)
    element.setAttribute("type", "plugin")
    element.setAttribute("name", LAYER_TYPE)
    # custom properties
    element.setAttribute("width", str(self.width))
    return True

Definition of the layer's type with auxiliary methods:

class [[SamplePluginLayerType]](QgsPluginLayerType):
  def +init+(self):
    [[QgsPluginLayerType]].+init+(self, LAYER_TYPE)

  def createLayer(self):
    return [[SamplePluginLayer]]()

  def showLayerProperties(self, layer):
    res = QInputDialog.getInt(None, "Sample plugin", "Set width of the rectangle", layer.width, 1, 1000)
    if resr1: # dialog was not cancelled
      layer.width = resr0
      # trigger repaint
      layer.setCacheImage(None)
      layer.emit(SIGNAL("repaintRequested()"))

    # indicate that we have shown the properties dialog
    return True

Registration:

    [[QgsPluginLayerRegistry]].instance().addPluginLayerType( [[SamplePluginLayerType]]() )

Creation of the layer:

layer = [[SamplePluginLayer]]()
# -or-
[[QgsPluginLayerRegistry]].instance().pluginLayerType(LAYER_TYPE).createLayer()

Finalization:

    [[QgsPluginLayerRegistry]].instance().removePluginLayerType(LAYER_TYPE)