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# -*- coding: utf-8 -*-
"""
/***************************************************************************
Name : DB Manager
Description : Database manager plugin for QGIS
Date : May 23, 2011
copyright : (C) 2011 by Giuseppe Sucameli
email : brush.tyler@gmail.com
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
"""
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.gui import QgsMapCanvas, QgsMapCanvasLayer
from qgis.core import QgsVectorLayer, QgsMapLayerRegistry
from .db_plugins.plugin import DbError, Table
class LayerPreview(QgsMapCanvas):
def __init__(self, parent=None):
QgsMapCanvas.__init__(self, parent)
self.setCanvasColor(QColor(255,255,255))
self.item = None
self.dirty = False
# reuse settings from QGIS
settings = QSettings()
self.enableAntiAliasing( settings.value( "/qgis/enable_anti_aliasing", False, type=bool ) )
action = settings.value( "/qgis/wheel_action", 0, type=float )
zoomFactor = settings.value( "/qgis/zoom_factor", 2, type=float )
self.setWheelAction( QgsMapCanvas.WheelAction(action), zoomFactor )
self._clear()
def refresh(self):
self.setDirty(True)
self.loadPreview( self.item )
def loadPreview(self, item, force=False):
if item == self.item and not self.dirty:
return
self._clear()
if item is None:
return
if isinstance(item, Table) and item.type in [Table.VectorType, Table.RasterType]:
# update the preview, but first let the manager chance to show the canvas
runPrev = lambda: self._loadTablePreview( item )
QTimer.singleShot(50, runPrev)
else:
return
self.item = item
self.connect(self.item, SIGNAL('aboutToChange'), self.setDirty)
def setDirty(self, val=True):
self.dirty = val
def _clear(self):
""" remove any layers from preview canvas """
if self.item is not None:
## skip exception on RuntimeError fixes #6892
try:
self.disconnect(self.item, SIGNAL('aboutToChange'), self.setDirty)
except RuntimeError:
pass
self.item = None
self.dirty = False
self.currentLayerId = None
self.setLayerSet( [] )
def _loadTablePreview(self, table, limit=False):
""" if has geometry column load to map canvas """
QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
self.setRenderFlag(False)
newLayerId = None
if table.geomType:
# limit the query result if required
if limit and table.rowCount > 1000:
uniqueField = table.getValidQGisUniqueFields(True)
if uniqueField == None:
QMessageBox.warning(self, QApplication.translate("DBManagerPlugin", "Sorry"), QApplication.translate("DBManagerPlugin", "Unable to find a valid unique field"))
return
uri = table.database().uri()
uri.setDataSource("", u"(SELECT * FROM %s LIMIT 1000)" % table.quotedName(), table.geomColumn, "", uniqueField.name)
provider = table.database().dbplugin().providerName()
vl = QgsVectorLayer(uri.uri(), table.name, provider)
else:
vl = table.toMapLayer()
if not vl.isValid():
self.setLayerSet( [] )
else:
newLayerId = vl.id() if hasattr(vl, 'id') else vl.id()
self.setLayerSet( [ QgsMapCanvasLayer(vl) ] )
QgsMapLayerRegistry.instance().addMapLayers([vl], False)
self.zoomToFullExtent()
# remove old layer (if any) and set new
if self.currentLayerId:
QgsMapLayerRegistry.instance().removeMapLayers([self.currentLayerId], False)
self.currentLayerId = newLayerId
self.setRenderFlag(True)
QApplication.restoreOverrideCursor()
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