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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 Qt, QSettings, QTimer, SIGNAL
from PyQt4.QtGui import QColor, QApplication, QCursor
from qgis.gui import QgsMapCanvas, QgsMapCanvasLayer, QgsMessageBar
from qgis.core import QgsVectorLayer, QgsMapLayerRegistry
from .db_plugins.plugin import Table
class LayerPreview(QgsMapCanvas):
def __init__(self, parent=None):
QgsMapCanvas.__init__(self, parent)
self.parent = parent
self.setCanvasColor(QColor(255, 255, 255))
self.item = None
self.dirty = False
self.currentLayer = None
# 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)
def refresh(self):
self.setDirty(True)
self.loadPreview(self.item)
def loadPreview(self, item):
if item == self.item and not self.dirty:
return
if item is None:
return
self._clear()
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._loadTablePreview(None)
def _loadTablePreview(self, table, limit=False):
""" if has geometry column load to map canvas """
QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
self.setRenderFlag(False)
vl = None
if table and table.geomType:
# limit the query result if required
if limit and table.rowCount > 1000:
uniqueField = table.getValidQGisUniqueFields(True)
if uniqueField is None:
self.parent.tabs.setCurrentWidget(self.parent.info)
self.parent.infoBar.pushMessage(
QApplication.translate("DBManagerPlugin", "Unable to find a valid unique field"),
QgsMessageBar.WARNING, self.parent.iface.messageTimeout())
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(False), table.name, provider)
else:
vl = table.toMapLayer()
if not vl.isValid():
vl.deleteLater()
vl = None
# remove old layer (if any) and set new
if self.currentLayer:
QgsMapLayerRegistry.instance().removeMapLayers([self.currentLayer.id()])
if vl:
self.setLayerSet([QgsMapCanvasLayer(vl)])
QgsMapLayerRegistry.instance().addMapLayers([vl], False)
self.zoomToFullExtent()
else:
self.setLayerSet([])
self.currentLayer = vl
self.setRenderFlag(True)
QApplication.restoreOverrideCursor()
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