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131 lines
4.6 KiB
Python
131 lines
4.6 KiB
Python
# -*- coding: utf-8 -*-
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"""
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/***************************************************************************
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Name : DB Manager
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Description : Database manager plugin for QGIS
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Date : May 23, 2011
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copyright : (C) 2011 by Giuseppe Sucameli
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email : brush.tyler@gmail.com
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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"""
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from qgis.PyQt.QtCore import Qt, QTimer
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from qgis.PyQt.QtGui import QColor, QCursor
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from qgis.PyQt.QtWidgets import QApplication
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from qgis.gui import QgsMapCanvas, QgsMessageBar
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from qgis.core import Qgis, QgsVectorLayer, QgsProject, QgsSettings
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from qgis.utils import OverrideCursor
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from .db_plugins.plugin import Table
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class LayerPreview(QgsMapCanvas):
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def __init__(self, parent=None):
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super(LayerPreview, self).__init__(parent)
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self.parent = parent
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self.setCanvasColor(QColor(255, 255, 255))
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self.item = None
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self.dirty = False
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self.current_layer = None
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# reuse settings from QGIS
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settings = QgsSettings()
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self.enableAntiAliasing(settings.value("/qgis/enable_anti_aliasing", False, type=bool))
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zoomFactor = settings.value("/qgis/zoom_factor", 2, type=float)
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self.setWheelFactor(zoomFactor)
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def refresh(self):
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self.setDirty(True)
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self.loadPreview(self.item)
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def loadPreview(self, item):
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if item == self.item and not self.dirty:
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return
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if item is None:
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return
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self._clear()
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if isinstance(item, Table) and item.type in [Table.VectorType, Table.RasterType]:
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# update the preview, but first let the manager chance to show the canvas
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def runPrev():
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return self._loadTablePreview(item)
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QTimer.singleShot(50, runPrev)
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else:
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return
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self.item = item
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self.item.aboutToChange.connect(self.setDirty)
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def setDirty(self, val=True):
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self.dirty = val
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def _clear(self):
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""" remove any layers from preview canvas """
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if self.item is not None:
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# skip exception on RuntimeError fixes #6892
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try:
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self.item.aboutToChange.disconnect(self.setDirty)
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except RuntimeError:
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pass
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self.item = None
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self.dirty = False
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self._loadTablePreview(None)
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def _loadTablePreview(self, table, limit=False):
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""" if has geometry column load to map canvas """
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with OverrideCursor(Qt.WaitCursor):
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self.freeze()
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vl = None
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if table and table.geomType:
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# limit the query result if required
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if limit and table.rowCount > 1000:
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uniqueField = table.getValidQgisUniqueFields(True)
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if uniqueField is None:
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self.parent.tabs.setCurrentWidget(self.parent.info)
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self.parent.infoBar.pushMessage(
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QApplication.translate("DBManagerPlugin", "Unable to find a valid unique field"),
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Qgis.Warning, self.parent.iface.messageTimeout())
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return
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uri = table.database().uri()
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uri.setDataSource("", "(SELECT * FROM %s LIMIT 1000)" % table.quotedName(), table.geomColumn, "",
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uniqueField.name)
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provider = table.database().dbplugin().providerName()
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vl = QgsVectorLayer(uri.uri(False), table.name, provider)
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else:
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vl = table.toMapLayer()
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if vl and not vl.isValid():
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vl.deleteLater()
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vl = None
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if vl and vl.isValid():
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self.current_layer = vl
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self.setLayers([self.current_layer])
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self.zoomToFullExtent()
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else:
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self.setLayers([])
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self.current_layer = None
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self.freeze(False)
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super().refresh()
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