Python QgsRasterLayer.previewAsImage方法代码示例

# 需要导入模块: from qgis.core import QgsRasterLayer [as 别名]
# 或者: from qgis.core.QgsRasterLayer import previewAsImage [as 别名]
    def testSetDataSource(self):
        """Test change data source"""

        temp_dir = QTemporaryDir()
        options = QgsDataProvider.ProviderOptions()
        myPath = os.path.join(unitTestDataPath('raster'),
                              'band1_float32_noct_epsg4326.tif')
        myFileInfo = QFileInfo(myPath)
        myBaseName = myFileInfo.baseName()
        layer = QgsRasterLayer(myPath, myBaseName)
        renderer = QgsSingleBandGrayRenderer(layer.dataProvider(), 2)

        image = layer.previewAsImage(QSize(400, 400))
        self.assertFalse(image.isNull())
        self.assertTrue(image.save(os.path.join(temp_dir.path(), 'expected.png'), "PNG"))

        layer.setDataSource(myPath.replace('4326.tif', '4326-BAD_SOURCE.tif'), 'bad_layer', 'gdal', options)
        self.assertFalse(layer.isValid())
        image = layer.previewAsImage(QSize(400, 400))
        self.assertTrue(image.isNull())

        layer.setDataSource(myPath.replace('4326-BAD_SOURCE.tif', '4326.tif'), 'bad_layer', 'gdal', options)
        self.assertTrue(layer.isValid())
        image = layer.previewAsImage(QSize(400, 400))
        self.assertFalse(image.isNull())
        self.assertTrue(image.save(os.path.join(temp_dir.path(), 'actual.png'), "PNG"))

        self.assertTrue(filecmp.cmp(os.path.join(temp_dir.path(), 'actual.png'), os.path.join(temp_dir.path(), 'expected.png')), False)

# 需要导入模块: from qgis.core import QgsRasterLayer [as 别名]
# 或者: from qgis.core.QgsRasterLayer import previewAsImage [as 别名]
    def replaceImage(self, filepath, title):
        self.title = title
        self.filepath = filepath

         # set custom properties
        self.setCustomProperty("title", title)
        self.setCustomProperty("filepath", self.filepath)
        self.setName(title)

        fileInfo = QFileInfo(filepath)
        ext = fileInfo.suffix()
        if ext == "pdf":
            s = QSettings()
            oldValidation = s.value("/Projections/defaultBehavior")
            s.setValue("/Projections/defaultBehavior", "useGlobal")  # for not asking about crs
            path = fileInfo.filePath()
            baseName = fileInfo.baseName()
            layer = QgsRasterLayer(path, baseName)
            self.image = layer.previewAsImage(QSize(layer.width(), layer.height()))
            s.setValue("/Projections/defaultBehavior", oldValidation)
        else:
            reader = QImageReader(filepath)
            self.image = reader.read()
        self.repaint()

# 需要导入模块: from qgis.core import QgsRasterLayer [as 别名]
# 或者: from qgis.core.QgsRasterLayer import previewAsImage [as 别名]
    def initializeLayer(self, screenExtent=None):
        if self.error or self.initialized or self.initializing:
            return

        if self.filepath is not None:
            # not safe...
            self.initializing = True
            filepath = self.getAbsoluteFilepath()

            if not os.path.exists(filepath):
                # TODO integrate with BadLayerHandler ?
                loadErrorDialog = LoadErrorDialog(filepath)
                result = loadErrorDialog.exec_()
                if result == 1:
                    # absolute
                    filepath = loadErrorDialog.lineEditImagePath.text()
                    # to relative if needed
                    self.filepath = utils.toRelativeToQGS(filepath)
                    self.setCustomProperty("filepath", self.filepath)
                    QgsProject.instance().setDirty(True)
                else:
                    self.error = True

                del loadErrorDialog

            fileInfo = QFileInfo(filepath)
            ext = fileInfo.suffix()
            if ext == "pdf":
                s = QSettings()
                oldValidation = s.value("/Projections/defaultBehavior")
                s.setValue("/Projections/defaultBehavior", "useGlobal") # for not asking about crs
                path = fileInfo.filePath()
                baseName = fileInfo.baseName()
                layer = QgsRasterLayer(path, baseName)
                self.image = layer.previewAsImage(QSize(layer.width(),layer.height()))
                s.setValue("/Projections/defaultBehavior", oldValidation)
            else:
                reader = QImageReader(filepath)
                self.image = reader.read()

            self.initialized = True
            self.initializing = False

            self.setupCrs()

            if screenExtent:
                # constructor called from AddLayer action
                # if not, layer loaded from QGS project file

                # check if image already has georef info
                # use GDAL
                dataset = gdal.Open(filepath, gdal.GA_ReadOnly)
                georef = None
                if dataset:
                    georef = dataset.GetGeoTransform()

                if georef and not self.is_default_geotransform(georef):
                    self.initializeExistingGeoreferencing(dataset, georef)
                else:
                    # init to default params
                    self.setCenter(screenExtent.center())
                    self.setRotation(0.0)

                    sw = screenExtent.width()
                    sh = screenExtent.height()

                    self.resetScale(sw, sh)

                    self.commitTransformParameters()