Python core.QgsRasterTransparency类代码示例

    def testTransparency(self):
        myPath = os.path.join(unitTestDataPath('raster'),
                              'band1_float32_noct_epsg4326.tif')
        myFileInfo = QFileInfo(myPath)
        myBaseName = myFileInfo.baseName()
        myRasterLayer = QgsRasterLayer(myPath, myBaseName)
        myMessage = 'Raster not loaded: %s' % myPath
        assert myRasterLayer.isValid(), myMessage

        renderer = QgsSingleBandGrayRenderer(myRasterLayer.dataProvider(), 1)
        myRasterLayer.setRenderer(renderer)
        myRasterLayer.setContrastEnhancementAlgorithm(
            QgsContrastEnhancement.StretchToMinimumMaximum,
            QgsRasterLayer.ContrastEnhancementMinMax)

        myContrastEnhancement = myRasterLayer.renderer().contrastEnhancement()
        #print ("myContrastEnhancement.minimumValue = %.17g" %
        #       myContrastEnhancement.minimumValue())
        #print ("myContrastEnhancement.maximumValue = %.17g" %
        #        myContrastEnhancement.maximumValue())

        # Unfortunately the minimum/maximum values calculated in C++ and Python
        # are slightly different (e.g. 3.3999999521443642e+38 x
        # 3.3999999521444001e+38)
        # It is not clear where the precision is lost.
        # We set the same values as C++.
        myContrastEnhancement.setMinimumValue(-3.3319999287625854e+38)
        myContrastEnhancement.setMaximumValue(3.3999999521443642e+38)
        #myType = myRasterLayer.dataProvider().dataType(1);
        #myEnhancement = QgsContrastEnhancement(myType);



        myTransparentSingleValuePixelList = []
        rasterTransparency = QgsRasterTransparency()

        myTransparentPixel1 = \
            QgsRasterTransparency.TransparentSingleValuePixel()
        myTransparentPixel1.min = -2.5840000772112106e+38
        myTransparentPixel1.max = -1.0879999684602689e+38
        myTransparentPixel1.percentTransparent = 50
        myTransparentSingleValuePixelList.append(myTransparentPixel1)

        myTransparentPixel2 = \
            QgsRasterTransparency.TransparentSingleValuePixel()
        myTransparentPixel2.min = 1.359999960575336e+37
        myTransparentPixel2.max = 9.520000231087593e+37
        myTransparentPixel2.percentTransparent = 70
        myTransparentSingleValuePixelList.append(myTransparentPixel2)

        rasterTransparency.setTransparentSingleValuePixelList(
            myTransparentSingleValuePixelList)

        rasterRenderer = myRasterLayer.renderer()
        assert rasterRenderer

        rasterRenderer.setRasterTransparency(rasterTransparency)

        QgsMapLayerRegistry.instance().addMapLayers([ myRasterLayer, ])

        myMapRenderer = QgsMapRenderer()

        myLayers = QStringList()
        myLayers.append(myRasterLayer.id())
        myMapRenderer.setLayerSet(myLayers)
        myMapRenderer.setExtent(myRasterLayer.extent())

        myChecker = QgsRenderChecker()
        myChecker.setControlName("expected_raster_transparency")
        myChecker.setMapRenderer(myMapRenderer)

        myResultFlag = myChecker.runTest("raster_transparency_python");
        assert myResultFlag, "Raster transparency rendering test failed"

def set_raster_style(raster_layer, style):
    """Set QGIS raster style based on InaSAFE style dictionary for QGIS >= 2.0.

    This function will set both the colour map and the transparency
    for the passed in layer.

    :param raster_layer: A QGIS raster layer that will be styled.
    :type raster_layer: QgsVectorLayer

    :param style: List of the form as in the example below.
    :type style: list

    Example::

        style_classes = [dict(colour='#38A800', quantity=2, transparency=0),
                         dict(colour='#38A800', quantity=5, transparency=50),
                         dict(colour='#79C900', quantity=10, transparency=50),
                         dict(colour='#CEED00', quantity=20, transparency=50),
                         dict(colour='#FFCC00', quantity=50, transparency=34),
                         dict(colour='#FF6600', quantity=100, transparency=77),
                         dict(colour='#FF0000', quantity=200, transparency=24),
                         dict(colour='#7A0000', quantity=300, transparency=22)]

    :returns: A two tuple containing a range list and a transparency list.
    :rtype: (list, list)

    """
    # Note imports here to prevent importing on unsupported QGIS versions
    # pylint: disable=E0611
    # pylint: disable=W0621
    # pylint: disable=W0404
    # noinspection PyUnresolvedReferences
    from qgis.core import (QgsRasterShader,
                           QgsColorRampShader,
                           QgsSingleBandPseudoColorRenderer,
                           QgsRasterTransparency)
    # pylint: enable=E0611
    # pylint: enable=W0621
    # pylint: enable=W0404

    ramp_item_list = []
    transparency_list = []
    LOGGER.debug(style)
    for style_class in style:

        LOGGER.debug('Evaluating class:\n%s\n' % style_class)

        if 'quantity' not in style_class:
            LOGGER.exception('Class has no quantity attribute')
            continue

        class_max = style_class['max']
        if math.isnan(class_max):
            LOGGER.debug('Skipping class - max is nan.')
            continue

        class_min = style_class['min']
        if math.isnan(class_min):
            LOGGER.debug('Skipping class - min is nan.')
            continue

        colour = QtGui.QColor(style_class['colour'])
        label = ''
        if 'label' in style_class:
            label = style_class['label']
        # noinspection PyCallingNonCallable
        ramp_item = QgsColorRampShader.ColorRampItem(class_max, colour, label)
        ramp_item_list.append(ramp_item)

        # Create opacity entries for this range
        transparency_percent = 0
        if 'transparency' in style_class:
            transparency_percent = int(style_class['transparency'])
        if transparency_percent > 0:
            # Check if range extrema are integers so we know if we can
            # use them to calculate a value range
            # noinspection PyCallingNonCallable
            pixel = QgsRasterTransparency.TransparentSingleValuePixel()
            pixel.min = class_min
            # We want it just a little bit smaller than max
            # so that ranges are discrete
            pixel.max = class_max
            # noinspection PyPep8Naming
            pixel.percentTransparent = transparency_percent
            transparency_list.append(pixel)

    band = 1  # gdal counts bands from base 1
    LOGGER.debug('Setting colour ramp list')
    raster_shader = QgsRasterShader()
    color_ramp_shader = QgsColorRampShader()
    color_ramp_shader.setColorRampType(QgsColorRampShader.INTERPOLATED)
    color_ramp_shader.setColorRampItemList(ramp_item_list)
    LOGGER.debug('Setting shader function')
    raster_shader.setRasterShaderFunction(color_ramp_shader)
    LOGGER.debug('Setting up renderer')
    renderer = QgsSingleBandPseudoColorRenderer(
        raster_layer.dataProvider(),
        band,
        raster_shader)
    LOGGER.debug('Assigning renderer to raster layer')
#.........这里部分代码省略.........

def _setNewRasterStyle(theQgsRasterLayer, theClasses):
    """Set QGIS raster style based on InaSAFE style dictionary for QGIS >= 2.0.

    This function will set both the colour map and the transparency
    for the passed in layer.

    Args:
        * theQgsRasterLayer: QgsRasterLayer
        * theClasses: List of the form as in the example below.

    Returns:
        * list: RangeList
        * list: TransparencyList

    Example:
        style_classes = [dict(colour='#38A800', quantity=2, transparency=0),
                         dict(colour='#38A800', quantity=5, transparency=50),
                         dict(colour='#79C900', quantity=10, transparency=50),
                         dict(colour='#CEED00', quantity=20, transparency=50),
                         dict(colour='#FFCC00', quantity=50, transparency=34),
                         dict(colour='#FF6600', quantity=100, transparency=77),
                         dict(colour='#FF0000', quantity=200, transparency=24),
                         dict(colour='#7A0000', quantity=300, transparency=22)]

    """
    # Note imports here to prevent importing on unsupported QGIS versions
    # pylint: disable=E0611
    # pylint: disable=W0621
    # pylint: disable=W0404
    from qgis.core import (QgsRasterShader,
                           QgsColorRampShader,
                           QgsSingleBandPseudoColorRenderer,
                           QgsRasterTransparency)
    # pylint: enable=E0611
    # pylint: enable=W0621
    # pylint: enable=W0404

    myRampItemList = []
    myTransparencyList = []
    LOGGER.debug(theClasses)
    for myClass in theClasses:

        LOGGER.debug('Evaluating class:\n%s\n' % myClass)

        if 'quantity' not in myClass:
            LOGGER.exception('Class has no quantity attribute')
            continue

        myMax = myClass['max']
        if math.isnan(myMax):
            LOGGER.debug('Skipping class - max is nan.')
            continue

        myMin = myClass['min']
        if math.isnan(myMin):
            LOGGER.debug('Skipping class - min is nan.')
            continue

        myColour = QtGui.QColor(myClass['colour'])
        myLabel = QtCore.QString()
        if 'label' in myClass:
            myLabel = QtCore.QString(myClass['label'])
        myRampItem = QgsColorRampShader.ColorRampItem(myMax, myColour, myLabel)
        myRampItemList.append(myRampItem)

        # Create opacity entries for this range
        myTransparencyPercent = 0
        if 'transparency' in myClass:
            myTransparencyPercent = int(myClass['transparency'])
        if myTransparencyPercent > 0:
            # Check if range extrema are integers so we know if we can
            # use them to calculate a value range
            myPixel = QgsRasterTransparency.TransparentSingleValuePixel()
            myPixel.min = myMin
            # We want it just a leeetle bit smaller than max
            # so that ranges are discrete
            myPixel.max = myMax
            myPixel.percentTransparent = myTransparencyPercent
            myTransparencyList.append(myPixel)

    myBand = 1  # gdal counts bands from base 1
    LOGGER.debug('Setting colour ramp list')
    myRasterShader = QgsRasterShader()
    myColorRampShader = QgsColorRampShader()
    myColorRampShader.setColorRampType(QgsColorRampShader.INTERPOLATED)
    myColorRampShader.setColorRampItemList(myRampItemList)
    LOGGER.debug('Setting shader function')
    myRasterShader.setRasterShaderFunction(myColorRampShader)
    LOGGER.debug('Setting up renderer')
    myRenderer = QgsSingleBandPseudoColorRenderer(
        theQgsRasterLayer.dataProvider(),
        myBand,
        myRasterShader)
    LOGGER.debug('Assigning renderer to raster layer')
    theQgsRasterLayer.setRenderer(myRenderer)

    LOGGER.debug('Setting raster transparency list')

    myRenderer = theQgsRasterLayer.renderer()
    myTransparency = QgsRasterTransparency()
#.........这里部分代码省略.........