Python QgsDistanceArea.setProjectionsEnabled方法代码示例

# 需要导入模块: from qgis.core import QgsDistanceArea [as 别名]
# 或者: from qgis.core.QgsDistanceArea import setProjectionsEnabled [as 别名]
    def draw_scalebar(self, composer_map, top_offset):
        """Add a numeric scale to the bottom left of the map.

        We draw the scale bar manually because QGIS does not yet support
        rendering a scale bar for a geographic map in km.

        .. seealso:: :meth:`drawNativeScaleBar`

        :param composer_map: Composer map on which to draw the scalebar.
        :type composer_map: QgsComposerMap

        :param top_offset: Vertical offset at which the logo should be drawn.
        :type top_offset: int
        """
        LOGGER.debug('InaSAFE Map drawScaleBar called')
        myCanvas = self.iface.mapCanvas()
        myRenderer = myCanvas.mapRenderer()
        #
        # Add a linear map scale
        #
        myDistanceArea = QgsDistanceArea()
        myDistanceArea.setSourceCrs(myRenderer.destinationCrs().srsid())
        myDistanceArea.setProjectionsEnabled(True)
        # Determine how wide our map is in km/m
        # Starting point at BL corner
        myComposerExtent = composer_map.extent()
        myStartPoint = QgsPoint(myComposerExtent.xMinimum(),
                                myComposerExtent.yMinimum())
        # Ending point at BR corner
        myEndPoint = QgsPoint(myComposerExtent.xMaximum(),
                              myComposerExtent.yMinimum())
        myGroundDistance = myDistanceArea.measureLine(myStartPoint, myEndPoint)
        # Get the equivalent map distance per page mm
        myMapWidth = self.mapWidth
        # How far is 1mm on map on the ground in meters?
        myMMToGroundDistance = myGroundDistance / myMapWidth
        #print 'MM:', myMMDistance
        # How long we want the scale bar to be in relation to the map
        myScaleBarToMapRatio = 0.5
        # How many divisions the scale bar should have
        myTickCount = 5
        myScaleBarWidthMM = myMapWidth * myScaleBarToMapRatio
        myPrintSegmentWidthMM = myScaleBarWidthMM / myTickCount
        # Segment width in real world (m)
        # We apply some logic here so that segments are displayed in meters
        # if each segment is less that 1000m otherwise km. Also the segment
        # lengths are rounded down to human looking numbers e.g. 1km not 1.1km
        myUnits = ''
        myGroundSegmentWidth = myPrintSegmentWidthMM * myMMToGroundDistance
        if myGroundSegmentWidth < 1000:
            myUnits = 'm'
            myGroundSegmentWidth = round(myGroundSegmentWidth)
            # adjust the segment width now to account for rounding
            myPrintSegmentWidthMM = myGroundSegmentWidth / myMMToGroundDistance
        else:
            myUnits = 'km'
            # Segment with in real world (km)
            myGroundSegmentWidth = round(myGroundSegmentWidth / 1000)
            myPrintSegmentWidthMM = ((myGroundSegmentWidth * 1000) /
                                     myMMToGroundDistance)
        # Now adjust the scalebar width to account for rounding
        myScaleBarWidthMM = myTickCount * myPrintSegmentWidthMM

        #print "SBWMM:", myScaleBarWidthMM
        #print "SWMM:", myPrintSegmentWidthMM
        #print "SWM:", myGroundSegmentWidthM
        #print "SWKM:", myGroundSegmentWidthKM
        # start drawing in line segments
        myScaleBarHeight = 5  # mm
        myLineWidth = 0.3  # mm
        myInsetDistance = 7  # how much to inset the scalebar into the map by
        myScaleBarX = self.pageMargin + myInsetDistance
        myScaleBarY = (
            top_offset + self.mapHeight - myInsetDistance -
            myScaleBarHeight)  # mm

        # Draw an outer background box - shamelessly hardcoded buffer
        myRect = QgsComposerShape(myScaleBarX - 4,  # left edge
                                  myScaleBarY - 3,  # top edge
                                  myScaleBarWidthMM + 13,  # right edge
                                  myScaleBarHeight + 6,  # bottom edge
                                  self.composition)

        myRect.setShapeType(QgsComposerShape.Rectangle)
        myRect.setLineWidth(myLineWidth)
        myRect.setFrame(False)
        myBrush = QtGui.QBrush(QtGui.QColor(255, 255, 255))
        # workaround for missing setTransparentFill missing from python api
        myRect.setBrush(myBrush)
        self.composition.addItem(myRect)
        # Set up the tick label font
        myFontWeight = QtGui.QFont.Normal
        myFontSize = 6
        myItalicsFlag = False
        myFont = QtGui.QFont('verdana',
                             myFontSize,
                             myFontWeight,
                             myItalicsFlag)
        # Draw the bottom line
        myUpshift = 0.3  # shift the bottom line up for better rendering
#.........这里部分代码省略.........