def test_missing_elements(self):
        """Test if we can get missing elements correctly."""
        # Copy the inasafe template to temp dir
        template_path = os.path.join(
            temp_dir('test'), 'inasafe-portrait-a4.qpt')
        shutil.copy2(INASAFE_TEMPLATE_PATH, template_path)

        template_composition = TemplateComposition(template_path=template_path)
        # No missing elements here
        component_ids = ['safe-logo', 'north-arrow', 'organisation-logo',
                         'impact-map', 'impact-legend']
        template_composition.component_ids = component_ids
        message = 'There should be no missing elements, but it gets: %s' % (
            template_composition.missing_elements)
        expected_result = []
        self.assertEqual(
            template_composition.missing_elements, expected_result, message)

        # There are missing elements
        component_ids = ['safe-logo', 'north-arrow', 'organisation-logo',
                         'impact-map', 'impact-legend',
                         'i-added-element-id-here-nooo']
        template_composition.component_ids = component_ids
        message = 'There should be no missing elements, but it gets: %s' % (
            template_composition.missing_elements)
        expected_result = ['i-added-element-id-here-nooo']
        self.assertEqual(
            template_composition.missing_elements, expected_result, message)

        # Remove test dir
        shutil.rmtree(temp_dir('test'))

    def test_load_template(self):
        """Test we can load template correctly."""
        # Copy the inasafe template to temp dir
        template_path = os.path.join(
            temp_dir('test'), 'a4-portrait-blue.qpt')
        shutil.copy2(INASAFE_TEMPLATE_PATH, template_path)

        template_composition = TemplateComposition(
            template_path=template_path,
            map_settings=CANVAS.mapSettings())
        template_composition.load_template()

        # Check the element of the composition
        # In that template, there should be these components:
        component_ids = [
            'white-inasafe-logo',
            'north-arrow',
            'organisation-logo',
            'impact-map',
            'impact-legend']
        for component_id in component_ids:
            component = template_composition.composition.getComposerItemById(
                component_id)
            message = ('In this template: %s, there should be this component '
                       '%s') % (INASAFE_TEMPLATE_PATH, component_id)
            self.assertIsNotNone(component, message)

    def __init__(self, iface, template, layer):
        """Constructor for the Composition Report class.

        :param iface: Reference to the QGIS iface object.
        :type iface: QgsAppInterface

        :param template: The QGIS template path.
        :type template: str
        """
        LOGGER.debug('InaSAFE Impact Report class initialised')
        self._iface = iface
        self._template = template
        self._layer = layer
        self._extent = self._iface.mapCanvas().extent()
        self._page_dpi = 300.0
        self._safe_logo = resources_path(
            'img', 'logos', 'inasafe-logo-url.svg')
        self._organisation_logo = default_organisation_logo_path()
        self._north_arrow = default_north_arrow_path()
        self._disclaimer = disclaimer()

        # For QGIS < 2.4 compatibility
        # QgsMapSettings is added in 2.4
        if qgis_version() < 20400:
            map_settings = self._iface.mapCanvas().mapRenderer()
        else:
            map_settings = self._iface.mapCanvas().mapSettings()

        self._template_composition = TemplateComposition(
            template_path=self.template,
            map_settings=map_settings)
        self._keyword_io = KeywordIO()

    def template(self, template):
        """Set template that will be used for report generation.

        :param template: Path to composer template
        :type template: str
        """
        if isinstance(template, str) and os.path.exists(template):
            self._template = template
        else:
            self._template = resources_path("qgis-composer-templates", "inasafe-portrait-a4.qpt")

        # Also recreate template composition
        self._template_composition = TemplateComposition(
            template_path=self.template, map_settings=self._iface.mapCanvas().mapSettings()
        )

class ImpactReport(object):
    """A class for creating report using QgsComposition."""
    def __init__(self, iface, template, layer):
        """Constructor for the Composition Report class.

        :param iface: Reference to the QGIS iface object.
        :type iface: QgsAppInterface

        :param template: The QGIS template path.
        :type template: str
        """
        LOGGER.debug('InaSAFE Impact Report class initialised')
        self._iface = iface
        self._template = template
        self._layer = layer
        self._extent = self._iface.mapCanvas().extent()
        self._page_dpi = 300.0
        self._safe_logo = resources_path(
            'img', 'logos', 'inasafe-logo-url.svg')
        self._organisation_logo = default_organisation_logo_path()
        self._north_arrow = default_north_arrow_path()
        self._disclaimer = disclaimer()

        # For QGIS < 2.4 compatibility
        # QgsMapSettings is added in 2.4
        if qgis_version() < 20400:
            map_settings = self._iface.mapCanvas().mapRenderer()
        else:
            map_settings = self._iface.mapCanvas().mapSettings()

        self._template_composition = TemplateComposition(
            template_path=self.template,
            map_settings=map_settings)
        self._keyword_io = KeywordIO()

    @property
    def template(self):
        """Getter to the template"""
        return self._template

    @template.setter
    def template(self, template):
        """Set template that will be used for report generation.

        :param template: Path to composer template
        :type template: str
        """
        if isinstance(template, str) and os.path.exists(template):
            self._template = template
        else:
            self._template = resources_path(
                'qgis-composer-templates', 'inasafe-portrait-a4.qpt')

        # Also recreate template composition
        self._template_composition = TemplateComposition(
            template_path=self.template,
            map_settings=self._iface.mapCanvas().mapSettings())

    @property
    def layer(self):
        """Getter to layer that will be used for stats, legend, reporting."""
        return self._layer

    @layer.setter
    def layer(self, layer):
        """Set the layer that will be used for stats, legend and reporting.

        :param layer: Layer that will be used for stats, legend and reporting.
        :type layer: QgsMapLayer, QgsRasterLayer, QgsVectorLayer
        """
        self._layer = layer

    @property
    def composition(self):
        """Getter to QgsComposition instance."""
        return self._template_composition.composition

    @property
    def extent(self):
        """Getter to extent for map component in composition."""
        return self._extent

    @extent.setter
    def extent(self, extent):
        """Set the extent that will be used for map component in composition.

        :param extent: The extent.
        :type extent: QgsRectangle
        """
        if isinstance(extent, QgsRectangle):
            self._extent = extent
        else:
            self._extent = self._iface.mapCanvas().extent()

    @property
    def page_dpi(self):
        """Getter to page resolution in dots per inch."""
        return self._page_dpi

    @page_dpi.setter
#.........这里部分代码省略.........

    def load_template(self, map_settings):
        """Load composer template for merged report.

        Validate it as well. The template needs to have:
        1. QgsComposerMap with id 'impact-map' for merged impact map.
        2. QgsComposerPicture with id 'safe-logo' for InaSAFE logo.
        3. QgsComposerLabel with id 'summary-report' for a summary of two
        impacts.
        4. QgsComposerLabel with id 'aggregation-area' to indicate the area
        of aggregation.
        5. QgsComposerScaleBar with id 'map-scale' for impact map scale.
        6. QgsComposerLegend with id 'map-legend' for impact map legend.
        7. QgsComposerPicture with id 'organisation-logo' for organisation
        logo.
        8. QgsComposerLegend with id 'impact-legend' for map legend.
        9. QgsComposerHTML with id 'merged-report-table' for the merged report.

        :param map_settings: Map settings.
        :type map_settings: QgsMapSettings, QgsMapRenderer

        """
        # Create Composition
        template_composition = TemplateComposition(
            self.template_path, map_settings)

        # Validate the component in the template
        component_ids = ['impact-map', 'safe-logo', 'summary-report',
                         'aggregation-area', 'map-scale', 'map-legend',
                         'organisation-logo', 'merged-report-table']
        template_composition.component_ids = component_ids
        if len(template_composition.missing_elements) > 0:
            raise ReportCreationError(self.tr(
                'Components: %s could not be found' % ', '.join(
                    template_composition.missing_elements)))

        # Prepare map substitution and set to composition
        impact_title = '%s and %s' % (
            self.first_impact['map_title'],
            self.second_impact['map_title'])
        substitution_map = {
            'impact-title': impact_title,
            'hazard-title': self.first_impact['hazard_title'],
            'disclaimer': self.disclaimer
        }
        template_composition.substitution = substitution_map

        # Load Template
        try:
            template_composition.load_template()
        except TemplateLoadingError:
            raise

        # Draw Composition
        # Set InaSAFE logo
        composition = template_composition.composition
        safe_logo = composition.getComposerItemById('safe-logo')
        safe_logo.setPictureFile(self.safe_logo_path)

        # set organisation logo
        org_logo = composition.getComposerItemById('organisation-logo')
        org_logo.setPictureFile(self.organisation_logo_path)

        # Set Map Legend
        legend = composition.getComposerItemById('map-legend')

        if qgis_version() < 20400:
            layers = map_settings.layerSet()
        else:
            layers = map_settings.layers()

        if qgis_version() < 20600:
            legend.model().setLayerSet(layers)
            legend.synchronizeWithModel()
        else:
            root_group = legend.modelV2().rootGroup()

            layer_ids = map_settings.layers()
            for layer_id in layer_ids:
                # noinspection PyUnresolvedReferences
                layer = QgsMapLayerRegistry.instance().mapLayer(layer_id)
                root_group.addLayer(layer)
            legend.synchronizeWithModel()

        return composition