9

I Am trying to build a plugin to load a print composer from file, generate an atlas and export to image. So far I have been successful in loading the template and exporting it to image.

I have been unable to add any of the layers in the legend (which are also in the toc) to the exported map, which results in a blank map and none of the field expressions working.

    # Get layers in the legend and append, must be a cleaner way to do this?
    layers = self.iface.legendInterface().layers()
    layerStringList = []
    for layer in layers:
        layerID = layer.id()
        layerStringList.append(layerID)

    # Add layer to map render
    myMapRenderer = QgsMapRenderer()
    myMapRenderer.setLayerSet(layerStringList)
    myMapRenderer.setProjectionsEnabled(False)

    # Load template
    myComposition = QgsComposition(myMapRenderer)
    myFile = os.path.join(os.path.dirname(__file__), 'MMR_Template.qpt')
    myTemplateFile = file(myFile, 'rt')
    myTemplateContent = myTemplateFile.read()
    myTemplateFile.close()
    myDocument = QDomDocument()
    myDocument.setContent(myTemplateContent)
    myComposition.loadFromTemplate(myDocument)

    # Save image
    myImagePath = os.path.join(os.path.dirname(__file__), 'come_on.png')
    myImage = myComposition.printPageAsRaster(0)
    myImage.save(myImagePath)

Here is a snippet from the loaded template which should setup the atlas:

 <Atlas hideCoverage="false" featureFilter="reference = '61922'"    coverageLayer="desktop_search20130615160118593" fixedScale="true" composerMap="0" singleFile="false" filenamePattern="&quot;reference&quot;" enabled="true" filterFeatures="true" sortFeatures="true" sortKey="0" sortAscending="true" margin="1"/>

I am also unsure of the best way to add all the layer in the toc to the instance of QgsMapRenderer().

Thanks

17

If anyone is interested here is the code I ended up with. This will turn on/off specific layers in the table of contents (from a list of layers), load a selected composer template from file, generate an atlas and export the map. Finally, returning the table of contents to its original state.

def sort_toc(self):

    # Turn on/off layers as required by search type
    legend = self.iface.legendInterface()
    layers = legend.layers()
    wanted_layers = metal_wanted
    global turn_on, turn_off, atlas_desktop
    turn_off = []
    turn_on = []
    all_layers = []
    for layer in layers:
        layername = layer.name()
        all_layers.append(layername)
        layerid = layer.id()
        if layername == "desktop_search":
            atlas_desktop = layer
        if layername in wanted_layers and legend.isLayerVisible(layer) is False:
            turn_off.append(layer)
            legend.setLayerVisible(layer, True)
        if layername not in wanted_layers and legend.isLayerVisible(layer) is True:
            turn_on.append(layer)
            legend.setLayerVisible(layer, False)
        else:
            pass

    # Checks for required layers missing from map file
    for layer in wanted_layers:
        missing = []
        if layer not in all_layers:
            missing.append(layer)
        else:
            pass
    if not missing:
        pass
    else:
        QMessageBox.warning(self.iface.mainWindow(), "Missing layers", "Required layers are missing from your map file. Details: %s" % (str(missing)))
    return atlas_desktop

def quick_export(self, ref, stype, scale):

    # Add all layers in map canvas to render
    myMapRenderer = self.iface.mapCanvas().mapRenderer()

    # Load template from file
    myComposition = QgsComposition(myMapRenderer)
    myFile = os.path.join(os.path.dirname(__file__), 'MMR_Template.qpt')
    myTemplateFile = file(myFile, 'rt')
    myTemplateContent = myTemplateFile.read()
    myTemplateFile.close()
    myDocument = QDomDocument()
    myDocument.setContent(myTemplateContent)
    myComposition.loadFromTemplate(myDocument)

    # Get map composition and define scale
    myAtlasMap = myComposition.getComposerMapById(0)
    myAtlasMap.setNewScale(int(scale))

    # Setup Atlas
    myAtlas = QgsAtlasComposition(myComposition)
    myAtlas.setCoverageLayer(atlas_desktop) # Atlas run from desktop_search
    myAtlas.setComposerMap(myAtlasMap)
    myAtlas.setFixedScale(True)
    myAtlas.fixedScale()
    myAtlas.setHideCoverage(False)
    myAtlas.setFilterFeatures(True)
    myAtlas.setFeatureFilter("reference = '%s'" % (str(ref)))
    myAtlas.setFilterFeatures(True)

    # Generate atlas
    myAtlas.beginRender()
    for i in range(0, myAtlas.numFeatures()):
        myAtlas.prepareForFeature( i )
        jobs = r"\\MSUKSERVER\BusinessMan Docs\Jobs"
        job_fol = os.path.join(jobs, str(ref))
        output_jpeg = os.path.join(job_fol, ref + "_BMS_plan.jpg")
        myImage = myComposition.printPageAsRaster(0)
        myImage.save(output_jpeg)
    myAtlas.endRender()

def return_toc(self):

    # Revert layers back to pre-script state (on/off)
    legend = self.iface.legendInterface()
    for wanted in turn_on:
        legend.setLayerVisible(wanted, True)
    for unwanted in turn_off:
        legend.setLayerVisible(unwanted, False)
  • Can you share usage examples for the different functions you created? Is this all within the QGIS Python Console? – raphael Dec 14 '16 at 19:33
  • @raphael I built this plugin quite a while ago, but I will try to dig out an example. – Matt Dec 18 '16 at 12:40
  • Thank you Matt for sharing this with us. Is it possible to get an example of use for these functions ? Thanks a lot ! Regards, Nathan – Nat Lebo Feb 23 '18 at 16:21
2

Perhaps this can work on you for getting all current layers:

registry = QgsMapLayerRegistry.instance()
layers = registry.mapLayers().values()
  • ah your way to get all the layers should work actually – akbargumbira Dec 3 '13 at 8:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.