I'm trying to follow the map rendering section from the pyqgis cookbook, but I'd like to test this as a standalone application. I can do the first part, using simple rendering, but I'm a bit stuck doing the second example using the map composer as a standalone script.
Here is a standalone example for the bit I can do:
from qgis.core import * from qgis.gui import * from PyQt4.QtCore import * from PyQt4.QtGui import * from PyQt4.QtXml import * QgsApplication.setPrefixPath("/usr/", True) QgsApplication.initQgis() fh = open("eg.csv","w") fh.write(""" x,y,name 153.0278, -27.4679, Brisbane 144.2500, -23.4500, Longreach 145.7753, -16.9256, Cairns """) fh.close() uri = "eg.csv?delimiter=%s&xField=%s&yField=%s" % (",", "x", "y") layer = QgsVectorLayer(uri, "eglayer", "delimitedtext") QgsMapLayerRegistry.instance().addMapLayer(layer) img = QImage(QSize(800,600), QImage.Format_ARGB32_Premultiplied) color = QColor(255,255,255) img.fill(color.rgb()) p = QPainter() p.begin(img) render = QgsMapRenderer() lst = [ layer.getLayerID() ] # add ID of every layer render.setLayerSet(lst) rect = QgsRectangle(render.fullExtent()) rect.scale(1.1) render.setExtent(rect) render.setOutputSize(img.size(), img.logicalDpiX()) render.render(p) p.end() img.save("render.png","png")
What I'd really like to do is the same, but use
QgsComposition, and save as for example pdf. The cookbook says:
When using composer in a standalone application, you can create your own map renderer instance the same way as shown in the section above and pass it to the composition.
This bit I couldn't do, all my attempts either get an empty map, or a segfault. I'm running linux mint 13, using qgis 1.8.0. It would be great if someone could show me how to modify the simple example to one that uses the composer.