Layout show label and each polygon make serrated image

Question

I want to develop "Print lay out functionality", but in output system is giving me whole image, I want to print only selected polygon. Also it is not displaying label names on print image.

Please suggest some way.

from PyQt4.QtGui import *
from PyQt4.QtCore import *
import time
l = iface.activeLayer()

for a in l.getFeatures():
     attrs = {16: 1}
     l.dataProvider().changeAttributeValues({a.id(): attrs})
     img = QImage(QSize(1280, 1024), QImage.Format_ARGB32_Premultiplied)
     # set image's background color
     color = QColor(255, 255, 255)
     img.fill(color.rgb())
     # create painter
     p = QPainter()
     p.begin(img)
     p.setRenderHint(QPainter.Antialiasing)
     render = QgsMapRenderer()
     palyr = QgsPalLayerSettings()
     palyr.readFromLayer(l)
     lst = [l.id()]
     render.setLayerSet(lst)
     render.setLabelingEngine(QgsPalLabeling())
     # set extent
     rect = QgsRectangle(render.fullExtent())
     rect.scale(1.1)
     render.setExtent(rect)
     render.setScale(1)
     render.setOutputSize(img.size(), img.logicalDpiX())
     render.render(p)
     p.end()
     # save image
     img.save("C:/example/Ashwin/%s.jpg" % a['CHALTA_NO'],"jpg")
     attrs = {16: 0}
     l.dataProvider().changeAttributeValues({a.id(): attrs})
     time.sleep(1)

Answer 1

Hint: for each feature, use the QgsFeature().geometry().boundingBox() to achieve the rectangle. In your case, is a.geometry().boundingBox() and it returns a QgsRectangle() object

rect = a.geometry().boundingBox()
...
render.setExtent(rect)