qgis - How to clip an Openlayers OSM Background to a Vector Boundary?

I'm new to QGIS. In my project i have two layers: one is my vector (city boundaries) and the other is the OSM (obtained with the plugin). How can I cut the OSM along the edges of the vector? I want to obtain only a region of the map, to save it as an image.

Answer

This way it works:

1. 
   

   unselect your vector data, to show only the Openstreetmap background

   
   


2. 
   

   File -> Save as Image

   
   


3. 
   

   Load the image as raster, set EPSG:3857 as CRS

   
   


4. 
   
   

   Delete the Openstreetmap background layer

   
   


5. 
   

   Raster -> Projection -> Reproject, choosing EPSG:3857 as source CRS and the CRS of the vector data as target CRS, saving as Geotiff under a different name, adding that to the canvas

   
   


6. 
   

   Remove the image loaded in step 3

   
   


7. 
   

   Raster -> Extraction -> Clipper check Mask layer with the vector data, and add the result to the canvas

   
   
   


8. 
   

   Remove the unclipped raster layer from step 5

   
   

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EDIT

If you want the clipping for all zoom levels, see my answer here:

How do I clip OSM basemap with a polygon?