added imgquality config file option for setting JPG quality

Original code by alexjurkiewicz, ported to new DTT code.
This closes #83.

overviewer.py

@@ -96,7 +96,8 @@ def main():
     parser.add_option("--chunklist", dest="chunklist", help="A file containing, on each line, a path to a chunkfile to update. Instead of scanning the world directory for chunks, it will just use this list. Normal caching rules still apply.")
     parser.add_option("--rendermodes", dest="rendermode", help="Specifies the render types, separated by commas. Use --list-rendermodes to list them all.", type="choice", choices=avail_rendermodes, required=True, default=avail_rendermodes[0], listify=True)
     parser.add_option("--list-rendermodes", dest="list_rendermodes", action="store_true", help="List available render modes and exit.", commandLineOnly=True)
-    parser.add_option("--imgformat", dest="imgformat", help="The image output format to use. Currently supported: png(default), jpg. NOTE: png will always be used as the intermediate image format.", configFileOnly=True )
+    parser.add_option("--imgformat", dest="imgformat", help="The image output format to use. Currently supported: png(default), jpg.", configFileOnly=True )
+    parser.add_option("--imgquality", dest="imgquality", default=95, help="Specify the quality of image output when using imgformat=\"jpg\".", type="int", configFileOnly=True)
     parser.add_option("--bg_color", dest="bg_color", help="Configures the background color for the GoogleMap output.  Specify in #RRGGBB format", configFileOnly=True, type="string", default="#1A1A1A")
     parser.add_option("--optimize-img", dest="optimizeimg", help="If using png, perform image file size optimizations on the output. Specify 1 for pngcrush, 2 for pngcrush+optipng+advdef. This may double (or more) render times, but will produce up to 30% smaller images. NOTE: requires corresponding programs in $PATH or %PATH%", configFileOnly=True)
     parser.add_option("--web-assets-hook", dest="web_assets_hook", help="If provided, run this function after the web assets have been copied, but before actual tile rendering begins. It should accept a QuadtreeGen object as its only argument.", action="store", metavar="SCRIPT", type="function", configFileOnly=True)
@@ -220,7 +221,7 @@ def main():
     # create the quadtrees
     # TODO chunklist
     q = []
-    qtree_args = {'depth' : options.zoom, 'imgformat' : imgformat, 'optimizeimg' : optimizeimg, 'bgcolor':bgcolor}
+    qtree_args = {'depth' : options.zoom, 'imgformat' : imgformat, 'imgquality' : options.imgquality, 'optimizeimg' : optimizeimg, 'bgcolor' : bgcolor}
     for rendermode in options.rendermode:
         if rendermode == 'normal':
             qtree = quadtree.QuadtreeGen(w, destdir, rendermode=rendermode, tiledir='tiles', **qtree_args)

quadtree.py

@@ -49,7 +49,7 @@ def iterate_base4(d):
     return itertools.product(xrange(4), repeat=d)
    
 class QuadtreeGen(object):
-    def __init__(self, worldobj, destdir, bgcolor, depth=None, tiledir=None, imgformat=None, optimizeimg=None, rendermode="normal"):
+    def __init__(self, worldobj, destdir, bgcolor, depth=None, tiledir=None, imgformat=None, imgquality=95, optimizeimg=None, rendermode="normal"):
         """Generates a quadtree from the world given into the
         given dest directory
 
@@ -61,6 +61,7 @@ class QuadtreeGen(object):
         """
         assert(imgformat)
         self.imgformat = imgformat
+        self.imgquality = imgquality
         self.optimizeimg = optimizeimg
         self.bgcolor = bgcolor
         self.rendermode = rendermode
@@ -336,7 +337,7 @@ class QuadtreeGen(object):
 
         # Save it
         if self.imgformat == 'jpg':
-            img.save(imgpath, quality=95, subsampling=0)
+            img.save(imgpath, quality=self.imgquality, subsampling=0)
         else: # png
             img.save(imgpath)
             
@@ -463,7 +464,10 @@ class QuadtreeGen(object):
                 pass
         
         # Save them
-        tileimg.save(imgpath)
+        if self.imgformat == 'jpg':
+            tileimg.save(imgpath, quality=self.imgquality, subsampling=0)
+        else: # png
+            tileimg.save(imgpath)
 
         if self.optimizeimg:
             optimize_image(imgpath, self.imgformat, self.optimizeimg)