fixed Result image wrong resolution

fix on this:
sethoscope#58

We ignore margin requirement and increase it to fit exact image dimension if it required(i suppose margin can only be increased, but not sure). Also fix not works it we not split common padding variable on padding.x and padding.y

heatmap.py

@@ -23,6 +23,7 @@
 import logging
 import math
 from PIL import Image
+from PIL import PngImagePlugin
 from PIL import ImageColor
 from itertools import chain
 import tempfile
@@ -178,15 +179,15 @@ def auto_set_scale(self, extent_in, padding, width=None, height=None):
         SCALE_FACTOR = 1000000.0
         self.pixels_per_degree = SCALE_FACTOR
         extent_out = extent_in.map(self.project)
-        padding *= 2  # padding-per-edge -> padding-in-each-dimension
+        # padding *= 2  # padding-per-edge -> padding-in-each-dimension
         try:
             if height:
                 self.pixels_per_degree = pixels_per_lat = (
-                    float(height - padding) /
+                    float(height - padding[1] * 2) /
                     extent_out.size().y * SCALE_FACTOR)
             if width:
                 self.pixels_per_degree = (
-                    float(width - padding) /
+                    float(width - padding[0] * 2) /
                     extent_out.size().x * SCALE_FACTOR)
                 if height:
                     self.pixels_per_degree = min(self.pixels_per_degree,
@@ -274,10 +275,10 @@ def size(self):
                                   self.max.y - self.min.y)
 
     def grow(self, pad):
-        self.min.x -= pad
-        self.min.y -= pad
-        self.max.x += pad
-        self.max.y += pad
+        self.min.x -= pad[0]
+        self.min.y -= pad[1]
+        self.max.x += pad[0]
+        self.max.y += pad[1]
 
     def resize(self, width=None, height=None):
         if width:
@@ -729,10 +730,10 @@ def choose_osm_zoom(config, padding):
     bbox_crazy_xy = config.extent_in.map(proj.project)
     if config.width:
         size_ratio = width_ratio = (
-            float(bbox_crazy_xy.size().x) / (config.width - 2 * padding))
+            float(bbox_crazy_xy.size().x) / (config.width - 2 * padding[0]))
     if config.height:
         size_ratio = (
-            float(bbox_crazy_xy.size().y) / (config.height - 2 * padding))
+            float(bbox_crazy_xy.size().y) / (config.height - 2 * padding[1]))
         if config.width:
             size_ratio = max(size_ratio, width_ratio)
     # TODO: We use --height and --width as upper bounds, choosing a zoom
@@ -752,6 +753,10 @@ def get_osm_background(config, padding):
     proj.pixels_per_degree = _scale_for_osm_zoom(zoom)
     bbox_xy = config.extent_in.map(proj.project)
     # We're not checking that the padding fits within the specified size.
+    if config.width:
+        padding[0] = (config.width - bbox_xy.size().x) / 2
+    if config.height:
+        padding[1] = (config.height - bbox_xy.size().y) / 2
     bbox_xy.grow(padding)
     bbox_ll = bbox_xy.map(proj.inverse_project)
     image, img_bbox_ll = _get_osm_image(bbox_ll, zoom, config.osm_base)
@@ -764,8 +769,8 @@ def get_osm_background(config, padding):
     image = image.crop((
         int(offset.x),
         int(offset.y),
-        int(offset.x + bbox_xy.size().x + 1),
-        int(offset.y + bbox_xy.size().y + 1)))
+        int(offset.x + bbox_xy.size().x),
+        int(offset.y + bbox_xy.size().y)))
     config.background_image = image
     config.extent_in = bbox_ll
     config.projection = proj
@@ -1193,15 +1198,16 @@ def fill_missing(self):
         if not self.shapes:
             raise ValueError('no input specified')
 
-        padding = self.margin + self.kernel.radius
+        padding = [self.margin + self.kernel.radius] * 2  # [x, y]. Can be changed if osm set
+
         if not self.extent_in:
             logging.debug('reading input data')
             self.shapes = list(self.shapes)
             logging.debug('read %d shapes' % len(self.shapes))
             self.extent_in = Extent(shapes=self.shapes)
 
         if self.osm:
-            get_osm_background(self, padding)
+            get_osm_background(self, padding)  # padding can be changed inside
         else:
             if not self.projection.is_scaled():
                 self.projection.auto_set_scale(self.extent_in, padding,