ensure that the transparency level option is passed to the octree encoder - closes #1556

src/image_util.cpp

@@ -239,7 +239,7 @@ void save_to_stream(T const& image,
             else if (colors < 0)
                 save_as_png(stream, image, compression, strategy);
             else if (use_octree)
-                save_as_png8_oct(stream, image, colors, compression, strategy);
+                save_as_png8_oct(stream, image, colors, compression, strategy, trans_mode);
             else
                 save_as_png8_hex(stream, image, colors, compression, strategy, trans_mode, gamma);
         }
@@ -288,7 +288,7 @@ void save_to_stream(T const& image,
             if (colors < 0)
                 save_as_png(stream, image, compression, strategy);
             else if (use_octree)
-                save_as_png8_oct(stream, image, colors, compression, strategy);
+                save_as_png8_oct(stream, image, colors, compression, strategy, trans_mode);
             else
                 save_as_png8_hex(stream, image, colors, compression, strategy, trans_mode, gamma);
         }

tests/python_tests/png_encoding_test.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys
+import os, mapnik
+from timeit import Timer, time
+from nose.tools import *
+from utilities import execution_path
+
+def setup():
+    # All of the paths used are relative, if we run the tests
+    # from another directory we need to chdir()
+    os.chdir(execution_path('.'))
+
+tmp_dir = '/tmp/mapnik-png/'
+if not os.path.exists(tmp_dir):
+   os.makedirs(tmp_dir)
+
+def test_transparency_levels():
+    # create partial transparency image
+    im = mapnik.Image(256,256)
+    im.background = mapnik.Color('rgba(255,255,255,.5)')
+    c2 = mapnik.Color('rgba(255,255,0,.2)')
+    c3 = mapnik.Color('rgb(0,255,255)')
+    for y in range(0,im.height()/2):
+        for x in range(0,im.width()/2):
+            im.set_pixel(x,y,c2)
+    for y in range(im.height()/2,im.height()):
+        for x in range(im.width()/2,im.width()):
+            im.set_pixel(x,y,c3)
+
+    t0 = tmp_dir + 'white0.png'
+    t2 = tmp_dir + 'white2.png'
+    t1 = tmp_dir + 'white1.png'
+
+    # octree
+    format = 'png8:m=o:t=0'
+    im.save(t0,format)
+    im_in = mapnik.Image.open(t0)
+    t0_len = len(im_in.tostring(format))
+    eq_(t0_len,len(mapnik.Image.open('images/support/transparency/white0.png').tostring(format)))
+    format = 'png8:m=o:t=1'
+    im.save(t1,format)
+    im_in = mapnik.Image.open(t1)
+    t1_len = len(im_in.tostring(format))
+    eq_(len(im.tostring(format)),len(mapnik.Image.open('images/support/transparency/white1.png').tostring(format)))
+    format = 'png8:m=o:t=2'
+    im.save(t2,format)
+    im_in = mapnik.Image.open(t2)
+    t2_len = len(im_in.tostring(format))
+    eq_(len(im.tostring(format)),len(mapnik.Image.open('images/support/transparency/white2.png').tostring(format)))
+
+    eq_(t0_len < t1_len < t2_len,True)
+
+    # hextree
+    format = 'png8:m=h:t=0'
+    im.save(t0,format)
+    im_in = mapnik.Image.open(t0)
+    t0_len = len(im_in.tostring(format))
+    eq_(t0_len,len(mapnik.Image.open('images/support/transparency/white0.png').tostring(format)))
+    format = 'png8:m=h:t=1'
+    im.save(t1,format)
+    im_in = mapnik.Image.open(t1)
+    t1_len = len(im_in.tostring(format))
+    eq_(len(im.tostring(format)),len(mapnik.Image.open('images/support/transparency/white1.png').tostring(format)))
+    format = 'png8:m=h:t=2'
+    im.save(t2,format)
+    im_in = mapnik.Image.open(t2)
+    t2_len = len(im_in.tostring(format))
+    eq_(len(im.tostring(format)),len(mapnik.Image.open('images/support/transparency/white2.png').tostring(format)))
+
+    eq_(t0_len < t1_len < t2_len,True)
+
+if __name__ == "__main__":
+    setup()
+    for t in dir():
+        if 'test_' in t:
+            eval(t)()