add miniz support - closes #1554

CHANGELOG.md

@@ -8,6 +8,8 @@ For a complete change history, see the git log.
 
 ## Future
 
+- Added alternative PNG/ZLIB implementation (`miniz`) that can be enabled with `e=miniz` (#1554)
+
 - Added support for setting zlib `Z_FIXED` strategy with format string: `png:z=fixed`
 
 - Fixed handling of transparency level option in Octree-based PNG encoding (#1556)

include/mapnik/miniz_png.hpp

@@ -0,0 +1,82 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2012 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+
+#ifndef MAPNIK_MINIZ_PNG_HPP
+#define MAPNIK_MINIZ_PNG_HPP
+
+// mapnik
+#include <mapnik/palette.hpp>
+
+// stl
+#include <vector>
+#include <iostream>
+#include <stdexcept>
+
+/* miniz.c porting issues:
+  - duplicate symbols in python bindings require moving miniz.c include to just cpp file
+  - due to http://code.google.com/p/miniz/issues/detail?id=7
+  - avoiding including miniz.c here requires fwd declaring the two structs below
+  - being able to fwd declare requires removing typedef from struct declarations in miniz.c
+  - being able to fwd declare also requires using pointers to structs
+*/
+
+// TODO: try using #define MINIZ_HEADER_FILE_ONLY
+struct tdefl_output_buffer;
+struct tdefl_compressor;
+
+namespace mapnik { namespace MiniZ {
+
+using mapnik::rgb;
+
+class PNGWriter {
+
+public:
+    PNGWriter(int level, int strategy);
+    ~PNGWriter();
+private:
+    inline void writeUInt32BE(unsigned char *target, unsigned int value);
+    size_t startChunk(const unsigned char header[], size_t length);
+    void finishChunk(size_t start);
+public:
+    void writeIHDR(unsigned int width, unsigned int height, unsigned char pixel_depth);
+    void writePLTE(std::vector<rgb> const& palette);
+    void writetRNS(std::vector<unsigned> const& alpha);
+    template<typename T>
+    void writeIDAT(T const& image);
+    void writeIEND();
+    void toStream(std::ostream& stream);
+
+private:
+    unsigned int flags;
+    tdefl_compressor *compressor;
+    tdefl_output_buffer *buffer;
+    static const unsigned char preamble[];
+    static const unsigned char IHDR_tpl[];
+    static const unsigned char PLTE_tpl[];
+    static const unsigned char tRNS_tpl[];
+    static const unsigned char IDAT_tpl[];
+    static const unsigned char IEND_tpl[];
+};
+
+}}
+
+#endif // MAPNIK_MINIZ_PNG_HPP