--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hedgewars/PNGh.pas	Thu Apr 12 23:10:35 2012 +0400
@@ -0,0 +1,90 @@
+(*
+ * Hedgewars, a free turn based strategy game
+ * Copyright (c) 2004-2012 Andrey Korotaev <unC0Rr@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ *)
+
+{$INCLUDE "options.inc"}
+
+unit PNGh;
+interface
+
+uses png;
+
+{$IFDEF FPC}
+    {$PACKRECORDS C}
+{$ELSE}
+    {$DEFINE cdecl attribute(cdecl)}
+{$ENDIF}
+
+const
+    // Constants for libpng, they are not defined in png unit.
+    // We actually don't need all of them.
+
+    // These describe the color_type field in png_info.
+    // color type masks
+    PNG_COLOR_MASK_PALETTE = 1;
+    PNG_COLOR_MASK_COLOR   = 2;
+    PNG_COLOR_MASK_ALPHA   = 4;
+
+    // color types.  Note that not all combinations are legal
+    PNG_COLOR_TYPE_GRAY       = 0;
+    PNG_COLOR_TYPE_PALETTE    = (PNG_COLOR_MASK_COLOR or PNG_COLOR_MASK_PALETTE);
+    PNG_COLOR_TYPE_RGB        = (PNG_COLOR_MASK_COLOR);
+    PNG_COLOR_TYPE_RGB_ALPHA  = (PNG_COLOR_MASK_COLOR or PNG_COLOR_MASK_ALPHA);
+    PNG_COLOR_TYPE_GRAY_ALPHA = (PNG_COLOR_MASK_ALPHA);
+
+    // aliases
+    PNG_COLOR_TYPE_RGBA = PNG_COLOR_TYPE_RGB_ALPHA;
+    PNG_COLOR_TYPE_GA   = PNG_COLOR_TYPE_GRAY_ALPHA;
+
+    // This is for compression type. PNG 1.0-1.2 only define the single type.
+    PNG_COMPRESSION_TYPE_BASE    = 0; // Deflate method 8, 32K window
+    PNG_COMPRESSION_TYPE_DEFAULT = PNG_COMPRESSION_TYPE_BASE;
+
+    // This is for filter type. PNG 1.0-1.2 only define the single type.
+    PNG_FILTER_TYPE_BASE        = 0;  // Single row per-byte filtering
+    PNG_INTRAPIXEL_DIFFERENCING = 64; // Used only in MNG datastreams
+    PNG_FILTER_TYPE_DEFAULT     = PNG_FILTER_TYPE_BASE;
+
+    // These are for the interlacing type.  These values should NOT be changed.
+    PNG_INTERLACE_NONE  = 0; // Non-interlaced image
+    PNG_INTERLACE_ADAM7 = 1; // Adam7 interlacing
+    PNG_INTERLACE_LAST  = 2; // Not a valid value
+
+type
+    // where is better place for this definition?
+    PFile = ^file;
+
+procedure png_init_pascal_io(png_ptr: png_structp; pf : PFile);
+
+implementation
+
+// We cannot get c-style FILE* pointer to pass it to libpng, so we implement our own writing functions
+procedure PngWriteData(png_ptr: png_structp; p: PByte; len: png_size_t); cdecl;
+begin
+    BlockWrite( PFile(png_get_io_ptr(png_ptr))^, p^, len);
+end;
+
+procedure PngFlushData(png_ptr: png_structp); cdecl;
+begin
+end;
+
+procedure png_init_pascal_io(png_ptr: png_structp; pf : PFile);
+begin
+    png_set_write_fn(png_ptr, pf, @PngWriteData, @PngFlushData);
+end;
+
+end.