From 84adefa331c4159d432d22840663c38f155cd4c1 Mon Sep 17 00:00:00 2001
From: Erlang/OTP <otp@erlang.org>
Date: Fri, 20 Nov 2009 14:54:40 +0000
Subject: The R13B03 release.

---
 lib/percept/src/egd_png.erl | 104 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100755 lib/percept/src/egd_png.erl

(limited to 'lib/percept/src/egd_png.erl')

diff --git a/lib/percept/src/egd_png.erl b/lib/percept/src/egd_png.erl
new file mode 100755
index 0000000000..3a0aaeef31
--- /dev/null
+++ b/lib/percept/src/egd_png.erl
@@ -0,0 +1,104 @@
+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 2008-2009. All Rights Reserved.
+%% 
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%% 
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%% 
+%% %CopyrightEnd%
+
+
+%% This code was originally written by Dan Gudmundsson for png-handling in
+%% wings3d (e3d__png).
+%%
+%% @doc egd 
+%%
+
+-module(egd_png).
+
+-export([binary/3]).
+
+-include("egd.hrl").
+
+-define(MAGIC, 137,$P,$N,$G,$\r,$\n,26,$\n).
+
+-define(GREYSCALE,   0).
+-define(TRUECOLOUR,  2).
+-define(INDEXED,     3).
+-define(GREYSCALE_A, 4).
+-define(TRUECOLOUR_A,6).
+
+-define(MAX_WBITS,15).
+
+-define(CHUNK, 240).
+
+-define(get4p1(Idx),((Idx)  bsr 4)).
+-define(get4p2(Idx),((Idx)  band 16#0F)).
+-define(get2p1(Idx),((Idx)  bsr 6)).
+-define(get2p2(Idx),(((Idx) bsr 4) band 3)).
+-define(get2p3(Idx),(((Idx) bsr 2) band 3)).
+-define(get2p4(Idx),((Idx)  band 3)).
+-define(get1p1(Idx),((Idx)  bsr 7)).
+-define(get1p2(Idx),(((Idx) bsr 6) band 1)).
+-define(get1p3(Idx),(((Idx) bsr 5) band 1)).
+-define(get1p4(Idx),(((Idx) bsr 4) band 1)).
+-define(get1p5(Idx),(((Idx) bsr 3) band 1)).
+-define(get1p6(Idx),(((Idx) bsr 2) band 1)).
+-define(get1p7(Idx),(((Idx) bsr 1) band 1)).
+-define(get1p8(Idx),((Idx)  band 1)).
+
+binary(W, H, Bitmap) when is_binary(Bitmap) ->
+    Z = zlib:open(),
+    Binary = bitmap2png(W, H, Bitmap, Z),
+    zlib:close(Z),
+    Binary.
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Begin Tainted
+
+bitmap2png(W, H, Bitmap,Z) ->
+    HDR = create_chunk(<<"IHDR",W:32,H:32,8:8,(png_type(r8g8b8)):8,0:8,0:8,0:8>>,Z),
+    DATA = create_chunk(["IDAT",compress_image(0,3*W,Bitmap,[])],Z),
+    END  = create_chunk(<<"IEND">>,Z),
+    list_to_binary([?MAGIC,HDR,DATA,END]).
+
+compress_image(I,RowLen, Bin, Acc) ->
+    Pos = I*RowLen,
+    case Bin of
+	<<_:Pos/binary,Row:RowLen/binary,_/binary>> ->
+	    Filtered = filter_row(Row,RowLen),
+	    compress_image(I+1,RowLen,Bin,[Filtered|Acc]);
+	_ when Pos == size(Bin) ->
+	    Filtered = list_to_binary(lists:reverse(Acc)),
+	    Compressed = zlib:compress(Filtered),
+	    Compressed
+    end.
+
+filter_row(Row,_RowLen) ->
+    [0,Row].
+
+% dialyzer warnings
+%png_type(g8) -> ?GREYSCALE;
+%png_type(a8) -> ?GREYSCALE;
+%png_type(r8g8b8a8) -> ?TRUECOLOUR_A;
+png_type(r8g8b8) -> ?TRUECOLOUR.
+
+create_chunk(Bin,Z) when is_list(Bin) ->
+    create_chunk(list_to_binary(Bin),Z);
+create_chunk(Bin,Z) when is_binary(Bin) ->
+    Sz = size(Bin)-4,
+    Crc = zlib:crc32(Z,Bin),
+    <<Sz:32,Bin/binary,Crc:32>>.
+
+% End tainted
-- 
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