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Got types 0, 2 & 3 of PNG images working in a PDf... need types 4 & 6.
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I've also got all the PDF structure coming out for types 4 & 6. Just need to extract the alpha channel out of the image scanlines.
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@CarlWright
CarlWright committed May 16, 2010
1 parent 65d26e4 commit 6c96648
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Showing 3 changed files with 152 additions and 28 deletions.
160 changes: 142 additions & 18 deletions src/eg_pdf_image.erl
View file
Expand Up @@ -31,7 +31,12 @@
%% Pack into XObjects
%%

-export([mk_images/4, get_head_info/1, process_header/1, get_png_content/1]).
-export([mk_images/4,
get_head_info/1,
process_header/1,
get_png_content/1,
deflate_stream/1,
inflate_stream/1]).

-include("../include/eg.hrl").

Expand All @@ -48,39 +53,112 @@ mk_images([], I, Is, Os) ->
lists:reverse(Is))}},
{I+1, {ptr,I,0}, lists:reverse([A|Os])};
mk_images([{ImageURI, #image{alias=Alias}=Im}|T], I, Fs, E) ->
O = mk_image(I, ImageURI, Im),
mk_images(T, I+1, [{Alias,I}|Fs], [O|E]).

List = case mk_image(I, ImageURI, Im) of
{J, [A,[]]} ->
[A|E] ;
{J, [A,B]} ->
[A,B|E]
end,
mk_images(T, J+1, [{Alias,I}|Fs], List).

mk_image(I, File, #image{alias=_Alias, width=W, height=H}) ->
Image = read_image(File),
case process_header(Image) of
{jpeg_head,{Width, Height, Ncomponents, Data_precision}} ->
Extras = [{"Filter", {name,"DCTDecode"}},
{"ColorSpace",{name, colorspace(Ncomponents)}},
{"BitsPerComponent", Data_precision}],
Image2 = Image;
Image2 = Image,
J = I,
ExtraObj = [];
{png_head,{Width, Height, Ncomponents, Data_precision}} ->
[_Params, MoreParams, Palette, Image2 , Alpha_channel] = get_png_content(File),
case Ncomponents of
0 ->
Extras = [{"Filter", {name,"FlateDecode"}},
{"DecodeParms", {dict,[{"Predictor", 15},
{"Colors", 3},
{"Colors", pngbits(Ncomponents)},
{"BitsPerComponent", Data_precision},
{"Columns", Width}] } },
{"ColorSpace",{name, pngspace(Ncomponents)}},
{"ColorSpace",{name, pngcolor(Ncomponents)}},
{"BitsPerComponent", Data_precision}],
[_Params, _MoreParams, _Palette, Image2 , _Alpha_channel] = get_png_content(File);
J = I,
ExtraObj = [];
2 ->
Extras = [{"Filter", {name,"FlateDecode"}},
{"BitsPerComponent", Data_precision},
{"DecodeParms", {dict,[{"Predictor", 15},
{"Colors", pngbits(Ncomponents)},
{"BitsPerComponent", Data_precision},
{"Columns", Width}] } },
{"ColorSpace",{name, pngcolor(Ncomponents)}}],
J = I,
ExtraObj = [];
3 ->
J = I + 1,
Extras = [{"Filter", {name,"FlateDecode"}},
{"BitsPerComponent", Data_precision},
{"DecodeParms", {dict,[{"Predictor", 15},
{"Colors", pngbits(Ncomponents)},
{"BitsPerComponent", Data_precision},
{"Columns", Width}] } },
{"ColorSpace",{array,[{name,"Indexed"},{name,"DeviceRGB"},
round(((length(binary_to_list(Palette))/3)-1)), {ptr, J, 0}] }}],

ExtraObj = {{obj,J, 0}, {stream, Palette}};

4 ->
J = I + 1,
Extras = [{"Filter", {name,"FlateDecode"}},
{"BitsPerComponent", Data_precision},
{"ColorSpace",{name, pngcolor(Ncomponents)}},
{"Smask", {ptr, J, 0}}],


ExtraObj = {{obj,J, 0}, {stream,
{dict,[{"Type",{name,"XObject"}},
{"Subtype",{name,"Image"}},
{"Width",Width},
{"Height", Height},
{"BitsPerComponent", Data_precision},
{"Filter", {name,"FlateDecode"}},
{"ColorSpace",{name, pngcolor(Ncomponents)}},
{"Decode",{array,[0,1]}}]},
Alpha_channel}};
6 ->
J = I + 1,
Extras = [{"Filter", {name,"FlateDecode"}},
{"BitsPerComponent", Data_precision},
{"ColorSpace",{name, pngcolor(Ncomponents)}},
{"Smask", {ptr, J, 0}}],


ExtraObj = {{obj,J, 0}, {stream,
{dict,[{"Type",{name,"XObject"}},
{"Subtype",{name,"Image"}},
{"Width",Width},
{"Height", Height},
{"BitsPerComponent", Data_precision},
{"Filter", {name,"FlateDecode"}},
{"ColorSpace",{name, "DeviceGray"}},
{"Decode",{array,[0,1]}}]},
Alpha_channel}}
end;
_ ->
{Width, Height} = {W,H},
Image2 = Image,
Extras = []
Extras = [],
J = I,
ExtraObj = []
end,
{{obj,I,0},
{J, [{{obj,I,0},
{stream,
{dict,[{"Type",{name,"XObject"}},
{"Subtype",{name,"Image"}},
{"Width",Width},
{"Height", Height}| Extras ]},
Image2}
}.
},ExtraObj]}.


colorspace(0)-> "DeviceGray";
Expand All @@ -89,11 +167,17 @@ colorspace(2)-> "DeviceGray";
colorspace(3)-> "DeviceRGB";
colorspace(4)-> "DeviceCMYK".

pngspace(0)-> "DeviceGray";
pngspace(2)-> "DeviceRGB";
pngspace(3)-> unknown;
pngspace(4)-> "DeviceGray";
pngspace(6)-> "DeviceRGB".
pngcolor(X) ->
{A,_} = pngspace(X),
A.
pngbits(X) ->
{_, B} = pngspace(X),
B.
pngspace(0)-> {"DeviceGray", 1};
pngspace(2)-> {"DeviceRGB", 3};
pngspace(3)-> {"DeviceGray", 1};
pngspace(4)-> {"DeviceGray", 1};
pngspace(6)-> {"DeviceRGB", 3}.

read_image(File) ->
case file:read_file(File) of
Expand Down Expand Up @@ -260,8 +344,48 @@ process_png( <<Length:32, $t:8, $R:8, $N:8, $S:8, Data:Length/binary-unit:8, _C

process_png( <<_Length:32, $I:8, $E:8, $N:8, $D:8, _Rest/binary >>,
Params, MoreParams, Palette, Image, Alpha_channel) ->
[Params, MoreParams, list_to_binary(Palette), list_to_binary(Image) , list_to_binary(Alpha_channel)];
{png_head,{Width, Height, Color_type, Data_precision}} = Params,
case Color_type of
0 ->
[Params, MoreParams, list_to_binary(Palette), list_to_binary(Image) , list_to_binary(Alpha_channel)];
2 ->
[Params, MoreParams, list_to_binary(Palette), list_to_binary(Image) , list_to_binary(Alpha_channel)];
3 ->
[Params, MoreParams, list_to_binary(Palette), list_to_binary(Image) , list_to_binary(Alpha_channel)];
4 ->
{ImageScan, AlphaCodes} = extractAlphaAndData(list_to_binary(Image)),
[Params, MoreParams, list_to_binary(Palette), ImageScan , AlphaCodes];
6 ->
{ImageScan, AlphaCodes} = extractAlphaAndData(list_to_binary(Image)),
[Params, MoreParams, list_to_binary(Palette), ImageScan , AlphaCodes]
end;

process_png( <<Length:32/integer, _ID:32, _:Length/binary-unit:8, _CRC:32, Rest/binary >>,
Params, MoreParams, Palette, Image, Alpha_channel) ->
process_png( Rest, Params, MoreParams, Palette, Image , Alpha_channel).
process_png( Rest, Params, MoreParams, Palette, Image , Alpha_channel).

extractAlphaAndData(Image) ->
{ok,Decompressed} = deflate_stream(Image),
{Decompressed,<< >>}.

%% @doc Decompress a bit stream using the zlib/deflate algorithm
%%
inflate_stream(Data) ->
Z = zlib:open(),
ok = zlib:inflateInit(Z),
Decompressed = zlib:inflate(Z, Data),
ok = zlib:inflateEnd(Z),
zlib:close(Z),
{ok,Decompressed}.

%% @doc Compress a bit stream using the zlib/deflate algorithm
%%
deflate_stream(Data) ->
Z = zlib:open(),
zlib:deflateInit(Z),
B1 = zlib:deflate(Z,Data),
B2 = zlib:deflate(Z,<< >>,finish),
zlib:deflateEnd(Z),
Compressed = list_to_binary([B1,B2]),
zlib:close(Z),
{ok,Compressed}.
20 changes: 10 additions & 10 deletions test/eg_test10.erl
View file
Expand Up @@ -34,17 +34,17 @@ test()->
PDF = eg_pdf:new(),
eg_pdf:set_pagesize(PDF,a4),
eg_pdf:set_page(PDF,1),
eg_pdf:set_font(PDF, "Victorias-Secret", 10),
eg_pdf_lib:moveAndShow(PDF, 100, 485, "Type 0"),
eg_pdf:image(PDF,"../test/images/web-links.png", {100,500},{height,100}),
eg_pdf_lib:moveAndShow(PDF, 350, 485, "Type 2"),
eg_pdf:image(PDF,"../test/images/ruport.png", {350,500},{height,100}),
eg_pdf_lib:moveAndShow(PDF, 1000, 185, "Type 3"),
eg_pdf:image(PDF,"../test/images/rails.png", {100,200},{height,100}),
eg_pdf_lib:moveAndShow(PDF, 350, 485, "Type 4"),
eg_pdf:image(PDF,"../test/images/page_white_text.png", {350,500},{height,100}),
eg_pdf:set_font(PDF, "Victorias-Secret", 14),
eg_pdf_lib:moveAndShow(PDF, 100, 685, "Type 0"),
eg_pdf:image(PDF,"../test/images/web-links.png", {100,700},{height,21}),
eg_pdf_lib:moveAndShow(PDF, 150, 685, "Type 2"),
eg_pdf:image(PDF,"../test/images/ruport.png", {150,700},{width,258}),
eg_pdf_lib:moveAndShow(PDF, 100, 485, "Type 3"),
eg_pdf:image(PDF,"../test/images/rails.png", {100,500},{height,50}),
eg_pdf_lib:moveAndShow(PDF, 350, 185, "Type 4"),
eg_pdf:image(PDF,"../test/images/page_white_text.png", {350,200},{height,16}),
eg_pdf_lib:moveAndShow(PDF, 50, 20, "Type 6"),
eg_pdf:image(PDF,"../test/images/dice.png",{50,35}, {height,120}),
eg_pdf:image(PDF,"../test/images/dice.png",{50,35}, {height,320}),
{Serialised, _PageNo} = eg_pdf:export(PDF),
file:write_file("../test/eg_test10.pdf",[Serialised]),
eg_pdf:delete(PDF).
Expand Down
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