1 /* === S Y N F I G ========================================================= */
2 /*!	\file trgt_gif.h
3 **	\brief Template Header
4 **
5 **	$Id$
6 **
7 **	\legal
8 **	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
9 **
10 **	This package is free software; you can redistribute it and/or
11 **	modify it under the terms of the GNU General Public License as
12 **	published by the Free Software Foundation; either version 2 of
13 **	the License, or (at your option) any later version.
14 **
15 **	This package is distributed in the hope that it will be useful,
16 **	but WITHOUT ANY WARRANTY; without even the implied warranty of
17 **	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 **	General Public License for more details.
19 **	\endlegal
20 **
21 ** === N O T E S ===========================================================
22 **
23 ** ========================================================================= */
24 
25 /* === S T A R T =========================================================== */
26 
27 #ifndef __SYNFIG_TRGT_GIF_H
28 #define __SYNFIG_TRGT_GIF_H
29 
30 /* === H E A D E R S ======================================================= */
31 
32 #include <synfig/target_scanline.h>
33 #include <synfig/string.h>
34 #include <synfig/smartfile.h>
35 #include <cstdio>
36 #include <synfig/surface.h>
37 #include <synfig/palette.h>
38 #include <synfig/targetparam.h>
39 
40 /* === M A C R O S ========================================================= */
41 
42 /* === T Y P E D E F S ===================================================== */
43 
44 /* === C L A S S E S & S T R U C T S ======================================= */
45 
46 class gif : public synfig::Target_Scanline
47 {
48 	SYNFIG_TARGET_MODULE_EXT
49 private:
50 	// Class for abstracting the
51 	// output of the codes
52 	struct bitstream
53 	{
54 		synfig::SmartFILE file;
55 		unsigned char pool;
56 		char curr_bit;
bitstreambitstream57 		bitstream():pool(0),curr_bit(0),curr_pos(0) {}
bitstreambitstream58 		bitstream(synfig::SmartFILE file):file(file),pool(0),curr_bit(0),curr_pos(0) {}
59 		unsigned char buffer[256];
60 		int curr_pos;
61 
62 		// Pushes a single bit onto the bit
push_bitbitstream63 		void push_bit(bool bit)
64 		{
65 			if(bit)
66 				pool|=(1<<(curr_bit));
67 			curr_bit++;
68 			if(curr_bit==8)
69 				empty();
70 		}
71 
72 		// Empties out the current pool into
73 		// the buffer. Calls 'dump()' if the
74 		// buffer is full.
emptybitstream75 		void empty()
76 		{
77 			buffer[curr_pos++]=pool;
78 			curr_bit=0;
79 			pool=0;
80 			if(curr_pos==255)dump();
81 		}
82 
83 		// If there is anything in the
84 		// buffer or in the pool, it
85 		// dumps it to the filestream.
86 		// Buffer and pool are cleared.
dumpbitstream87 		void dump()
88 		{
89 			if(curr_bit)
90 				empty();
91 			if(curr_pos || curr_bit)
92 			{
93 				fputc(curr_pos,file.get());
94 				fwrite(buffer,curr_pos,1,file.get());
95 				curr_pos=0;
96 			}
97 		}
98 
99 		// Pushes a symbol of the given size
100 		// onto the bitstream.
push_valuebitstream101 		void push_value(int value, int size)
102 		{
103 			int i;
104 			for(i=0;i<size;i++)
105 				push_bit((value>>(i))&1);
106 		}
107 	};
108 
109 	// Class for dealing with the LZW codes
110 	struct lzwcode
111 	{
112 		int value; // the data element or character
113 		int code; // lzwcode
114 		struct lzwcode* kids; // children of this node
115 		struct lzwcode* next; // siblings of this node
116 
lzwcodelzwcode117 		lzwcode():value(0),code(0),kids(0),next(0) { }
118 
FindCodelzwcode119 		lzwcode *FindCode(int value)
120 		{
121 			lzwcode *node=this;
122 
123 			// check the children (kids) of the node for the value
124 			for (node = node->kids; node != 0; node = node->next)
125 				if (node->value == value)
126 					return(node);
127 			return(0);
128 		}
129 
AddNodelzwcode130 		void AddNode(unsigned short code, unsigned short value)
131 		{
132 			lzwcode *n = new lzwcode;
133 
134 			// add a new child to node; the child will have code and value
135 			n->value = value;
136 			n->code = code;
137 			n->kids = 0;
138 			n->next = this->kids;
139 			this->kids = n;
140 		}
141 
NewTablelzwcode142 		static lzwcode * NewTable(int values)
143 		{
144 			int i;
145 			lzwcode * table = new lzwcode;
146 
147 			table->kids = 0;
148 			for (i = 0; i < values; i++)
149 				table->AddNode( i, i);
150 
151 			return(table);
152 		}
153 
154 		// Destructor just deletes any
155 		// children and siblings.
~lzwcodelzwcode156 		~lzwcode()
157 		{
158 			if(kids)
159 				delete kids;
160 			if(next)
161 				delete next;
162 		}
163 	};
164 
165 private:
166 	bitstream bs;
167 	synfig::String filename;
168 	synfig::SmartFILE file;
169 	int
170 		i,			// General-purpose index
171 		codesize,	// Current code size
172 		rootsize,	// Size of pixel bits (will be recalculated)
173 		nextcode;	// Next code to use
174 	lzwcode *table,*next,*node;
175 
176 	synfig::Surface curr_surface;
177 	etl::surface<unsigned char> curr_frame;
178 	etl::surface<unsigned char> prev_frame;
179 
180 	int imagecount;
181 	int cur_scanline;
182 
183 
184 	// GIF compression parameters
185 	bool lossy;
186 	bool multi_image;
187 	bool dithering;
188 	int color_bits;
189 	int iframe_density;
190 	int loop_count;
191 	bool local_palette;
192 
193 	synfig::Palette curr_palette;
194 
195 	void output_curr_palette();
196 
197 public:
198 	gif(const char *filename, const synfig::TargetParam& /* params */);
199 
200 	virtual bool set_rend_desc(synfig::RendDesc *desc);
201 	virtual bool init(synfig::ProgressCallback *cb);
202 	virtual bool start_frame(synfig::ProgressCallback *cb);
203 	virtual void end_frame();
204 
205 	virtual ~gif();
206 
207 	virtual synfig::Color * start_scanline(int scanline);
208 	virtual bool end_scanline(void);
209 
210 };
211 
212 /* === E N D =============================================================== */
213 
214 #endif
215