synfig-core  1.0.3
trgt_gif.h
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1 /* === S Y N F I G ========================================================= */
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 
47 {
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;
57  bitstream():pool(0),curr_bit(0),curr_pos(0) {}
58  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
63  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.
75  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.
87  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.
101  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 
117  lzwcode():value(0),code(0),kids(0),next(0) { }
118 
119  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 
130  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 
142  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.
156  ~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