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gtk/gdk-pixbuf/io-gif.c
Matthias Clasen 3806847935 Remove the pointless refusal to load images with dubious disposal mode on 
2003-06-23  Matthias Clasen  <maclas@gmx.de>

	* io-gif.c (gif_get_frame_info): Remove the pointless refusal to load images with dubious
	disposal mode on the first frame. Just ignore it, as everybody else does.
2003-06-23 20:20:15 +00:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
/* GdkPixbuf library - GIF image loader
*
* Copyright (C) 1999 Mark Crichton
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Jonathan Blandford <jrb@redhat.com>
* Adapted from the gimp gif filter written by Adam Moss <adam@gimp.org>
* Gimp work based on earlier work.
* Permission to relicense under the LGPL obtained.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* This loader is very hairy code.
*
* The main loop was not designed for incremental loading, so when it was hacked
* in it got a bit messy. Basicly, every function is written to expect a failed
* read_gif, and lets you call it again assuming that the bytes are there.
*
* Return vals.
* Unless otherwise specified, these are the return vals for most functions:
*
* 0 -> success
* -1 -> more bytes needed.
* -2 -> failure; abort the load
* -3 -> control needs to be passed back to the main loop
* \_ (most of the time returning 0 will get this, but not always)
*
* >1 -> for functions that get a guchar, the char will be returned.
*
* -jrb (11/03/1999)
*/
/*
* If you have any images that crash this code, please, please let me know and
* send them to me.
* <jrb@redhat.com>
*/
#include <config.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "gdk-pixbuf-private.h"
#include "gdk-pixbuf-io.h"
#include "io-gif-animation.h"
#undef DUMP_IMAGE_DETAILS
#undef IO_GIFDEBUG
#define MAXCOLORMAPSIZE 256
#define MAX_LZW_BITS 12
#define INTERLACE 0x40
#define LOCALCOLORMAP 0x80
#define BitSet(byte, bit) (((byte) & (bit)) == (bit))
#define LM_to_uint(a,b) (((b)<<8)|(a))
typedef unsigned char CMap[3][MAXCOLORMAPSIZE];
/* Possible states we can be in. */
enum {
GIF_START,
GIF_GET_COLORMAP,
GIF_GET_NEXT_STEP,
GIF_GET_FRAME_INFO,
GIF_GET_EXTENSION,
GIF_GET_COLORMAP2,
GIF_PREPARE_LZW,
GIF_LZW_FILL_BUFFER,
GIF_LZW_CLEAR_CODE,
GIF_GET_LZW,
GIF_DONE
};
typedef struct _Gif89 Gif89;
struct _Gif89
{
int transparent;
int delay_time;
int input_flag;
int disposal;
};
typedef struct _GifContext GifContext;
struct _GifContext
{
int state; /* really only relevant for progressive loading */
unsigned int width;
unsigned int height;
gboolean has_global_cmap;
CMap global_color_map;
gint global_colormap_size;
unsigned int global_bit_pixel;
unsigned int global_color_resolution;
unsigned int background_index;
gboolean frame_cmap_active;
CMap frame_color_map;
gint frame_colormap_size;
unsigned int frame_bit_pixel;
unsigned int aspect_ratio;
GdkPixbufGifAnim *animation;
GdkPixbufFrame *frame;
Gif89 gif89;
/* stuff per frame. */
int frame_len;
int frame_height;
int frame_interlace;
int x_offset;
int y_offset;
/* Static read only */
FILE *file;
/* progressive read, only. */
GdkPixbufModulePreparedFunc prepare_func;
GdkPixbufModuleUpdatedFunc update_func;
gpointer user_data;
guchar *buf;
guint ptr;
guint size;
guint amount_needed;
/* extension context */
guchar extension_label;
guchar extension_flag;
gboolean in_loop_extension;
/* get block context */
guchar block_count;
guchar block_buf[280];
gint block_ptr;
int old_state; /* used by lzw_fill buffer */
/* get_code context */
int code_curbit;
int code_lastbit;
int code_done;
int code_last_byte;
int lzw_code_pending;
/* lzw context */
gint lzw_fresh;
gint lzw_code_size;
guchar lzw_set_code_size;
gint lzw_max_code;
gint lzw_max_code_size;
gint lzw_firstcode;
gint lzw_oldcode;
gint lzw_clear_code;
gint lzw_end_code;
gint *lzw_sp;
gint lzw_table[2][(1 << MAX_LZW_BITS)];
gint lzw_stack[(1 << (MAX_LZW_BITS)) * 2 + 1];
/* painting context */
gint draw_xpos;
gint draw_ypos;
gint draw_pass;
/* error pointer */
GError **error;
};
static int GetDataBlock (GifContext *, unsigned char *);
#ifdef IO_GIFDEBUG
static int count = 0;
#endif
/* Returns TRUE if read is OK,
* FALSE if more memory is needed. */
static gboolean
gif_read (GifContext *context, guchar *buffer, size_t len)
{
gboolean retval;
#ifdef IO_GIFDEBUG
gint i;
#endif
if (context->file) {
#ifdef IO_GIFDEBUG
count += len;
g_print ("Fsize :%d\tcount :%d\t", len, count);
#endif
retval = (fread(buffer, len, 1, context->file) != 0);
if (!retval && ferror (context->file))
g_set_error (context->error,
G_FILE_ERROR,
g_file_error_from_errno (errno),
_("Failure reading GIF: %s"), strerror (errno));
#ifdef IO_GIFDEBUG
if (len < 100) {
for (i = 0; i < len; i++)
g_print ("%d ", buffer[i]);
}
g_print ("\n");
#endif
return retval;
} else {
#ifdef IO_GIFDEBUG
/* g_print ("\tlooking for %d bytes. size == %d, ptr == %d\n", len, context->size, context->ptr); */
#endif
if ((context->size - context->ptr) >= len) {
#ifdef IO_GIFDEBUG
count += len;
#endif
memcpy (buffer, context->buf + context->ptr, len);
context->ptr += len;
context->amount_needed = 0;
#ifdef IO_GIFDEBUG
g_print ("Psize :%d\tcount :%d\t", len, count);
if (len < 100) {
for (i = 0; i < len; i++)
g_print ("%d ", buffer[i]);
}
g_print ("\n");
#endif
return TRUE;
}
context->amount_needed = len - (context->size - context->ptr);
}
return FALSE;
}
/* Changes the stage to be GIF_GET_COLORMAP */
static void
gif_set_get_colormap (GifContext *context)
{
context->global_colormap_size = 0;
context->state = GIF_GET_COLORMAP;
}
static void
gif_set_get_colormap2 (GifContext *context)
{
context->frame_colormap_size = 0;
context->state = GIF_GET_COLORMAP2;
}
static gint
gif_get_colormap (GifContext *context)
{
unsigned char rgb[3];
while (context->global_colormap_size < context->global_bit_pixel) {
if (!gif_read (context, rgb, sizeof (rgb))) {
return -1;
}
context->global_color_map[0][context->global_colormap_size] = rgb[0];
context->global_color_map[1][context->global_colormap_size] = rgb[1];
context->global_color_map[2][context->global_colormap_size] = rgb[2];
if (context->global_colormap_size == context->background_index) {
context->animation->bg_red = rgb[0];
context->animation->bg_green = rgb[1];
context->animation->bg_blue = rgb[2];
}
context->global_colormap_size ++;
}
return 0;
}
static gint
gif_get_colormap2 (GifContext *context)
{
unsigned char rgb[3];
while (context->frame_colormap_size < context->frame_bit_pixel) {
if (!gif_read (context, rgb, sizeof (rgb))) {
return -1;
}
context->frame_color_map[0][context->frame_colormap_size] = rgb[0];
context->frame_color_map[1][context->frame_colormap_size] = rgb[1];
context->frame_color_map[2][context->frame_colormap_size] = rgb[2];
context->frame_colormap_size ++;
}
return 0;
}
/*
* in order for this function to work, we need to perform some black magic.
* We want to return -1 to let the calling function know, as before, that it needs
* more bytes. If we return 0, we were able to successfully read all block->count bytes.
* Problem is, we don't want to reread block_count every time, so we check to see if
* context->block_count is 0 before we read in the function.
*
* As a result, context->block_count MUST be 0 the first time the get_data_block is called
* within a context, and cannot be 0 the second time it's called.
*/
static int
get_data_block (GifContext *context,
unsigned char *buf,
gint *empty_block)
{
if (context->block_count == 0) {
if (!gif_read (context, &context->block_count, 1)) {
return -1;
}
}
if (context->block_count == 0)
if (empty_block) {
*empty_block = TRUE;
return 0;
}
if (!gif_read (context, buf, context->block_count)) {
return -1;
}
return 0;
}
static void
gif_set_get_extension (GifContext *context)
{
context->state = GIF_GET_EXTENSION;
context->extension_flag = TRUE;
context->extension_label = 0;
context->block_count = 0;
context->block_ptr = 0;
}
static int
gif_get_extension (GifContext *context)
{
gint retval;
gint empty_block = FALSE;
if (context->extension_flag) {
if (context->extension_label == 0) {
/* I guess bad things can happen if we have an extension of 0 )-: */
/* I should look into this sometime */
if (!gif_read (context, & context->extension_label , 1)) {
return -1;
}
}
switch (context->extension_label) {
case 0xf9: /* Graphic Control Extension */
retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
if (retval != 0)
return retval;
if (context->frame == NULL) {
/* I only want to set the transparency if I haven't
* created the frame yet.
*/
context->gif89.disposal = (context->block_buf[0] >> 2) & 0x7;
context->gif89.input_flag = (context->block_buf[0] >> 1) & 0x1;
context->gif89.delay_time = LM_to_uint (context->block_buf[1], context->block_buf[2]);
if ((context->block_buf[0] & 0x1) != 0) {
context->gif89.transparent = context->block_buf[3];
} else {
context->gif89.transparent = -1;
}
}
/* Now we've successfully loaded this one, we continue on our way */
context->block_count = 0;
context->extension_flag = FALSE;
break;
case 0xff: /* application extension */
if (!context->in_loop_extension) {
retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
if (retval != 0)
return retval;
if (!strncmp (context->block_buf, "NETSCAPE2.0", 11) ||
!strncmp (context->block_buf, "ANIMEXTS1.0", 11)) {
context->in_loop_extension = TRUE;
}
context->block_count = 0;
}
if (context->in_loop_extension) {
do {
retval = get_data_block (context, (unsigned char *) context->block_buf, &empty_block);
if (retval != 0)
return retval;
if (context->block_buf[0] == 0x01) {
context->animation->loop = context->block_buf[1] + (context->block_buf[2] << 8);
if (context->animation->loop != 0)
context->animation->loop++;
}
context->block_count = 0;
}
while (!empty_block);
context->in_loop_extension = FALSE;
context->extension_flag = FALSE;
return 0;
}
break;
default:
/* Unhandled extension */
break;
}
}
/* read all blocks, until I get an empty block, in case there was an extension I didn't know about. */
do {
retval = get_data_block (context, (unsigned char *) context->block_buf, &empty_block);
if (retval != 0)
return retval;
context->block_count = 0;
} while (!empty_block);
return 0;
}
static int ZeroDataBlock = FALSE;
static int
GetDataBlock (GifContext *context,
unsigned char *buf)
{
/* unsigned char count; */
if (!gif_read (context, &context->block_count, 1)) {
/*g_message (_("GIF: error in getting DataBlock size\n"));*/
return -1;
}
ZeroDataBlock = context->block_count == 0;
if ((context->block_count != 0) && (!gif_read (context, buf, context->block_count))) {
/*g_message (_("GIF: error in reading DataBlock\n"));*/
return -1;
}
return context->block_count;
}
static void
gif_set_lzw_fill_buffer (GifContext *context)
{
context->block_count = 0;
context->old_state = context->state;
context->state = GIF_LZW_FILL_BUFFER;
}
static int
gif_lzw_fill_buffer (GifContext *context)
{
gint retval;
if (context->code_done) {
if (context->code_curbit >= context->code_lastbit) {
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF file was missing some data (perhaps it was truncated somehow?)"));
return -2;
}
/* Is this supposed to be an error or what? */
/* g_message ("trying to read more data after we've done stuff\n"); */
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_FAILED,
_("Internal error in the GIF loader (%s)"),
G_STRLOC);
return -2;
}
context->block_buf[0] = context->block_buf[context->code_last_byte - 2];
context->block_buf[1] = context->block_buf[context->code_last_byte - 1];
retval = get_data_block (context, &context->block_buf[2], NULL);
if (retval == -1)
return -1;
if (context->block_count == 0)
context->code_done = TRUE;
context->code_last_byte = 2 + context->block_count;
context->code_curbit = (context->code_curbit - context->code_lastbit) + 16;
context->code_lastbit = (2 + context->block_count) * 8;
context->state = context->old_state;
return 0;
}
static int
get_code (GifContext *context,
int code_size)
{
int i, j, ret;
if ((context->code_curbit + code_size) >= context->code_lastbit){
gif_set_lzw_fill_buffer (context);
return -3;
}
ret = 0;
for (i = context->code_curbit, j = 0; j < code_size; ++i, ++j)
ret |= ((context->block_buf[i / 8] & (1 << (i % 8))) != 0) << j;
context->code_curbit += code_size;
return ret;
}
static void
set_gif_lzw_clear_code (GifContext *context)
{
context->state = GIF_LZW_CLEAR_CODE;
context->lzw_code_pending = -1;
}
static int
gif_lzw_clear_code (GifContext *context)
{
gint code;
code = get_code (context, context->lzw_code_size);
if (code == -3)
return -0;
context->lzw_firstcode = context->lzw_oldcode = code;
context->lzw_code_pending = code;
context->state = GIF_GET_LZW;
return 0;
}
#define CHECK_LZW_SP() G_STMT_START { \
if ((guchar *)context->lzw_sp >= \
(guchar *)context->lzw_stack + sizeof (context->lzw_stack)) { \
g_set_error (context->error, \
GDK_PIXBUF_ERROR, \
GDK_PIXBUF_ERROR_CORRUPT_IMAGE, \
_("Stack overflow")); \
return -2; \
} \
} G_STMT_END
static int
lzw_read_byte (GifContext *context)
{
int code, incode;
gint retval;
gint my_retval;
register int i;
if (context->lzw_code_pending != -1) {
retval = context->lzw_code_pending;
context->lzw_code_pending = -1;
return retval;
}
if (context->lzw_fresh) {
context->lzw_fresh = FALSE;
do {
retval = get_code (context, context->lzw_code_size);
if (retval < 0) {
return retval;
}
context->lzw_firstcode = context->lzw_oldcode = retval;
} while (context->lzw_firstcode == context->lzw_clear_code);
return context->lzw_firstcode;
}
if (context->lzw_sp > context->lzw_stack) {
my_retval = *--(context->lzw_sp);
return my_retval;
}
while ((code = get_code (context, context->lzw_code_size)) >= 0) {
if (code == context->lzw_clear_code) {
for (i = 0; i < context->lzw_clear_code; ++i) {
context->lzw_table[0][i] = 0;
context->lzw_table[1][i] = i;
}
for (; i < (1 << MAX_LZW_BITS); ++i)
context->lzw_table[0][i] = context->lzw_table[1][i] = 0;
context->lzw_code_size = context->lzw_set_code_size + 1;
context->lzw_max_code_size = 2 * context->lzw_clear_code;
context->lzw_max_code = context->lzw_clear_code + 2;
context->lzw_sp = context->lzw_stack;
set_gif_lzw_clear_code (context);
return -3;
} else if (code == context->lzw_end_code) {
int count;
unsigned char buf[260];
/* FIXME - we should handle this case */
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_FAILED,
_("GIF image loader can't understand this image."));
return -2;
if (ZeroDataBlock) {
return -2;
}
while ((count = GetDataBlock (context, buf)) > 0)
;
if (count != 0) {
/*g_print (_("GIF: missing EOD in data stream (common occurence)"));*/
return -2;
}
}
incode = code;
if (code >= context->lzw_max_code) {
CHECK_LZW_SP ();
*(context->lzw_sp)++ = context->lzw_firstcode;
code = context->lzw_oldcode;
}
while (code >= context->lzw_clear_code) {
if (code >= (1 << MAX_LZW_BITS)) {
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("Bad code encountered"));
return -2;
}
CHECK_LZW_SP ();
*(context->lzw_sp)++ = context->lzw_table[1][code];
if (code == context->lzw_table[0][code]) {
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("Circular table entry in GIF file"));
return -2;
}
code = context->lzw_table[0][code];
}
CHECK_LZW_SP ();
*(context->lzw_sp)++ = context->lzw_firstcode = context->lzw_table[1][code];
if ((code = context->lzw_max_code) < (1 << MAX_LZW_BITS)) {
context->lzw_table[0][code] = context->lzw_oldcode;
context->lzw_table[1][code] = context->lzw_firstcode;
++context->lzw_max_code;
if ((context->lzw_max_code >= context->lzw_max_code_size) &&
(context->lzw_max_code_size < (1 << MAX_LZW_BITS))) {
context->lzw_max_code_size *= 2;
++context->lzw_code_size;
}
}
context->lzw_oldcode = incode;
if (context->lzw_sp > context->lzw_stack) {
my_retval = *--(context->lzw_sp);
return my_retval;
}
}
return code;
}
static void
gif_set_get_lzw (GifContext *context)
{
context->state = GIF_GET_LZW;
context->draw_xpos = 0;
context->draw_ypos = 0;
context->draw_pass = 0;
}
static void
gif_fill_in_pixels (GifContext *context, guchar *dest, gint offset, guchar v)
{
guchar *pixel = NULL;
guchar (*cmap)[MAXCOLORMAPSIZE];
if (context->frame_cmap_active)
cmap = context->frame_color_map;
else
cmap = context->global_color_map;
if (context->gif89.transparent != -1) {
pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 4;
*pixel = cmap [0][(guchar) v];
*(pixel+1) = cmap [1][(guchar) v];
*(pixel+2) = cmap [2][(guchar) v];
*(pixel+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 255);
} else {
pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 3;
*pixel = cmap [0][(guchar) v];
*(pixel+1) = cmap [1][(guchar) v];
*(pixel+2) = cmap [2][(guchar) v];
}
}
/* only called if progressive and interlaced */
static void
gif_fill_in_lines (GifContext *context, guchar *dest, guchar v)
{
switch (context->draw_pass) {
case 0:
if (context->draw_ypos > 4) {
gif_fill_in_pixels (context, dest, -4, v);
gif_fill_in_pixels (context, dest, -3, v);
}
if (context->draw_ypos < (context->frame_height - 4)) {
gif_fill_in_pixels (context, dest, 3, v);
gif_fill_in_pixels (context, dest, 4, v);
}
/* we don't need a break here. We draw the outer pixels first, then the
* inner ones, then the innermost ones. case 0 needs to draw all 3 bands.
* case 1, just the last two, and case 2 just draws the last one*/
case 1:
if (context->draw_ypos > 2)
gif_fill_in_pixels (context, dest, -2, v);
if (context->draw_ypos < (context->frame_height - 2))
gif_fill_in_pixels (context, dest, 2, v);
/* no break as above. */
case 2:
if (context->draw_ypos > 1)
gif_fill_in_pixels (context, dest, -1, v);
if (context->draw_ypos < (context->frame_height - 1))
gif_fill_in_pixels (context, dest, 1, v);
case 3:
default:
break;
}
}
static void
set_need_recomposite (gpointer data, gpointer user_data)
{
GdkPixbufFrame *frame = (GdkPixbufFrame *)data;
frame->need_recomposite = TRUE;
}
/* Clips a rectancle to the base dimensions. Returns TRUE if the clipped rectangle is non-empty. */
static gboolean
clip_frame (GifContext *context,
gint *x,
gint *y,
gint *width,
gint *height)
{
gint orig_x, orig_y;
orig_x = *x;
orig_y = *y;
*x = MAX (0, *x);
*y = MAX (0, *y);
*width = MIN (context->width, orig_x + *width) - *x;
*height = MIN (context->height, orig_y + *height) - *y;
if (*width > 0 && *height > 0)
return TRUE;
/* The frame is completely off-bounds */
*x = 0;
*y = 0;
*width = 0;
*height = 0;
return FALSE;
}
/* Call update_func on the given rectangle, unless it is completely off-bounds */
static void
maybe_update (GifContext *context,
gint x,
gint y,
gint width,
gint height)
{
if (clip_frame (context, &x, &y, &width, &height))
(*context->update_func) (context->frame->pixbuf,
x, y, width, height,
context->user_data);
}
static int
gif_get_lzw (GifContext *context)
{
guchar *dest, *temp;
gint lower_bound, upper_bound; /* bounds for emitting the area_updated signal */
gboolean bound_flag;
gint first_pass; /* bounds for emitting the area_updated signal */
gint v;
if (context->frame == NULL) {
context->frame = g_new (GdkPixbufFrame, 1);
context->frame->composited = NULL;
context->frame->revert = NULL;
if (context->frame_len == 0 || context->frame_height == 0) {
/* An empty frame, we just output a single transparent
* pixel at (0, 0).
*/
context->x_offset = 0;
context->y_offset = 0;
context->frame_len = 1;
context->frame_height = 1;
context->frame->pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
if (context->frame->pixbuf) {
guchar *pixels;
pixels = gdk_pixbuf_get_pixels (context->frame->pixbuf);
pixels[0] = 0;
pixels[1] = 0;
pixels[2] = 0;
pixels[3] = 0;
}
} else
context->frame->pixbuf =
gdk_pixbuf_new (GDK_COLORSPACE_RGB,
TRUE,
8,
context->frame_len,
context->frame_height);
if (!context->frame->pixbuf) {
g_free (context->frame);
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
_("Not enough memory to load GIF file"));
return -2;
}
context->frame->x_offset = context->x_offset;
context->frame->y_offset = context->y_offset;
context->frame->need_recomposite = TRUE;
/* GIF delay is in hundredths, we want thousandths */
context->frame->delay_time = context->gif89.delay_time * 10;
/* Some GIFs apparently have delay time of 0,
* that crashes everything so set it to "fast".
* Also, timeouts less than 20 or so just lock up
* the app or make the animation choppy, so fix them.
*/
if (context->frame->delay_time < 20)
context->frame->delay_time = 20; /* 20 = "fast" */
context->frame->elapsed = context->animation->total_time;
context->animation->total_time += context->frame->delay_time;
switch (context->gif89.disposal) {
case 0:
case 1:
context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
break;
case 2:
context->frame->action = GDK_PIXBUF_FRAME_DISPOSE;
break;
case 3:
context->frame->action = GDK_PIXBUF_FRAME_REVERT;
break;
default:
context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
break;
}
context->frame->bg_transparent = (context->gif89.transparent == context->background_index);
context->animation->n_frames ++;
context->animation->frames = g_list_append (context->animation->frames, context->frame);
/* Only call prepare_func for the first frame */
if (context->animation->frames->next == NULL) {
if (context->prepare_func)
(* context->prepare_func) (context->frame->pixbuf,
GDK_PIXBUF_ANIMATION (context->animation),
context->user_data);
} else {
/* Otherwise init frame with last frame */
GList *link;
GdkPixbufFrame *prev_frame;
gint x, y, w, h;
link = g_list_find (context->animation->frames, context->frame);
prev_frame = link->prev->data;
gdk_pixbuf_gif_anim_frame_composite (context->animation, prev_frame);
x = context->frame->x_offset;
y = context->frame->y_offset;
w = gdk_pixbuf_get_width (context->frame->pixbuf);
h = gdk_pixbuf_get_height (context->frame->pixbuf);
if (clip_frame (context, &x, &y, &w, &h))
gdk_pixbuf_copy_area (prev_frame->composited,
x, y, w, h,
context->frame->pixbuf,
0, 0);
}
}
dest = gdk_pixbuf_get_pixels (context->frame->pixbuf);
bound_flag = FALSE;
lower_bound = upper_bound = context->draw_ypos;
first_pass = context->draw_pass;
while (TRUE) {
guchar (*cmap)[MAXCOLORMAPSIZE];
if (context->frame_cmap_active)
cmap = context->frame_color_map;
else
cmap = context->global_color_map;
v = lzw_read_byte (context);
if (v < 0) {
goto finished_data;
}
bound_flag = TRUE;
g_assert (gdk_pixbuf_get_has_alpha (context->frame->pixbuf));
temp = dest + context->draw_ypos * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 4;
*temp = cmap [0][(guchar) v];
*(temp+1) = cmap [1][(guchar) v];
*(temp+2) = cmap [2][(guchar) v];
*(temp+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 255);
if (context->prepare_func && context->frame_interlace)
gif_fill_in_lines (context, dest, v);
context->draw_xpos++;
if (context->draw_xpos == context->frame_len) {
context->draw_xpos = 0;
if (context->frame_interlace) {
switch (context->draw_pass) {
case 0:
case 1:
context->draw_ypos += 8;
break;
case 2:
context->draw_ypos += 4;
break;
case 3:
context->draw_ypos += 2;
break;
}
if (context->draw_ypos >= context->frame_height) {
context->draw_pass++;
switch (context->draw_pass) {
case 1:
context->draw_ypos = 4;
break;
case 2:
context->draw_ypos = 2;
break;
case 3:
context->draw_ypos = 1;
break;
default:
goto done;
}
}
} else {
context->draw_ypos++;
}
if (context->draw_pass != first_pass) {
if (context->draw_ypos > lower_bound) {
lower_bound = 0;
upper_bound = context->frame_height;
} else {
}
} else
upper_bound = context->draw_ypos;
}
if (context->draw_ypos >= context->frame_height)
break;
}
done:
context->state = GIF_GET_NEXT_STEP;
v = 0;
finished_data:
if (bound_flag)
context->frame->need_recomposite = TRUE;
if (bound_flag && context->update_func) {
if (lower_bound <= upper_bound && first_pass == context->draw_pass) {
maybe_update (context,
context->frame->x_offset,
context->frame->y_offset + lower_bound,
gdk_pixbuf_get_width (context->frame->pixbuf),
upper_bound - lower_bound);
} else {
if (lower_bound <= upper_bound) {
maybe_update (context,
context->frame->x_offset,
context->frame->y_offset,
gdk_pixbuf_get_width (context->frame->pixbuf),
gdk_pixbuf_get_height (context->frame->pixbuf));
} else {
maybe_update (context,
context->frame->x_offset,
context->frame->y_offset,
gdk_pixbuf_get_width (context->frame->pixbuf),
upper_bound);
maybe_update (context,
context->frame->x_offset,
context->frame->y_offset + lower_bound,
gdk_pixbuf_get_width (context->frame->pixbuf),
gdk_pixbuf_get_height (context->frame->pixbuf) - lower_bound);
}
}
}
if (context->state == GIF_GET_NEXT_STEP) {
/* Will be freed with context->animation, we are just
* marking that we're done with it (no current frame)
*/
context->frame = NULL;
context->frame_cmap_active = FALSE;
}
return v;
}
static void
gif_set_prepare_lzw (GifContext *context)
{
context->state = GIF_PREPARE_LZW;
context->lzw_code_pending = -1;
}
static int
gif_prepare_lzw (GifContext *context)
{
gint i;
if (!gif_read (context, &(context->lzw_set_code_size), 1)) {
/*g_message (_("GIF: EOF / read error on image data\n"));*/
return -1;
}
if (context->lzw_set_code_size > MAX_LZW_BITS) {
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF image is corrupt (incorrect LZW compression)"));
return -2;
}
context->lzw_code_size = context->lzw_set_code_size + 1;
context->lzw_clear_code = 1 << context->lzw_set_code_size;
context->lzw_end_code = context->lzw_clear_code + 1;
context->lzw_max_code_size = 2 * context->lzw_clear_code;
context->lzw_max_code = context->lzw_clear_code + 2;
context->lzw_fresh = TRUE;
context->code_curbit = 0;
context->code_lastbit = 0;
context->code_last_byte = 0;
context->code_done = FALSE;
g_assert (context->lzw_clear_code <=
G_N_ELEMENTS (context->lzw_table[0]));
for (i = 0; i < context->lzw_clear_code; ++i) {
context->lzw_table[0][i] = 0;
context->lzw_table[1][i] = i;
}
for (; i < (1 << MAX_LZW_BITS); ++i)
context->lzw_table[0][i] = context->lzw_table[1][0] = 0;
context->lzw_sp = context->lzw_stack;
gif_set_get_lzw (context);
return 0;
}
/* needs 13 bytes to proceed. */
static gint
gif_init (GifContext *context)
{
unsigned char buf[16];
char version[4];
if (!gif_read (context, buf, 6)) {
/* Unable to read magic number,
* gif_read() should have set error
*/
return -1;
}
if (strncmp ((char *) buf, "GIF", 3) != 0) {
/* Not a GIF file */
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("File does not appear to be a GIF file"));
return -2;
}
strncpy (version, (char *) buf + 3, 3);
version[3] = '\0';
if ((strcmp (version, "87a") != 0) && (strcmp (version, "89a") != 0)) {
/* bad version number, not '87a' or '89a' */
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("Version %s of the GIF file format is not supported"),
version);
return -2;
}
/* read the screen descriptor */
if (!gif_read (context, buf, 7)) {
/* Failed to read screen descriptor, error set */
return -1;
}
context->width = LM_to_uint (buf[0], buf[1]);
context->height = LM_to_uint (buf[2], buf[3]);
/* The 4th byte is
* high bit: whether to use the background index
* next 3: color resolution
* next: whether colormap is sorted by priority of allocation
* last 3: size of colormap
*/
context->global_bit_pixel = 2 << (buf[4] & 0x07);
context->global_color_resolution = (((buf[4] & 0x70) >> 3) + 1);
context->has_global_cmap = (buf[4] & 0x80) != 0;
context->background_index = buf[5];
context->aspect_ratio = buf[6];
/* Use background of transparent black as default, though if
* one isn't set explicitly no one should ever use it.
*/
context->animation->bg_red = 0;
context->animation->bg_green = 0;
context->animation->bg_blue = 0;
context->animation->width = context->width;
context->animation->height = context->height;
if (context->has_global_cmap) {
gif_set_get_colormap (context);
} else {
context->state = GIF_GET_NEXT_STEP;
}
#ifdef DUMP_IMAGE_DETAILS
g_print (">Image width: %d height: %d global_cmap: %d background: %d\n",
context->width, context->height, context->has_global_cmap, context->background_index);
#endif
return 0;
}
static void
gif_set_get_frame_info (GifContext *context)
{
context->state = GIF_GET_FRAME_INFO;
}
static gint
gif_get_frame_info (GifContext *context)
{
unsigned char buf[9];
if (!gif_read (context, buf, 9)) {
return -1;
}
/* Okay, we got all the info we need. Lets record it */
context->frame_len = LM_to_uint (buf[4], buf[5]);
context->frame_height = LM_to_uint (buf[6], buf[7]);
context->x_offset = LM_to_uint (buf[0], buf[1]);
context->y_offset = LM_to_uint (buf[2], buf[3]);
if (context->animation->frames == NULL &&
context->gif89.disposal == 3) {
/* First frame can't have "revert to previous" as its
* dispose mode. Silently use "retain" instead.
*/
context->gif89.disposal = 0;
}
context->frame_interlace = BitSet (buf[8], INTERLACE);
#ifdef DUMP_IMAGE_DETAILS
g_print (">width: %d height: %d xoffset: %d yoffset: %d disposal: %d delay: %d transparent: %d interlace: %d\n",
context->frame_len, context->frame_height, context->x_offset, context->y_offset,
context->gif89.disposal, context->gif89.delay_time, context->gif89.transparent, context->frame_interlace);
#endif
if (BitSet (buf[8], LOCALCOLORMAP)) {
#ifdef DUMP_IMAGE_DETAILS
g_print (">has local colormap\n");
#endif
/* Does this frame have it's own colormap. */
/* really only relevant when looking at the first frame
* of an animated gif. */
/* if it does, we need to re-read in the colormap,
* the gray_scale, and the bit_pixel */
context->frame_cmap_active = TRUE;
context->frame_bit_pixel = 1 << ((buf[8] & 0x07) + 1);
gif_set_get_colormap2 (context);
return 0;
}
if (!context->has_global_cmap) {
context->state = GIF_DONE;
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF image has no global colormap, and a frame inside it has no local colormap."));
return -2;
}
gif_set_prepare_lzw (context);
return 0;
}
static gint
gif_get_next_step (GifContext *context)
{
unsigned char c;
while (TRUE) {
if (!gif_read (context, &c, 1)) {
return -1;
}
if (c == ';') {
/* GIF terminator */
/* hmm. Not 100% sure what to do about this. Should
* i try to return a blank image instead? */
context->state = GIF_DONE;
return 0;
}
if (c == '!') {
/* Check the extention */
gif_set_get_extension (context);
return 0;
}
/* look for frame */
if (c != ',') {
/* Not a valid start character */
continue;
}
/* load the frame */
gif_set_get_frame_info (context);
return 0;
}
}
#define LOG(x) /* g_print ("%d: %s\n", __LINE__, x); */
static gint
gif_main_loop (GifContext *context)
{
gint retval = 0;
do {
switch (context->state) {
case GIF_START:
LOG("start\n");
retval = gif_init (context);
break;
case GIF_GET_COLORMAP:
LOG("get_colormap\n");
retval = gif_get_colormap (context);
if (retval == 0)
context->state = GIF_GET_NEXT_STEP;
break;
case GIF_GET_NEXT_STEP:
LOG("next_step\n");
retval = gif_get_next_step (context);
break;
case GIF_GET_FRAME_INFO:
LOG("frame_info\n");
retval = gif_get_frame_info (context);
break;
case GIF_GET_EXTENSION:
LOG("get_extension\n");
retval = gif_get_extension (context);
if (retval == 0)
context->state = GIF_GET_NEXT_STEP;
break;
case GIF_GET_COLORMAP2:
LOG("get_colormap2\n");
retval = gif_get_colormap2 (context);
if (retval == 0)
gif_set_prepare_lzw (context);
break;
case GIF_PREPARE_LZW:
LOG("prepare_lzw\n");
retval = gif_prepare_lzw (context);
break;
case GIF_LZW_FILL_BUFFER:
LOG("fill_buffer\n");
retval = gif_lzw_fill_buffer (context);
break;
case GIF_LZW_CLEAR_CODE:
LOG("clear_code\n");
retval = gif_lzw_clear_code (context);
break;
case GIF_GET_LZW:
LOG("get_lzw\n");
retval = gif_get_lzw (context);
break;
case GIF_DONE:
LOG("done\n");
default:
retval = 0;
goto done;
};
} while ((retval == 0) || (retval == -3));
done:
return retval;
}
static GifContext *
new_context (void)
{
GifContext *context;
context = g_try_malloc (sizeof (GifContext));
if (context == NULL)
return NULL;
memset (context, 0, sizeof (GifContext));
context->animation = g_object_new (GDK_TYPE_PIXBUF_GIF_ANIM, NULL);
context->frame = NULL;
context->file = NULL;
context->state = GIF_START;
context->prepare_func = NULL;
context->update_func = NULL;
context->user_data = NULL;
context->buf = NULL;
context->amount_needed = 0;
context->gif89.transparent = -1;
context->gif89.delay_time = -1;
context->gif89.input_flag = -1;
context->gif89.disposal = -1;
context->animation->loop = 1;
context->in_loop_extension = FALSE;
return context;
}
/* Shared library entry point */
static GdkPixbuf *
gdk_pixbuf__gif_image_load (FILE *file, GError **error)
{
GifContext *context;
GdkPixbuf *pixbuf;
g_return_val_if_fail (file != NULL, NULL);
context = new_context ();
if (context == NULL) {
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
_("Not enough memory to load GIF file"));
return NULL;
}
context->file = file;
context->error = error;
if (gif_main_loop (context) == -1 || context->animation->frames == NULL) {
if (context->error && *(context->error) == NULL)
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF file was missing some data (perhaps it was truncated somehow?)"));
}
pixbuf = gdk_pixbuf_animation_get_static_image (GDK_PIXBUF_ANIMATION (context->animation));
if (pixbuf)
g_object_ref (pixbuf);
g_object_unref (context->animation);
g_free (context->buf);
g_free (context);
return pixbuf;
}
static gpointer
gdk_pixbuf__gif_image_begin_load (GdkPixbufModuleSizeFunc size_func,
GdkPixbufModulePreparedFunc prepare_func,
GdkPixbufModuleUpdatedFunc update_func,
gpointer user_data,
GError **error)
{
GifContext *context;
#ifdef IO_GIFDEBUG
count = 0;
#endif
context = new_context ();
if (context == NULL) {
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
_("Not enough memory to load GIF file"));
return NULL;
}
context->error = error;
context->prepare_func = prepare_func;
context->update_func = update_func;
context->user_data = user_data;
return (gpointer) context;
}
static gboolean
gdk_pixbuf__gif_image_stop_load (gpointer data, GError **error)
{
GifContext *context = (GifContext *) data;
gboolean retval = TRUE;
if (context->state != GIF_DONE) {
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF image was truncated or incomplete."));
retval = FALSE;
}
g_object_unref (context->animation);
g_free (context->buf);
g_free (context);
return retval;
}
static gboolean
gdk_pixbuf__gif_image_load_increment (gpointer data,
const guchar *buf, guint size,
GError **error)
{
gint retval;
GifContext *context = (GifContext *) data;
context->error = error;
if (context->amount_needed == 0) {
/* we aren't looking for some bytes. */
/* we can use buf now, but we don't want to keep it around at all.
* it will be gone by the end of the call. */
context->buf = (guchar*) buf; /* very dubious const cast */
context->ptr = 0;
context->size = size;
} else {
/* we need some bytes */
if (size < context->amount_needed) {
context->amount_needed -= size;
/* copy it over and return */
memcpy (context->buf + context->size, buf, size);
context->size += size;
return TRUE;
} else if (size == context->amount_needed) {
memcpy (context->buf + context->size, buf, size);
context->size += size;
} else {
context->buf = g_realloc (context->buf, context->size + size);
memcpy (context->buf + context->size, buf, size);
context->size += size;
}
}
retval = gif_main_loop (context);
if (retval == -2) {
if (context->buf == buf)
context->buf = NULL;
return FALSE;
}
if (retval == -1) {
/* we didn't have enough memory */
/* prepare for the next image_load_increment */
if (context->buf == buf) {
g_assert (context->size == size);
context->buf = (guchar *)g_new (guchar, context->amount_needed + (context->size - context->ptr));
memcpy (context->buf, buf + context->ptr, context->size - context->ptr);
} else {
/* copy the left overs to the begining of the buffer */
/* and realloc the memory */
memmove (context->buf, context->buf + context->ptr, context->size - context->ptr);
context->buf = g_realloc (context->buf, context->amount_needed + (context->size - context->ptr));
}
context->size = context->size - context->ptr;
context->ptr = 0;
} else {
/* we are prolly all done */
if (context->buf == buf)
context->buf = NULL;
}
return TRUE;
}
static GdkPixbufAnimation *
gdk_pixbuf__gif_image_load_animation (FILE *file,
GError **error)
{
GifContext *context;
GdkPixbufAnimation *animation;
g_return_val_if_fail (file != NULL, NULL);
context = new_context ();
if (context == NULL) {
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
_("Not enough memory to load GIF file"));
return NULL;
}
context->error = error;
context->file = file;
if (gif_main_loop (context) == -1 || context->animation->frames == NULL) {
if (context->error && *(context->error) == NULL)
g_set_error (context->error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
_("GIF file was missing some data (perhaps it was truncated somehow?)"));
g_object_unref (context->animation);
context->animation = NULL;
}
if (context->animation)
animation = GDK_PIXBUF_ANIMATION (context->animation);
else
animation = NULL;
if (context->error && *(context->error))
g_print ("%s\n", (*(context->error))->message);
g_free (context->buf);
g_free (context);
return animation;
}
void
MODULE_ENTRY (gif, fill_vtable) (GdkPixbufModule *module)
{
module->load = gdk_pixbuf__gif_image_load;
module->begin_load = gdk_pixbuf__gif_image_begin_load;
module->stop_load = gdk_pixbuf__gif_image_stop_load;
module->load_increment = gdk_pixbuf__gif_image_load_increment;
module->load_animation = gdk_pixbuf__gif_image_load_animation;
}
void
MODULE_ENTRY (gif, fill_info) (GdkPixbufFormat *info)
{
static GdkPixbufModulePattern signature[] = {
{ "GIF8", NULL, 100 },
{ NULL, NULL, 0 }
};
static gchar * mime_types[] = {
"image/gif",
NULL
};
static gchar * extensions[] = {
"gif",
NULL
};
info->name = "gif";
info->signature = signature;
info->description = N_("The GIF image format");
info->mime_types = mime_types;
info->extensions = extensions;
info->flags = 0;
}
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