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gimp/plug-ins/common/file-gif-export.c

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/* GIF exporting file filter for GIMP
*
* Copyright
* - Adam D. Moss
* - Peter Mattis
* - Spencer Kimball
*
* Based around original GIF code by David Koblas.
*
*
* Version 4.1.0 - 2003-06-16
* Adam D. Moss - <adam@gimp.org> <adam@foxbox.org>
*/
/*
* This filter uses code taken from the "giftopnm" and "ppmtogif" programs
* which are part of the "netpbm" package.
*/
/*
* "The Graphics Interchange Format(c) is the Copyright property of
* CompuServe Incorporated. GIF(sm) is a Service Mark property of
* CompuServe Incorporated."
*/
/* Copyright notice for GIF code from which this plugin was long ago */
/* derived (David Koblas has granted permission to relicense): */
/* +-------------------------------------------------------------------+ */
/* | Copyright 1990, 1991, 1993, David Koblas. (koblas@extra.com) | */
/* +-------------------------------------------------------------------+ */
#include "config.h"
#include <string.h>
#include <libgimp/gimp.h>
#include <libgimp/gimpui.h>
#include "libgimp/stdplugins-intl.h"
#define EXPORT_PROC "file-gif-export"
#define PLUG_IN_BINARY "file-gif-export"
/* uncomment the line below for a little debugging info */
/* #define GIFDEBUG yesplease */
enum
{
DISPOSE_UNSPECIFIED,
DISPOSE_COMBINE,
DISPOSE_REPLACE
};
typedef struct _Gif Gif;
typedef struct _GifClass GifClass;
struct _Gif
{
GimpPlugIn parent_instance;
};
struct _GifClass
{
GimpPlugInClass parent_class;
};
#define GIF_TYPE (gif_get_type ())
#define GIF(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GIF_TYPE, Gif))
GType gif_get_type (void) G_GNUC_CONST;
static GList * gif_query_procedures (GimpPlugIn *plug_in);
static GimpProcedure * gif_create_procedure (GimpPlugIn *plug_in,
const gchar *name);
static GimpValueArray * gif_export (GimpProcedure *procedure,
GimpRunMode run_mode,
GimpImage *image,
GFile *file,
GimpExportOptions *options,
GimpMetadata *metadata,
GimpProcedureConfig *config,
gpointer run_data);
static gboolean export_image (GFile *file,
GimpImage *image,
GimpDrawable *drawable,
GimpImage *orig_image,
GObject *config,
GError **error);
static void export_edit_options (GimpProcedure *procedure,
GimpProcedureConfig *config,
GimpExportOptions *options,
gpointer create_data);
static GimpPDBStatusType sanity_check (GFile *file,
GimpImage **image,
GimpRunMode run_mode,
GError **error);
static gboolean bad_bounds_dialog (void);
static gboolean save_dialog (GimpImage *image,
GimpImage *orig_image,
GimpProcedure *procedure,
GObject *config);
G_DEFINE_TYPE (Gif, gif, GIMP_TYPE_PLUG_IN)
GIMP_MAIN (GIF_TYPE)
DEFINE_STD_SET_I18N
static gint Interlace; /* For compression code */
static void
gif_class_init (GifClass *klass)
{
GimpPlugInClass *plug_in_class = GIMP_PLUG_IN_CLASS (klass);
plug_in_class->query_procedures = gif_query_procedures;
plug_in_class->create_procedure = gif_create_procedure;
plug_in_class->set_i18n = STD_SET_I18N;
}
static void
gif_init (Gif *gif)
{
}
static GList *
gif_query_procedures (GimpPlugIn *plug_in)
{
return g_list_append (NULL, g_strdup (EXPORT_PROC));
}
static GimpProcedure *
gif_create_procedure (GimpPlugIn *plug_in,
const gchar *name)
{
GimpProcedure *procedure = NULL;
if (! strcmp (name, EXPORT_PROC))
{
procedure = gimp_export_procedure_new (plug_in, name,
GIMP_PDB_PROC_TYPE_PLUGIN,
FALSE, gif_export, NULL, NULL);
gimp_procedure_set_image_types (procedure, "INDEXED*, GRAY*");
gimp_procedure_set_menu_label (procedure, _("GIF image"));
gimp_file_procedure_set_format_name (GIMP_FILE_PROCEDURE (procedure),
_("GIF"));
gimp_procedure_set_documentation (procedure,
_("exports files in GIF "
"file format"),
/* xgettext: no-c-format */
_("Export a file in GIF "
"format, with possible animation, "
"transparency, and comment. To export "
"an animation, operate on a multi-layer "
"file and give the 'as-animation' "
"parameter as TRUE. The plug-in will "
"interpret <50% alpha as transparent. "
"When run non-interactively, the value "
"for the comment is taken from the "
"'gimp-comment' parasite."),
name);
gimp_procedure_set_attribution (procedure,
"Spencer Kimball, Peter Mattis, "
"Adam Moss, David Koblas",
"Spencer Kimball, Peter Mattis, "
"Adam Moss, David Koblas",
"1995-1997");
gimp_file_procedure_set_handles_remote (GIMP_FILE_PROCEDURE (procedure),
TRUE);
gimp_file_procedure_set_mime_types (GIMP_FILE_PROCEDURE (procedure),
"image/gif");
gimp_file_procedure_set_extensions (GIMP_FILE_PROCEDURE (procedure),
"gif");
gimp_export_procedure_set_capabilities (GIMP_EXPORT_PROCEDURE (procedure),
GIMP_EXPORT_CAN_HANDLE_INDEXED |
GIMP_EXPORT_CAN_HANDLE_GRAY |
GIMP_EXPORT_CAN_HANDLE_ALPHA,
export_edit_options, NULL, NULL);
gimp_procedure_add_boolean_argument (procedure, "interlace",
_("_Interlace"),
_("Try to export as interlaced"),
FALSE,
G_PARAM_READWRITE);
gimp_procedure_add_boolean_argument (procedure, "loop",
_("Loop _Forever"),
_("(animated gif) Loop infinitely"),
TRUE,
G_PARAM_READWRITE);
gimp_procedure_add_int_argument (procedure, "number-of-repeats",
_("_Number of repeats"),
_("(animated gif) Number of repeats "
"(Ignored if 'loop' is TRUE)"),
0, G_MAXSHORT - 1, 0,
G_PARAM_READWRITE);
gimp_procedure_add_int_argument (procedure, "default-delay",
_("_Delay between frames when unspecified"),
_("(animated gif) Default delay between frames "
"in milliseconds"),
0, G_MAXINT, 100,
G_PARAM_READWRITE);
gimp_procedure_add_choice_argument (procedure, "default-dispose",
_("Frame disposal _when unspecified"),
_("(animated gif) Default disposal type"),
gimp_choice_new_with_values ("unspecified", DISPOSE_UNSPECIFIED, _("I don't care"), NULL,
"combine", DISPOSE_COMBINE, _("Cumulative layers (combine)"), NULL,
"replace", DISPOSE_REPLACE, _("One frame per layer (replace)"), NULL,
NULL),
"unspecified",
G_PARAM_READWRITE);
gimp_procedure_add_boolean_argument (procedure, "as-animation",
_("_As animation"),
_("Export GIF as animation?"),
FALSE,
G_PARAM_READWRITE);
gimp_procedure_add_boolean_argument (procedure, "force-delay",
_("_Use delay entered above for all frames"),
_("(animated gif) Use specified delay for all frames"),
FALSE,
G_PARAM_READWRITE);
gimp_procedure_add_boolean_argument (procedure, "force-dispose",
_("Use dis_posal entered above "
"for all frames"),
_("(animated gif) Use specified disposal for all frames"),
FALSE,
G_PARAM_READWRITE);
gimp_procedure_add_boolean_aux_argument (procedure, "save-comment",
_("Sa_ve comment"),
_("Save the image comment in the GIF file"),
gimp_export_comment (),
G_PARAM_READWRITE);
gimp_procedure_add_string_aux_argument (procedure, "gimp-comment",
_("Commen_t"),
_("Image comment"),
gimp_get_default_comment (),
G_PARAM_READWRITE);
gimp_procedure_set_argument_sync (procedure, "gimp-comment",
GIMP_ARGUMENT_SYNC_PARASITE);
}
return procedure;
}
static GimpValueArray *
gif_export (GimpProcedure *procedure,
GimpRunMode run_mode,
GimpImage *image,
GFile *file,
GimpExportOptions *options,
GimpMetadata *metadata,
GimpProcedureConfig *config,
gpointer run_data)
{
GimpPDBStatusType status = GIMP_PDB_SUCCESS;
GimpExportReturn export = GIMP_EXPORT_IGNORE;
GimpImage *orig_image;
GimpImage *sanitized_image = NULL;
GimpParasite *parasite = NULL;
GError *error = NULL;
gegl_init (NULL, NULL);
orig_image = image;
if (run_mode == GIMP_RUN_INTERACTIVE ||
run_mode == GIMP_RUN_WITH_LAST_VALS)
gimp_ui_init (PLUG_IN_BINARY);
status = sanity_check (file, &image, run_mode, &error);
/* Get the export options */
if (status == GIMP_PDB_SUCCESS)
{
/* If the sanity check succeeded, the image_ID will point to a
* duplicate image to delete later.
*/
sanitized_image = image;
/* If imported as an animation, set the animation configurations
* when overwriting the file */
parasite = gimp_image_get_parasite (image, "gif/animated");
if (parasite)
{
gint num_loops;
gchar *parasite_data;
guint32 parasite_size;
parasite_data = (gchar *) gimp_parasite_get_data (parasite, &parasite_size);
parasite_data = g_strndup (parasite_data, parasite_size);
if (sscanf (parasite_data, "%i", &num_loops) == 1)
{
gboolean loop = (num_loops == 0);
g_object_set (config,
"as-animation", TRUE,
"loop", loop,
"number-of-repeats", num_loops,
NULL);
}
gimp_image_detach_parasite (image, "gif/animated");
g_free (parasite);
g_free (parasite_data);
}
if (run_mode == GIMP_RUN_INTERACTIVE)
{
if (! save_dialog (image, orig_image, procedure, G_OBJECT (config)))
{
gimp_image_delete (sanitized_image);
return gimp_procedure_new_return_values (procedure,
GIMP_PDB_CANCEL,
NULL);
}
}
}
if (status == GIMP_PDB_SUCCESS)
{
GList *drawables;
export = gimp_export_options_get_image (options, &image);
drawables = gimp_image_list_layers (image);
if (! export_image (file, image, drawables->data, orig_image,
G_OBJECT (config), &error))
{
status = GIMP_PDB_EXECUTION_ERROR;
}
gimp_image_delete (sanitized_image);
g_list_free (drawables);
}
if (export == GIMP_EXPORT_EXPORT)
gimp_image_delete (image);
return gimp_procedure_new_return_values (procedure, status, error);
}
/* ppmtogif.c - read a portable pixmap and produce a GIF file
**
** Based on GIFENCOD by David Rowley <mgardi@watdscu.waterloo.edu>. A
** Lempel-Ziv compression based on "compress".
**
** Modified by Marcel Wijkstra <wijkstra@fwi.uva.nl>
**
**
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation. This software is provided "as is" without express or
** implied warranty.
**
** The Graphics Interchange Format(c) is the Copyright property of
** CompuServe Incorporated. GIF(sm) is a Service Mark property of
** CompuServe Incorporated.
*/
#define MAXCOLORS 256
/*
* Pointer to function returning an int
*/
typedef gint (* ifunptr) (gint x,
gint y);
static gint find_unused_ia_color (const guchar *pixels,
gint numpixels,
gint num_indices,
gint *colors);
static void special_flatten_indexed_alpha (guchar *pixels,
gint transparent,
gint numpixels);
static gint colors_to_bpp (gint colors);
static gint bpp_to_colors (gint bpp);
static gint get_pixel (gint x,
gint y);
static gint gif_next_pixel (ifunptr getpixel);
static void bump_pixel (void);
static gboolean gif_encode_header (GOutputStream *output,
gboolean gif89,
gint width,
gint height,
gint background,
gint bpp,
gint *red,
gint *green,
gint *blue,
ifunptr get_pixel,
GError **error);
static gboolean gif_encode_graphic_control_ext (GOutputStream *output,
gint disposal,
gint delay89,
gint n_frames,
gint width,
gint height,
gint transparent,
gint bpp,
ifunptr get_pixel,
GError **error);
static gboolean gif_encode_image_data (GOutputStream *output,
gint width,
gint height,
gint interlace,
gint bpp,
ifunptr get_pixel,
gint offset_x,
gint offset_y,
GError **error);
static gboolean gif_encode_close (GOutputStream *output,
GError **error);
static gboolean gif_encode_loop_ext (GOutputStream *output,
guint n_loops,
GError **error);
static gboolean gif_encode_comment_ext (GOutputStream *output,
const gchar *comment,
GError **error);
static gint rowstride;
static guchar *pixels;
static gint cur_progress;
static gint max_progress;
static gboolean compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error);
static gboolean no_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error);
static gboolean rle_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error);
static gboolean normal_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error);
static gboolean put_byte (GOutputStream *output,
guchar b,
GError **error);
static gboolean put_word (GOutputStream *output,
gint w,
GError **error);
static gboolean put_string (GOutputStream *output,
const gchar *s,
GError **error);
static gboolean output_code (GOutputStream *output,
gint code,
GError **error);
static gboolean cl_block (GOutputStream *output,
GError **error);
static void cl_hash (glong hsize);
static void char_init (void);
static gboolean char_out (GOutputStream *output,
gint c,
GError **error);
static gboolean char_flush (GOutputStream *output,
GError **error);
static gint
find_unused_ia_color (const guchar *pixels,
gint numpixels,
gint num_indices,
gint *colors)
{
gboolean ix_used[256];
gint i;
#ifdef GIFDEBUG
g_printerr ("GIF: fuiac: Image claims to use %d/%d indices - finding free "
"index...\n", *colors, num_indices);
#endif
for (i = 0; i < 256; i++)
ix_used[i] = FALSE;
for (i = 0; i < numpixels; i++)
{
if (pixels[i * 2 + 1])
ix_used[pixels[i * 2]] = TRUE;
}
for (i = num_indices - 1; i >= 0; i--)
{
if (! ix_used[i])
{
#ifdef GIFDEBUG
g_printerr ("GIF: Found unused color index %d.\n", (int) i);
#endif
return i;
}
}
/* Couldn't find an unused color index within the number of bits per
* pixel we wanted. Will have to increment the number of colors in
* the image and assign a transparent pixel there.
*/
if (*colors < 256)
{
(*colors)++;
g_printerr ("GIF: 2nd pass "
"- Increasing bounds and using color index %d.\n",
*colors - 1);
return ((*colors) - 1);
}
g_message (_("Couldn't simply reduce colors further. Exporting as opaque."));
return -1;
}
static void
special_flatten_indexed_alpha (guchar *pixels,
gint transparent,
gint numpixels)
{
gint i;
/* Each transparent pixel in the image is mapped to a uniform value
* for encoding, if image already has <=255 colors
*/
if (transparent == -1) /* tough, no indices left for the trans. index */
{
for (i = 0; i < numpixels; i++)
pixels[i] = pixels[i * 2];
}
else /* make transparent */
{
for (i = 0; i < numpixels; i++)
{
if (! (pixels[i * 2 + 1] & 128))
{
pixels[i] = (guchar) transparent;
}
else
{
pixels[i] = pixels[i * 2];
}
}
}
}
static gint
parse_ms_tag (const gchar *str)
{
gint sum = 0;
gint offset = 0;
gint length;
length = strlen (str);
find_another_bra:
while ((offset < length) && (str[offset] != '('))
offset++;
if (offset >= length)
return(-1);
if (! g_ascii_isdigit (str[++offset]))
goto find_another_bra;
do
{
sum *= 10;
sum += str[offset] - '0';
offset++;
}
while ((offset < length) && (g_ascii_isdigit (str[offset])));
if (length - offset <= 2)
return(-3);
if ((g_ascii_toupper (str[offset]) != 'M') ||
(g_ascii_toupper (str[offset + 1]) != 'S'))
return -4;
return sum;
}
static gint
parse_disposal_tag (const gchar *str,
gint default_dispose)
{
gint offset = 0;
gint length;
length = strlen (str);
while ((offset + 9) <= length)
{
if (strncmp (&str[offset], "(combine)", 9) == 0)
return 0x01;
if (strncmp (&str[offset], "(replace)", 9) == 0)
return 0x02 ;
offset++;
}
return default_dispose;
}
static GimpPDBStatusType
sanity_check (GFile *file,
GimpImage **image,
GimpRunMode run_mode,
GError **error)
{
GList *layers;
GList *list;
gint image_width;
gint image_height;
image_width = gimp_image_get_width (*image);
image_height = gimp_image_get_height (*image);
if (image_width > G_MAXUSHORT || image_height > G_MAXUSHORT)
{
g_set_error (error, 0, 0,
_("Unable to export '%s'. "
"The GIF file format does not support images that are "
"more than %d pixels wide or tall."),
gimp_file_get_utf8_name (file), G_MAXUSHORT);
return GIMP_PDB_EXECUTION_ERROR;
}
*image = gimp_image_duplicate (*image);
/* Convert image to 8 bit precision if necessary */
if (gimp_image_get_precision (*image) != GIMP_PRECISION_U8_NON_LINEAR &&
gimp_image_get_precision (*image) != GIMP_PRECISION_U8_LINEAR &&
gimp_image_get_precision (*image) != GIMP_PRECISION_U8_PERCEPTUAL)
{
gboolean converted = FALSE;
converted = gimp_image_convert_precision (*image,
GIMP_PRECISION_U8_NON_LINEAR);
if (! converted)
{
g_set_error (error, 0, 0,
_("Unable to export '%s'. "
"Please convert your image to 8 bit integer "
"precision, as the GIF file format does not "
"support higher precisions."),
gimp_file_get_utf8_name (file));
return GIMP_PDB_EXECUTION_ERROR;
}
}
/*** Iterate through the layers to make sure they're all ***/
/*** within the bounds of the image ***/
layers = gimp_image_list_layers (*image);
for (list = layers; list; list = g_list_next (list))
{
GimpDrawable *drawable = list->data;
gint offset_x;
gint offset_y;
gimp_drawable_get_offsets (drawable, &offset_x, &offset_y);
if (offset_x < 0 ||
offset_y < 0 ||
offset_x + gimp_drawable_get_width (drawable) > image_width ||
offset_y + gimp_drawable_get_height (drawable) > image_height)
{
g_list_free (layers);
/* Image has illegal bounds - ask the user what it wants to do */
/* Do the crop if we can't talk to the user, or if we asked
* the user and they said yes.
*/
if ((run_mode == GIMP_RUN_NONINTERACTIVE) || bad_bounds_dialog ())
{
gimp_image_crop (*image, image_width, image_height, 0, 0);
return GIMP_PDB_SUCCESS;
}
else
{
gimp_image_delete (*image);
return GIMP_PDB_CANCEL;
}
}
}
g_list_free (layers);
return GIMP_PDB_SUCCESS;
}
static gboolean
export_image (GFile *file,
GimpImage *image,
GimpDrawable *drawable,
GimpImage *orig_image,
GObject *config,
GError **error)
{
GeglBuffer *buffer;
GimpImageType drawable_type;
const Babl *format = NULL;
GOutputStream *output;
gint Red[MAXCOLORS];
gint Green[MAXCOLORS];
gint Blue[MAXCOLORS];
guchar *cmap;
guint rows, cols;
gint BitsPerPixel;
gint liberalBPP = 0;
gint useBPP = 0;
gint colors;
gint i;
gint transparent;
gint offset_x, offset_y;
GList *layers;
GList *list;
gint nlayers;
gboolean is_gif89 = FALSE;
gint Delay89;
gint Disposal;
gchar *layer_name;
guchar bgred = 255;
guchar bggreen = 255;
guchar bgblue = 255;
guchar bgindex = 0;
guint best_error = 0xFFFFFFFF;
gboolean config_interlace;
gboolean config_loop;
gint config_number_of_repeats;
gint config_default_delay;
gint config_default_dispose;
gboolean config_use_default_delay;
gboolean config_use_default_dispose;
gboolean config_as_animation;
gboolean config_save_comment;
gchar *config_comment;
g_object_get (config,
"interlace", &config_interlace,
"loop", &config_loop,
"number-of-repeats", &config_number_of_repeats,
"default-delay", &config_default_delay,
"force-delay", &config_use_default_delay,
"force-dispose", &config_use_default_dispose,
"as-animation", &config_as_animation,
"save-comment", &config_save_comment,
"gimp-comment", &config_comment,
NULL);
config_default_dispose =
gimp_procedure_config_get_choice_id (GIMP_PROCEDURE_CONFIG (config),
"default-dispose");
/* The GIF spec says 7bit ASCII for the comment block. */
if (config_save_comment && config_comment && strlen (config_comment))
{
const gchar *c = config_comment;
gint len;
for (len = strlen (c); len; c++, len--)
{
if ((guchar) *c > 127)
{
g_message (_("The GIF format only supports comments in "
"7bit ASCII encoding. No comment is saved."));
g_free (config_comment);
config_comment = NULL;
config_save_comment = FALSE;
break;
}
}
}
else
{
config_save_comment = FALSE;
}
/* get a list of layers for this image */
layers = gimp_image_list_layers (image);
nlayers = g_list_length (layers);
drawable_type = gimp_drawable_type (layers->data);
/* If the image has multiple layers (i.e. will be animated), a
* comment, or transparency, then it must be encoded as a GIF89a
* file, not a vanilla GIF87a.
*/
if (nlayers > 1)
{
is_gif89 = TRUE;
/* Layers can be with or without alpha channel. Make sure we set
* alpha if there is at least one layer with alpha channel. */
if (drawable_type == GIMP_GRAY_IMAGE ||
drawable_type == GIMP_INDEXED_IMAGE)
{
for (list = layers; list; list = g_list_next (list))
{
GimpImageType dr_type = gimp_drawable_type (list->data);
if (dr_type == GIMP_GRAYA_IMAGE ||
dr_type == GIMP_INDEXEDA_IMAGE)
{
drawable_type = dr_type;
break;
}
}
}
}
if (config_save_comment)
is_gif89 = TRUE;
switch (drawable_type)
{
case GIMP_INDEXEDA_IMAGE:
is_gif89 = TRUE;
case GIMP_INDEXED_IMAGE:
{
GeglColor *background;
guchar bg[3];
cmap = gimp_palette_get_colormap (gimp_image_get_palette (image), babl_format ("R'G'B' u8"), &colors, NULL);
background = gimp_context_get_background ();
gegl_color_get_pixel (background, babl_format_with_space ("R'G'B' u8", NULL), bg);
g_object_unref (background);
bgred = bg[0];
bggreen = bg[1];
bgblue = bg[2];
for (i = 0; i < colors; i++)
{
Red[i] = *cmap++;
Green[i] = *cmap++;
Blue[i] = *cmap++;
}
for ( ; i < 256; i++)
{
Red[i] = bgred;
Green[i] = bggreen;
Blue[i] = bgblue;
}
}
break;
case GIMP_GRAYA_IMAGE:
is_gif89 = TRUE;
case GIMP_GRAY_IMAGE:
colors = 256; /* FIXME: Not ideal. */
for ( i = 0; i < 256; i++)
{
Red[i] = Green[i] = Blue[i] = i;
}
break;
default:
g_message (_("Cannot export RGB color images. Convert to "
"indexed color or grayscale first."));
return FALSE;
}
/* find earliest index in palette which is closest to the background
* color, and ATTEMPT to use that as the GIF's default background
* color.
*/
for (i = 255; i >= 0; --i)
{
guint local_error = 0;
local_error += (Red[i] - bgred) * (Red[i] - bgred);
local_error += (Green[i] - bggreen) * (Green[i] - bggreen);
local_error += (Blue[i] - bgblue) * (Blue[i] - bgblue);
if (local_error <= best_error)
{
bgindex = i;
best_error = local_error;
}
}
/* init the progress meter */
gimp_progress_init_printf (_("Exporting '%s'"),
gimp_file_get_utf8_name (file));
/* open the destination file for writing */
output = G_OUTPUT_STREAM (g_file_replace (file,
NULL, FALSE, G_FILE_CREATE_NONE,
NULL, error));
if (output)
{
GDataOutputStream *data_output;
data_output = g_data_output_stream_new (output);
g_object_unref (output);
g_data_output_stream_set_byte_order (data_output,
G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN);
output = G_OUTPUT_STREAM (data_output);
}
else
{
return FALSE;
}
/* write the GIFheader */
if (colors < 256)
{
/* we keep track of how many bits we promised to have in
* liberalBPP, so that we don't accidentally come under this
* when doing clever transparency stuff where we can re-use
* wasted indices.
*/
liberalBPP = BitsPerPixel =
colors_to_bpp (colors + ((drawable_type==GIMP_INDEXEDA_IMAGE) ? 1 : 0));
}
else
{
liberalBPP = BitsPerPixel =
colors_to_bpp (256);
if (drawable_type == GIMP_INDEXEDA_IMAGE)
{
g_printerr ("GIF: Too many colors?\n");
}
}
cols = gimp_image_get_width (image);
rows = gimp_image_get_height (image);
Interlace = config_interlace;
if (! gif_encode_header (output, is_gif89, cols, rows, bgindex,
BitsPerPixel, Red, Green, Blue, get_pixel,
error))
return FALSE;
/* If the image has multiple layers it'll be made into an animated
* GIF, so write out the looping extension
*/
if (nlayers > 1)
{
/* If 'Forever' toggle was checked, override number_of_repeats */
if (config_loop)
config_number_of_repeats = 0;
if (config_loop || config_number_of_repeats > 0)
if (! gif_encode_loop_ext (output, config_number_of_repeats, error))
return FALSE;
}
/* Write comment extension - mustn't be written before the looping ext. */
if (config_save_comment && config_comment && strlen (config_comment))
{
if (! gif_encode_comment_ext (output, config_comment, error))
return FALSE;
}
/*** Now for each layer in the image, save an image in a compound GIF ***/
/************************************************************************/
cur_progress = 0;
max_progress = nlayers * rows;
layers = g_list_reverse (layers);
for (list = layers, i = nlayers - 1;
list && i >= 0;
list = g_list_next (list), i--, cur_progress = (nlayers - i) * rows)
{
GimpDrawable *drawable = list->data;
drawable_type = gimp_drawable_type (drawable);
if (drawable_type == GIMP_GRAYA_IMAGE)
{
format = babl_format ("Y'A u8");
}
else if (drawable_type == GIMP_GRAY_IMAGE)
{
format = babl_format ("Y' u8");
}
buffer = gimp_drawable_get_buffer (drawable);
gimp_drawable_get_offsets (drawable, &offset_x, &offset_y);
cols = gimp_drawable_get_width (drawable);
rows = gimp_drawable_get_height (drawable);
rowstride = cols;
pixels = g_new (guchar, (cols * rows *
(((drawable_type == GIMP_INDEXEDA_IMAGE) ||
(drawable_type == GIMP_GRAYA_IMAGE)) ? 2 : 1)));
gegl_buffer_get (buffer, GEGL_RECTANGLE (0, 0, cols, rows), 1.0,
format, pixels,
GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
/* sort out whether we need to do transparency jiggery-pokery */
if ((drawable_type == GIMP_INDEXEDA_IMAGE) ||
(drawable_type == GIMP_GRAYA_IMAGE))
{
/* Try to find an entry which isn't actually used in the
* image, for a transparency index.
*/
transparent =
find_unused_ia_color (pixels,
cols * rows,
bpp_to_colors (colors_to_bpp (colors)),
&colors);
special_flatten_indexed_alpha (pixels,
transparent,
cols * rows);
}
else
{
transparent = -1;
}
BitsPerPixel = colors_to_bpp (colors);
if (BitsPerPixel != liberalBPP)
{
/* We were able to re-use an index within the existing
* bitspace, whereas the estimate in the header was
* pessimistic but still needs to be upheld...
*/
#ifdef GIFDEBUG
static gboolean onceonly = FALSE;
if (! onceonly)
{
g_warning ("Promised %d bpp, pondered writing chunk with %d bpp!",
liberalBPP, BitsPerPixel);
onceonly = TRUE;
}
#endif
}
useBPP = (BitsPerPixel > liberalBPP) ? BitsPerPixel : liberalBPP;
if (is_gif89)
{
if (i > 0 && ! config_use_default_dispose)
{
layer_name = gimp_item_get_name (list->next->data);
Disposal = parse_disposal_tag (layer_name,
config_default_dispose);
g_free (layer_name);
}
else
{
Disposal = config_default_dispose;
}
layer_name = gimp_item_get_name (GIMP_ITEM (drawable));
Delay89 = parse_ms_tag (layer_name);
g_free (layer_name);
if (Delay89 < 0 || config_use_default_delay)
Delay89 = (config_default_delay + 5) / 10;
else
Delay89 = (Delay89 + 5) / 10;
/* don't allow a CPU-sucking completely 0-delay looping anim */
if ((nlayers > 1) && config_loop && (Delay89 == 0))
{
static gboolean onceonly = FALSE;
if (! onceonly)
{
g_message (_("Delay inserted to prevent evil "
"CPU-sucking animation."));
onceonly = TRUE;
}
Delay89 = 1;
}
if (! gif_encode_graphic_control_ext (output,
Disposal, Delay89, nlayers,
cols, rows,
transparent,
useBPP,
get_pixel,
error))
return FALSE;
}
if (! gif_encode_image_data (output, cols, rows,
(rows > 4) ? config_interlace : 0,
useBPP,
get_pixel,
offset_x, offset_y,
error))
return FALSE;
gimp_progress_update (1.0);
g_object_unref (buffer);
g_free (pixels);
}
g_list_free (layers);
if (! gif_encode_close (output, error))
return FALSE;
return TRUE;
}
static void
export_edit_options (GimpProcedure *procedure,
GimpProcedureConfig *config,
GimpExportOptions *options,
gpointer create_data)
{
GimpExportCapabilities capabilities;
gboolean as_animation;
g_object_get (G_OBJECT (config),
"as-animation", &as_animation,
NULL);
capabilities = (GIMP_EXPORT_CAN_HANDLE_INDEXED |
GIMP_EXPORT_CAN_HANDLE_GRAY |
GIMP_EXPORT_CAN_HANDLE_ALPHA);
if (as_animation)
capabilities |= GIMP_EXPORT_CAN_HANDLE_LAYERS;
g_object_set (G_OBJECT (options),
"capabilities", capabilities,
NULL);
}
static gboolean
bad_bounds_dialog (void)
{
GtkWidget *dialog;
gboolean crop;
dialog = gtk_message_dialog_new (NULL, 0,
GTK_MESSAGE_WARNING, GTK_BUTTONS_NONE,
_("The image you are trying to export as a "
"GIF contains layers which extend beyond "
"the actual borders of the image."));
gtk_dialog_add_buttons (GTK_DIALOG (dialog),
_("_Cancel"), GTK_RESPONSE_CANCEL,
_("Cr_op"), GTK_RESPONSE_OK,
NULL);
gimp_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
GTK_RESPONSE_OK,
GTK_RESPONSE_CANCEL,
-1);
gimp_window_set_transient (GTK_WINDOW (dialog));
gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog),
_("The GIF file format does not "
"allow this. You may choose "
"whether to crop all of the "
"layers to the image borders, "
"or cancel this export."));
gtk_widget_show (dialog);
crop = (gtk_dialog_run (GTK_DIALOG (dialog)) == GTK_RESPONSE_OK);
gtk_widget_destroy (dialog);
return crop;
}
static gboolean
save_dialog (GimpImage *image,
GimpImage *orig_image,
GimpProcedure *procedure,
GObject *config)
{
GtkWidget *dialog;
GtkWidget *vbox;
GtkWidget *text_view;
GtkTextBuffer *text_buffer;
GimpLayer **layers;
gint32 n_layers;
gboolean animation_supported;
gboolean run;
layers = gimp_image_get_layers (image);
n_layers = gimp_core_object_array_get_length ((GObject **) layers);
g_free (layers);
animation_supported = n_layers > 1;
dialog = gimp_export_procedure_dialog_new (GIMP_EXPORT_PROCEDURE (procedure),
GIMP_PROCEDURE_CONFIG (config),
image);
/* Warn user that image will be converted to 8 bits if not already */
if (gimp_image_get_precision (orig_image) != GIMP_PRECISION_U8_NON_LINEAR &&
gimp_image_get_precision (orig_image) != GIMP_PRECISION_U8_LINEAR &&
gimp_image_get_precision (orig_image) != GIMP_PRECISION_U8_PERCEPTUAL)
{
GtkWidget *hint;
/* Used to create vbox to store hintbox in */
gimp_procedure_dialog_get_label (GIMP_PROCEDURE_DIALOG (dialog),
"spacer-8-bit", " ",
FALSE, FALSE);
vbox = gimp_procedure_dialog_fill_box (GIMP_PROCEDURE_DIALOG (dialog),
"8-bit-warning-vbox", "spacer-8-bit",
NULL);
hint = g_object_new (GIMP_TYPE_HINT_BOX,
"icon-name", GIMP_ICON_DIALOG_WARNING,
"hint", _("The GIF format only supports 8 bit "
"integer precision.\n"
"Your image will be converted on "
"export, which may change the pixel "
"values."),
NULL);
gtk_widget_set_visible (hint, TRUE);
gtk_box_pack_start (GTK_BOX (vbox), hint, FALSE, FALSE, 0);
gtk_box_reorder_child (GTK_BOX (vbox), hint, 0);
gimp_procedure_dialog_fill (GIMP_PROCEDURE_DIALOG (dialog),
"8-bit-warning-vbox", NULL);
}
#define MAX_COMMENT 240
text_view = gimp_procedure_dialog_get_widget (GIMP_PROCEDURE_DIALOG (dialog),
"gimp-comment",
GTK_TYPE_TEXT_VIEW);
text_buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));
g_object_set_data (G_OBJECT (text_buffer), "max-len",
GINT_TO_POINTER (MAX_COMMENT));
gimp_procedure_dialog_fill_scrolled_window (GIMP_PROCEDURE_DIALOG (dialog),
"comment-scrolled",
"gimp-comment");
gimp_procedure_dialog_fill_frame (GIMP_PROCEDURE_DIALOG (dialog),
"comment-frame", "save-comment", FALSE,
"comment-scrolled");
gimp_procedure_dialog_fill (GIMP_PROCEDURE_DIALOG (dialog),
"interlace", "comment-frame", NULL);
if (animation_supported)
{
GtkWidget *grid;
GtkWidget *widget;
grid = gtk_grid_new ();
gtk_grid_set_column_spacing (GTK_GRID (grid), 1);
gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
gtk_widget_show (grid);
widget = gimp_procedure_dialog_get_widget (GIMP_PROCEDURE_DIALOG (dialog),
"number-of-repeats",
GIMP_TYPE_LABEL_SPIN);
gtk_grid_attach (GTK_GRID (grid), widget, 0, 0, 1, 1);
gtk_widget_set_visible (widget, TRUE);
widget = gimp_procedure_dialog_get_widget (GIMP_PROCEDURE_DIALOG (dialog),
"loop", GTK_TYPE_CHECK_BUTTON);
gtk_grid_attach (GTK_GRID (grid), widget, 1, 0, 1, 1);
gimp_procedure_dialog_set_sensitive (GIMP_PROCEDURE_DIALOG (dialog),
"number-of-repeats", TRUE,
config, "loop",
TRUE);
widget = gimp_procedure_dialog_get_widget (GIMP_PROCEDURE_DIALOG (dialog),
"default-delay",
GIMP_TYPE_LABEL_SPIN);
gtk_grid_attach (GTK_GRID (grid), widget, 0, 1, 1, 1);
gtk_widget_set_visible (widget, TRUE);
widget = gimp_procedure_dialog_get_label (GIMP_PROCEDURE_DIALOG (dialog),
"milliseconds",
_("milliseconds"),
FALSE, FALSE);
gtk_label_set_xalign (GTK_LABEL (widget), 0.1);
gtk_grid_attach (GTK_GRID (grid), widget, 1, 1, 1, 1);
gtk_widget_set_visible (widget, TRUE);
widget = gimp_procedure_dialog_get_widget (GIMP_PROCEDURE_DIALOG (dialog),
"default-dispose",
G_TYPE_NONE);
gtk_grid_attach (GTK_GRID (grid), widget, 0, 2, 2, 1);
gtk_widget_set_visible (widget, TRUE);
vbox = gimp_procedure_dialog_fill_box (GIMP_PROCEDURE_DIALOG (dialog),
"animation-vbox", "force-delay",
"force-dispose", NULL);
gtk_box_pack_start (GTK_BOX (vbox), grid, FALSE, FALSE, 0);
gtk_box_reorder_child (GTK_BOX (vbox), grid, 0);
gimp_procedure_dialog_fill_frame (GIMP_PROCEDURE_DIALOG (dialog),
"ani-frame", "as-animation", FALSE,
"animation-vbox");
gimp_procedure_dialog_fill (GIMP_PROCEDURE_DIALOG (dialog),
"ani-frame", NULL);
}
else
{
GtkWidget *hint;
/* Used to create vbox to store hintbox in */
gimp_procedure_dialog_get_label (GIMP_PROCEDURE_DIALOG (dialog),
"spacer", " ",
FALSE, FALSE);
gimp_procedure_dialog_get_label (GIMP_PROCEDURE_DIALOG (dialog),
"no-ani-title", _("Animated GIF"),
FALSE, FALSE);
vbox = gimp_procedure_dialog_fill_box (GIMP_PROCEDURE_DIALOG (dialog),
"no-animation-vbox", "spacer",
NULL);
hint = gimp_hint_box_new (_("You can only export as animation when the "
"image has more than one layer.\n"
"The image you are trying to export only "
"has one layer."));
gtk_box_pack_start (GTK_BOX (vbox), hint, FALSE, FALSE, 0);
gtk_widget_set_margin_bottom (vbox, 12);
gtk_widget_show (hint);
gtk_box_reorder_child (GTK_BOX (vbox), hint, 0);
gimp_procedure_dialog_fill_frame (GIMP_PROCEDURE_DIALOG (dialog),
"no-ani-frame", "no-ani-title", FALSE,
"no-animation-vbox");
gimp_procedure_dialog_fill (GIMP_PROCEDURE_DIALOG (dialog),
"no-ani-frame", NULL);
}
gtk_widget_show (dialog);
run = gimp_procedure_dialog_run (GIMP_PROCEDURE_DIALOG (dialog));
gtk_widget_destroy (dialog);
return run;
}
static int
colors_to_bpp (gint colors)
{
gint bpp;
if (colors <= 2)
bpp = 1;
else if (colors <= 4)
bpp = 2;
else if (colors <= 8)
bpp = 3;
else if (colors <= 16)
bpp = 4;
else if (colors <= 32)
bpp = 5;
else if (colors <= 64)
bpp = 6;
else if (colors <= 128)
bpp = 7;
else if (colors <= 256)
bpp = 8;
else
{
g_warning ("GIF: colors_to_bpp - Eep! too many colors: %d\n", colors);
return 8;
}
return bpp;
}
static int
bpp_to_colors (gint bpp)
{
gint colors;
if (bpp > 8)
{
g_warning ("GIF: bpp_to_colors - Eep! bpp==%d !\n", bpp);
return 256;
}
colors = 1 << bpp;
return colors;
}
static gint
get_pixel (gint x,
gint y)
{
return *(pixels + (rowstride * (long) y) + (long) x);
}
/*****************************************************************************
*
* GIFENCODE.C - GIF Image compression interface
*
* GIFEncode( FName, GHeight, GWidth, GInterlace, Background, Transparent,
* BitsPerPixel, Red, Green, Blue, get_pixel )
*
*****************************************************************************/
static gint Width, Height;
static gint curx, cury;
static glong CountDown;
static gint Pass = 0;
/*
* Bump the 'curx' and 'cury' to point to the next pixel
*/
static void
bump_pixel (void)
{
/*
* Bump the current X position
*/
curx++;
/*
* If we are at the end of a scan line, set curx back to the beginning
* If we are interlaced, bump the cury to the appropriate spot,
* otherwise, just increment it.
*/
if (curx == Width)
{
cur_progress++;
if ((cur_progress % 20) == 0)
gimp_progress_update ((gdouble) cur_progress / (gdouble) max_progress);
curx = 0;
if (! Interlace)
++cury;
else
{
switch (Pass)
{
case 0:
cury += 8;
if (cury >= Height)
{
Pass++;
cury = 4;
}
break;
case 1:
cury += 8;
if (cury >= Height)
{
Pass++;
cury = 2;
}
break;
case 2:
cury += 4;
if (cury >= Height)
{
Pass++;
cury = 1;
}
break;
case 3:
cury += 2;
break;
}
}
}
}
/*
* Return the next pixel from the image
*/
static gint
gif_next_pixel (ifunptr getpixel)
{
gint r;
if (CountDown == 0)
return EOF;
--CountDown;
r = (*getpixel) (curx, cury);
bump_pixel ();
return r;
}
/* public */
static gboolean
gif_encode_header (GOutputStream *output,
gboolean gif89,
gint GWidth,
gint GHeight,
gint Background,
gint BitsPerPixel,
gint Red[],
gint Green[],
gint Blue[],
ifunptr get_pixel,
GError **error)
{
gint B;
gint RWidth, RHeight;
gint Resolution;
gint ColorMapSize;
gint i;
ColorMapSize = 1 << BitsPerPixel;
RWidth = Width = GWidth;
RHeight = Height = GHeight;
Resolution = BitsPerPixel;
/*
* Calculate number of bits we are expecting
*/
CountDown = (long) Width *(long) Height;
/*
* Indicate which pass we are on (if interlace)
*/
Pass = 0;
/*
* Set up the current x and y position
*/
curx = cury = 0;
/*
* Write the Magic header
*/
if (! put_string (output, gif89 ? "GIF89a" : "GIF87a", error))
return FALSE;
/*
* Write out the screen width and height
*/
if (! put_word (output, RWidth, error) ||
! put_word (output, RHeight, error))
return FALSE;
/*
* Indicate that there is a global color map
*/
B = 0x80; /* Yes, there is a color map */
/*
* OR in the resolution
*/
B |= (Resolution - 1) << 5;
/*
* OR in the Bits per Pixel
*/
B |= (BitsPerPixel - 1);
/*
* Write it out
*/
if (! put_byte (output, B, error))
return FALSE;
/*
* Write out the Background color
*/
if (! put_byte (output, Background, error))
return FALSE;
/*
* Byte of 0's (future expansion)
*/
if (! put_byte (output, 0, error))
return FALSE;
/*
* Write out the Global Color Map
*/
for (i = 0; i < ColorMapSize; i++)
{
if (! put_byte (output, Red[i], error) ||
! put_byte (output, Green[i], error) ||
! put_byte (output, Blue[i], error))
return FALSE;
}
return TRUE;
}
static gboolean
gif_encode_graphic_control_ext (GOutputStream *output,
int Disposal,
int Delay89,
int NumFramesInImage,
int GWidth,
int GHeight,
int Transparent,
int BitsPerPixel,
ifunptr get_pixel,
GError **error)
{
Width = GWidth;
Height = GHeight;
/*
* Calculate number of bits we are expecting
*/
CountDown = (long) Width *(long) Height;
/*
* Indicate which pass we are on (if interlace)
*/
Pass = 0;
/*
* Set up the current x and y position
*/
curx = cury = 0;
/*
* Write out extension for transparent color index, if necessary.
*/
if ( (Transparent >= 0) || (NumFramesInImage > 1) )
{
/* Extension Introducer - fixed. */
if (! put_byte (output, '!', error))
return FALSE;
/* Graphic Control Label - fixed. */
if (! put_byte (output, 0xf9, error))
return FALSE;
/* Block Size - fixed. */
if (! put_byte (output, 4, error))
return FALSE;
/* Packed Fields - XXXdddut (d=disposal, u=userInput, t=transFlag) */
/* s8421 */
if (! put_byte (output,
((Transparent >= 0) ? 0x01 : 0x00) /* TRANSPARENCY */
/* DISPOSAL */
| ((NumFramesInImage > 1) ? (Disposal << 2) : 0x00 ),
/* 0x03 or 0x01 build frames cumulatively */
/* 0x02 clears frame before drawing */
/* 0x00 'don't care' */
error))
return FALSE;
if (! put_word (output, Delay89, error))
return FALSE;
if (! put_byte (output, Transparent, error) ||
! put_byte (output, 0, error))
return FALSE;
}
return TRUE;
}
static gboolean
gif_encode_image_data (GOutputStream *output,
int GWidth,
int GHeight,
int GInterlace,
int BitsPerPixel,
ifunptr get_pixel,
gint offset_x,
gint offset_y,
GError **error)
{
gint LeftOfs, TopOfs;
gint InitCodeSize;
Interlace = GInterlace;
Width = GWidth;
Height = GHeight;
LeftOfs = (gint) offset_x;
TopOfs = (gint) offset_y;
/*
* Calculate number of bits we are expecting
*/
CountDown = (long) Width * (long) Height;
/*
* Indicate which pass we are on (if interlace)
*/
Pass = 0;
/*
* The initial code size
*/
if (BitsPerPixel <= 1)
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
/*
* Set up the current x and y position
*/
curx = cury = 0;
/*
* Write an Image separator
*/
if (! put_byte (output, ',', error))
return FALSE;
/*
* Write the Image header
*/
if (! put_word (output, LeftOfs, error) ||
! put_word (output, TopOfs, error) ||
! put_word (output, Width, error) ||
! put_word (output, Height, error))
return FALSE;
/*
* Write out whether or not the image is interlaced
*/
if (Interlace)
{
if (! put_byte (output, 0x40, error))
return FALSE;
}
else
{
if (! put_byte (output, 0x00, error))
return FALSE;
}
/*
* Write out the initial code size
*/
if (! put_byte (output, InitCodeSize, error))
return FALSE;
/*
* Go and actually compress the data
*/
if (! compress (output, InitCodeSize + 1, get_pixel, error))
return FALSE;
/*
* Write out a Zero-length packet (to end the series)
*/
if (! put_byte (output, 0, error))
return FALSE;
#if 0
/***************************/
Interlace = GInterlace;
Width = GWidth;
Height = GHeight;
LeftOfs = TopOfs = 0;
CountDown = (long) Width *(long) Height;
Pass = 0;
/*
* The initial code size
*/
if (BitsPerPixel <= 1)
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
/*
* Set up the current x and y position
*/
curx = cury = 0;
#endif
return TRUE;
}
static gboolean
gif_encode_close (GOutputStream *output,
GError **error)
{
/*
* Write the GIF file terminator
*/
if (! put_byte (output, ';', error))
return FALSE;
/*
* And close the file
*/
return g_output_stream_close (output, NULL, error);
}
static gboolean
gif_encode_loop_ext (GOutputStream *output,
guint num_loops,
GError **error)
{
return (put_byte (output, 0x21, error) &&
put_byte (output, 0xff, error) &&
put_byte (output, 0x0b, error) &&
put_string (output, "NETSCAPE2.0", error) &&
put_byte (output, 0x03, error) &&
put_byte (output, 0x01, error) &&
put_word (output, num_loops, error) &&
put_byte (output, 0x00, error));
/* NOTE: num_loops == 0 means 'loop infinitely' */
}
static gboolean
gif_encode_comment_ext (GOutputStream *output,
const gchar *comment,
GError **error)
{
if (!comment || !*comment)
return TRUE;
if (strlen (comment) > 240)
{
g_printerr ("GIF: warning:"
"comment too large - comment block not written.\n");
return TRUE;
}
return (put_byte (output, 0x21, error) &&
put_byte (output, 0xfe, error) &&
put_byte (output, strlen (comment), error) &&
put_string (output, comment, error) &&
put_byte (output, 0x00, error));
}
/*
* Write stuff to the GIF file
*/
static gboolean
put_byte (GOutputStream *output,
guchar b,
GError **error)
{
return g_data_output_stream_put_byte (G_DATA_OUTPUT_STREAM (output),
b, NULL, error);
}
static gboolean
put_word (GOutputStream *output,
gint w,
GError **error)
{
return g_data_output_stream_put_int16 (G_DATA_OUTPUT_STREAM (output),
w, NULL, error);
}
static gboolean
put_string (GOutputStream *output,
const gchar *s,
GError **error)
{
return g_data_output_stream_put_string (G_DATA_OUTPUT_STREAM (output),
s, NULL, error);
}
/***************************************************************************
*
* GIFCOMPR.C - GIF Image compression routines
*
* Lempel-Ziv compression based on 'compress'. GIF modifications by
* David Rowley (mgardi@watdcsu.waterloo.edu)
*
***************************************************************************/
/*
* General DEFINEs
*/
#define GIF_BITS 12
#define HSIZE 5003 /* 80% occupancy */
/*
* GIF Image compression - modified 'compress'
*
* Based on: compress.c - File compression ala IEEE Computer, June 1984.
*
* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
* Jim McKie (decvax!mcvax!jim)
* Steve Davies (decvax!vax135!petsd!peora!srd)
* Ken Turkowski (decvax!decwrl!turtlevax!ken)
* James A. Woods (decvax!ihnp4!ames!jaw)
* Joe Orost (decvax!vax135!petsd!joe)
*
*/
static gint n_bits; /* number of bits/code */
static gint maxbits = GIF_BITS; /* user settable max # bits/code */
static gint maxcode; /* maximum code, given n_bits */
static gint maxmaxcode = (gint) 1 << GIF_BITS; /* should NEVER generate this code */
#ifdef COMPATIBLE /* But wrong! */
#define MAXCODE(Mn_bits) ((gint) 1 << (Mn_bits) - 1)
#else /*COMPATIBLE */
#define MAXCODE(Mn_bits) (((gint) 1 << (Mn_bits)) - 1)
#endif /*COMPATIBLE */
static glong htab[HSIZE];
static gushort codetab[HSIZE];
#define HashTabOf(i) htab[i]
#define CodeTabOf(i) codetab[i]
static const gint hsize = HSIZE; /* the original reason for this being
variable was "for dynamic table sizing",
but since it was never actually changed
I made it const --Adam. */
static gint free_ent = 0; /* first unused entry */
/*
* block compression parameters -- after all codes are used up,
* and compression rate changes, start over.
*/
static gint clear_flg = 0;
static gint offset;
static glong in_count = 1; /* length of input */
static glong out_count = 0; /* # of codes output (for debugging) */
/*
* compress stdin to stdout
*
* Algorithm: use open addressing double hashing (no chaining) on the
* prefix code / next character combination. We do a variant of Knuth's
* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
* secondary probe. Here, the modular division first probe is gives way
* to a faster exclusive-or manipulation. Also do block compression with
* an adaptive reset, whereby the code table is cleared when the compression
* ratio decreases, but after the table fills. The variable-length output
* codes are re-sized at this point, and a special CLEAR code is generated
* for the decompressor. Late addition: construct the table according to
* file size for noticeable speed improvement on small files. Please direct
* questions about this implementation to ames!jaw.
*/
static gint g_init_bits;
static gint ClearCode;
static gint EOFCode;
static gulong cur_accum;
static gint cur_bits;
static gulong masks[] =
{
0x0000, 0x0001, 0x0003, 0x0007,
0x000F, 0x001F, 0x003F, 0x007F,
0x00FF, 0x01FF, 0x03FF, 0x07FF,
0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF,
0xFFFF
};
static gboolean
compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error)
{
if (FALSE)
return no_compress (output, init_bits, ReadValue, error);
else if (FALSE)
return rle_compress (output, init_bits, ReadValue, error);
else
return normal_compress (output, init_bits, ReadValue, error);
}
static gboolean
no_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error)
{
glong fcode;
gint i /* = 0 */ ;
gint c;
gint ent;
gint hsize_reg;
gint hshift;
/*
* Set up the globals: g_init_bits - initial number of bits
*/
g_init_bits = init_bits;
cur_bits = 0;
cur_accum = 0;
/*
* Set up the necessary values
*/
offset = 0;
out_count = 0;
clear_flg = 0;
in_count = 1;
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
/* Had some problems here... should be okay now. --Adam */
n_bits = g_init_bits;
maxcode = MAXCODE (n_bits);
char_init();
ent = gif_next_pixel (ReadValue);
hshift = 0;
for (fcode = (long) hsize; fcode < 65536L; fcode *= 2L)
++hshift;
hshift = 8 - hshift; /* set hash code range bound */
hsize_reg = hsize;
cl_hash ((glong) hsize_reg); /* clear hash table */
if (! output_code (output, (gint) ClearCode, error))
return FALSE;
while ((c = gif_next_pixel (ReadValue)) != EOF)
{
++in_count;
fcode = (long) (((long) c << maxbits) + ent);
i = (((gint) c << hshift) ^ ent); /* xor hashing */
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
ent = c;
if (free_ent < maxmaxcode)
{
CodeTabOf (i) = free_ent++; /* code -> hashtable */
HashTabOf (i) = fcode;
}
else
{
if (! cl_block (output, error))
return FALSE;
}
}
/*
* Put out the final code.
*/
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
if (! output_code (output, (gint) EOFCode, error))
return FALSE;
return TRUE;
}
static gboolean
rle_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error)
{
glong fcode;
gint i /* = 0 */ ;
gint c, last;
gint ent;
gint disp;
gint hsize_reg;
gint hshift;
/*
* Set up the globals: g_init_bits - initial number of bits
*/
g_init_bits = init_bits;
cur_bits = 0;
cur_accum = 0;
/*
* Set up the necessary values
*/
offset = 0;
out_count = 0;
clear_flg = 0;
in_count = 1;
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
/* Had some problems here... should be okay now. --Adam */
n_bits = g_init_bits;
maxcode = MAXCODE (n_bits);
char_init ();
last = ent = gif_next_pixel (ReadValue);
hshift = 0;
for (fcode = (long) hsize; fcode < 65536L; fcode *= 2L)
++hshift;
hshift = 8 - hshift; /* set hash code range bound */
hsize_reg = hsize;
cl_hash ((glong) hsize_reg); /* clear hash table */
if (! output_code (output, (gint) ClearCode, error))
return FALSE;
while ((c = gif_next_pixel (ReadValue)) != EOF)
{
++in_count;
fcode = (long) (((long) c << maxbits) + ent);
i = (((gint) c << hshift) ^ ent); /* xor hashing */
if (last == c) {
if (HashTabOf (i) == fcode)
{
ent = CodeTabOf (i);
continue;
}
else if ((long) HashTabOf (i) < 0) /* empty slot */
goto nomatch;
disp = hsize_reg - i; /* secondary hash (after G. Knott) */
if (i == 0)
disp = 1;
probe:
if ((i -= disp) < 0)
i += hsize_reg;
if (HashTabOf (i) == fcode)
{
ent = CodeTabOf (i);
continue;
}
if ((long) HashTabOf (i) > 0)
goto probe;
}
nomatch:
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
last = ent = c;
if (free_ent < maxmaxcode)
{
CodeTabOf (i) = free_ent++; /* code -> hashtable */
HashTabOf (i) = fcode;
}
else
{
if (! cl_block (output, error))
return FALSE;
}
}
/*
* Put out the final code.
*/
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
if (! output_code (output, (gint) EOFCode, error))
return FALSE;
return TRUE;
}
static gboolean
normal_compress (GOutputStream *output,
gint init_bits,
ifunptr ReadValue,
GError **error)
{
glong fcode;
gint i /* = 0 */ ;
gint c;
gint ent;
gint disp;
gint hsize_reg;
gint hshift;
/*
* Set up the globals: g_init_bits - initial number of bits
*/
g_init_bits = init_bits;
cur_bits = 0;
cur_accum = 0;
/*
* Set up the necessary values
*/
offset = 0;
out_count = 0;
clear_flg = 0;
in_count = 1;
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
/* Had some problems here... should be okay now. --Adam */
n_bits = g_init_bits;
maxcode = MAXCODE (n_bits);
char_init();
ent = gif_next_pixel (ReadValue);
hshift = 0;
for (fcode = (long) hsize; fcode < 65536L; fcode *= 2L)
++hshift;
hshift = 8 - hshift; /* set hash code range bound */
hsize_reg = hsize;
cl_hash ((glong) hsize_reg); /* clear hash table */
if (! output_code (output, (gint) ClearCode, error))
return FALSE;
while ((c = gif_next_pixel (ReadValue)) != EOF)
{
++in_count;
fcode = (long) (((long) c << maxbits) + ent);
i = (((gint) c << hshift) ^ ent); /* xor hashing */
if (HashTabOf (i) == fcode)
{
ent = CodeTabOf (i);
continue;
}
else if ((long) HashTabOf (i) < 0) /* empty slot */
goto nomatch;
disp = hsize_reg - i; /* secondary hash (after G. Knott) */
if (i == 0)
disp = 1;
probe:
if ((i -= disp) < 0)
i += hsize_reg;
if (HashTabOf (i) == fcode)
{
ent = CodeTabOf (i);
continue;
}
if ((long) HashTabOf (i) > 0)
goto probe;
nomatch:
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
ent = c;
if (free_ent < maxmaxcode)
{
CodeTabOf (i) = free_ent++; /* code -> hashtable */
HashTabOf (i) = fcode;
}
else
{
if (! cl_block (output, error))
return FALSE;
}
}
/*
* Put out the final code.
*/
if (! output_code (output, (gint) ent, error))
return FALSE;
++out_count;
if (! output_code (output, (gint) EOFCode, error))
return FALSE;
return TRUE;
}
/*****************************************************************
* TAG( output )
*
* Output the given code.
* Inputs:
* code: A n_bits-bit integer. If == -1, then EOF. This assumes
* that n_bits =< (long)wordsize - 1.
* Outputs:
* Outputs code to the file.
* Assumptions:
* Chars are 8 bits long.
* Algorithm:
* Maintain a GIF_BITS character long buffer (so that 8 codes will
* fit in it exactly). Use the VAX insv instruction to insert each
* code in turn. When the buffer fills up empty it and start over.
*/
static gboolean
output_code (GOutputStream *output,
gint code,
GError **error)
{
cur_accum &= masks[cur_bits];
if (cur_bits > 0)
cur_accum |= ((long) code << cur_bits);
else
cur_accum = code;
cur_bits += n_bits;
while (cur_bits >= 8)
{
if (! char_out (output, (guchar) (cur_accum & 0xff), error))
return FALSE;
cur_accum >>= 8;
cur_bits -= 8;
}
/*
* If the next entry is going to be too big for the code size,
* then increase it, if possible.
*/
if (free_ent > maxcode || clear_flg)
{
if (clear_flg)
{
maxcode = MAXCODE (n_bits = g_init_bits);
clear_flg = 0;
}
else
{
++n_bits;
if (n_bits == maxbits)
maxcode = maxmaxcode;
else
maxcode = MAXCODE (n_bits);
}
}
if (code == EOFCode)
{
/*
* At EOF, write the rest of the buffer.
*/
while (cur_bits > 0)
{
if (! char_out (output, (guchar) (cur_accum & 0xff), error))
return FALSE;
cur_accum >>= 8;
cur_bits -= 8;
}
if (! char_flush (output, error))
return FALSE;
}
return TRUE;
}
/*
* Clear out the hash table
*/
static gboolean
cl_block (GOutputStream *output,
GError **error) /* table clear for block compress */
{
cl_hash ((glong) hsize);
free_ent = ClearCode + 2;
clear_flg = 1;
return output_code (output, (gint) ClearCode, error);
}
static void
cl_hash (glong hsize) /* reset code table */
{
glong *htab_p = htab + hsize;
long i;
long m1 = -1;
i = hsize - 16;
do
{ /* might use Sys V memset(3) here */
*(htab_p - 16) = m1;
*(htab_p - 15) = m1;
*(htab_p - 14) = m1;
*(htab_p - 13) = m1;
*(htab_p - 12) = m1;
*(htab_p - 11) = m1;
*(htab_p - 10) = m1;
*(htab_p - 9) = m1;
*(htab_p - 8) = m1;
*(htab_p - 7) = m1;
*(htab_p - 6) = m1;
*(htab_p - 5) = m1;
*(htab_p - 4) = m1;
*(htab_p - 3) = m1;
*(htab_p - 2) = m1;
*(htab_p - 1) = m1;
htab_p -= 16;
}
while ((i -= 16) >= 0);
for (i += 16; i > 0; --i)
*--htab_p = m1;
}
/******************************************************************************
* GIF Specific routines
******************************************************************************/
/*
* Number of characters so far in this 'packet'
*/
static int a_count;
/*
* Set up the 'byte output' routine
*/
static void
char_init (void)
{
a_count = 0;
}
/*
* Define the storage for the packet accumulator
*/
static char accum[256];
/*
* Add a character to the end of the current packet, and if it is 254
* characters, flush the packet to disk.
*/
static gboolean
char_out (GOutputStream *output,
gint c,
GError **error)
{
accum[a_count++] = c;
if (a_count >= 254)
return char_flush (output, error);
return TRUE;
}
/*
* Flush the packet to disk, and reset the accumulator
*/
static gboolean
char_flush (GOutputStream *output,
GError **error)
{
if (a_count > 0)
{
if (! put_byte (output, a_count, error))
return FALSE;
if (! g_output_stream_write_all (output, accum, a_count,
NULL, NULL, error))
return FALSE;
a_count = 0;
}
return TRUE;
}
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