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libvips/libvips/foreign/gifload.c

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/* load a GIF with giflib
*
* 10/2/16
* - from svgload.c
* 25/4/16
* - add giflib5 support
* 26/7/16
* - transparency was wrong if there was no EXTENSION_RECORD
* - write 1, 2, 3, or 4 bands depending on file contents
* 17/8/16
* - support unicode on win
* 19/8/16
* - better transparency detection, thanks diegocsandrim
* 25/11/16
* - support @n, page-height
* 5/10/17
* - colormap can be missing thanks Kleis
* 21/11/17
* - add "gif-delay", "gif-loop", "gif-comment" metadata
* - add dispose handling
* 13/8/18
* - init pages to 0 before load
* 14/2/19
* - rework as a sequential loader ... simpler, much lower mem use
* 6/7/19 [deftomat]
* - support array of delays
* 24/7/19
* - close early on minimise
* - close early on error
* 23/8/18
* - allow GIF read errors during header scan
* - better feof() handling
* 27/8/19
* - check image and frame bounds, since giflib does not
* 1/9/19
* - improve early close again
* 30/1/19
* - rework on top of VipsSource
* - add gifload_source
* 5/2/20 alon-ne
* - fix DISPOSE_BACKGROUND and DISPOSE_PREVIOUS
* 2/7/20
* - clip out of bounds images against canvas
* - fix PREVIOUS handling, again
* 19/2/21 781545872
* - read out background, if we can
*/
/*
This file is part of VIPS.
VIPS 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 program 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 program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG_VERBOSE
#define VIPS_DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <vips/vips.h>
#include <vips/buf.h>
#include <vips/internal.h>
#include <vips/debug.h>
#ifdef HAVE_GIFLIB
#include <gif_lib.h>
/* giflib 5 is rather different :-( functions have error returns and there's
* no LastError().
*
* GIFLIB_MAJOR was introduced in 4.1.6. Use it to test for giflib 5.x.
*/
#ifdef GIFLIB_MAJOR
# if GIFLIB_MAJOR > 4
# define HAVE_GIFLIB_5
# endif
#endif
/* Added in giflib5.
*/
#ifndef HAVE_GIFLIB_5
#define DISPOSAL_UNSPECIFIED 0
#define DISPOSE_DO_NOT 1
#define DISPOSE_BACKGROUND 2
#define DISPOSE_PREVIOUS 3
#endif
#define NO_TRANSPARENT_INDEX -1
#define TRANSPARENT_MASK 0x01
#define DISPOSE_MASK 0x07
#define DISPOSE_SHIFT 2
#define VIPS_TYPE_FOREIGN_LOAD_GIF (vips_foreign_load_gif_get_type())
#define VIPS_FOREIGN_LOAD_GIF( obj ) \
(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
VIPS_TYPE_FOREIGN_LOAD_GIF, VipsForeignLoadGif ))
#define VIPS_FOREIGN_LOAD_GIF_CLASS( klass ) \
(G_TYPE_CHECK_CLASS_CAST( (klass), \
VIPS_TYPE_FOREIGN_LOAD_GIF, VipsForeignLoadGifClass))
#define VIPS_FOREIGN_LOAD_GIF_GET_CLASS( obj ) \
(G_TYPE_INSTANCE_GET_CLASS( (obj), \
VIPS_TYPE_FOREIGN_LOAD_GIF, VipsForeignLoadGifClass ))
typedef struct _VipsForeignLoadGif {
VipsForeignLoad parent_object;
/* Load from this page (frame number).
*/
int page;
/* Load this many pages.
*/
int n;
/* Load from this source (set by subclasses).
*/
VipsSource *source;
GifFileType *file;
/* We decompress the whole thing to a huge RGBA memory image, and
* as we render, watch for bands and transparency. At the end of
* loading, we copy 1 or 3 bands, with or without transparency to
* output.
*/
gboolean has_transparency;
gboolean has_colour;
/* Delays between frames (in milliseconds).
*/
int *delays;
int delays_length;
/* Number of times to loop the animation.
*/
int loop;
/* The GIF comment, if any.
*/
char *comment;
/* The number of pages (frame) in the image.
*/
int n_pages;
/* A memory image the size of one frame ... we accumulate to this as
* we scan the image, and copy lines to the output on generate.
*/
VipsImage *frame;
/* A scratch buffer the size of the largest Image inside the GIF. We
* decompress lines from the GIF to this.
*/
VipsImage *scratch;
/* A copy of the previous frame, in case we need a DISPOSE_PREVIOUS.
*/
VipsImage *previous;
/* The position of @frame, in pages.
*/
int current_page;
/* Decompress lines of the gif file to here. This is large enough to
* hold one line of the widest sub-image in the GIF.
*/
int max_image_width;
GifPixelType *line;
/* The current dispose method.
*/
int dispose;
/* Set for EOF detected.
*/
gboolean eof;
/* The current cmap unpacked to a simple LUT. Each uint32 is really an
* RGBA pixel ready to be blasted into @frame.
*/
guint32 cmap[256];
/* As we scan the file, the index of the transparent pixel for this
* frame.
*/
int transparent_index;
} VipsForeignLoadGif;
typedef VipsForeignLoadClass VipsForeignLoadGifClass;
G_DEFINE_ABSTRACT_TYPE( VipsForeignLoadGif, vips_foreign_load_gif,
VIPS_TYPE_FOREIGN_LOAD );
/* From gif2rgb.c ... offsets and jumps for interlaced GIF images.
*/
static int
InterlacedOffset[] = { 0, 4, 2, 1 },
InterlacedJumps[] = { 8, 8, 4, 2 };
/* giflib4 was missing this.
*/
static const char *
vips_foreign_load_gif_errstr( int error_code )
{
#ifdef HAVE_GIFLIB_5
return( GifErrorString( error_code ) );
#else /*!HAVE_GIFLIB_5*/
switch( error_code ) {
case D_GIF_ERR_OPEN_FAILED:
return( _( "Failed to open given file" ) );
case D_GIF_ERR_READ_FAILED:
return( _( "Failed to read from given file" ) );
case D_GIF_ERR_NOT_GIF_FILE:
return( _( "Data is not a GIF file" ) );
case D_GIF_ERR_NO_SCRN_DSCR:
return( _( "No screen descriptor detected" ) );
case D_GIF_ERR_NO_IMAG_DSCR:
return( _( "No image descriptor detected" ) );
case D_GIF_ERR_NO_COLOR_MAP:
return( _( "Neither global nor local color map" ) );
case D_GIF_ERR_WRONG_RECORD:
return( _( "Wrong record type detected" ) );
case D_GIF_ERR_DATA_TOO_BIG:
return( _( "Number of pixels bigger than width * height" ) );
case D_GIF_ERR_NOT_ENOUGH_MEM:
return( _( "Failed to allocate required memory" ) );
case D_GIF_ERR_CLOSE_FAILED:
return( _( "Failed to close given file" ) );
case D_GIF_ERR_NOT_READABLE:
return( _( "Given file was not opened for read" ) );
case D_GIF_ERR_IMAGE_DEFECT:
return( _( "Image is defective, decoding aborted" ) );
case D_GIF_ERR_EOF_TOO_SOON:
return( _( "Image EOF detected, before image complete" ) );
default:
return( _( "Unknown error" ) );
}
#endif /*HAVE_GIFLIB_5*/
}
static void
vips_foreign_load_gif_error_vips( VipsForeignLoadGif *gif, int error )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
const char *message;
if( (message = vips_foreign_load_gif_errstr( error )) )
vips_error( class->nickname, "%s", message );
}
static void
vips_foreign_load_gif_error( VipsForeignLoadGif *gif )
{
int error;
error = 0;
#ifdef HAVE_GIFLIB_5
if( gif->file )
error = gif->file->Error;
#else
error = GifLastError();
#endif
if( error )
vips_foreign_load_gif_error_vips( gif, error );
}
/* Shut down giflib plus any underlying file resource.
*/
static int
vips_foreign_load_gif_close_giflib( VipsForeignLoadGif *gif )
{
VIPS_DEBUG_MSG( "vips_foreign_load_gif_close_giflib:\n" );
#ifdef HAVE_GIFLIB_5
if( gif->file ) {
int error;
if( DGifCloseFile( gif->file, &error ) == GIF_ERROR ) {
vips_foreign_load_gif_error_vips( gif, error );
gif->file = NULL;
return( -1 );
}
gif->file = NULL;
}
#else
if( gif->file ) {
if( DGifCloseFile( gif->file ) == GIF_ERROR ) {
vips_foreign_load_gif_error_vips( gif, GifLastError() );
gif->file = NULL;
return( -1 );
}
gif->file = NULL;
}
#endif
if( gif->source )
vips_source_minimise( gif->source );
return( 0 );
}
/* Callback from the gif loader.
*
* Read up to len bytes into buffer, return number of bytes read. This is
* called by giflib exactly as fread, so it does not distinguish between EOF
* and read error.
*/
static int
vips_giflib_read( GifFileType *file, GifByteType *buf, int n )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) file->UserData;
int to_read;
to_read = n;
while( to_read > 0 ) {
gint64 bytes_read;
bytes_read = vips_source_read( gif->source, buf, n );
if( bytes_read == 0 ) {
gif->eof = TRUE;
return( -1 );
}
if( bytes_read < 0 )
return( -1 );
if( bytes_read > INT_MAX )
return( -1 );
to_read -= bytes_read;
buf += bytes_read;
}
return( (int) n );
}
/* Open any underlying file resource, then giflib.
*/
static int
vips_foreign_load_gif_open_giflib( VipsForeignLoadGif *gif )
{
VIPS_DEBUG_MSG( "vips_foreign_load_gif_open_giflib:\n" );
g_assert( !gif->file );
/* Must always rewind before opening giflib again.
*/
vips_source_rewind( gif->source );
#ifdef HAVE_GIFLIB_5
{
int error;
if( !(gif->file = DGifOpen( gif, vips_giflib_read, &error )) ) {
vips_foreign_load_gif_error_vips( gif, error );
(void) vips_foreign_load_gif_close_giflib( gif );
return( -1 );
}
}
#else
if( !(gif->file = DGifOpen( gif, vips_giflib_read )) ) {
vips_foreign_load_gif_error_vips( gif, GifLastError() );
(void) vips_foreign_load_gif_close_giflib( gif );
return( -1 );
}
#endif
gif->eof = FALSE;
gif->current_page = 0;
gif->max_image_width = 0;
return( 0 );
}
static void
vips_foreign_load_gif_dispose( GObject *gobject )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) gobject;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_dispose:\n" );
vips_foreign_load_gif_close_giflib( gif );
VIPS_UNREF( gif->source );
VIPS_UNREF( gif->frame );
VIPS_UNREF( gif->scratch );
VIPS_UNREF( gif->previous );
VIPS_FREE( gif->comment );
VIPS_FREE( gif->line );
VIPS_FREE( gif->delays );
G_OBJECT_CLASS( vips_foreign_load_gif_parent_class )->
dispose( gobject );
}
static VipsForeignFlags
vips_foreign_load_gif_get_flags_filename( const char *filename )
{
return( VIPS_FOREIGN_SEQUENTIAL );
}
static VipsForeignFlags
vips_foreign_load_gif_get_flags( VipsForeignLoad *load )
{
return( VIPS_FOREIGN_SEQUENTIAL );
}
static gboolean
vips_foreign_load_gif_is_a_source( VipsSource *source )
{
const unsigned char *data;
if( (data = vips_source_sniff( source, 4 )) &&
data[0] == 'G' &&
data[1] == 'I' &&
data[2] == 'F' &&
data[3] == '8' )
return( TRUE );
return( FALSE );
}
/* Make sure delays is allocated and large enough.
*/
static void
vips_foreign_load_gif_allocate_delays( VipsForeignLoadGif *gif )
{
if( gif->n_pages >= gif->delays_length ) {
int old = gif->delays_length;
int i;
gif->delays_length = gif->delays_length + gif->n_pages + 64;
gif->delays = (int *) g_realloc( gif->delays,
gif->delays_length * sizeof( int ) );
for( i = old; i < gif->delays_length; i++ )
gif->delays[i] = 40;
}
}
static int
vips_foreign_load_gif_ext_next( VipsForeignLoadGif *gif,
GifByteType **extension )
{
if( DGifGetExtensionNext( gif->file, extension ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
#ifdef DEBUG_VERBOSE
if( *extension )
printf( "gifload: EXTENSION_NEXT\n" );
#endif /*DEBUG_VERBOSE*/
return( 0 );
}
static int
vips_foreign_load_gif_code_next( VipsForeignLoadGif *gif,
GifByteType **extension )
{
if( DGifGetCodeNext( gif->file, extension ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
#ifdef DEBUG_VERBOSE
if( *extension )
printf( "gifload: CODE_NEXT\n" );
#endif /*DEBUG_VERBOSE*/
return( 0 );
}
/* Quickly scan an image record.
*/
static int
vips_foreign_load_gif_scan_image( VipsForeignLoadGif *gif )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
GifFileType *file = gif->file;
ColorMapObject *map;
GifByteType *extension;
if( DGifGetImageDesc( file ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
VIPS_DEBUG_MSG( "vips_foreign_load_gif_scan_image: "
"frame of %dx%d pixels at %dx%d\n",
file->Image.Width, file->Image.Height,
file->Image.Left, file->Image.Top );
/* giflib does no checking of image dimensions, not even for 0.
*/
if( file->Image.Width <= 0 ||
file->Image.Width > VIPS_MAX_COORD ||
file->Image.Height <= 0 ||
file->Image.Height > VIPS_MAX_COORD ) {
vips_error( class->nickname,
"%s", _( "image size out of bounds" ) );
return( -1 );
}
/* We need to find the max scanline size inside the GIF
* so we can allocate the decompress buffer.
*/
gif->max_image_width = VIPS_MAX( gif->max_image_width,
file->Image.Width );
/* Test for a non-greyscale colourmap for this frame.
*/
map = file->Image.ColorMap ? file->Image.ColorMap : file->SColorMap;
if( !gif->has_colour &&
map ) {
int i;
for( i = 0; i < map->ColorCount; i++ )
if( map->Colors[i].Red != map->Colors[i].Green ||
map->Colors[i].Green != map->Colors[i].Blue ) {
gif->has_colour = TRUE;
break;
}
}
/* Step over compressed image data.
*/
do {
if( vips_foreign_load_gif_code_next( gif, &extension ) )
return( -1 );
} while( extension != NULL );
return( 0 );
}
static int
vips_foreign_load_gif_scan_application_ext( VipsForeignLoadGif *gif,
GifByteType *extension )
{
gboolean have_netscape;
/* The 11-byte NETSCAPE extension.
*/
have_netscape = FALSE;
if( extension[0] == 11 &&
(vips_isprefix( "NETSCAPE2.0",
(const char*) (extension + 1) ) ||
vips_isprefix( "ANIMEXTS1.0",
(const char*) (extension + 1) )) )
have_netscape = TRUE;
while( extension != NULL ) {
if( vips_foreign_load_gif_ext_next( gif, &extension ) )
return( -1 );
if( have_netscape &&
extension &&
extension[0] == 3 &&
extension[1] == 1 ) {
gif->loop = extension[2] | (extension[3] << 8);
if( gif->loop != 0 )
gif->loop += 1;
}
}
return( 0 );
}
static int
vips_foreign_load_gif_scan_comment_ext( VipsForeignLoadGif *gif,
GifByteType *extension )
{
VIPS_DEBUG_MSG( "gifload: type: comment\n" );
if( !gif->comment ) {
/* Up to 257 with a NULL terminator.
*/
char comment[257];
vips_strncpy( comment, (char *) (extension + 1), 256 );
comment[extension[0]] = '\0';
gif->comment = g_strdup( comment );
}
while( extension != NULL )
if( vips_foreign_load_gif_ext_next( gif, &extension ) )
return( -1 );
return( 0 );
}
static int
vips_foreign_load_gif_scan_extension( VipsForeignLoadGif *gif )
{
GifByteType *extension;
int ext_code;
if( DGifGetExtension( gif->file, &ext_code, &extension ) ==
GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
if( extension )
switch( ext_code ) {
case GRAPHICS_EXT_FUNC_CODE:
if( extension[0] == 4 &&
extension[1] & TRANSPARENT_MASK ) {
VIPS_DEBUG_MSG( "gifload: has transp.\n" );
gif->has_transparency = TRUE;
}
/* giflib uses centiseconds, we use ms.
*/
gif->delays[gif->n_pages] =
(extension[2] | (extension[3] << 8)) * 10;
while( extension != NULL )
if( vips_foreign_load_gif_ext_next( gif,
&extension ) )
return( -1 );
break;
case APPLICATION_EXT_FUNC_CODE:
if( vips_foreign_load_gif_scan_application_ext( gif,
extension ) )
return( -1 );
break;
case COMMENT_EXT_FUNC_CODE:
if( vips_foreign_load_gif_scan_comment_ext( gif,
extension ) )
return( -1 );
break;
default:
/* Step over any NEXT blocks for unknown extensions.
*/
while( extension != NULL )
if( vips_foreign_load_gif_ext_next( gif,
&extension ) )
return( -1 );
break;
}
return( 0 );
}
static int
vips_foreign_load_gif_set_header( VipsForeignLoadGif *gif, VipsImage *image )
{
const gint64 total_height = (gint64) gif->file->SHeight * gif->n;
ColorMapObject *map = gif->file->SColorMap;
if( total_height <= 0 ||
total_height > VIPS_MAX_COORD ) {
vips_error( "gifload", "%s", _( "image size out of bounds" ) );
return( -1 );
}
vips_image_init_fields( image,
gif->file->SWidth, total_height,
(gif->has_colour ? 3 : 1) + (gif->has_transparency ? 1 : 0),
VIPS_FORMAT_UCHAR, VIPS_CODING_NONE,
gif->has_colour ?
VIPS_INTERPRETATION_sRGB : VIPS_INTERPRETATION_B_W,
1.0, 1.0 );
vips_image_pipelinev( image, VIPS_DEMAND_STYLE_FATSTRIP, NULL );
if( vips_object_argument_isset( VIPS_OBJECT( gif ), "n" ) )
vips_image_set_int( image,
VIPS_META_PAGE_HEIGHT, gif->file->SHeight );
vips_image_set_int( image, VIPS_META_N_PAGES, gif->n_pages );
vips_image_set_int( image, "loop", gif->loop );
/* DEPRECATED "gif-loop"
*
* Not the correct behavior as loop=1 became gif-loop=0
* but we want to keep the old behavior untouched!
*/
vips_image_set_int( image,
"gif-loop", gif->loop == 0 ? 0 : gif->loop - 1 );
if( gif->delays ) {
/* The deprecated gif-delay field is in centiseconds.
*/
vips_image_set_int( image,
"gif-delay", VIPS_RINT( gif->delays[0] / 10.0 ) );
vips_image_set_array_int( image,
"delay", gif->delays, gif->n_pages );
}
else
vips_image_set_int( image, "gif-delay", 4 );
if( gif->comment )
vips_image_set_string( image, "gif-comment", gif->comment );
if( map &&
gif->file->SBackGroundColor >= 0 &&
gif->file->SBackGroundColor < map->ColorCount ) {
double array[3];
array[0] = map->Colors[gif->file->SBackGroundColor].Red;
array[1] = map->Colors[gif->file->SBackGroundColor].Green;
array[2] = map->Colors[gif->file->SBackGroundColor].Blue;
vips_image_set_array_double( image, "background", array, 3 );
}
return( 0 );
}
/* Attempt to quickly scan a GIF and discover what we need for our header. We
* need to scan the whole file to get n_pages, transparency, colour etc.
*
* Don't flag errors during header scan. Many GIFs do not follow spec.
*/
static int
vips_foreign_load_gif_scan( VipsForeignLoadGif *gif )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
GifRecordType record;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_scan:\n" );
gif->n_pages = 0;
do {
if( DGifGetRecordType( gif->file, &record ) == GIF_ERROR )
continue;
switch( record ) {
case IMAGE_DESC_RECORD_TYPE:
(void) vips_foreign_load_gif_scan_image( gif );
gif->n_pages += 1;
vips_foreign_load_gif_allocate_delays( gif );
break;
case EXTENSION_RECORD_TYPE:
/* We need to fetch the extensions to check for
* cmaps and transparency.
*/
(void) vips_foreign_load_gif_scan_extension( gif );
break;
case TERMINATE_RECORD_TYPE:
gif->eof = TRUE;
break;
case SCREEN_DESC_RECORD_TYPE:
case UNDEFINED_RECORD_TYPE:
break;
default:
break;
}
} while( !gif->eof );
if( gif->n == -1 )
gif->n = gif->n_pages - gif->page;
if( gif->page < 0 ||
gif->n <= 0 ||
gif->page + gif->n > gif->n_pages ) {
vips_error( class->nickname, "%s", _( "bad page number" ) );
return( -1 );
}
if( gif->max_image_width <= 0 ||
gif->max_image_width > VIPS_MAX_COORD ) {
vips_error( class->nickname, "%s", _( "bad image size" ) );
return( -1 );
}
return( 0 );
}
/* Scan the GIF and set the libvips header. We always close after scan, even
* on an error.
*/
static int
vips_foreign_load_gif_header( VipsForeignLoad *load )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( load );
VipsForeignLoadGif *gif = VIPS_FOREIGN_LOAD_GIF( load );
VIPS_DEBUG_MSG( "vips_foreign_load_gif_header: %p\n", gif );
if( vips_foreign_load_gif_open_giflib( gif ) )
return( -1 );
/* giflib does no checking of image dimensions, not even for 0.
*/
if( gif->file->SWidth <= 0 ||
gif->file->SWidth > VIPS_MAX_COORD ||
gif->file->SHeight <= 0 ||
gif->file->SHeight > VIPS_MAX_COORD ) {
vips_error( class->nickname,
"%s", _( "image size out of bounds" ) );
(void) vips_foreign_load_gif_close_giflib( gif );
return( -1 );
}
/* Allocate a line buffer now that we have the GIF width.
*/
if( vips_foreign_load_gif_scan( gif ) ||
!(gif->line = VIPS_ARRAY( NULL,
gif->max_image_width, GifPixelType )) ||
vips_foreign_load_gif_set_header( gif, load->out ) ) {
(void) vips_foreign_load_gif_close_giflib( gif );
return( -1 );
}
(void) vips_foreign_load_gif_close_giflib( gif );
return( 0 );
}
static void
vips_foreign_load_gif_build_cmap( VipsForeignLoadGif *gif )
{
ColorMapObject *map = gif->file->Image.ColorMap ?
gif->file->Image.ColorMap : gif->file->SColorMap;
int v;
for( v = 0; v < 256; v++ ) {
VipsPel *q = (VipsPel *) &gif->cmap[v];
if( map &&
v < map->ColorCount ) {
q[0] = map->Colors[v].Red;
q[1] = map->Colors[v].Green;
q[2] = map->Colors[v].Blue;
q[3] = 255;
}
else {
/* If there's no map, just save the index.
*/
q[0] = v;
q[1] = v;
q[2] = v;
q[3] = 255;
}
}
}
/* Paint line y from the image left/top/width/height into scratch, clipping as
* we go.
*/
static void
vips_foreign_load_gif_render_line( VipsForeignLoadGif *gif,
int y,
int left, int top, int width, int height,
VipsPel *line )
{
VipsRect canvas;
VipsRect row;
VipsRect overlap;
/* Many GIFs have frames which lie outside the canvas. We have to
* clip.
*/
canvas.left = 0;
canvas.top = 0;
canvas.width = gif->file->SWidth;
canvas.height = gif->file->SHeight;
row.left = left;
row.top = top + y;
row.width = width;
row.height = height;
vips_rect_intersectrect( &canvas, &row, &overlap );
if( !vips_rect_isempty( &overlap ) ) {
VipsPel *dst = VIPS_IMAGE_ADDR( gif->scratch,
overlap.left, overlap.top );
guint32 * restrict idst = (guint32 *) dst;
VipsPel * restrict src = line + (overlap.left - row.left);
int x;
for( x = 0; x < overlap.width; x++ ) {
VipsPel v = src[x];
if( v != gif->transparent_index )
idst[x] = gif->cmap[v];
}
}
}
/* Render the current gif frame into an RGBA buffer. GIFs can accumulate,
* depending on the current dispose mode.
*/
static int
vips_foreign_load_gif_render( VipsForeignLoadGif *gif )
{
GifFileType *file = gif->file;
if( DGifGetImageDesc( file ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
/* Update the colour map for this frame.
*/
vips_foreign_load_gif_build_cmap( gif );
/* If this is PREVIOUS, then after we're done, we'll need to restore
* the frame to what it was previously. Make a note of the current
* state.
*/
if( gif->dispose == DISPOSE_PREVIOUS )
memcpy( VIPS_IMAGE_ADDR( gif->previous, 0, 0 ),
VIPS_IMAGE_ADDR( gif->frame, 0, 0 ),
VIPS_IMAGE_SIZEOF_IMAGE( gif->previous ) );
if( file->Image.Interlace ) {
int i;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_render: "
"interlaced frame of %d x %d pixels at %d x %d\n",
file->Image.Width, file->Image.Height,
file->Image.Left, file->Image.Top );
for( i = 0; i < 4; i++ ) {
int y;
for( y = InterlacedOffset[i]; y < file->Image.Height;
y += InterlacedJumps[i] ) {
if( DGifGetLine( gif->file,
gif->line, file->Image.Width ) ==
GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
vips_foreign_load_gif_render_line( gif, y,
file->Image.Left,
file->Image.Top,
file->Image.Width,
file->Image.Height,
gif->line );
}
}
}
else {
int y;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_render: "
"non-interlaced frame of %d x %d pixels at %d x %d\n",
file->Image.Width, file->Image.Height,
file->Image.Left, file->Image.Top );
for( y = 0; y < file->Image.Height; y++ ) {
if( DGifGetLine( gif->file,
gif->line, file->Image.Width ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
vips_foreign_load_gif_render_line( gif, y,
file->Image.Left,
file->Image.Top,
file->Image.Width,
file->Image.Height,
gif->line );
}
}
/* Copy the result to frame, ready to be copied to our output.
*/
memcpy( VIPS_IMAGE_ADDR( gif->frame, 0, 0 ),
VIPS_IMAGE_ADDR( gif->scratch, 0, 0 ),
VIPS_IMAGE_SIZEOF_IMAGE( gif->frame ) );
if( gif->dispose == DISPOSE_BACKGROUND ) {
/* BACKGROUND means we reset the area we just painted to
* transparent. We have to clip against the canvas.
*/
VipsRect canvas;
VipsRect image;
VipsRect overlap;
canvas.left = 0;
canvas.top = 0;
canvas.width = gif->file->SWidth;
canvas.height = gif->file->SHeight;
image.left = file->Image.Left,
image.top = file->Image.Top,
image.width = file->Image.Width,
image.height = file->Image.Height,
vips_rect_intersectrect( &canvas, &image, &overlap );
if( !vips_rect_isempty( &overlap ) ) {
guint32 *q = (guint32 *) VIPS_IMAGE_ADDR( gif->scratch,
overlap.left, overlap.top );
/* What we write for transparent pixels. We want RGB
* to be 255, and A to be 0.
*/
guint32 transparent = GUINT32_TO_BE( 0xffffff00 );
int x, y;
/* Generate the first line a pixel at a time,
* memcpy() for subsequent lines.
*/
for( x = 0; x < overlap.width; x++ )
q[x] = transparent;
for( y = 1; y < overlap.height; y++ )
memcpy( q + gif->scratch->Xsize * y,
q,
overlap.width * sizeof( guint32 ) );
}
}
else if( gif->dispose == DISPOSE_PREVIOUS )
/* PREVIOUS means we restore the previous state of the scratch
* area.
*/
memcpy( VIPS_IMAGE_ADDR( gif->scratch, 0, 0 ),
VIPS_IMAGE_ADDR( gif->previous, 0, 0 ),
VIPS_IMAGE_SIZEOF_IMAGE( gif->scratch ) );
/* Reset values, as the Graphic Control Extension is optional
*/
gif->dispose = DISPOSAL_UNSPECIFIED;
gif->transparent_index = NO_TRANSPARENT_INDEX;
return( 0 );
}
#ifdef VIPS_DEBUG
static const char *
dispose2str( int dispose )
{
switch( dispose ) {
case DISPOSAL_UNSPECIFIED: return( "DISPOSAL_UNSPECIFIED" );
case DISPOSE_DO_NOT: return( "DISPOSE_DO_NOT" );
case DISPOSE_BACKGROUND: return( "DISPOSE_BACKGROUND" );
case DISPOSE_PREVIOUS: return( "DISPOSE_PREVIOUS" );
default: return( "<unknown>" );
}
}
#endif /*VIPS_DEBUG*/
static int
vips_foreign_load_gif_extension( VipsForeignLoadGif *gif )
{
GifByteType *extension;
int ext_code;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_extension:\n" );
if( DGifGetExtension( gif->file, &ext_code, &extension ) ==
GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
if( extension &&
ext_code == GRAPHICS_EXT_FUNC_CODE &&
extension[0] == 4 ) {
int flags = extension[1];
/* Bytes are flags, delay low, delay high, transparency.
* Flag bit 1 means transparency is being set.
*/
gif->transparent_index = (flags & TRANSPARENT_MASK) ?
extension[4] : NO_TRANSPARENT_INDEX;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_extension: "
"transparency = %d\n", gif->transparent_index );
/* Set the current dispose mode. This is read during frame load
* to set the meaning of background and transparent pixels.
*/
gif->dispose = (flags >> DISPOSE_SHIFT) & DISPOSE_MASK;
VIPS_DEBUG_MSG( "vips_foreign_load_gif_extension: "
"dispose = %s\n", dispose2str( gif->dispose ) );
}
while( extension != NULL )
if( vips_foreign_load_gif_ext_next( gif, &extension ) )
return( -1 );
return( 0 );
}
/* Read the next page from the file into @frame.
*/
static int
vips_foreign_load_gif_next_page( VipsForeignLoadGif *gif )
{
GifRecordType record;
gboolean have_read_frame;
have_read_frame = FALSE;
do {
if( DGifGetRecordType( gif->file, &record ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
switch( record ) {
case IMAGE_DESC_RECORD_TYPE:
VIPS_DEBUG_MSG( "vips_foreign_load_gif_next_page: "
"IMAGE_DESC_RECORD_TYPE\n" );
if( vips_foreign_load_gif_render( gif ) )
return( -1 );
have_read_frame = TRUE;
break;
case EXTENSION_RECORD_TYPE:
if( vips_foreign_load_gif_extension( gif ) )
return( -1 );
break;
case TERMINATE_RECORD_TYPE:
VIPS_DEBUG_MSG( "vips_foreign_load_gif_next_page: "
"TERMINATE_RECORD_TYPE\n" );
gif->eof = TRUE;
break;
case SCREEN_DESC_RECORD_TYPE:
VIPS_DEBUG_MSG( "vips_foreign_load_gif_next_page: "
"SCREEN_DESC_RECORD_TYPE\n" );
break;
case UNDEFINED_RECORD_TYPE:
VIPS_DEBUG_MSG( "vips_foreign_load_gif_next_page: "
"UNDEFINED_RECORD_TYPE\n" );
break;
default:
break;
}
} while( !have_read_frame &&
!gif->eof );
return( 0 );
}
static int
vips_foreign_load_gif_generate( VipsRegion *or,
void *seq, void *a, void *b, gboolean *stop )
{
VipsRect *r = &or->valid;
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) a;
int y;
#ifdef DEBUG_VERBOSE
printf( "vips_foreign_load_gif_generate: %p "
"left = %d, top = %d, width = %d, height = %d\n",
gif,
r->left, r->top, r->width, r->height );
#endif /*DEBUG_VERBOSE*/
for( y = 0; y < r->height; y++ ) {
/* The page for this output line, and the line number in page.
*/
int page = (r->top + y) / gif->file->SHeight + gif->page;
int line = (r->top + y) % gif->file->SHeight;
VipsPel *p, *q;
int x;
g_assert( line >= 0 && line < gif->frame->Ysize );
g_assert( page >= 0 && page < gif->n_pages );
/* current_page == 0 means we've not loaded any pages yet. So
* we need to have loaded the page beyond the page we want.
*/
while( gif->current_page <= page ) {
if( vips_foreign_load_gif_next_page( gif ) )
return( -1 );
gif->current_page += 1;
}
/* @frame is always RGBA, but or may be G, GA, RGB or RGBA.
* We have to pick out the values we want.
*/
p = VIPS_IMAGE_ADDR( gif->frame, 0, line );
q = VIPS_REGION_ADDR( or, 0, r->top + y );
switch( or->im->Bands ) {
case 1:
for( x = 0; x < gif->frame->Xsize; x++ ) {
q[0] = p[1];
q += 1;
p += 4;
}
break;
case 2:
for( x = 0; x < gif->frame->Xsize; x++ ) {
q[0] = p[1];
q[1] = p[3];
q += 2;
p += 4;
}
break;
case 3:
for( x = 0; x < gif->frame->Xsize; x++ ) {
q[0] = p[0];
q[1] = p[1];
q[2] = p[2];
q += 3;
p += 4;
}
break;
case 4:
memcpy( q, p, VIPS_IMAGE_SIZEOF_LINE( gif->frame ) );
break;
default:
g_assert_not_reached();
break;
}
}
return( 0 );
}
static void
vips_foreign_load_gif_minimise( VipsObject *object, VipsForeignLoadGif *gif )
{
vips_source_minimise( gif->source );
}
static VipsImage *
vips_foreign_load_gif_temp( VipsForeignLoadGif *gif )
{
VipsImage *temp;
temp = vips_image_new_memory();
vips_image_init_fields( temp,
gif->file->SWidth, gif->file->SHeight, 4, VIPS_FORMAT_UCHAR,
VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, 1.0, 1.0 );
if( vips_image_write_prepare( temp ) ) {
VIPS_UNREF( temp );
return( NULL );
}
return( temp );
}
static int
vips_foreign_load_gif_load( VipsForeignLoad *load )
{
VipsForeignLoadGif *gif = VIPS_FOREIGN_LOAD_GIF( load );
VipsImage **t = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( load ), 4 );
VIPS_DEBUG_MSG( "vips_foreign_load_gif_load: %p\n", gif );
if( vips_foreign_load_gif_open_giflib( gif ) )
return( -1 );
/* Set of temp images we use during rendering.
*/
if( !(gif->frame = vips_foreign_load_gif_temp( gif )) ||
!(gif->scratch = vips_foreign_load_gif_temp( gif )) ||
!(gif->previous = vips_foreign_load_gif_temp( gif )) )
return( -1 );
/* Make the output pipeline.
*/
t[0] = vips_image_new();
if( vips_foreign_load_gif_set_header( gif, t[0] ) )
return( -1 );
/* Close input immediately at end of read.
*/
g_signal_connect( t[0], "minimise",
G_CALLBACK( vips_foreign_load_gif_minimise ), gif );
/* Strips 8 pixels high to avoid too many tiny regions.
*/
if( vips_image_generate( t[0],
NULL, vips_foreign_load_gif_generate, NULL, gif, NULL ) ||
vips_sequential( t[0], &t[1],
"tile_height", VIPS__FATSTRIP_HEIGHT,
NULL ) ||
vips_image_write( t[1], load->real ) )
return( -1 );
return( 0 );
}
static void
vips_foreign_load_gif_class_init( VipsForeignLoadGifClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;
gobject_class->dispose = vips_foreign_load_gif_dispose;
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "gifload_base";
object_class->description = _( "load GIF with giflib" );
load_class->header = vips_foreign_load_gif_header;
load_class->load = vips_foreign_load_gif_load;
load_class->get_flags_filename =
vips_foreign_load_gif_get_flags_filename;
load_class->get_flags = vips_foreign_load_gif_get_flags;
VIPS_ARG_INT( class, "page", 20,
_( "Page" ),
_( "Load this page from the file" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGif, page ),
0, 100000, 0 );
VIPS_ARG_INT( class, "n", 21,
_( "n" ),
_( "Load this many pages" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGif, n ),
-1, 100000, 1 );
}
static void
vips_foreign_load_gif_init( VipsForeignLoadGif *gif )
{
gif->n = 1;
gif->transparent_index = NO_TRANSPARENT_INDEX;
gif->delays = NULL;
gif->delays_length = 0;
gif->loop = 1;
gif->comment = NULL;
gif->dispose = DISPOSAL_UNSPECIFIED;
vips_foreign_load_gif_allocate_delays( gif );
}
typedef struct _VipsForeignLoadGifFile {
VipsForeignLoadGif parent_object;
/* Filename for load.
*/
char *filename;
} VipsForeignLoadGifFile;
typedef VipsForeignLoadGifClass VipsForeignLoadGifFileClass;
G_DEFINE_TYPE( VipsForeignLoadGifFile, vips_foreign_load_gif_file,
vips_foreign_load_gif_get_type() );
static int
vips_foreign_load_gif_file_build( VipsObject *object )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) object;
VipsForeignLoadGifFile *file = (VipsForeignLoadGifFile *) object;
if( file->filename )
if( !(gif->source =
vips_source_new_from_file( file->filename )) )
return( -1 );
if( VIPS_OBJECT_CLASS( vips_foreign_load_gif_file_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static const char *vips_foreign_gif_suffs[] = {
".gif",
NULL
};
static gboolean
vips_foreign_load_gif_file_is_a( const char *filename )
{
VipsSource *source;
gboolean result;
if( !(source = vips_source_new_from_file( filename )) )
return( FALSE );
result = vips_foreign_load_gif_is_a_source( source );
VIPS_UNREF( source );
return( result );
}
static void
vips_foreign_load_gif_file_class_init(
VipsForeignLoadGifFileClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsForeignClass *foreign_class = (VipsForeignClass *) class;
VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "gifload";
object_class->description = _( "load GIF with giflib" );
object_class->build = vips_foreign_load_gif_file_build;
foreign_class->suffs = vips_foreign_gif_suffs;
load_class->is_a = vips_foreign_load_gif_file_is_a;
VIPS_ARG_STRING( class, "filename", 1,
_( "Filename" ),
_( "Filename to load from" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGifFile, filename ),
NULL );
}
static void
vips_foreign_load_gif_file_init( VipsForeignLoadGifFile *file )
{
}
typedef struct _VipsForeignLoadGifBuffer {
VipsForeignLoadGif parent_object;
/* Load from a buffer.
*/
VipsArea *blob;
} VipsForeignLoadGifBuffer;
typedef VipsForeignLoadGifClass VipsForeignLoadGifBufferClass;
G_DEFINE_TYPE( VipsForeignLoadGifBuffer, vips_foreign_load_gif_buffer,
vips_foreign_load_gif_get_type() );
static int
vips_foreign_load_gif_buffer_build( VipsObject *object )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) object;
VipsForeignLoadGifBuffer *buffer =
(VipsForeignLoadGifBuffer *) object;
if( buffer->blob &&
!(gif->source = vips_source_new_from_memory(
VIPS_AREA( buffer->blob )->data,
VIPS_AREA( buffer->blob )->length )) )
return( -1 );
if( VIPS_OBJECT_CLASS( vips_foreign_load_gif_buffer_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static gboolean
vips_foreign_load_gif_buffer_is_a_buffer( const void *buf, size_t len )
{
VipsSource *source;
gboolean result;
if( !(source = vips_source_new_from_memory( buf, len )) )
return( FALSE );
result = vips_foreign_load_gif_is_a_source( source );
VIPS_UNREF( source );
return( result );
}
static void
vips_foreign_load_gif_buffer_class_init(
VipsForeignLoadGifBufferClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "gifload_buffer";
object_class->description = _( "load GIF with giflib" );
object_class->build = vips_foreign_load_gif_buffer_build;
load_class->is_a_buffer = vips_foreign_load_gif_buffer_is_a_buffer;
VIPS_ARG_BOXED( class, "buffer", 1,
_( "Buffer" ),
_( "Buffer to load from" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGifBuffer, blob ),
VIPS_TYPE_BLOB );
}
static void
vips_foreign_load_gif_buffer_init( VipsForeignLoadGifBuffer *buffer )
{
}
typedef struct _VipsForeignLoadGifSource {
VipsForeignLoadGif parent_object;
/* Load from a source.
*/
VipsSource *source;
} VipsForeignLoadGifSource;
typedef VipsForeignLoadGifClass VipsForeignLoadGifSourceClass;
G_DEFINE_TYPE( VipsForeignLoadGifSource, vips_foreign_load_gif_source,
vips_foreign_load_gif_get_type() );
static int
vips_foreign_load_gif_source_build( VipsObject *object )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) object;
VipsForeignLoadGifSource *source =
(VipsForeignLoadGifSource *) object;
if( source->source ) {
gif->source = source->source;
g_object_ref( gif->source );
}
if( VIPS_OBJECT_CLASS( vips_foreign_load_gif_source_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static void
vips_foreign_load_gif_source_class_init(
VipsForeignLoadGifSourceClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "gifload_source";
object_class->description = _( "load GIF with giflib" );
object_class->build = vips_foreign_load_gif_source_build;
load_class->is_a_source = vips_foreign_load_gif_is_a_source;
VIPS_ARG_OBJECT( class, "source", 1,
_( "Source" ),
_( "Source to load from" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGifSource, source ),
VIPS_TYPE_SOURCE );
}
static void
vips_foreign_load_gif_source_init( VipsForeignLoadGifSource *source )
{
}
#endif /*HAVE_GIFLIB*/
/**
* vips_gifload:
* @filename: file to load
* @out: (out): output image
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @page: %gint, page (frame) to read
* * @n: %gint, load this many pages
*
* Read a GIF file into a libvips image.
*
* Use @page to select a page to render, numbering from zero.
*
* Use @n to select the number of pages to render. The default is 1. Pages are
* rendered in a vertical column. Set to -1 to mean "until the end of the
* document". Use vips_grid() to change page layout.
*
* The output image will be 1, 2, 3 or 4 bands for mono, mono plus
* transparency, RGB, or RGB plus transparency.
*
* See also: vips_image_new_from_file().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_gifload( const char *filename, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "gifload", ap, filename, out );
va_end( ap );
return( result );
}
/**
* vips_gifload_buffer:
* @buf: (array length=len) (element-type guint8): memory area to load
* @len: (type gsize): size of memory area
* @out: (out): image to write
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @page: %gint, page (frame) to read
* * @n: %gint, load this many pages
*
* Read a GIF-formatted memory block into a VIPS image. Exactly as
* vips_gifload(), but read from a memory buffer.
*
* You must not free the buffer while @out is active. The
* #VipsObject::postclose signal on @out is a good place to free.
*
* See also: vips_gifload().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_gifload_buffer( void *buf, size_t len, VipsImage **out, ... )
{
va_list ap;
VipsBlob *blob;
int result;
/* We don't take a copy of the data or free it.
*/
blob = vips_blob_new( NULL, buf, len );
va_start( ap, out );
result = vips_call_split( "gifload_buffer", ap, blob, out );
va_end( ap );
vips_area_unref( VIPS_AREA( blob ) );
return( result );
}
/**
* vips_gifload_source:
* @source: source to load
* @out: (out): image to write
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @page: %gint, page (frame) to read
* * @n: %gint, load this many pages
*
* Exactly as vips_gifload(), but read from a source.
*
* See also: vips_gifload().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_gifload_source( VipsSource *source, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "gifload_source", ap, source, out );
va_end( ap );
return( result );
}
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