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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
*/
/*
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 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
typedef struct _VipsForeignLoadGif {
VipsForeignLoad parent_object;
/* Load this page (frame number).
*/
int page;
/* Load this many pages.
*/
int n;
GifFileType *file;
/* The current read position, in pages.
*/
int current_page;
/* Set for EOF detected.
*/
gboolean eof;
/* As we scan the file, the index of the transparent pixel for this
* frame.
*/
int transparency;
/* Decompress lines of the gif file to here.
*/
GifPixelType *line;
/* 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;
/* The FILE* we read from.
*/
FILE *fp;
} 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 );
}
static void
vips_foreign_load_gif_close( VipsForeignLoadGif *gif )
{
#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;
}
#else
if( gif->file ) {
if( DGifCloseFile( gif->file ) == GIF_ERROR )
vips_foreign_load_gif_error_vips( gif, GifLastError() );
gif->file = NULL;
}
#endif
VIPS_FREEF( fclose, gif->fp );
}
/* Our input function for file open. We can't use DGifOpenFileName(), since
* that just calls open() and won't work with unicode on win32. We can't use
* DGifOpenFileHandle() since that's an fd from open() and you can't pass those
* acoss DLL boundaries on Windows.
*/
static int
vips_giflib_file_read( GifFileType *file, GifByteType *buffer, int n )
{
FILE *fp = (FILE *) file->UserData;
return( (int) fread( (void *) buffer, 1, n, fp ) );
}
static int
vips_foreign_load_gif_open( VipsForeignLoadGif *gif, const char *filename )
{
g_assert( !gif->file );
g_assert( !gif->fp );
if( !(gif->fp = vips__file_open_read( filename, NULL, FALSE )) )
return( -1 );
#ifdef HAVE_GIFLIB_5
{
int error;
if( !(gif->file =
DGifOpen( gif->fp, vips_giflib_file_read, &error )) ) {
vips_foreign_load_gif_error_vips( gif, error );
return( -1 );
}
}
#else
if( !(gif->file = DGifOpen( gif->fp, vips_giflib_file_read )) ) {
vips_foreign_load_gif_error_vips( gif, GifLastError() );
return( -1 );
}
#endif
return( 0 );
}
static int
vips_foreign_load_gif_open_buffer( VipsForeignLoadGif *gif, InputFunc read_fn )
{
g_assert( !gif->file );
#ifdef HAVE_GIFLIB_5
{
int error;
if( !(gif->file = DGifOpen( gif, read_fn, &error )) ) {
vips_foreign_load_gif_error_vips( gif, error );
return( -1 );
}
}
#else
if( !(gif->file = DGifOpen( gif, read_fn )) ) {
vips_foreign_load_gif_error_vips( gif, GifLastError() );
return( -1 );
}
#endif
return( 0 );
}
static void
vips_foreign_load_gif_dispose( GObject *gobject )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) gobject;
vips_foreign_load_gif_close( gif );
G_OBJECT_CLASS( vips_foreign_load_gif_parent_class )->
dispose( gobject );
}
static VipsForeignFlags
vips_foreign_load_gif_get_flags_filename( const char *filename )
{
/* We can render any part of the image on demand.
*/
return( VIPS_FOREIGN_PARTIAL );
}
static VipsForeignFlags
vips_foreign_load_gif_get_flags( VipsForeignLoad *load )
{
return( VIPS_FOREIGN_PARTIAL );
}
static gboolean
vips_foreign_load_gif_is_a_buffer( const void *buf, size_t len )
{
const guchar *str = (const guchar *) buf;
if( len >= 4 &&
str[0] == 'G' &&
str[1] == 'I' &&
str[2] == 'F' &&
str[3] == '8' )
return( 1 );
return( 0 );
}
static gboolean
vips_foreign_load_gif_is_a( const char *filename )
{
unsigned char buf[4];
if( vips__get_bytes( filename, buf, 4 ) &&
vips_foreign_load_gif_is_a_buffer( buf, 4 ) )
return( 1 );
return( 0 );
}
static void
vips_foreign_load_gif_render_line( VipsForeignLoadGif *gif,
int width, VipsPel * restrict q, VipsPel * restrict p )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
ColorMapObject *map = gif->file->Image.ColorMap ?
gif->file->Image.ColorMap : gif->file->SColorMap;
int x;
for( x = 0; x < width; x++ ) {
VipsPel v = p[x];
if( v >= map->ColorCount ) {
vips_warn( class->nickname,
"%s", _( "pixel value out of range" ) );
continue;
}
if( v != gif->transparency ) {
q[0] = map->Colors[v].Red;
q[1] = map->Colors[v].Green;
q[2] = map->Colors[v].Blue;
q[3] = 255;
}
else {
q[0] = 0;
q[1] = 0;
q[2] = 0;
q[3] = 0;
}
q += 4;
}
}
/* Render the current gif frame into an RGBA buffer. GIFs
* accumulate, so don't clear the buffer first, we need to paint a
* series of frames on top of each other.
*/
static int
vips_foreign_load_gif_render( VipsForeignLoadGif *gif, VipsImage *out )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
GifFileType *file = gif->file;
ColorMapObject *map = file->Image.ColorMap ?
file->Image.ColorMap : file->SColorMap;
/* Check that the frame lies within our image.
*/
if( file->Image.Left < 0 ||
file->Image.Left + file->Image.Width > out->Xsize ||
file->Image.Top < 0 ||
file->Image.Top + file->Image.Height > out->Ysize ) {
vips_error( class->nickname,
"%s", _( "frame is outside image area" ) );
return( -1 );
}
/* Check if we have a non-greyscale colourmap for this frame.
*/
if( !gif->has_colour ) {
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 ) {
VIPS_DEBUG_MSG( "gifload: not mono\n" );
gif->has_colour = TRUE;
break;
}
}
/* We need a line buffer to decompress to.
*/
if( !gif->line )
if( !(gif->line = VIPS_ARRAY( gif,
gif->file->SWidth, GifPixelType )) )
return( -1 );
if( file->Image.Interlace ) {
int i;
VIPS_DEBUG_MSG( "gifload: 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] ) {
VipsPel *q = VIPS_IMAGE_ADDR( out,
file->Image.Left, file->Image.Top + 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,
file->Image.Width, q, gif->line );
}
}
}
else {
int y;
VIPS_DEBUG_MSG( "gifload: 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++ ) {
VipsPel *q = VIPS_IMAGE_ADDR( out,
file->Image.Left, file->Image.Top + 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,
file->Image.Width, q, gif->line );
}
}
return( 0 );
}
/* Write the next page, if there is one, to @page. Set EOF if we hit the end of
* the file. @page must be a memory image of the right size.
*/
static int
vips_foreign_load_gif_page( VipsForeignLoadGif *gif, VipsImage *out )
{
GifRecordType record;
int n_pages;
n_pages = 0;
do {
GifByteType *extension;
int ext_code;
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( "gifload: IMAGE_DESC_RECORD_TYPE:\n" );
if( DGifGetImageDesc( gif->file ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
if( vips_foreign_load_gif_render( gif, out ) )
return( -1 );
n_pages += 1;
VIPS_DEBUG_MSG( "gifload: page %d:\n",
gif->current_page + n_pages );
break;
case EXTENSION_RECORD_TYPE:
VIPS_DEBUG_MSG( "gifload: EXTENSION_RECORD_TYPE:\n" );
gif->transparency = -1;
if( DGifGetExtension( gif->file,
&ext_code, &extension ) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
if( ext_code == GRAPHICS_EXT_FUNC_CODE &&
extension &&
extension[0] == 4 &&
(extension[1] & 0x1) ) {
/* Bytes are 4, 1, delay low, delay high,
* transparency. Bit 1 means transparency
* is being set.
*/
gif->transparency = extension[4];
gif->has_transparency = TRUE;
VIPS_DEBUG_MSG( "gifload: "
"seen transparency %d\n",
gif->transparency );
}
while( extension != NULL ) {
if( DGifGetExtensionNext( gif->file,
&extension) == GIF_ERROR ) {
vips_foreign_load_gif_error( gif );
return( -1 );
}
#ifdef VIPS_DEBUG
if( extension )
VIPS_DEBUG_MSG( "gifload: "
"EXTENSION_NEXT:\n" );
#endif
}
break;
case TERMINATE_RECORD_TYPE:
VIPS_DEBUG_MSG( "gifload: TERMINATE_RECORD_TYPE:\n" );
gif->eof = TRUE;
break;
case SCREEN_DESC_RECORD_TYPE:
VIPS_DEBUG_MSG( "gifload: SCREEN_DESC_RECORD_TYPE:\n" );
break;
case UNDEFINED_RECORD_TYPE:
VIPS_DEBUG_MSG( "gifload: UNDEFINED_RECORD_TYPE:\n" );
break;
default:
break;
}
} while( n_pages < 1 &&
!gif->eof );
gif->current_page += n_pages;
return( 0 );
}
static VipsImage *
vips_foreign_load_gif_new_page( VipsForeignLoadGif *gif )
{
VipsImage *out;
out = vips_image_new_memory();
vips_image_init_fields( out,
gif->file->SWidth, gif->file->SHeight, 4, VIPS_FORMAT_UCHAR,
VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, 1.0, 1.0 );
/* We will have the whole GIF frame in memory, so we can render any
* area.
*/
vips_image_pipelinev( out, VIPS_DEMAND_STYLE_ANY, NULL );
/* Turn out into a memory image which we then render the GIF frames
* into.
*/
if( vips_image_write_prepare( out ) ) {
g_object_unref( out );
return( NULL );
}
return( out );
}
static void
unref_array( GSList *list )
{
g_slist_free_full( list, (GDestroyNotify) g_object_unref );
}
/* We render each frame to a separate memory image held in a linked
* list, then assemble to out. We don't know the number of frames in advance,
* so we can't just allocate a large area.
*/
static int
vips_foreign_load_gif_pages( VipsForeignLoadGif *gif, VipsImage **out )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( gif );
GSList *frames;
VipsImage *frame;
VipsImage *previous;
VipsImage **t;
int n_frames;
int i;
frames = NULL;
previous = NULL;
/* Accumulate any start stuff up to the first frame we need.
*/
if( !(frame = vips_foreign_load_gif_new_page( gif )) )
return( -1 );
do {
if( vips_foreign_load_gif_page( gif, frame ) ) {
g_object_unref( frame );
return( -1 );
}
} while( !gif->eof &&
gif->current_page <= gif->page );
if( gif->eof ) {
vips_error( class->nickname,
"%s", _( "too few frames in GIF file" ) );
g_object_unref( frame );
return( -1 );
}
frames = g_slist_append( frames, frame );
previous = frame;
while( gif->n == -1 ||
gif->current_page < gif->page + gif->n ) {
/* We might need a frame for this read to render to.
*/
if( !(frame = vips_foreign_load_gif_new_page( gif )) ) {
unref_array( frames );
return( -1 );
}
/* And init with the previous frame, if any.
*/
if( previous )
memcpy( VIPS_IMAGE_ADDR( frame, 0, 0 ),
VIPS_IMAGE_ADDR( previous, 0, 0 ),
VIPS_IMAGE_SIZEOF_IMAGE( frame ) );
if( vips_foreign_load_gif_page( gif, frame ) ) {
g_object_unref( frame );
unref_array( frames );
return( -1 );
}
if( gif->eof ) {
/* Nope, didn't need the new frame.
*/
g_object_unref( frame );
break;
}
else {
frames = g_slist_append( frames, frame );
previous = frame;
}
}
n_frames = g_slist_length( frames );
if( gif->eof &&
gif->n != -1 &&
n_frames < gif->n ) {
unref_array( frames );
vips_error( class->nickname,
"%s", _( "too few frames in GIF file" ) );
return( -1 );
}
/* We've rendered to a set of memory images ... we can shut down the GIF
* reader now.
*/
vips_foreign_load_gif_close( gif );
if( !(t = VIPS_ARRAY( gif, n_frames, VipsImage * )) ) {
unref_array( frames );
return( -1 );
}
for( i = 0; i < n_frames; i++ )
t[i] = (VipsImage *) g_slist_nth_data( frames, i );
if( vips_arrayjoin( t, out, n_frames,
"across", 1,
NULL ) ) {
unref_array( frames );
return( -1 );
}
unref_array( frames );
if( n_frames > 1 )
vips_image_set_int( *out, VIPS_META_PAGE_HEIGHT, frame->Ysize );
return( 0 );
}
static int
vips_foreign_load_gif_load( VipsForeignLoad *load )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) load;
VipsImage **t = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( load ), 4 );
VipsImage *im;
if( vips_foreign_load_gif_pages( gif, &t[0] ) )
return( -1 );
im = t[0];
/* Depending on what we found, transform and write to load->real.
*/
if( gif->has_colour &&
gif->has_transparency ) {
/* Nothing to do.
*/
}
else if( gif->has_colour ) {
/* RGB.
*/
if( vips_extract_band( im, &t[1], 0,
"n", 3,
NULL ) )
return( -1 );
im = t[1];
}
else if( gif->has_transparency ) {
/* GA. Take BA so we have neighboring channels.
*/
if( vips_extract_band( im, &t[1], 2,
"n", 2,
NULL ) )
return( -1 );
im = t[1];
im->Type = VIPS_INTERPRETATION_B_W;
}
else {
/* G.
*/
if( vips_extract_band( im, &t[1], 0, NULL ) )
return( -1 );
im = t[1];
im->Type = VIPS_INTERPRETATION_B_W;
}
if( vips_image_write( im, load->out ) )
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";
object_class->description = _( "load GIF with giflib" );
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", 10,
_( "Page" ),
_( "Load this page from the file" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGif, page ),
0, 100000, 0 );
VIPS_ARG_INT( class, "n", 6,
_( "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->transparency = -1;
}
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_header( VipsForeignLoad *load )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) load;
VipsForeignLoadGifFile *file = (VipsForeignLoadGifFile *) load;
if( vips_foreign_load_gif_open( gif, file->filename ) )
return( -1 );
VIPS_SETSTR( load->out->filename, file->filename );
return( vips_foreign_load_gif_load( load ) );
}
static const char *vips_foreign_gif_suffs[] = {
".gif",
NULL
};
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" );
foreign_class->suffs = vips_foreign_gif_suffs;
load_class->is_a = vips_foreign_load_gif_is_a;
load_class->header = vips_foreign_load_gif_file_header;
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 *buf;
/* Current read point, bytes left in buffer.
*/
VipsPel *p;
size_t bytes_to_go;
} VipsForeignLoadGifBuffer;
typedef VipsForeignLoadGifClass VipsForeignLoadGifBufferClass;
G_DEFINE_TYPE( VipsForeignLoadGifBuffer, vips_foreign_load_gif_buffer,
vips_foreign_load_gif_get_type() );
/* Callback from the gif loader.
*
* Read up to len bytes into buffer, return number of bytes read, 0 for EOF.
*/
static int
vips_giflib_buffer_read( GifFileType *file, GifByteType *buf, int n )
{
VipsForeignLoadGifBuffer *buffer =
(VipsForeignLoadGifBuffer *) file->UserData;
size_t will_read = VIPS_MIN( n, buffer->bytes_to_go );
memcpy( buf, buffer->p, will_read );
buffer->p += will_read;
buffer->bytes_to_go -= will_read;
return( will_read );
}
static int
vips_foreign_load_gif_buffer_header( VipsForeignLoad *load )
{
VipsForeignLoadGif *gif = (VipsForeignLoadGif *) load;
VipsForeignLoadGifBuffer *buffer = (VipsForeignLoadGifBuffer *) load;
/* Init the read point.
*/
buffer->p = buffer->buf->data;
buffer->bytes_to_go = buffer->buf->length;
if( vips_foreign_load_gif_open_buffer( gif, vips_giflib_buffer_read ) )
return( -1 );
return( vips_foreign_load_gif_load( load ) );
}
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" );
load_class->is_a_buffer = vips_foreign_load_gif_is_a_buffer;
load_class->header = vips_foreign_load_gif_buffer_header;
VIPS_ARG_BOXED( class, "buffer", 1,
_( "Buffer" ),
_( "Buffer to load from" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsForeignLoadGifBuffer, buf ),
VIPS_TYPE_BLOB );
}
static void
vips_foreign_load_gif_buffer_init( VipsForeignLoadGifBuffer *buffer )
{
}
#endif /*HAVE_GIFLIB*/
/**
* vips_gifload:
* @filename: file to load
* @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 VIPS image. Rendering uses the giflib library.
*
* 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, with each individual page aligned to the
* left. Set to -1 to mean "until the end of the document". Use vips_grid()
* to change page layout.
*
* The whole GIF is rendered into memory on header access. The output image
* will be 1, 2, 3 or 4 bands depending on what the reader finds in the file.
*
* 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: memory area to load
* @len: size of memory area
* @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 );
}
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