static int
thumbnail2( const char *filename, int shrink )
{
IMAGE *in;
IMAGE *out;
char *tn_filename;
int result;
/* Open in sequential mode.
*/
if( shrink > 1 ) {
if( vips_foreign_load( filename, &in,
"sequential", TRUE,
"shrink", shrink,
NULL ) )
return( -1 );
}
else {
if( vips_foreign_load( filename, &in,
"sequential", TRUE,
NULL ) )
return( -1 );
}
tn_filename = make_thumbnail_name( filename );
if( !(out = im_open( tn_filename, "w" )) ) {
im_close( in );
g_free( tn_filename );
return( -1 );
}
result = thumbnail3( in, out );
g_free( tn_filename );
im_close( out );
im_close( in );
return( result );
}
/* Open an image, returning the best version of that image for thumbnailing.
*
* jpegs can have embedded thumbnails ... use that if it's large enough.
*
* libjpeg supports fast shrink-on-read, so if we have a JPEG, we can ask
* VIPS to load a lower resolution version.
*/
static VipsImage *
thumbnail_open( VipsObject *process, const char *filename )
{
const char *loader;
VipsImage *im;
vips_info( "vipsthumbnail", "thumbnailing %s", filename );
if( linear_processing )
vips_info( "vipsthumbnail", "linear mode" );
if( !(loader = vips_foreign_find_load( filename )) )
return( NULL );
vips_info( "vipsthumbnail", "selected loader is %s", loader );
if( strcmp( loader, "VipsForeignLoadJpegFile" ) == 0 ) {
VipsImage *thumb;
/* This will just read in the header and is quick.
*/
if( !(im = vips_image_new_from_file( filename )) )
return( NULL );
/* Try to read an embedded thumbnail. If we find one, use that
* instead.
*/
if( (thumb = thumbnail_get_thumbnail( im )) ) {
/* @thumb has not been fully decoded yet ...
* we must not close @im
* until we're done with @thumb.
*/
vips_object_local( VIPS_OBJECT( thumb ), im );
im = thumb;
}
else {
int jpegshrink;
vips_info( "vipsthumbnail",
"processing main jpeg image" );
jpegshrink = thumbnail_find_jpegshrink( im );
g_object_unref( im );
vips_info( "vipsthumbnail",
"loading jpeg with factor %d pre-shrink",
jpegshrink );
if( vips_foreign_load( filename, &im,
"access", VIPS_ACCESS_SEQUENTIAL,
"shrink", jpegshrink,
NULL ) )
return( NULL );
}
}
else {
/* All other formats.
*/
if( vips_foreign_load( filename, &im,
"access", VIPS_ACCESS_SEQUENTIAL,
NULL ) )
return( NULL );
}
vips_object_local( process, im );
return( im );
}