/* Open an image, returning the best version of that image for thumbnailing.
*
* 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 ) {
int jpegshrink;
/* This will just read in the header and is quick.
*/
if( !(im = vips_image_new_from_file( filename, NULL )) )
return( NULL );
jpegshrink = thumbnail_find_jpegshrink( im );
g_object_unref( im );
vips_info( "vipsthumbnail",
"loading jpeg with factor %d pre-shrink",
jpegshrink );
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
"shrink", jpegshrink,
NULL )) )
return( NULL );
}
else {
/* All other formats.
*/
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
NULL )) )
return( NULL );
}
vips_object_local( process, im );
return( im );
}
/* Try to read an embedded thumbnail.
*/
static VipsImage *
thumbnail_get_thumbnail( VipsImage *im )
{
void *ptr;
size_t size;
VipsImage *thumb;
double residual;
int jpegshrink;
if( !vips_image_get_typeof( im, THUMBNAIL ) ||
vips_image_get_blob( im, THUMBNAIL, &ptr, &size ) ||
vips_jpegload_buffer( ptr, size, &thumb, NULL ) ) {
vips_info( "vipsthumbnail", "no jpeg thumbnail" );
return( NULL );
}
calculate_shrink( thumb->Xsize, thumb->Ysize, &residual );
if( residual > 1.0 ) {
vips_info( "vipsthumbnail", "jpeg thumbnail too small" );
g_object_unref( thumb );
return( NULL );
}
/* Reload with the correct downshrink.
*/
jpegshrink = thumbnail_find_jpegshrink( thumb );
vips_info( "vipsthumbnail",
"loading jpeg thumbnail with factor %d pre-shrink",
jpegshrink );
g_object_unref( thumb );
if( vips_jpegload_buffer( ptr, size, &thumb,
"shrink", jpegshrink,
NULL ) ) {
vips_info( "vipsthumbnail", "jpeg thumbnail reload failed" );
return( NULL );
}
vips_info( "vipsthumbnail", "using %dx%d jpeg thumbnail",
thumb->Xsize, thumb->Ysize );
return( thumb );
}
/* Open an image, returning the best version of that image for thumbnailing.
*
* 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 ) {
int jpegshrink;
/* This will just read in the header and is quick.
*/
if( !(im = vips_image_new_from_file( filename, NULL )) )
return( NULL );
jpegshrink = thumbnail_find_jpegshrink( im );
g_object_unref( im );
vips_info( "vipsthumbnail",
"loading jpeg with factor %d pre-shrink",
jpegshrink );
/* We can't use UNBUFERRED safely on very-many-core systems.
*/
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
"shrink", jpegshrink,
NULL )) )
return( NULL );
}
else if( strcmp( loader, "VipsForeignLoadPdfFile" ) == 0 ||
strcmp( loader, "VipsForeignLoadSvgFile" ) == 0 ) {
double shrink;
/* This will just read in the header and is quick.
*/
if( !(im = vips_image_new_from_file( filename, NULL )) )
return( NULL );
shrink = calculate_shrink( im );
g_object_unref( im );
vips_info( "vipsthumbnail",
"loading PDF/SVG with factor %g pre-shrink",
shrink );
/* We can't use UNBUFERRED safely on very-many-core systems.
*/
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
"scale", 1.0 / shrink,
NULL )) )
return( NULL );
}
else if( strcmp( loader, "VipsForeignLoadWebpFile" ) == 0 ) {
double shrink;
/* This will just read in the header and is quick.
*/
if( !(im = vips_image_new_from_file( filename, NULL )) )
return( NULL );
shrink = calculate_shrink( im );
g_object_unref( im );
vips_info( "vipsthumbnail",
"loading webp with factor %g pre-shrink",
shrink );
/* We can't use UNBUFERRED safely on very-many-core systems.
*/
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
"shrink", (int) shrink,
NULL )) )
return( NULL );
}
else {
/* All other formats. We can't use UNBUFERRED safely on
* very-many-core systems.
*/
if( !(im = vips_image_new_from_file( filename,
"access", VIPS_ACCESS_SEQUENTIAL,
NULL )) )
return( NULL );
}
vips_object_local( process, im );
return( im );
}
/* 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 );
}
