/* Find the best jpeg preload shrink.
*/
static int
thumbnail_find_jpegshrink( VipsImage *im )
{
double shrink = calculate_shrink( im );
/* We can't use pre-shrunk images in linear mode. libjpeg shrinks in Y
* (of YCbCR), not linear space.
*/
if( linear_processing )
return( 1 );
/* Shrink-on-load is a simple block shrink and will add quite a bit of
* extra sharpness to the image. We want to block shrink to a
* bit above our target, then vips_resize() to the final size.
*
* Leave at least a factor of two for the final resize step.
*/
if( shrink >= 16 )
return( 8 );
else if( shrink >= 8 )
return( 4 );
else if( shrink >= 4 )
return( 2 );
else
return( 1 );
}
static int
thumbnail3( IMAGE *in, IMAGE *out )
{
int shrink;
double residual;
VipsInterpolate *interp;
int result;
shrink = calculate_shrink( in->Xsize, in->Ysize, &residual );
/* For images smaller than the thumbnail, we upscale with nearest
* neighbor. Otherwise we makes thumbnails that look fuzzy and awful.
*/
if( !(interp = VIPS_INTERPOLATE( vips_object_new_from_string(
g_type_class_ref( VIPS_TYPE_INTERPOLATE ),
residual > 1.0 ? "nearest" : interpolator ) )) )
return( -1 );
if( verbose ) {
printf( "integer shrink by %d\n", shrink );
printf( "residual scale by %g\n", residual );
printf( "%s interpolation\n",
VIPS_OBJECT_GET_CLASS( interp )->nickname );
}
result = shrink_factor( in, out, shrink, residual, interp );
g_object_unref( interp );
return( result );
}
/* 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 );
}
/* JPEGs get special treatment. libjpeg supports fast shrink-on-read,
* so if we have a JPEG, we can ask VIPS to load a lower resolution
* version.
*/
static int
thumbnail( const char *filename )
{
VipsFormatClass *format;
int shrink;
if( verbose )
printf( "thumbnailing %s\n", filename );
if( !(format = vips_format_for_file( filename )) )
return( -1 );
if( verbose )
printf( "detected format as %s\n",
VIPS_OBJECT_CLASS( format )->nickname );
shrink = 1;
if( strcmp( VIPS_OBJECT_CLASS( format )->nickname, "jpeg" ) == 0 ) {
IMAGE *im;
/* This will just read in the header and is quick.
*/
if( !(im = im_open( filename, "r" )) )
return( -1 );
shrink = calculate_shrink( im->Xsize, im->Ysize, NULL );
im_close( im );
if( shrink > 8 )
shrink = 8;
else if( shrink > 4 )
shrink = 4;
else if( shrink > 2 )
shrink = 2;
else
shrink = 1;
if( verbose )
printf( "using fast jpeg shrink, factor %d\n", shrink );
}
return( thumbnail2( filename, shrink ) );
}
static VipsInterpolate *
thumbnail_interpolator( VipsObject *process, VipsImage *in )
{
double residual;
VipsInterpolate *interp;
calculate_shrink( in, &residual );
/* For images smaller than the thumbnail, we upscale with nearest
* neighbor. Otherwise we makes thumbnails that look fuzzy and awful.
*/
if( !(interp = VIPS_INTERPOLATE( vips_object_new_from_string(
g_type_class_ref( VIPS_TYPE_INTERPOLATE ),
residual > 1.0 ? "nearest" : interpolator ) )) )
return( NULL );
vips_object_local( process, interp );
return( interp );
}
/* Find the best jpeg preload shrink.
*/
static int
thumbnail_find_jpegshrink( VipsImage *im )
{
int shrink = calculate_shrink( im, NULL );
/* We can't use pre-shrunk images in linear mode. libjpeg shrinks in Y
* (of YCbCR), not linear space.
*/
if( linear_processing )
return( 1 );
else if( shrink >= 8 )
return( 8 );
else if( shrink >= 4 )
return( 4 );
else if( shrink >= 2 )
return( 2 );
else
return( 1 );
}
static VipsImage *
thumbnail_shrink( VipsObject *process, VipsImage *in,
VipsInterpolate *interp, VipsImage *sharpen )
{
VipsImage **t = (VipsImage **) vips_object_local_array( process, 10 );
VipsInterpretation interpretation = linear_processing ?
VIPS_INTERPRETATION_XYZ : VIPS_INTERPRETATION_sRGB;
int shrink;
double residual;
int tile_width;
int tile_height;
int nlines;
/* RAD needs special unpacking.
*/
if( in->Coding == VIPS_CODING_RAD ) {
vips_info( "vipsthumbnail", "unpacking Rad to float" );
/* rad is scrgb.
*/
if( vips_rad2float( in, &t[0], NULL ) )
return( NULL );
in = t[0];
}
/* In linear mode, we import right at the start.
*
* This is only going to work for images in device space. If you have
* an image in PCS which also has an attached profile, strange things
* will happen.
*/
if( linear_processing &&
in->Coding == VIPS_CODING_NONE &&
(in->BandFmt == VIPS_FORMAT_UCHAR ||
in->BandFmt == VIPS_FORMAT_USHORT) &&
(vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ||
import_profile) ) {
if( vips_image_get_typeof( in, VIPS_META_ICC_NAME ) )
vips_info( "vipsthumbnail",
"importing with embedded profile" );
else
vips_info( "vipsthumbnail",
"importing with profile %s", import_profile );
if( vips_icc_import( in, &t[1],
"input_profile", import_profile,
"embedded", TRUE,
"pcs", VIPS_PCS_XYZ,
NULL ) )
return( NULL );
in = t[1];
}
/* To the processing colourspace. This will unpack LABQ as well.
*/
vips_info( "vipsthumbnail", "converting to processing space %s",
vips_enum_nick( VIPS_TYPE_INTERPRETATION, interpretation ) );
if( vips_colourspace( in, &t[2], interpretation, NULL ) )
return( NULL );
in = t[2];
shrink = calculate_shrink( in, &residual );
vips_info( "vipsthumbnail", "integer shrink by %d", shrink );
if( vips_shrink( in, &t[3], shrink, shrink, NULL ) )
return( NULL );
in = t[3];
/* We want to make sure we read the image sequentially.
* However, the convolution we may be doing later will force us
* into SMALLTILE or maybe FATSTRIP mode and that will break
* sequentiality.
*
* So ... read into a cache where tiles are scanlines, and make sure
* we keep enough scanlines to be able to serve a line of tiles.
*
* We use a threaded tilecache to avoid a deadlock: suppose thread1,
* evaluating the top block of the output, is delayed, and thread2,
* evaluating the second block, gets here first (this can happen on
* a heavily-loaded system).
*
* With an unthreaded tilecache (as we had before), thread2 will get
* the cache lock and start evaling the second block of the shrink.
* When it reaches the png reader it will stall until the first block
* has been used ... but it never will, since thread1 will block on
* this cache lock.
*/
vips_get_tile_size( in,
&tile_width, &tile_height, &nlines );
if( vips_tilecache( in, &t[4],
"tile_width", in->Xsize,
"tile_height", 10,
"max_tiles", (nlines * 2) / 10,
"access", VIPS_ACCESS_SEQUENTIAL,
"threaded", TRUE,
NULL ) ||
vips_affine( t[4], &t[5], residual, 0, 0, residual,
"interpolate", interp,
NULL ) )
return( NULL );
in = t[5];
vips_info( "vipsthumbnail", "residual scale by %g", residual );
vips_info( "vipsthumbnail", "%s interpolation",
VIPS_OBJECT_GET_CLASS( interp )->nickname );
/* Colour management.
*
* In linear mode, just export. In device space mode, do a combined
* import/export to transform to the target space.
*/
if( linear_processing ) {
if( export_profile ||
vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
vips_info( "vipsthumbnail",
"exporting to device space with a profile" );
if( vips_icc_export( in, &t[7],
"output_profile", export_profile,
NULL ) )
return( NULL );
in = t[7];
}
else {
vips_info( "vipsthumbnail", "converting to sRGB" );
if( vips_colourspace( in, &t[6],
VIPS_INTERPRETATION_sRGB, NULL ) )
return( NULL );
in = t[6];
}
}
else if( export_profile &&
(vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ||
import_profile) ) {
if( vips_image_get_typeof( in, VIPS_META_ICC_NAME ) )
vips_info( "vipsthumbnail",
"importing with embedded profile" );
else
vips_info( "vipsthumbnail",
"importing with profile %s", import_profile );
vips_info( "vipsthumbnail",
"exporting with profile %s", export_profile );
if( vips_icc_transform( in, &t[6], export_profile,
"input_profile", import_profile,
"embedded", TRUE,
NULL ) )
return( NULL );
in = t[6];
}
/* If we are upsampling, don't sharpen, since nearest looks dumb
* sharpened.
*/
if( shrink >= 1 &&
residual <= 1.0 &&
sharpen ) {
vips_info( "vipsthumbnail", "sharpening thumbnail" );
if( vips_conv( in, &t[8], sharpen, NULL ) )
return( NULL );
in = t[8];
}
if( delete_profile &&
vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
vips_info( "vipsthumbnail",
"deleting profile from output image" );
if( !vips_image_remove( in, VIPS_META_ICC_NAME ) )
return( NULL );
}
return( in );
}
static VipsImage *
thumbnail_shrink( VipsObject *process, VipsImage *in )
{
VipsImage **t = (VipsImage **) vips_object_local_array( process, 10 );
VipsInterpretation interpretation = linear_processing ?
VIPS_INTERPRETATION_XYZ : VIPS_INTERPRETATION_sRGB;
/* TRUE if we've done the import of an ICC transform and still need to
* export.
*/
gboolean have_imported;
/* TRUE if we've premultiplied and need to unpremultiply.
*/
gboolean have_premultiplied;
VipsBandFormat unpremultiplied_format;
/* Sniff the incoming image and try to guess what the alpha max is.
*/
double max_alpha;
double shrink;
/* RAD needs special unpacking.
*/
if( in->Coding == VIPS_CODING_RAD ) {
vips_info( "vipsthumbnail", "unpacking Rad to float" );
/* rad is scrgb.
*/
if( vips_rad2float( in, &t[0], NULL ) )
return( NULL );
in = t[0];
}
/* Try to guess what the maximum alpha might be.
*/
max_alpha = 255;
if( in->BandFmt == VIPS_FORMAT_USHORT )
max_alpha = 65535;
/* In linear mode, we import right at the start.
*
* We also have to import the whole image if it's CMYK, since
* vips_colourspace() (see below) doesn't know about CMYK.
*
* This is only going to work for images in device space. If you have
* an image in PCS which also has an attached profile, strange things
* will happen.
*/
have_imported = FALSE;
if( (linear_processing ||
in->Type == VIPS_INTERPRETATION_CMYK) &&
in->Coding == VIPS_CODING_NONE &&
(in->BandFmt == VIPS_FORMAT_UCHAR ||
in->BandFmt == VIPS_FORMAT_USHORT) &&
(vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ||
import_profile) ) {
if( vips_image_get_typeof( in, VIPS_META_ICC_NAME ) )
vips_info( "vipsthumbnail",
"importing with embedded profile" );
else
vips_info( "vipsthumbnail",
"importing with profile %s", import_profile );
if( vips_icc_import( in, &t[1],
"input_profile", import_profile,
"embedded", TRUE,
"pcs", VIPS_PCS_XYZ,
NULL ) )
return( NULL );
in = t[1];
have_imported = TRUE;
}
/* To the processing colourspace. This will unpack LABQ as well.
*/
vips_info( "vipsthumbnail", "converting to processing space %s",
vips_enum_nick( VIPS_TYPE_INTERPRETATION, interpretation ) );
if( vips_colourspace( in, &t[2], interpretation, NULL ) )
return( NULL );
in = t[2];
/* If there's an alpha, we have to premultiply before shrinking. See
* https://github.com/jcupitt/libvips/issues/291
*/
have_premultiplied = FALSE;
if( in->Bands == 2 ||
(in->Bands == 4 && in->Type != VIPS_INTERPRETATION_CMYK) ||
in->Bands == 5 ) {
vips_info( "vipsthumbnail", "premultiplying alpha" );
if( vips_premultiply( in, &t[3],
"max_alpha", max_alpha,
NULL ) )
return( NULL );
have_premultiplied = TRUE;
/* vips_premultiply() makes a float image. When we
* vips_unpremultiply() below, we need to cast back to the
* pre-premultiply format.
*/
unpremultiplied_format = in->BandFmt;
in = t[3];
}
shrink = calculate_shrink( in );
if( vips_resize( in, &t[4], 1.0 / shrink, NULL ) )
return( NULL );
in = t[4];
if( have_premultiplied ) {
vips_info( "vipsthumbnail", "unpremultiplying alpha" );
if( vips_unpremultiply( in, &t[5],
"max_alpha", max_alpha,
NULL ) ||
vips_cast( t[5], &t[6], unpremultiplied_format, NULL ) )
return( NULL );
in = t[6];
}
/* Colour management.
*
* If we've already imported, just export. Otherwise, we're in
* device space and we need a combined import/export to transform to
* the target space.
*/
if( have_imported ) {
if( export_profile ||
vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
vips_info( "vipsthumbnail",
"exporting to device space with a profile" );
if( vips_icc_export( in, &t[7],
"output_profile", export_profile,
NULL ) )
return( NULL );
in = t[7];
}
else {
vips_info( "vipsthumbnail", "converting to sRGB" );
if( vips_colourspace( in, &t[7],
VIPS_INTERPRETATION_sRGB, NULL ) )
return( NULL );
in = t[7];
}
}
else if( export_profile &&
(vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ||
import_profile) ) {
VipsImage *out;
vips_info( "vipsthumbnail",
"exporting with profile %s", export_profile );
/* We first try with the embedded profile, if any, then if
* that fails try again with the supplied fallback profile.
*/
out = NULL;
if( vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
vips_info( "vipsthumbnail",
"importing with embedded profile" );
if( vips_icc_transform( in, &t[7], export_profile,
"embedded", TRUE,
NULL ) ) {
vips_warn( "vipsthumbnail",
_( "unable to import with "
"embedded profile: %s" ),
vips_error_buffer() );
vips_error_clear();
}
else
out = t[7];
}
if( !out &&
import_profile ) {
vips_info( "vipsthumbnail",
"importing with fallback profile" );
if( vips_icc_transform( in, &t[7], export_profile,
"input_profile", import_profile,
"embedded", FALSE,
NULL ) )
return( NULL );
out = t[7];
}
/* If the embedded profile failed and there's no fallback or
* the fallback failed, out will still be NULL.
*/
if( out )
in = out;
}
if( delete_profile &&
vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
vips_info( "vipsthumbnail",
"deleting profile from output image" );
if( !vips_image_remove( in, VIPS_META_ICC_NAME ) )
return( NULL );
}
return( in );
}
/* 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 );
}
