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Merge pull request #518 from UlysseM/master 

Better support for exif resolution
This commit is contained in:
John Cupitt 2016-09-07 13:52:09 +01:00 committed by GitHub
parent 0ac65161cc af4282e0e2
commit 9f9c077974
1 changed files with 61 additions and 8 deletions
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69
libvips/foreign/jpeg2vips.c
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@ -76,6 +76,9 @@
* - switch to new orientation tag
* 11/7/16
* - new --fail handling
* 07/09/16
* - Don't use the exif resolution if x_resolution / y_resolution /
* resolution_unit is missing
*/
/*
@ -347,6 +350,19 @@ show_values( ExifData *data )
#endif /*HAVE_EXIF*/
#ifdef HAVE_EXIF
static ExifData*
vips_exif_load_data_without_fix(const unsigned char* data, unsigned int size)
{
ExifData *edata = exif_data_new();
if ( !edata )
return NULL;
exif_data_unset_option(edata, EXIF_DATA_OPTION_FOLLOW_SPECIFICATION);
exif_data_load_data (edata, data, size);
return edata;
}
static int
vips_exif_get_int( ExifData *ed,
ExifEntry *entry, unsigned long component, int *out )
@ -526,6 +542,34 @@ get_entry_double( ExifData *ed, int ifd, ExifTag tag, double *out )
return( vips_exif_get_double( ed, entry, 0, out ) );
}
static void
set_entry_double( ExifData *ed, int ifd, ExifTag tag, double in)
{
ExifEntry *entry;
if( (entry = exif_content_get_entry( ed->ifd[ifd], tag )) ) {
/* Let's remove the current value */
exif_content_remove_entry( ed->ifd[ifd], entry );
entry = NULL;
}
if ( !( entry = exif_entry_new() ) )
return;
entry->tag = tag;
exif_content_add_entry( ed->ifd[ifd], entry );
exif_entry_initialize( entry, tag );
/* This is a simple yet sufficient implementation */
ExifRational value;
value.numerator = in * 1000;
value.denominator = 1000;
if ( entry->data )
exif_set_rational( entry->data, exif_data_get_byte_order( ed ), value );
}
static int
get_entry_int( ExifData *ed, int ifd, ExifTag tag, int *out )
{
@ -538,7 +582,7 @@ get_entry_int( ExifData *ed, int ifd, ExifTag tag, int *out )
return( vips_exif_get_int( ed, entry, 0, out ) );
}
static void
static int
res_from_exif( VipsImage *im, ExifData *ed )
{
double xres, yres;
@ -552,7 +596,7 @@ res_from_exif( VipsImage *im, ExifData *ed )
get_entry_int( ed, 0, EXIF_TAG_RESOLUTION_UNIT, &unit ) ) {
vips_warn( "VipsJpeg",
"%s", _( "error reading resolution" ) );
return;
return( -1 );
}
#ifdef DEBUG
@ -589,7 +633,7 @@ res_from_exif( VipsImage *im, ExifData *ed )
default:
vips_warn( "VipsJpeg",
"%s", _( "unknown EXIF resolution unit" ) );
return;
return( -1 );
}
#ifdef DEBUG
@ -599,6 +643,8 @@ res_from_exif( VipsImage *im, ExifData *ed )
im->Xres = xres;
im->Yres = yres;
return( 0 );
}
static int
@ -626,7 +672,7 @@ parse_exif( VipsImage *im, void *data, int data_length )
ExifData *ed;
VipsExif ve;
if( !(ed = exif_data_new_from_data( data, data_length )) )
if( !(ed = vips_exif_load_data_without_fix( data, data_length )) )
return( -1 );
#ifdef DEBUG_VERBOSE
@ -645,16 +691,23 @@ parse_exif( VipsImage *im, void *data, int data_length )
*/
ve.image = im;
ve.ed = ed;
exif_data_foreach_content( ed,
(ExifDataForeachContentFunc) attach_exif_content, &ve );
/* Look for resolution fields and use them to set the VIPS
* xres/yres fields.
* If the fields are missing, write the one from the jfif.
*/
res_from_exif( im, ed );
if ( res_from_exif( im, ed ) ) {
set_entry_double( ed, 0, EXIF_TAG_X_RESOLUTION, im->Xres );
set_entry_double( ed, 0, EXIF_TAG_Y_RESOLUTION, im->Yres );
}
/* Let's make sure the fields are valid. */
exif_data_fix( ed );
exif_data_foreach_content( ed,
(ExifDataForeachContentFunc) attach_exif_content, &ve );
attach_thumbnail( im, ed );
exif_data_free( ed );
}
#endif /*HAVE_EXIF*/