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fix cast on uint images

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we could get sign and overflow mixed up for casts on uint images

see https://github.com/libvips/nip2/issues/74
This commit is contained in:
John Cupitt 2018-11-14 17:07:49 +00:00
parent b84bf6d4f4
commit 07d58f81b3
2 changed files with 76 additions and 137 deletions
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1
ChangeLog
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@ -4,6 +4,7 @@
- add XMP support to png read/write [jcupitt] - add XMP support to png read/write [jcupitt]
- deprecate thumbnail auto_rotate, add no_rotate [jcupitt] - deprecate thumbnail auto_rotate, add no_rotate [jcupitt]
- implement thumbnail shrink-on-load for openslide images [jcupitt] - implement thumbnail shrink-on-load for openslide images [jcupitt]
- revise vips_cast() to improve behaviour with uint images [erdmann]
23/9/18 started 8.7.1 23/9/18 started 8.7.1
- update function list in docs [janko-m] - update function list in docs [janko-m]

212
libvips/conversion/cast.c
View File

@ -51,6 +51,9 @@
* - add @shift option * - add @shift option
* 1/3/16 * 1/3/16
* - better behaviour for shift of non-int types (thanks apacheark) * - better behaviour for shift of non-int types (thanks apacheark)
* 14/11/18
* - revise for better uint/int clipping [erdmann]
* - remove old overflow/underflow detect
*/ */
/* /*
@ -107,84 +110,30 @@ typedef struct _VipsCast {
VipsBandFormat format; VipsBandFormat format;
gboolean shift; gboolean shift;
int underflow; /* Number of underflows */
int overflow; /* Number of overflows */
} VipsCast; } VipsCast;
typedef VipsConversionClass VipsCastClass; typedef VipsConversionClass VipsCastClass;
G_DEFINE_TYPE( VipsCast, vips_cast, VIPS_TYPE_CONVERSION ); G_DEFINE_TYPE( VipsCast, vips_cast, VIPS_TYPE_CONVERSION );
static void /* Various saturated casts. We want to cast int to uchar, for example, and
vips_cast_preeval( VipsImage *image, VipsProgress *progress, VipsCast *cast ) * clip the range. X is an int.
{
cast->overflow = 0;
cast->underflow = 0;
}
static void
vips_cast_posteval( VipsImage *image, VipsProgress *progress, VipsCast *cast )
{
if( cast->overflow ||
cast->underflow )
g_warning( _( "%d underflows and %d overflows detected" ),
cast->underflow, cast->overflow );
}
/* Our sequence value: the region this sequence is using, and two local stats.
*/ */
typedef struct {
VipsRegion *ir; /* Input region */
int underflow; /* Number of underflows */ #define CAST_UCHAR( X ) VIPS_CLIP( 0, (X), UCHAR_MAX )
int overflow; /* Number of overflows */ #define CAST_CHAR( X ) VIPS_CLIP( SCHAR_MIN, (X), SCHAR_MAX )
} VipsCastSequence; #define CAST_USHORT( X ) VIPS_CLIP( 0, (X), USHRT_MAX )
#define CAST_SHORT( X ) VIPS_CLIP( SHRT_MIN, (X), SHRT_MAX )
/* Destroy a sequence value. /* We know the source cannot be the same as the dest, so we will only use
* CAST_UINT() for an INT source, and vice versa.
*/ */
static int #define CAST_UINT( X ) VIPS_MAX( 0, (X) )
vips_cast_stop( void *vseq, void *a, void *b ) #define CAST_INT( X ) VIPS_MIN( (X), INT_MAX )
{
VipsCastSequence *seq = (VipsCastSequence *) vseq;
VipsCast *cast = (VipsCast *) b;
/* Add to global stats.
*/
cast->underflow += seq->underflow;
cast->overflow += seq->overflow;
VIPS_FREEF( g_object_unref, seq->ir );
g_free( seq );
return( 0 );
}
/* Make a sequence value.
*/
static void *
vips_cast_start( VipsImage *out, void *a, void *b )
{
VipsImage *in = (VipsImage *) a;
VipsCastSequence *seq;
seq = g_new( VipsCastSequence, 1 );
seq->ir = vips_region_new( in );
seq->overflow = 0;
seq->underflow = 0;
if( !seq->ir ) {
vips_cast_stop( seq, a, b );
return( NULL );
}
return( seq );
}
/* Rightshift an integer type, ie. sizeof(ITYPE) > sizeof(OTYPE). /* Rightshift an integer type, ie. sizeof(ITYPE) > sizeof(OTYPE).
*/ */
#define VIPS_SHIFT_RIGHT( ITYPE, OTYPE ) { \ #define SHIFT_RIGHT( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
int n = ((int) sizeof( ITYPE ) << 3) - ((int) sizeof( OTYPE ) << 3); \ int n = ((int) sizeof( ITYPE ) << 3) - ((int) sizeof( OTYPE ) << 3); \
@ -198,7 +147,7 @@ vips_cast_start( VipsImage *out, void *a, void *b )
/* Leftshift an integer type, ie. sizeof(ITYPE) < sizeof(OTYPE). We need to /* Leftshift an integer type, ie. sizeof(ITYPE) < sizeof(OTYPE). We need to
* copy the bottom bit up into the fresh new bits * copy the bottom bit up into the fresh new bits
*/ */
#define VIPS_SHIFT_LEFT( ITYPE, OTYPE ) { \ #define SHIFT_LEFT( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
int n = ((int) sizeof( OTYPE ) << 3) - ((int) sizeof( ITYPE ) << 3); \ int n = ((int) sizeof( OTYPE ) << 3) - ((int) sizeof( ITYPE ) << 3); \
@ -209,70 +158,66 @@ vips_cast_start( VipsImage *out, void *a, void *b )
q[x] = (p[x] << n) | (((p[x] & 1) << n) - (p[x] & 1)); \ q[x] = (p[x] << n) | (((p[x] & 1) << n) - (p[x] & 1)); \
} }
/* Cast int types to an int type. /* Cast int types to an int type. We need to pass in the type of the
* intermediate value, either uint or int, or we'll have problems with uint
* sources turning -ve.
*/ */
#define VIPS_CLIP_INT_INT( ITYPE, OTYPE, VIPS_CLIP ) { \ #define CAST_INT_INT( ITYPE, OTYPE, TEMP, CAST ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
for( x = 0; x < sz; x++ ) { \ for( x = 0; x < sz; x++ ) { \
int t = p[x]; \ TEMP t = (TEMP) p[x]; \
\ \
VIPS_CLIP( t, seq ); \ q[x] = CAST( t ); \
\
q[x] = t; \
} \ } \
} }
/* Int to int handling. /* Int to int handling.
*/ */
#define VIPS_INT_INT( ITYPE, OTYPE, VIPS_CLIP ) { \ #define INT_INT( ITYPE, OTYPE, TEMP, CAST ) { \
if( cast->shift && \ if( cast->shift && \
sizeof( ITYPE ) > sizeof( OTYPE ) ) { \ sizeof( ITYPE ) > sizeof( OTYPE ) ) { \
VIPS_SHIFT_RIGHT( ITYPE, OTYPE ); \ SHIFT_RIGHT( ITYPE, OTYPE ); \
} \ } \
else if( cast->shift ) { \ else if( cast->shift ) { \
VIPS_SHIFT_LEFT( ITYPE, OTYPE ); \ SHIFT_LEFT( ITYPE, OTYPE ); \
} \ } \
else { \ else { \
VIPS_CLIP_INT_INT( ITYPE, OTYPE, VIPS_CLIP ); \ CAST_INT_INT( ITYPE, OTYPE, TEMP, CAST ); \
} \ } \
} }
/* Cast float types to an int type. /* Cast float types to an int type.
*/ */
#define VIPS_CLIP_FLOAT_INT( ITYPE, OTYPE, VIPS_CLIP ) { \ #define CAST_FLOAT_INT( ITYPE, OTYPE, TEMP, CAST ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
for( x = 0; x < sz; x++ ) { \ for( x = 0; x < sz; x++ ) { \
ITYPE v = VIPS_FLOOR( p[x] ); \ TEMP v = VIPS_FLOOR( p[x] ); \
\ \
VIPS_CLIP( v, seq ); \ q[x] = CAST( v ); \
\
q[x] = v; \
} \ } \
} }
/* Cast complex types to an int type. Just take the real part. /* Cast complex types to an int type. Just take the real part.
*/ */
#define VIPS_CLIP_COMPLEX_INT( ITYPE, OTYPE, VIPS_CLIP ) { \ #define CAST_COMPLEX_INT( ITYPE, OTYPE, TEMP, CAST ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
for( x = 0; x < sz; x++ ) { \ for( x = 0; x < sz; x++ ) { \
ITYPE v = VIPS_FLOOR( p[0] ); \ TEMP v = VIPS_FLOOR( p[0] ); \
\
p += 2; \ p += 2; \
\ q[x] = CAST( v ); \
VIPS_CLIP( v, seq ); \
\
q[x] = v; \
} \ } \
} }
/* Cast non-complex types to a float type. /* Cast non-complex types to a float type.
*/ */
#define VIPS_CLIP_REAL_FLOAT( ITYPE, OTYPE ) { \ #define CAST_REAL_FLOAT( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
@ -282,7 +227,7 @@ vips_cast_start( VipsImage *out, void *a, void *b )
/* Cast complex types to a float type ... just take real. /* Cast complex types to a float type ... just take real.
*/ */
#define VIPS_CLIP_COMPLEX_FLOAT( ITYPE, OTYPE ) { \ #define CAST_COMPLEX_FLOAT( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
@ -294,7 +239,7 @@ vips_cast_start( VipsImage *out, void *a, void *b )
/* Cast any non-complex to a complex type ... set imaginary to zero. /* Cast any non-complex to a complex type ... set imaginary to zero.
*/ */
#define VIPS_CLIP_REAL_COMPLEX( ITYPE, OTYPE ) { \ #define CAST_REAL_COMPLEX( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
@ -307,7 +252,7 @@ vips_cast_start( VipsImage *out, void *a, void *b )
/* Cast any complex to a complex type. /* Cast any complex to a complex type.
*/ */
#define VIPS_CLIP_COMPLEX_COMPLEX( ITYPE, OTYPE ) { \ #define CAST_COMPLEX_COMPLEX( ITYPE, OTYPE ) { \
ITYPE * restrict p = (ITYPE *) in; \ ITYPE * restrict p = (ITYPE *) in; \
OTYPE * restrict q = (OTYPE *) out; \ OTYPE * restrict q = (OTYPE *) out; \
\ \
@ -322,27 +267,27 @@ vips_cast_start( VipsImage *out, void *a, void *b )
#define BAND_SWITCH_INNER( ITYPE, INT, FLOAT, COMPLEX ) { \ #define BAND_SWITCH_INNER( ITYPE, INT, FLOAT, COMPLEX ) { \
switch( conversion->out->BandFmt ) { \ switch( conversion->out->BandFmt ) { \
case VIPS_FORMAT_UCHAR: \ case VIPS_FORMAT_UCHAR: \
INT( ITYPE, unsigned char, VIPS_CLIP_UCHAR ); \ INT( ITYPE, unsigned char, unsigned int, CAST_UCHAR ); \
break; \ break; \
\ \
case VIPS_FORMAT_CHAR: \ case VIPS_FORMAT_CHAR: \
INT( ITYPE, signed char, VIPS_CLIP_CHAR ); \ INT( ITYPE, signed char, int, CAST_CHAR ); \
break; \ break; \
\ \
case VIPS_FORMAT_USHORT: \ case VIPS_FORMAT_USHORT: \
INT( ITYPE, unsigned short, VIPS_CLIP_USHORT ); \ INT( ITYPE, unsigned short, unsigned int, CAST_USHORT ); \
break; \ break; \
\ \
case VIPS_FORMAT_SHORT: \ case VIPS_FORMAT_SHORT: \
INT( ITYPE, signed short, VIPS_CLIP_SHORT ); \ INT( ITYPE, signed short, int, CAST_SHORT ); \
break; \ break; \
\ \
case VIPS_FORMAT_UINT: \ case VIPS_FORMAT_UINT: \
INT( ITYPE, unsigned int, VIPS_CLIP_UINT ); \ INT( ITYPE, unsigned int, unsigned int, CAST_UINT ); \
break; \ break; \
\ \
case VIPS_FORMAT_INT: \ case VIPS_FORMAT_INT: \
INT( ITYPE, signed int, VIPS_CLIP_NONE ); \ INT( ITYPE, signed int, int, CAST_INT ); \
break; \ break; \
\ \
case VIPS_FORMAT_FLOAT: \ case VIPS_FORMAT_FLOAT: \
@ -367,11 +312,9 @@ vips_cast_start( VipsImage *out, void *a, void *b )
} }
static int static int
vips_cast_gen( VipsRegion *or, void *vseq, void *a, void *b, vips_cast_gen( VipsRegion *or, void *vseq, void *a, void *b, gboolean *stop )
gboolean *stop )
{ {
VipsCastSequence *seq = (VipsCastSequence *) vseq; VipsRegion *ir = (VipsRegion *) vseq;
VipsRegion *ir = seq->ir;
VipsCast *cast = (VipsCast *) b; VipsCast *cast = (VipsCast *) b;
VipsConversion *conversion = (VipsConversion *) b; VipsConversion *conversion = (VipsConversion *) b;
VipsRect *r = &or->valid; VipsRect *r = &or->valid;
@ -391,72 +334,72 @@ vips_cast_gen( VipsRegion *or, void *vseq, void *a, void *b,
switch( ir->im->BandFmt ) { switch( ir->im->BandFmt ) {
case VIPS_FORMAT_UCHAR: case VIPS_FORMAT_UCHAR:
BAND_SWITCH_INNER( unsigned char, BAND_SWITCH_INNER( unsigned char,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_CHAR: case VIPS_FORMAT_CHAR:
BAND_SWITCH_INNER( signed char, BAND_SWITCH_INNER( signed char,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_USHORT: case VIPS_FORMAT_USHORT:
BAND_SWITCH_INNER( unsigned short, BAND_SWITCH_INNER( unsigned short,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_SHORT: case VIPS_FORMAT_SHORT:
BAND_SWITCH_INNER( signed short, BAND_SWITCH_INNER( signed short,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_UINT: case VIPS_FORMAT_UINT:
BAND_SWITCH_INNER( unsigned int, BAND_SWITCH_INNER( unsigned int,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_INT: case VIPS_FORMAT_INT:
BAND_SWITCH_INNER( signed int, BAND_SWITCH_INNER( signed int,
VIPS_INT_INT, INT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_FLOAT: case VIPS_FORMAT_FLOAT:
BAND_SWITCH_INNER( float, BAND_SWITCH_INNER( float,
VIPS_CLIP_FLOAT_INT, CAST_FLOAT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_DOUBLE: case VIPS_FORMAT_DOUBLE:
BAND_SWITCH_INNER( double, BAND_SWITCH_INNER( double,
VIPS_CLIP_FLOAT_INT, CAST_FLOAT_INT,
VIPS_CLIP_REAL_FLOAT, CAST_REAL_FLOAT,
VIPS_CLIP_REAL_COMPLEX ); CAST_REAL_COMPLEX );
break; break;
case VIPS_FORMAT_COMPLEX: case VIPS_FORMAT_COMPLEX:
BAND_SWITCH_INNER( float, BAND_SWITCH_INNER( float,
VIPS_CLIP_COMPLEX_INT, CAST_COMPLEX_INT,
VIPS_CLIP_COMPLEX_FLOAT, CAST_COMPLEX_FLOAT,
VIPS_CLIP_COMPLEX_COMPLEX ); CAST_COMPLEX_COMPLEX );
break; break;
case VIPS_FORMAT_DPCOMPLEX: case VIPS_FORMAT_DPCOMPLEX:
BAND_SWITCH_INNER( double, BAND_SWITCH_INNER( double,
VIPS_CLIP_COMPLEX_INT, CAST_COMPLEX_INT,
VIPS_CLIP_COMPLEX_FLOAT, CAST_COMPLEX_FLOAT,
VIPS_CLIP_COMPLEX_COMPLEX ); CAST_COMPLEX_COMPLEX );
break; break;
default: default:
@ -513,13 +456,8 @@ vips_cast_build( VipsObject *object )
conversion->out->BandFmt = cast->format; conversion->out->BandFmt = cast->format;
g_signal_connect( in, "preeval",
G_CALLBACK( vips_cast_preeval ), cast );
g_signal_connect( in, "posteval",
G_CALLBACK( vips_cast_posteval ), cast );
if( vips_image_generate( conversion->out, if( vips_image_generate( conversion->out,
vips_cast_start, vips_cast_gen, vips_cast_stop, vips_start_one, vips_cast_gen, vips_stop_one,
in, cast ) ) in, cast ) )
return( -1 ); return( -1 );