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Adds MEAN and MEDIAN methods for region shrink

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This commit is contained in:
Simon Harris 2018-03-27 21:15:48 +11:00
parent cf36336e8e
commit eada4a7731
4 changed files with 121 additions and 32 deletions
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2
libvips/foreign/dzsave.c
View File

@ -1404,7 +1404,7 @@ strip_shrink( Layer *layer )
if( vips_rect_isempty( &target ) )
break;
(void) vips_region_shrink( from, to, &target );
(void) vips_region_shrink( from, to, &target, VIPS_REGION_SHRINK_MEAN );
below->write_y += target.height;

2
libvips/foreign/vips2tiff.c
View File

@ -1392,7 +1392,7 @@ layer_strip_shrink( Layer *layer )
if( vips_rect_isempty( &target ) )
break;
(void) vips_region_shrink( from, to, &target );
(void) vips_region_shrink( from, to, &target, VIPS_REGION_SHRINK_MEAN );
below->write_y += target.height;

9
libvips/include/vips/region.h
View File

@ -55,6 +55,12 @@ extern "C" {
(G_TYPE_INSTANCE_GET_CLASS( (obj), \
VIPS_TYPE_REGION, VipsRegionClass ))
typedef enum {
VIPS_REGION_SHRINK_MEAN,
VIPS_REGION_SHRINK_MEDIAN,
VIPS_REGION_SHRINK_LAST
} VipsRegionShrink;
/* Sub-area of image.
*/
typedef struct _VipsRegion {
@ -118,7 +124,8 @@ void vips_region_black( VipsRegion *reg );
void vips_region_copy( VipsRegion *reg, VipsRegion *dest,
const VipsRect *r, int x, int y );
int vips_region_shrink( VipsRegion *from,
VipsRegion *to, const VipsRect *target );
VipsRegion *to, const VipsRect *target,
VipsRegionShrink method );
int vips_region_prepare( VipsRegion *reg, const VipsRect *r );
int vips_region_prepare_to( VipsRegion *reg,

108
libvips/iofuncs/region.c
View File

@ -1166,7 +1166,7 @@ vips_region_shrink_labpack( VipsRegion *from,
}
}
#define SHRINK_TYPE_INT( TYPE ) \
#define SHRINK_TYPE_MEAN_INT( TYPE ) \
for( x = 0; x < target->width; x++ ) { \
TYPE *tp = (TYPE *) p; \
TYPE *tp1 = (TYPE *) (p + ls); \
@ -1185,7 +1185,7 @@ vips_region_shrink_labpack( VipsRegion *from,
q += ps; \
}
#define SHRINK_TYPE_FLOAT( TYPE ) \
#define SHRINK_TYPE_MEAN_FLOAT( TYPE ) \
for( x = 0; x < target->width; x++ ) { \
TYPE *tp = (TYPE *) p; \
TYPE *tp1 = (TYPE *) (p + ls); \
@ -1204,10 +1204,30 @@ vips_region_shrink_labpack( VipsRegion *from,
q += ps; \
}
// This *DOES* gurantee the result is taken from one of the input values
// It therefore does *NOT* interpolate between the two middle values
// It is *NOT* stable with respect to the set of values
// It *IS* however stable with respect to the initial arrangement of values
#define SHRINK_TYPE_MEDIAN( TYPE ) \
for( x = 0; x < target->width; x++ ) { \
TYPE *tp = (TYPE *) p; \
TYPE *tp1 = (TYPE *) (p + ls); \
TYPE *tq = (TYPE *) q; \
\
for( z = 0; z < nb; z++ ) { \
tq[z] = VIPS_MIN( VIPS_MAX( tp[z], tp[z + nb] ), VIPS_MAX( tp1[z], tp1[z + nb] ) ); \
} \
\
/* Move on two pels in input. \
*/ \
p += ps << 1; \
q += ps; \
}
/* Generate area @target in @to using pixels in @from. Non-complex.
*/
static void
vips_region_shrink_uncoded( VipsRegion *from,
vips_region_shrink_uncoded_mean( VipsRegion *from,
VipsRegion *to, const VipsRect *target )
{
int ls = VIPS_REGION_LSKIP( from );
@ -1226,21 +1246,21 @@ vips_region_shrink_uncoded( VipsRegion *from,
*/
switch( from->im->BandFmt ) {
case VIPS_FORMAT_UCHAR:
SHRINK_TYPE_INT( unsigned char ); break;
SHRINK_TYPE_MEAN_INT( unsigned char ); break;
case VIPS_FORMAT_CHAR:
SHRINK_TYPE_INT( signed char ); break;
SHRINK_TYPE_MEAN_INT( signed char ); break;
case VIPS_FORMAT_USHORT:
SHRINK_TYPE_INT( unsigned short ); break;
SHRINK_TYPE_MEAN_INT( unsigned short ); break;
case VIPS_FORMAT_SHORT:
SHRINK_TYPE_INT( signed short ); break;
SHRINK_TYPE_MEAN_INT( signed short ); break;
case VIPS_FORMAT_UINT:
SHRINK_TYPE_INT( unsigned int ); break;
SHRINK_TYPE_MEAN_INT( unsigned int ); break;
case VIPS_FORMAT_INT:
SHRINK_TYPE_INT( signed int ); break;
SHRINK_TYPE_MEAN_INT( signed int ); break;
case VIPS_FORMAT_FLOAT:
SHRINK_TYPE_FLOAT( float ); break;
SHRINK_TYPE_MEAN_FLOAT( float ); break;
case VIPS_FORMAT_DOUBLE:
SHRINK_TYPE_FLOAT( double ); break;
SHRINK_TYPE_MEAN_FLOAT( double ); break;
default:
g_assert_not_reached();
@ -1248,6 +1268,67 @@ vips_region_shrink_uncoded( VipsRegion *from,
}
}
/* Generate area @target in @to using pixels in @from. Non-complex.
*/
static void
vips_region_shrink_uncoded_median( VipsRegion *from,
VipsRegion *to, const VipsRect *target )
{
int ls = VIPS_REGION_LSKIP( from );
int ps = VIPS_IMAGE_SIZEOF_PEL( from->im );
int nb = from->im->Bands;
int x, y, z;
for( y = 0; y < target->height; y++ ) {
VipsPel *p = VIPS_REGION_ADDR( from,
target->left * 2, (target->top + y) * 2 );
VipsPel *q = VIPS_REGION_ADDR( to,
target->left, target->top + y );
/* Process this line of pels.
*/
switch( from->im->BandFmt ) {
case VIPS_FORMAT_UCHAR:
SHRINK_TYPE_MEDIAN( unsigned char ); break;
case VIPS_FORMAT_CHAR:
SHRINK_TYPE_MEDIAN( signed char ); break;
case VIPS_FORMAT_USHORT:
SHRINK_TYPE_MEDIAN( unsigned short ); break;
case VIPS_FORMAT_SHORT:
SHRINK_TYPE_MEDIAN( signed short ); break;
case VIPS_FORMAT_UINT:
SHRINK_TYPE_MEDIAN( unsigned int ); break;
case VIPS_FORMAT_INT:
SHRINK_TYPE_MEDIAN( signed int ); break;
case VIPS_FORMAT_FLOAT:
SHRINK_TYPE_MEDIAN( float ); break;
case VIPS_FORMAT_DOUBLE:
SHRINK_TYPE_MEDIAN( double ); break;
default:
g_assert_not_reached();
}
}
}
/* Generate area @target in @to using pixels in @from. Non-complex.
*/
static void
vips_region_shrink_uncoded( VipsRegion *from,
VipsRegion *to, const VipsRect *target, VipsRegionShrink method )
{
switch( method ) {
case VIPS_REGION_SHRINK_MEAN:
vips_region_shrink_uncoded_mean( from, to, target ); break;
case VIPS_REGION_SHRINK_MEDIAN:
vips_region_shrink_uncoded_median( from, to, target ); break;
default:
g_assert_not_reached();
}
}
/* No point having an int path, this will always be horribly slow.
*/
#define SHRINK_ALPHA_TYPE( TYPE ) { \
@ -1336,6 +1417,7 @@ vips_region_shrink_alpha( VipsRegion *from,
* @from: source region
* @to: (inout): destination region
* @target: #VipsRect of pixels you need to copy
* @method: #VipsRegionShrink method to use when generating target pixels
*
* Write the pixels @target in @to from the x2 larger area in @from.
* Non-complex uncoded images and LABQ only. Images with alpha (see
@ -1344,7 +1426,7 @@ vips_region_shrink_alpha( VipsRegion *from,
* See also: vips_region_copy().
*/
int
vips_region_shrink( VipsRegion *from, VipsRegion *to, const VipsRect *target )
vips_region_shrink( VipsRegion *from, VipsRegion *to, const VipsRect *target, VipsRegionShrink method )
{
VipsImage *image = from->im;
@ -1358,7 +1440,7 @@ vips_region_shrink( VipsRegion *from, VipsRegion *to, const VipsRect *target )
if( vips_image_hasalpha( image ) )
vips_region_shrink_alpha( from, to, target );
else
vips_region_shrink_uncoded( from, to, target );
vips_region_shrink_uncoded( from, to, target, method );
}
else
vips_region_shrink_labpack( from, to, target );