static int
vips_affine_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
{
VipsRegion *ir = (VipsRegion *) seq;
const VipsAffine *affine = (VipsAffine *) b;
const VipsImage *in = (VipsImage *) a;
const int window_size =
vips_interpolate_get_window_size( affine->interpolate );
const int window_offset =
vips_interpolate_get_window_offset( affine->interpolate );
const VipsInterpolateMethod interpolate =
vips_interpolate_get_method( affine->interpolate );
/* Area we generate in the output image.
*/
const VipsRect *r = &or->valid;
const int le = r->left;
const int ri = VIPS_RECT_RIGHT( r );
const int to = r->top;
const int bo = VIPS_RECT_BOTTOM( r );
const VipsRect *iarea = &affine->trn.iarea;
const VipsRect *oarea = &affine->trn.oarea;
int ps = VIPS_IMAGE_SIZEOF_PEL( in );
int x, y, z;
VipsRect image, want, need, clipped;
#ifdef DEBUG_VERBOSE
printf( "vips_affine_gen: "
"generating left=%d, top=%d, width=%d, height=%d\n",
r->left,
r->top,
r->width,
r->height );
#endif /*DEBUG_VERBOSE*/
/* We are generating this chunk of the transformed image. This takes
* us to space 4.
*/
want = *r;
want.left += oarea->left;
want.top += oarea->top;
/* Find the area of the input image we need. This takes us to space 3.
*/
vips__transform_invert_rect( &affine->trn, &want, &need );
/* That does round-to-nearest, because it has to stop rounding errors
* growing images unexpectedly. We need round-down, so we must
* add half a pixel along the left and top. But we are int :( so add 1
* pixel.
*
* Add an extra line along the right and bottom as well, for rounding.
*/
vips_rect_marginadjust( &need, 1 );
/* We need to fetch a larger area for the interpolator.
*/
need.left -= window_offset;
need.top -= window_offset;
need.width += window_size - 1;
need.height += window_size - 1;
/* Now go to space 2, the expanded input image. This is the one we
* read pixels from.
*/
need.left += window_offset;
need.top += window_offset;
/* Clip against the size of (2).
*/
image.left = 0;
image.top = 0;
image.width = in->Xsize;
image.height = in->Ysize;
vips_rect_intersectrect( &need, &image, &clipped );
#ifdef DEBUG_VERBOSE
printf( "vips_affine_gen: "
"preparing left=%d, top=%d, width=%d, height=%d\n",
clipped.left,
clipped.top,
clipped.width,
clipped.height );
#endif /*DEBUG_VERBOSE*/
if( vips_rect_isempty( &clipped ) ) {
vips_region_black( or );
return( 0 );
}
if( vips_region_prepare( ir, &clipped ) )
return( -1 );
VIPS_GATE_START( "vips_affine_gen: work" );
/* Resample! x/y loop over pixels in the output image (5).
*/
for( y = to; y < bo; y++ ) {
/* Input clipping rectangle. We offset this so we can clip in
* space 2.
*/
const int ile = iarea->left + window_offset;
const int ito = iarea->top + window_offset;
const int iri = ile + iarea->width;
const int ibo = ito + iarea->height;
/* Derivative of matrix.
*/
const double ddx = affine->trn.ia;
const double ddy = affine->trn.ic;
/* Continuous cods in transformed space.
*/
const double ox = le + oarea->left - affine->trn.odx;
const double oy = y + oarea->top - affine->trn.ody;
/* Continuous cods in input space.
*/
double ix, iy;
VipsPel *q;
/* To (3).
*/
ix = affine->trn.ia * ox + affine->trn.ib * oy;
iy = affine->trn.ic * ox + affine->trn.id * oy;
/* And the input offset in (3).
*/
ix -= affine->trn.idx;
iy -= affine->trn.idy;
/* Finally to 2.
*/
ix += window_offset;
iy += window_offset;
q = VIPS_REGION_ADDR( or, le, y );
for( x = le; x < ri; x++ ) {
int fx, fy;
fx = FAST_PSEUDO_FLOOR( ix );
fy = FAST_PSEUDO_FLOOR( iy );
/* Clip against iarea.
*/
if( fx >= ile &&
fx < iri &&
fy >= ito &&
fy < ibo ) {
/* Verify that we can read the whole stencil.
* With DEBUG on this will range-check.
*/
g_assert( VIPS_REGION_ADDR( ir,
(int) ix - window_offset,
(int) iy - window_offset ) );
g_assert( VIPS_REGION_ADDR( ir,
(int) ix - window_offset +
window_size - 1,
(int) iy - window_offset +
window_size - 1 ) );
interpolate( affine->interpolate,
q, ir, ix, iy );
}
else {
for( z = 0; z < ps; z++ )
q[z] = 0;
}
ix += ddx;
iy += ddy;
q += ps;
}
}
VIPS_GATE_STOP( "vips_affine_gen: work" );
return( 0 );
}
const gdouble absolute_x,
const gdouble absolute_y,
GeglMatrix2 *scale,
void* restrict output)
{
const gint pixels_per_buffer_row = 64;
const gint channels = 4;
/*
* floor's surrogate FAST_PSEUDO_FLOOR is used to make
* sure that the transition through 0 is smooth. If it is known that
* negative absolute_x and absolute_y will never be used, plain
* cast---that is, const gint ix = absolute_x---is recommended
* instead.
*/
const gint ix = FAST_PSEUDO_FLOOR (absolute_x);
const gint iy = FAST_PSEUDO_FLOOR (absolute_y);
/*
* x is the x-coordinate of the sampling point relative to the
* position of the top left pixel center. Similarly for y. Range of
* values: [0,1].
*/
const gfloat x = absolute_x - ix;
const gfloat y = absolute_y - iy;
/*
* Point the data tile pointer to the first channel of the top_left
* pixel value:
*/
const gfloat* restrict in_bptr = gegl_sampler_get_ptr (self, ix, iy);
double absolute_y )
{
/*
* Floor's surrogate FAST_PSEUDO_FLOOR is used to make sure that the
* transition through 0 is smooth. If it is known that absolute_x
* and absolute_y will never be less than 0, plain cast---that is,
* const int ix = absolute_x---should be used instead. Actually,
* any function which agrees with floor for non-integer values, and
* picks one of the two possibilities for integer values, can be
* used. FAST_PSEUDO_FLOOR fits the bill.
*
* Then, x is the x-coordinate of the sampling point relative to the
* position of the center of the convex hull of the 2x2 block of
* closest pixels. Similarly for y. Range of values: [-.5,.5).
*/
const int ix = FAST_PSEUDO_FLOOR( absolute_x + .5 );
const int iy = FAST_PSEUDO_FLOOR( absolute_y + .5 );
/*
* Move the pointer to (the first band of) the top/left pixel of the
* 2x2 group of pixel centers which contains the sampling location
* in its convex hull:
*/
const PEL* restrict p = (PEL *) IM_REGION_ADDR( in, ix, iy );
const double relative_x = absolute_x - ix;
const double relative_y = absolute_y - iy;
/*
* VIPS versions of Nicolas's pixel addressing values.
*/
static int
vips_affine_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
{
VipsRegion *ir = (VipsRegion *) seq;
const VipsAffine *affine = (VipsAffine *) b;
const VipsImage *in = (VipsImage *) a;
const int window_size =
vips_interpolate_get_window_size( affine->interpolate );
const int window_offset =
vips_interpolate_get_window_offset( affine->interpolate );
const VipsInterpolateMethod interpolate =
vips_interpolate_get_method( affine->interpolate );
/* Area we generate in the output image.
*/
const VipsRect *r = &or->valid;
const int le = r->left;
const int ri = VIPS_RECT_RIGHT( r );
const int to = r->top;
const int bo = VIPS_RECT_BOTTOM( r );
const VipsRect *iarea = &affine->trn.iarea;
const VipsRect *oarea = &affine->trn.oarea;
int ps = VIPS_IMAGE_SIZEOF_PEL( in );
int x, y, z;
VipsRect image, want, need, clipped;
#ifdef DEBUG
printf( "affine: generating left=%d, top=%d, width=%d, height=%d\n",
r->left,
r->top,
r->width,
r->height );
#endif /*DEBUG*/
/* We are generating this chunk of the transformed image.
*/
want = *r;
want.left += oarea->left;
want.top += oarea->top;
/* Find the area of the input image we need.
*/
vips__transform_invert_rect( &affine->trn, &want, &need );
/* That does round-to-nearest, because it has to stop rounding errors
* growing images unexpectedly. We need round-down, so we must
* add half a pixel along the left and top. But we are int :( so add 1
* pixel.
*
* Add an extra line along the right and bottom as well, for rounding.
*/
vips_rect_marginadjust( &need, 1 );
/* Now go to space (2) above.
*/
need.left += iarea->left;
need.top += iarea->top;
/* Add a border for interpolation.
*/
need.width += window_size - 1;
need.height += window_size - 1;
need.left -= window_offset;
need.top -= window_offset;
/* Clip against the size of (2).
*/
image.left = 0;
image.top = 0;
image.width = in->Xsize;
image.height = in->Ysize;
vips_rect_intersectrect( &need, &image, &clipped );
/* Outside input image? All black.
*/
if( vips_rect_isempty( &clipped ) ) {
vips_region_black( or );
return( 0 );
}
/* We do need some pixels from the input image to make our output -
* ask for them.
*/
if( vips_region_prepare( ir, &clipped ) )
return( -1 );
#ifdef DEBUG
printf( "affine: preparing left=%d, top=%d, width=%d, height=%d\n",
clipped.left,
clipped.top,
clipped.width,
clipped.height );
#endif /*DEBUG*/
/* Resample! x/y loop over pixels in the output image (5).
*/
for( y = to; y < bo; y++ ) {
/* Input clipping rectangle.
*/
const int ile = iarea->left;
const int ito = iarea->top;
const int iri = iarea->left + iarea->width;
const int ibo = iarea->top + iarea->height;
/* Derivative of matrix.
*/
const double ddx = affine->trn.ia;
const double ddy = affine->trn.ic;
/* Continuous cods in transformed space.
*/
const double ox = le + oarea->left - affine->trn.odx;
const double oy = y + oarea->top - affine->trn.ody;
/* Continuous cods in input space.
*/
double ix, iy;
VipsPel *q;
/* To (3).
*/
ix = affine->trn.ia * ox + affine->trn.ib * oy;
iy = affine->trn.ic * ox + affine->trn.id * oy;
/* Now move to (2).
*/
ix += iarea->left;
iy += iarea->top;
/* And the input offset.
*/
ix -= affine->trn.idx;
iy -= affine->trn.idy;
q = VIPS_REGION_ADDR( or, le, y );
for( x = le; x < ri; x++ ) {
int fx, fy;
fx = FAST_PSEUDO_FLOOR( ix );
fy = FAST_PSEUDO_FLOOR( iy );
/* Clipping!
*/
if( fx < ile || fx >= iri || fy < ito || fy >= ibo ) {
for( z = 0; z < ps; z++ )
q[z] = 0;
}
else {
interpolate( affine->interpolate,
q, ir, ix, iy );
}
ix += ddx;
iy += ddy;
q += ps;
}
}
return( 0 );
}
