libvips/libsrc/conversion/im_zoom.c

375 lines
8.5 KiB
C

/* @(#) Zoom an image by pixel replication. Any non-coded type, also works for
* @(#) IM_CODING_LABQ.
* @(#)
* @(#) int im_zoom( in, out, factor )
* @(#) IMAGE *in, *out;
* @(#) int factor;
* @(#)
* @(#) Returns: -1 on error, else 0
* Author: N. Martinez 1991
* 6/6/94 JC
* - rewritten to ANSI-C
* - now works for any type, including IM_CODING_LABQ
* 7/10/94 JC
* - new IM_ARRAY() macro
* 26/1/96 JC
* - separate x and y zoom factors
* 21/8/96 JC
* - partial, yuk! this is so complicated ...
* 30/8/96 JC
* - sets demand_hint
* 10/2/00 JC
* - check for integer overflow in zoom facs ... was happening with ip's
* zoom on large images
* 3/8/02 JC
* - fall back to im_copy() for x & y factors == 1
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
* TODO:
* Test for pixel size and use memcpy() on individual pixels once they reach
* sizes of the order of tens of bytes. char-wise copy is quiker than
* memcpy() for smaller pixels.
*
* Also, I haven't tested it but int-wise copying may be faster still, as
* long as alignment permits it.
*
* tcv. 2006-09-01
*/
/* Turn off assert().
#define NDEBUG 1
*/
/* Turn on IM_REGION_ADDR() range checks.
#define DEBUG 1
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <limits.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Round N down to P boundary.
*/
#define ROUND_DOWN(N,P) ((N) - ((N) % P))
/* Round N up to P boundary.
*/
#define ROUND_UP(N,P) (ROUND_DOWN( (N) + (P) - 1, (P) ))
/* Our main parameter struct.
*/
typedef struct {
int xfac; /* Scale factors */
int yfac;
} ZoomInfo;
/* Paint the part of the region containing only whole pels.
*/
static void
paint_whole( REGION *or, REGION *ir, ZoomInfo *zm,
const int left, const int right, const int top, const int bottom )
{
const int ps = IM_IMAGE_SIZEOF_PEL( ir->im );
const int ls = IM_REGION_LSKIP( or );
const int rs = ps * (right - left);
/* Transform to ir coordinates.
*/
const int ileft = left / zm->xfac;
const int iright = right / zm->xfac;
const int itop = top / zm->yfac;
const int ibottom = bottom / zm->yfac;
int x, y, z, i;
/* We know this!
*/
assert( right > left && bottom > top &&
right % zm->xfac == 0 &&
left % zm->xfac == 0 &&
top % zm->yfac == 0 &&
bottom % zm->yfac == 0 );
/* Loop over input, as we know we are all whole.
*/
for( y = itop; y < ibottom; y++ ) {
PEL *p = (PEL *) IM_REGION_ADDR( ir, ileft, y );
PEL *q = (PEL *) IM_REGION_ADDR( or, left, y * zm->yfac );
PEL *r;
/* Expand the first line of pels.
*/
r = q;
for( x = ileft; x < iright; x++ ) {
/* Copy each pel xfac times.
*/
for( z = 0; z < zm->xfac; z++ ) {
for( i = 0; i < ps; i++ )
r[i] = p[i];
r += ps;
}
p += ps;
}
/* Copy the expanded line yfac-1 times.
*/
r = q + ls;
for( z = 1; z < zm->yfac; z++ ) {
memcpy( r, q, rs );
r += ls;
}
}
}
/* Paint the part of the region containing only part-pels.
*/
static void
paint_part( REGION *or, REGION *ir, const ZoomInfo *zm,
const int left, const int right, const int top, const int bottom )
{
const int ps = IM_IMAGE_SIZEOF_PEL( ir->im );
const int ls = IM_REGION_LSKIP( or );
const int rs = ps * (right - left);
/* Start position in input.
*/
const int ix = left / zm->xfac;
const int iy = top / zm->yfac;
/* Pels down to yfac boundary, pels down to bottom. Do the smallest of
* these for first y loop.
*/
const int ptbound = (iy + 1) * zm->yfac - top;
const int ptbot = bottom - top;
int yt = IM_MIN( ptbound, ptbot );
int x, y, z, i;
/* Only know this.
*/
assert( right - left >= 0 && bottom - top >= 0 );
/* Have to loop over output.
*/
for( y = top; y < bottom; ) {
PEL *p = (PEL *) IM_REGION_ADDR( ir, ix, y / zm->yfac );
PEL *q = (PEL *) IM_REGION_ADDR( or, left, y );
PEL *r;
/* Output pels until we jump the input pointer.
*/
int xt = (ix + 1) * zm->xfac - left;
/* Loop for this output line.
*/
r = q;
for( x = left; x < right; x++ ) {
/* Copy 1 pel.
*/
for( i = 0; i < ps; i++ )
r[i] = p[i];
r += ps;
/* Move input if on boundary.
*/
--xt;
if( xt == 0 ) {
xt = zm->xfac;
p += ps;
}
}
/* Repeat that output line until the bottom of this pixel
* boundary, or we hit bottom.
*/
r = q + ls;
for( z = 1; z < yt; z++ ) {
memcpy( r, q, rs );
r += ls;
}
/* Move y on by the number of lines we wrote.
*/
y += yt;
/* Reset yt for next iteration.
*/
yt = zm->yfac;
}
}
/* Zoom a REGION.
*/
static int
zoom_gen( REGION *or, void *seq, void *a, void *b )
{
REGION *ir = (REGION *) seq;
ZoomInfo *zm = (ZoomInfo *) b;
/* Output area we are building.
*/
const Rect *r = &or->valid;
const int ri = IM_RECT_RIGHT( r );
const int bo = IM_RECT_BOTTOM(r);
Rect s;
int left, right, top, bottom;
int width, height;
/* Area of input we need. We have to round out, as we may have
* part-pixels all around the edges.
*/
left = ROUND_DOWN( r->left, zm->xfac );
right = ROUND_UP( ri, zm->xfac );
top = ROUND_DOWN( r->top, zm->yfac );
bottom = ROUND_UP( bo, zm->yfac );
width = right - left;
height = bottom - top;
s.left = left / zm->xfac;
s.top = top / zm->yfac;
s.width = width / zm->xfac;
s.height = height / zm->yfac;
if( im_prepare( ir, &s ) )
return( -1 );
/* Find the part of the output (if any) which uses only whole pels.
*/
left = ROUND_UP( r->left, zm->xfac );
right = ROUND_DOWN( ri, zm->xfac );
top = ROUND_UP( r->top, zm->yfac );
bottom = ROUND_DOWN( bo, zm->yfac );
width = right - left;
height = bottom - top;
/* Stage 1: we just paint the whole pels in the centre of the region.
* As we know they are not clipped, we can do it quickly.
*/
if( width > 0 && height > 0 )
paint_whole( or, ir, zm, left, right, top, bottom );
/* Just fractional pixels left. Paint in the top, left, right and
* bottom parts.
*/
if( top - r->top > 0 )
/* Some top pixels.
*/
paint_part( or, ir, zm,
r->left, ri, r->top, IM_MIN( top, bo ) );
if( left - r->left > 0 && height > 0 )
/* Left pixels.
*/
paint_part( or, ir, zm,
r->left, IM_MIN( left, ri ), top, bottom );
if( ri - right > 0 && height > 0 )
/* Right pixels.
*/
paint_part( or, ir, zm,
IM_MAX( right, r->left ), ri, top, bottom );
if( bo - bottom > 0 && height >= 0 )
/* Bottom pixels.
*/
paint_part( or, ir, zm,
r->left, ri, IM_MAX( bottom, r->top ), bo );
return( 0 );
}
int
im_zoom( IMAGE *in, IMAGE *out, int xfac, int yfac )
{
ZoomInfo *zm;
/* Check arguments.
*/
if( in->Coding != IM_CODING_NONE && in->Coding != IM_CODING_LABQ ) {
im_error( "im_zoom", _( "unknown coding type" ) );
return( -1 );
}
if( xfac <= 0 || yfac <= 0 ) {
im_error( "im_zoom", _( "zoom factors should be >= 0" ) );
return( -1 );
}
if( (double) in->Xsize * xfac > (double) INT_MAX / 2 ||
(double) in->Ysize * yfac > (double) INT_MAX / 2 ) {
/* Make sure we won't get integer overflow.
*/
im_error( "im_zoom", _( "zoom factors too large" ) );
return( -1 );
}
if( xfac == 1 && yfac == 1 )
return( im_copy( in, out ) );
if( im_piocheck( in, out ) )
return( -1 );
/* Make output.
*/
if( im_cp_desc( out, in ) )
return( -1 );
out->Xsize = in->Xsize * xfac;
out->Ysize = in->Ysize * yfac;
/* Save parameters.
*/
if( !(zm = IM_NEW( out, ZoomInfo )) )
return( -1 );
zm->xfac = xfac;
zm->yfac = yfac;
/* Set demand hints. THINSTRIP will prevent us from using
* paint_whole() too much ... so go for FATSTRIP.
*/
if( im_demand_hint( out, IM_FATSTRIP, in, NULL ) )
return( -1 );
/* Generate!
*/
if( im_generate( out,
im_start_one, zoom_gen, im_stop_one, in, zm ) )
return( -1 );
return( 0 );
}