libvips/libsrc/conversion/im_grid.c

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2007-08-29 18:23:50 +02:00
/* chop a tall thin image up into a grid ... useful for displaying volumetric
* images
*
* 4/8/05
* 7/9/05
* - oops, clipping was wrong
*/
/*
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
*/
/* Turn on debugging output.
#define DEBUG
#define DEBUG_PAINT
#define DEBUG_MAKE
*/
#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 <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
typedef struct _Grid {
IMAGE *in;
IMAGE *out;
int tile_height;
int across;
int down;
} Grid;
static int
grid_gen( REGION *or, REGION *ir, IMAGE *in, Grid *grid )
{
Rect *r = &or->valid;
int twidth = grid->in->Xsize;
int theight = grid->tile_height;
int x, y;
Rect tile;
/* Find top left of tiles we need.
*/
int xs = (r->left / twidth) * twidth;
int ys = (r->top / theight) * theight;
/* The tile enclosing the top-left corner of the requested area.
*/
tile.left = xs;
tile.top = ys;
tile.width = twidth;
tile.height = theight;
/* If the request fits inside a single tile, we can just pointer-copy.
*/
if( im_rect_includesrect( &tile, r ) ) {
Rect irect;
/* Translate request to input space.
*/
irect = *r;
irect.left -= xs;
irect.top -= ys;
irect.top += grid->across * ys + theight * (xs / twidth);
if( im_prepare( ir, &irect ) ||
im_region_region( or, ir, r, irect.left, irect.top ) )
return( -1 );
return( 0 );
}
for( y = ys; y < IM_RECT_BOTTOM( r ); y += theight )
for( x = xs; x < IM_RECT_RIGHT( r ); x += twidth ) {
Rect paint;
Rect input;
/* Whole tile at x, y
*/
tile.left = x;
tile.top = y;
tile.width = twidth;
tile.height = theight;
/* Which parts touch the area of the output we are
* building.
*/
im_rect_intersectrect( &tile, r, &paint );
assert( !im_rect_isempty( &paint ) );
/* Translate back to ir coordinates.
*/
input = paint;
input.left -= x;
input.top -= y;
input.top += grid->across * y + theight * (x / twidth);
/* Render into or.
*/
if( im_prepare_to( ir, or, &input,
paint.left, paint.top ) )
return( -1 );
}
return( 0 );
}
int
im_grid( IMAGE *in, IMAGE *out, int tile_height, int across, int down )
{
Grid *grid = IM_NEW( out, Grid );
if( !grid || im_piocheck( in, out ) )
return( -1 );
if( across <= 0 || down <= 0 ) {
im_error( "im_grid", _( "bad parameters" ) );
return( -1 );
}
if( in->Ysize % tile_height != 0 ||
in->Ysize / tile_height != across * down ) {
im_error( "im_grid", _( "bad grid geometry" ) );
return( -1 );
}
grid->in = in;
grid->out = out;
grid->tile_height = tile_height;
grid->across = across;
grid->down = down;
if( im_cp_desc( out, in ) )
return( -1 );
out->Xsize = in->Xsize * across;
out->Ysize = tile_height * down;
/* We can render small tiles with pointer copies.
*/
if( im_demand_hint( out, IM_SMALLTILE, in, NULL ) )
return( -1 );
if( im_generate( out,
im_start_one, grid_gen, im_stop_one, in, grid ) )
return( -1 );
return( 0 );
}