libvips/libvips/inplace/im_draw_line.c
2010-11-01 17:46:47 +00:00

430 lines
8.9 KiB
C

/* draw straight lines
*
* Copyright: J. Cupitt
* Written: 15/06/1992
* Modified : 22/10/92 - clipping constraints changed
* 22/7/93 JC
* - im_incheck() added
* 16/8/94 JC
* - im_incheck() changed to im_makerw()
* 5/12/06
* - im_invalidate() after paint
* 1/3/10
* - oops, lineset needs to ask for WIO of mask and ink
* 6/3/10
* - don't im_invalidate() after paint, this now needs to be at a higher
* level
* 27/9/10
* - gtk-doc
* - use draw.c base class
* - do pointwise clipping
* - rename as im_draw_line() for consistency
* - cleanups!
*/
/*
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
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <vips/vips.h>
#include "draw.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
typedef struct _Line {
Draw draw;
int x1, y1;
int x2, y2;
int dx;
int dy;
VipsPlotFn plot;
void *a;
void *b;
void *c;
} Line;
static void
line_free( Line *line )
{
im__draw_free( DRAW( line ) );
im_free( line );
}
static Line *
line_new( VipsImage *im, int x1, int y1, int x2, int y2, PEL *ink )
{
Line *line;
if( !(line = IM_NEW( NULL, Line )) )
return( NULL );
if( !im__draw_init( DRAW( line ), im, ink ) ) {
line_free( line );
return( NULL );
}
/* Find offsets.
*/
line->dx = x2 - x1;
line->dy = y2 - y1;
/* Swap endpoints to reduce number of cases.
*/
if( abs( line->dx ) >= abs( line->dy ) && line->dx < 0 ) {
/* Swap to get all x greater or equal cases going to the
* right. Do diagonals here .. just have up and right and down
* and right now.
*/
IM_SWAP( int, x1, x2 );
IM_SWAP( int, y1, y2 );
}
else if( abs( line->dx ) < abs( line->dy ) && line->dy < 0 ) {
/* Swap to get all y greater cases going down the screen.
*/
IM_SWAP( int, x1, x2 );
IM_SWAP( int, y1, y2 );
}
/* Recalculate dx, dy.
*/
line->dx = x2 - x1;
line->dy = y2 - y1;
line->x1 = x1;
line->y1 = y1;
line->x2 = x2;
line->y2 = y2;
line->plot = NULL;
line->a = NULL;
line->b = NULL;
line->c = NULL;
if( x1 < im->Xsize && x1 >= 0 &&
x2 < im->Xsize && x2 >= 0 &&
y1 < im->Ysize && y1 >= 0 &&
y2 < im->Ysize && y2 >= 0 )
DRAW( line )->noclip = TRUE;
return( line );
}
static inline int
line_plot( Line *line, int x, int y )
{
return( line->plot( DRAW( line )->im, x, y,
line->a, line->b, line->c ) );
}
static int
line_draw( Line *line )
{
int x, y, err;
/* Start point and offset.
*/
x = line->x1;
y = line->y1;
/* Special case: zero width and height is single point.
*/
if( line->dx == 0 && line->dy == 0 ) {
if( line_plot( line, x, y ) )
return( -1 );
}
/* Special case vertical and horizontal lines for speed.
*/
else if( line->dx == 0 ) {
/* Vertical line going down.
*/
for( ; y <= line->y2; y++ ) {
if( line_plot( line, x, y ) )
return( -1 );
}
}
else if( line->dy == 0 ) {
/* Horizontal line to the right.
*/
for( ; x <= line->x2; x++ ) {
if( line_plot( line, x, y ) )
return( -1 );
}
}
/* Special case diagonal lines.
*/
else if( abs( line->dy ) == abs( line->dx ) && line->dy > 0 ) {
/* Diagonal line going down and right.
*/
for( ; x <= line->x2; x++, y++ ) {
if( line_plot( line, x, y ) )
return( -1 );
}
}
else if( abs( line->dy ) == abs( line->dx ) && line->dy < 0 ) {
/* Diagonal line going up and right.
*/
for( ; x <= line->x2; x++, y-- ) {
if( line_plot( line, x, y ) )
return( -1 );
}
}
else if( abs( line->dy ) < abs( line->dx ) && line->dy > 0 ) {
/* Between -45 and 0 degrees.
*/
for( err = 0; x <= line->x2; x++ ) {
if( line_plot( line, x, y ) )
return( -1 );
err += line->dy;
if( err >= line->dx ) {
err -= line->dx;
y++;
}
}
}
else if( abs( line->dy ) < abs( line->dx ) && line->dy < 0 ) {
/* Between 0 and 45 degrees.
*/
for( err = 0; x <= line->x2; x++ ) {
if( line_plot( line, x, y ) )
return( -1 );
err -= line->dy;
if( err >= line->dx ) {
err -= line->dx;
y--;
}
}
}
else if( abs( line->dy ) > abs( line->dx ) && line->dx > 0 ) {
/* Between -45 and -90 degrees.
*/
for( err = 0; y <= line->y2; y++ ) {
if( line_plot( line, x, y ) )
return( -1 );
err += line->dx;
if( err >= line->dy ) {
err -= line->dy;
x++;
}
}
}
else if( abs( line->dy ) > abs( line->dx ) && line->dx < 0 ) {
/* Between -90 and -135 degrees.
*/
for( err = 0; y <= line->y2; y++ ) {
if( line_plot( line, x, y ) )
return( -1 );
err -= line->dx;
if( err >= line->dy ) {
err -= line->dy;
x--;
}
}
}
else
g_assert( 0 );
return( 0 );
}
/**
* VipsPlotFn:
* @image: image to draw on
* @x: position to draw at
* @y: position to draw at
* @a: user data
* @b: user data
* @c: user data
*
* A plot function, as used by im_draw_line_user() to draw on an image.
*/
/**
* im_draw_line_user:
* @image: image to draw on
* @x1: start point
* @y1: start point
* @x2: end point
* @y2: end point
* @plot: draw operation
* @a: draw operation parameter
* @b: draw operation parameter
* @c: draw operation parameter
*
* Calls @plot for every point on the line connecting @x1, @y1 and @x2, @y2.
* If you pass im_draw_mask() as the plot operation, you can draw wide lines
* or lines with various brushes.
*
* See also: im_draw_mask(), im_draw_line(), im_draw_circle().
*
* Returns: 0 on success, or -1 on error.
*/
int
im_draw_line_user( VipsImage *image,
int x1, int y1, int x2, int y2,
VipsPlotFn plot, void *a, void *b, void *c )
{
Line *line;
if( im_check_coding_known( "im_draw_line_user", image ) ||
!(line = line_new( image, x1, y1, x2, y2, NULL )) )
return( -1 );
line->plot = plot;
line->a = a;
line->b = b;
line->c = c;
if( line_draw( line ) ) {
line_free( line );
return( -1 );
}
line_free( line );
return( 0 );
}
static int
line_plot_point( VipsImage *im, int x, int y,
void *a, void *b, void *c )
{
Draw *draw = (Draw *) a;
if( draw->noclip )
im__draw_pel( draw, (PEL *) IM_IMAGE_ADDR( draw->im, x, y ) );
else
im__draw_pel_clip( draw, x, y );
return( 0 );
}
/**
* im_draw_line:
* @image: image to draw on
* @x1: start point
* @y1: start point
* @x2: end point
* @y2: end point
* @ink: value to draw
*
* Draws a 1-pixel-wide line on an image.
*
* @ink is an array of bytes
* containing a valid pixel for the image's format.
* It must have at least IM_IMAGE_SIZEOF_PEL( @image ) bytes.
*
* See also: im_draw_circle().
*
* Returns: 0 on success, or -1 on error.
*/
int
im_draw_line( VipsImage *image, int x1, int y1, int x2, int y2, PEL *ink )
{
Line *line;
if( im_check_coding_known( "im_draw_line", image ) ||
!(line = line_new( image, x1, y1, x2, y2, ink )) )
return( -1 );
line->plot = line_plot_point;
line->a = line;
if( line_draw( line ) ) {
line_free( line );
return( 0 );
}
line_free( line );
return( 0 );
}
/* Draw a set of lines with an ink and a mask. A non-inplace operation, handy
* for nip2.
*/
int
im_lineset( IMAGE *in, IMAGE *out, IMAGE *mask, IMAGE *ink,
int n, int *x1v, int *y1v, int *x2v, int *y2v )
{
Rect mask_rect;
int i;
if( mask->Bands != 1 || mask->BandFmt != IM_BANDFMT_UCHAR ||
mask->Coding != IM_CODING_NONE ) {
im_error( "im_lineset",
"%s", _( "mask image not 1 band 8 bit uncoded" ) );
return( -1 );
}
if( ink->Bands != in->Bands || ink->BandFmt != in->BandFmt ||
ink->Coding != in->Coding ) {
im_error( "im_lineset",
"%s", _( "ink image does not match in image" ) );
return( -1 );
}
if( ink->Xsize != 1 || ink->Ysize != 1 ) {
im_error( "im_lineset", "%s", _( "ink image not 1x1 pixels" ) );
return( -1 );
}
/* Copy the image then fastline to it ... this will render to a "t"
* usually.
*/
if( im_copy( in, out ) )
return( -1 );
mask_rect.left = mask->Xsize / 2;
mask_rect.top = mask->Ysize / 2;
mask_rect.width = mask->Xsize;
mask_rect.height = mask->Ysize;
if( im_incheck( ink ) ||
im_incheck( mask ) )
return( -1 );
for( i = 0; i < n; i++ ) {
if( im_fastlineuser( out, x1v[i], y1v[i], x2v[i], y2v[i],
im_plotmask, ink->data, mask->data, &mask_rect ) )
return( -1 );
}
return( 0 );
}