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libvips/libvips/draw/draw_line.c

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/* draw straight draw_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, draw_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!
* 6/2/14
* - redo as a class
*/
/*
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 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 <vips/internal.h>
#include "drawink.h"
typedef struct _VipsDrawLine {
VipsDrawink parent_object;
int x1;
int y1;
int x2;
int y2;
} VipsDrawLine;
typedef struct _VipsDrawLineClass {
VipsDrawinkClass parent_class;
} VipsDrawLineClass;
G_DEFINE_TYPE( VipsDrawLine, vips_draw_line, VIPS_TYPE_DRAWINK );
void
vips__draw_line_direct( VipsImage *image, int x1, int y1, int x2, int y2,
VipsDrawPoint draw_point, void *client )
{
int dx, dy;
int x, y, err;
dx = x2 - x1;
dy = y2 - y1;
/* Swap endpoints to reduce number of cases.
*/
if( abs( dx ) >= abs( dy ) &&
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.
*/
VIPS_SWAP( int, x1, x2 );
VIPS_SWAP( int, y1, y2 );
}
else if( abs( dx ) < abs( dy ) &&
dy < 0 ) {
/* Swap to get all y greater cases going down the screen.
*/
VIPS_SWAP( int, x1, x2 );
VIPS_SWAP( int, y1, y2 );
}
dx = x2 - x1;
dy = y2 - y1;
x = x1;
y = y1;
/* Special case: zero width and height is single point.
*/
if( dx == 0 &&
dy == 0 )
draw_point( image, x, y, client );
/* Special case vertical and horizontal lines for speed.
*/
else if( dx == 0 ) {
/* Vertical line going down.
*/
for( ; y <= y2; y++ )
draw_point( image, x, y, client );
}
else if( dy == 0 ) {
/* Horizontal line to the right.
*/
for( ; x <= x2; x++ )
draw_point( image, x, y, client );
}
/* Special case diagonal lines.
*/
else if( abs( dy ) == abs( dx ) &&
dy > 0 ) {
/* Diagonal line going down and right.
*/
for( ; x <= x2; x++, y++ )
draw_point( image, x, y, client );
}
else if( abs( dy ) == abs( dx ) &&
dy < 0 ) {
/* Diagonal line going up and right.
*/
for( ; x <= x2; x++, y-- )
draw_point( image, x, y, client );
}
else if( abs( dy ) < abs( dx ) &&
dy > 0 ) {
/* Between -45 and 0 degrees.
*/
for( err = 0; x <= x2; x++ ) {
draw_point( image, x, y, client );
err += dy;
if( err >= dx ) {
err -= dx;
y++;
}
}
}
else if( abs( dy ) < abs( dx ) &&
dy < 0 ) {
/* Between 0 and 45 degrees.
*/
for( err = 0; x <= x2; x++ ) {
draw_point( image, x, y, client );
err -= dy;
if( err >= dx ) {
err -= dx;
y--;
}
}
}
else if( abs( dy ) > abs( dx ) &&
dx > 0 ) {
/* Between -45 and -90 degrees.
*/
for( err = 0; y <= y2; y++ ) {
draw_point( image, x, y, client );
err += dx;
if( err >= dy ) {
err -= dy;
x++;
}
}
}
else if( abs( dy ) > abs( dx ) &&
dx < 0 ) {
/* Between -90 and -135 degrees.
*/
for( err = 0; y <= y2; y++ ) {
draw_point( image, x, y, client );
err -= dx;
if( err >= dy ) {
err -= dy;
x--;
}
}
}
else
g_assert_not_reached();
}
static void
vips_draw_line_draw_point_noclip( VipsImage *image, int x, int y, void *client )
{
VipsPel *ink = (VipsPel *) client;
VipsPel *q = VIPS_IMAGE_ADDR( image, x, y );
int psize = VIPS_IMAGE_SIZEOF_PEL( image );
int j;
/* Faster than memcopy() for n < about 20.
*/
for( j = 0; j < psize; j++ )
q[j] = ink[j];
}
static void
vips_draw_line_draw_point_clip( VipsImage *image, int x, int y, void *client )
{
if( x >= 0 &&
x < image->Xsize &&
y >= 0 &&
y < image->Ysize )
vips_draw_line_draw_point_noclip( image, x, y, client );
}
static int
vips_draw_line_build( VipsObject *object )
{
VipsDraw *draw = VIPS_DRAW( object );
VipsDrawink *drawink = VIPS_DRAWINK( object );
VipsDrawLine *line = (VipsDrawLine *) object;
VipsDrawPoint draw_point;
if( VIPS_OBJECT_CLASS( vips_draw_line_parent_class )->build( object ) )
return( -1 );
if( line->x1 < draw->image->Xsize &&
line->x1 >= 0 &&
line->x2 < draw->image->Xsize &&
line->x2 >= 0 &&
line->y1 < draw->image->Ysize &&
line->y1 >= 0 &&
line->y2 < draw->image->Ysize &&
line->y2 >= 0 )
draw_point = vips_draw_line_draw_point_noclip;
else
draw_point = vips_draw_line_draw_point_clip;
vips__draw_line_direct( draw->image,
line->x1, line->y1, line->x2, line->y2,
draw_point, drawink->pixel_ink );
return( 0 );
}
static void
vips_draw_line_class_init( VipsDrawLineClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "draw_line";
vobject_class->description = _( "draw a line on an image" );
vobject_class->build = vips_draw_line_build;
VIPS_ARG_INT( class, "x1", 3,
_( "x1" ),
_( "Start of draw_line" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsDrawLine, x1 ),
-1000000000, 1000000000, 0 );
VIPS_ARG_INT( class, "y1", 4,
_( "y1" ),
_( "Start of draw_line" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsDrawLine, y1 ),
-1000000000, 1000000000, 0 );
VIPS_ARG_INT( class, "x2", 5,
_( "x2" ),
_( "End of draw_line" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsDrawLine, x2 ),
-1000000000, 1000000000, 0 );
VIPS_ARG_INT( class, "y2", 6,
_( "y2" ),
_( "End of draw_line" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsDrawLine, y2 ),
-1000000000, 1000000000, 0 );
}
static void
vips_draw_line_init( VipsDrawLine *draw_line )
{
}
static int
vips_draw_linev( VipsImage *image,
double *ink, int n, int x1, int y1, int x2, int y2, va_list ap )
{
VipsArea *area_ink;
int result;
area_ink = VIPS_AREA( vips_array_double_new( ink, n ) );
result = vips_call_split( "draw_line", ap,
image, area_ink, x1, y1, x2, y2 );
vips_area_unref( area_ink );
return( result );
}
/**
* vips_draw_line: (method)
* @image: image to draw on
* @ink: (array length=n): value to draw
* @n: length of ink array
* @x1: start of draw_line
* @y1: start of draw_line
* @x2: end of draw_line
* @y2: end of draw_line
* @...: %NULL-terminated list of optional named arguments
*
* Draws a 1-pixel-wide line on an image.
*
* @ink is an array of double containing values to draw.
*
* See also: vips_draw_line1(), vips_draw_circle(), vips_draw_mask().
*
* Returns: 0 on success, or -1 on error.
*/
int
vips_draw_line( VipsImage *image,
double *ink, int n, int x1, int y1, int x2, int y2, ... )
{
va_list ap;
int result;
va_start( ap, y2 );
result = vips_draw_linev( image, ink, n, x1, y1, x2, y2, ap );
va_end( ap );
return( result );
}
/**
* vips_draw_line1: (method)
* @image: image to draw on
* @ink: value to draw
* @x1: start of draw_line
* @y1: start of draw_line
* @x2: end of draw_line
* @y2: end of draw_line
* @...: %NULL-terminated list of optional named arguments
*
* As vips_draw_line(), but just take a single double for @ink.
*
* See also: vips_draw_line().
*
* Returns: 0 on success, or -1 on error.
*/
int
vips_draw_line1( VipsImage *image,
double ink, int x1, int y1, int x2, int y2, ... )
{
double array_ink[1];
va_list ap;
int result;
array_ink[0] = ink;
va_start( ap, y2 );
result = vips_draw_linev( image, array_ink, 1, x1, y1, x2, y2, ap );
va_end( ap );
return( result );
}
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