libvips/libvips/draw/draw.c

/* base class for drawing operations
 *
 * 27/9/10
 *	- from im_draw_circle()
 * 17/11/10
 * 	- oops, scanline clipping was off by 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., 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 <glib/gi18n-lib.h>

#include <string.h>

#include <vips/vips.h>
#include <vips/internal.h>

#include "pdraw.h"

/** 
 * SECTION: draw
 * @short_description: drawing operations: flood, paste, line, circle
 * @stability: Stable
 * @include: vips/vips.h
 *
 * These operations directly modify the image. They do not thread, on 32-bit
 * machines they will be limited to 2GB images, and a little care needs to be
 * taken if you use them as part of an image pipeline. 
 * They are mostly supposed to be useful for paintbox-style programs.
 *
 * libvips operations are all functional: they take zero or more existing input 
 * images and generate zero or more new output images. Images are
 * never altered, you always create new images. This means libvips can cache
 * and thread very aggressively.
 *
 * The downside is that creating entirely fresh images each time can be very
 * slow. libvips has a range of tricks to avoid these problems, but there are
 * still times when you really have to be able to modify an image. An example
 * might be drawing a curved line from a set of straight line segments: if you
 * need to draw 1,000 straight lines, a 1,000 operation-deep pipeline is going
 * to be a slow way to do it. This is where the draw operations come in.
 *
 * To use these operations, use vips_image_copy_memory() to make a private 
 * memory copy of the image you want to modify, then call a 
 * series of draw operations.
 *
 * Once you are done drawing, return to normal use of vips operations. Any time
 * you want to start drawing again, you'll need to copy again. 
 */

/** 
 * VipsCombineMode:
 * @VIPS_COMBINE_MODE_SET: set pixels to the new value
 * @VIPS_COMBINE_MODE_ADD: add pixels
 *
 * See vips_draw_image() and so on.
 *
 * Operations like vips_draw_image() need to be told how to combine images
 * from two sources. 
 *
 * See also: vips_join().
 */

G_DEFINE_ABSTRACT_TYPE( VipsDraw, vips_draw, VIPS_TYPE_OPERATION );

static int
vips_draw_build( VipsObject *object )
{
	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
	VipsDraw *draw = VIPS_DRAW( object );

#ifdef DEBUG
	printf( "vips_draw_build: " );
	vips_object_print_name( object );
	printf( "\n" );
#endif /*DEBUG*/

	if( VIPS_OBJECT_CLASS( vips_draw_parent_class )->build( object ) )
		return( -1 );

	if( vips_check_coding_known( class->nickname, draw->image ) ||
		vips_image_inplace( draw->image ) )
		return( -1 );

	draw->lsize = VIPS_IMAGE_SIZEOF_LINE( draw->image );
	draw->psize = VIPS_IMAGE_SIZEOF_PEL( draw->image );
	draw->noclip = FALSE;

	return( 0 );
}

static void
vips_draw_class_init( VipsDrawClass *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";
	vobject_class->description = _( "draw operations" );
	vobject_class->build = vips_draw_build;

	VIPS_ARG_IMAGE( class, "image", 1, 
		_( "Image" ), 
		_( "Image to draw on" ),
		VIPS_ARGUMENT_REQUIRED_INPUT | VIPS_ARGUMENT_MODIFY, 
		G_STRUCT_OFFSET( VipsDraw, image ) );

}

static void
vips_draw_init( VipsDraw *draw )
{
}

void
vips_draw_operation_init( void )
{
	extern GType vips_draw_rect_get_type( void ); 
	extern GType vips_draw_image_get_type( void ); 
	extern GType vips_draw_mask_get_type( void ); 
	extern GType vips_draw_line_get_type( void ); 
	extern GType vips_draw_circle_get_type( void ); 
	extern GType vips_draw_flood_get_type( void ); 
	extern GType vips_draw_smudge_get_type( void ); 

	vips_draw_rect_get_type();
	vips_draw_image_get_type();
	vips_draw_mask_get_type();
	vips_draw_line_get_type();
	vips_draw_circle_get_type();
	vips_draw_flood_get_type();
	vips_draw_smudge_get_type();
}