/* 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 <glib/gi18n-lib.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;
}
