libtwin/twin_path.c

/*
 * Twin - A Tiny Window System
 * Copyright © 2004 Keith Packard <keithp@keithp.com>
 * All rights reserved.
 *
 * This Library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This Library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with the Twin Library; see the file COPYING.  If not,
 * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "twinint.h"

static int
_twin_current_subpath_len (twin_path_t *path)
{
    int	start;
    
    if (path->nsublen)
	start = path->sublen[path->nsublen-1];
    else
	start = 0;
    return path->npoints - start;
}

twin_spoint_t
_twin_path_current_spoint (twin_path_t *path)
{
    if (!path->npoints)
	twin_path_move (path, 0, 0);
    return path->points[path->npoints - 1];
}

twin_spoint_t
_twin_path_subpath_first_spoint (twin_path_t *path)
{
    int	start;
    
    if (!path->npoints)
	twin_path_move (path, 0, 0);

    if (path->nsublen)
	start = path->sublen[path->nsublen-1];
    else
	start = 0;
    
    return path->points[start];
}

void
_twin_path_sfinish (twin_path_t *path)
{
    switch (_twin_current_subpath_len(path)) {
    case 1:
	path->npoints--;
    case 0:
	return;
    }
    
    if (path->nsublen == path->size_sublen)
    {
	int	size_sublen;
	int	*sublen;
	
	if (path->size_sublen > 0)
	    size_sublen = path->size_sublen * 2;
	else
	    size_sublen = 1;
	if (path->sublen)
	    sublen = realloc (path->sublen, size_sublen * sizeof (int));
	else
	    sublen = malloc (size_sublen * sizeof (int));
	if (!sublen)
	    return;
	path->sublen = sublen;
	path->size_sublen = size_sublen;
    }
    path->sublen[path->nsublen] = path->npoints;
    path->nsublen++;
}

void 
_twin_path_smove (twin_path_t *path, twin_sfixed_t x, twin_sfixed_t y)
{
    switch (_twin_current_subpath_len (path)) {
    default:
	_twin_path_sfinish (path);
    case 0:
	_twin_path_sdraw (path, x, y);
	break;
    case 1:
	path->points[path->npoints-1].x = x;
	path->points[path->npoints-1].y = y;
	break;
    }
}

void
_twin_path_sdraw (twin_path_t *path, twin_sfixed_t x, twin_sfixed_t y)
{
    if (_twin_current_subpath_len(path) > 0 &&
	path->points[path->npoints-1].x == x &&
	path->points[path->npoints-1].y == y)
	return;
    if (path->npoints == path->size_points)
    {
	int		size_points;
	twin_spoint_t	*points;
	
	if (path->size_points > 0)
	    size_points = path->size_points * 2;
	else
	    size_points = 16;
	if (path->points)
	    points = realloc (path->points, size_points * sizeof (twin_spoint_t));
	else
	    points = malloc (size_points * sizeof (twin_spoint_t));
	if (!points)
	    return;
	path->points = points;
	path->size_points = size_points;
    }
    path->points[path->npoints].x = x;
    path->points[path->npoints].y = y;
    path->npoints++;
}

void
twin_path_move (twin_path_t *path, twin_fixed_t x, twin_fixed_t y)
{
    _twin_path_smove (path, 
		      _twin_matrix_x (&path->state.matrix, x, y),
		      _twin_matrix_y (&path->state.matrix, x, y));
}

void
twin_path_rmove (twin_path_t *path, twin_fixed_t dx, twin_fixed_t dy)
{
    twin_spoint_t   here = _twin_path_current_spoint (path);
    _twin_path_smove (path, 
		      here.x + 
		      _twin_matrix_dx (&path->state.matrix, dx, dy),
		      here.y + 
		      _twin_matrix_dy (&path->state.matrix, dx, dy));
}

void
twin_path_draw (twin_path_t *path, twin_fixed_t x, twin_fixed_t y)
{
    _twin_path_sdraw (path, 
		      _twin_matrix_x (&path->state.matrix, x, y),
		      _twin_matrix_y (&path->state.matrix, x, y));
}

void
twin_path_rdraw (twin_path_t *path, twin_fixed_t dx, twin_fixed_t dy)
{
    twin_spoint_t   here = _twin_path_current_spoint (path);
    _twin_path_sdraw (path, 
		      here.x +
		      _twin_matrix_dx (&path->state.matrix, dx, dy),
		      here.y + 
		      _twin_matrix_dy (&path->state.matrix, dx, dy));
}

void
twin_path_close (twin_path_t *path)
{
    twin_spoint_t   f;
    
    switch (_twin_current_subpath_len(path)) {
    case 0:
    case 1:
	break;
    default:
	f = _twin_path_subpath_first_spoint (path);
	_twin_path_sdraw (path, f.x, f.y);
	break;
    }
}

void
twin_path_circle (twin_path_t	*path, 
		  twin_fixed_t	x,
		  twin_fixed_t	y,
		  twin_fixed_t radius)
{
    twin_path_ellipse (path, x, y, radius, radius);
}

void
twin_path_ellipse (twin_path_t *path, 
		   twin_fixed_t x, 
		   twin_fixed_t	y,
		   twin_fixed_t x_radius, 
		   twin_fixed_t	y_radius)
{
    twin_path_move (path, x + x_radius, y);
    twin_path_arc (path, x, y, x_radius, y_radius, 0, TWIN_ANGLE_360);
    twin_path_close (path);
}

#define twin_fixed_abs(f)   ((f) < 0 ? -(f) : (f))

static twin_fixed_t
_twin_matrix_max_radius (twin_matrix_t *m)
{
    return (twin_fixed_abs (m->m[0][0]) + twin_fixed_abs (m->m[0][1]) +
	    twin_fixed_abs (m->m[1][0]) + twin_fixed_abs (m->m[1][1]));
}

void
twin_path_arc (twin_path_t  *path,
	       twin_fixed_t x,
	       twin_fixed_t y,
	       twin_fixed_t x_radius,
	       twin_fixed_t y_radius,
	       twin_angle_t start,
	       twin_angle_t extent)
{
    twin_matrix_t   save = twin_path_current_matrix (path);
    twin_fixed_t    max_radius;
    int32_t    	    sides;
    int32_t    	    n;
    twin_angle_t    a;
    twin_angle_t    first, last, step, inc;
    twin_angle_t    epsilon;

    twin_path_translate (path, x, y);
    twin_path_scale (path, x_radius, y_radius);

    max_radius = _twin_matrix_max_radius (&path->state.matrix);
    sides = max_radius / twin_sfixed_to_fixed (TWIN_SFIXED_TOLERANCE);
    if (sides > 1024) sides = 1024;

    n = 2;
    while ((1 << n) < sides)
	n++;

    sides = (1 << n);

    step = TWIN_ANGLE_360 >> n;
    inc = step;
    epsilon = 1;
    if (extent < 0)
    {
	inc = -inc;
	epsilon = -1;
    }
    
    first = (start + inc - epsilon) & ~(step - 1);
    last = (start + extent - inc + epsilon) & ~(step - 1);

    if (first != start)
	twin_path_draw (path, twin_cos(start), twin_sin(start));
    
    for (a = first; a != last; a += inc)
	twin_path_draw (path, twin_cos (a), twin_sin (a));
    
    if (last != start + extent)
	twin_path_draw (path, twin_cos (start+extent), twin_sin(start+extent));

    twin_path_set_matrix (path, save);
}

void
twin_path_rectangle (twin_path_t    *path,
		     twin_fixed_t   x,
		     twin_fixed_t   y,
		     twin_fixed_t   w,
		     twin_fixed_t   h)
{
    twin_path_move (path, x, y);
    twin_path_draw (path, x+w, y);
    twin_path_draw (path, x+w, y+h);
    twin_path_draw (path, x, y+h);
    twin_path_close (path);
}
		     
void
twin_path_rounded_rectangle (twin_path_t	*path,
			     twin_fixed_t	x,
			     twin_fixed_t	y,
			     twin_fixed_t	w,
			     twin_fixed_t	h,
			     twin_fixed_t	x_radius,
			     twin_fixed_t	y_radius)
{
    twin_matrix_t   save = twin_path_current_matrix (path);

    twin_path_translate (path, x, y);
    twin_path_move  (path,
		     0, y_radius);
    twin_path_arc (path, x_radius, y_radius, x_radius, y_radius,
		   TWIN_ANGLE_180, TWIN_ANGLE_90);
    twin_path_draw  (path, 
		     w - x_radius, 0);
    twin_path_arc (path, w - x_radius, y_radius, x_radius, y_radius,
		   TWIN_ANGLE_270, TWIN_ANGLE_90);
    twin_path_draw  (path,
		     w, h - y_radius);
    twin_path_arc (path, w - x_radius, h - y_radius, x_radius, y_radius,
		   TWIN_ANGLE_0, TWIN_ANGLE_90);
    twin_path_draw  (path,
		     x_radius, h);
    twin_path_arc (path, x_radius, h - y_radius, x_radius, y_radius,
		   TWIN_ANGLE_90, TWIN_ANGLE_90);
    twin_path_close (path);
    twin_path_set_matrix (path, save);
}
			
void
twin_path_lozenge (twin_path_t	*path,
		   twin_fixed_t	x,
		   twin_fixed_t	y,
		   twin_fixed_t	w,
		   twin_fixed_t	h)
{
    twin_fixed_t    radius;

    if (w > h)
	radius = h / 2;
    else
	radius = w / 2;
    twin_path_rounded_rectangle (path, x, y, w, h, radius, radius);
}

void
twin_path_tab (twin_path_t	*path,
	       twin_fixed_t	x,
	       twin_fixed_t	y,
	       twin_fixed_t	w,
	       twin_fixed_t	h,
	       twin_fixed_t	x_radius,
	       twin_fixed_t	y_radius)
{
    twin_matrix_t   save = twin_path_current_matrix (path);

    twin_path_translate (path, x, y);
    twin_path_move  (path,
		     0, y_radius);
    twin_path_arc (path, x_radius, y_radius, x_radius, y_radius,
		   TWIN_ANGLE_180, TWIN_ANGLE_90);
    twin_path_draw  (path, 
		     w - x_radius, 0);
    twin_path_arc (path, w - x_radius, y_radius, x_radius, y_radius,
		   TWIN_ANGLE_270, TWIN_ANGLE_90);
    twin_path_draw  (path,
		     w, h);
    twin_path_draw  (path,
		     0, h);
    twin_path_close (path);
    twin_path_set_matrix (path, save);
}

void
twin_path_set_matrix (twin_path_t *path, twin_matrix_t matrix)
{
    path->state.matrix = matrix;
}

twin_matrix_t
twin_path_current_matrix (twin_path_t *path)
{
    return path->state.matrix;
}

void
twin_path_identity (twin_path_t *path)
{
    twin_matrix_identity (&path->state.matrix);
}

void
twin_path_translate (twin_path_t *path, twin_fixed_t tx, twin_fixed_t ty)
{
    twin_matrix_translate (&path->state.matrix, tx, ty);
}

void
twin_path_scale (twin_path_t *path, twin_fixed_t sx, twin_fixed_t sy)
{
    twin_matrix_scale (&path->state.matrix, sx, sy);
}
    
void
twin_path_rotate (twin_path_t *path, twin_angle_t a)
{
    twin_matrix_rotate (&path->state.matrix, a);
}
    
void
twin_path_set_font_size (twin_path_t *path, twin_fixed_t font_size)
{
    path->state.font_size = font_size;
}

twin_fixed_t
twin_path_current_font_size (twin_path_t *path)
{
    return path->state.font_size;
}

void
twin_path_set_font_style (twin_path_t *path, twin_style_t font_style)
{
    path->state.font_style = font_style;
}

twin_style_t
twin_path_current_font_style (twin_path_t *path)
{
    return path->state.font_style;
}

void
twin_path_set_cap_style (twin_path_t *path, twin_cap_t cap_style)
{
    path->state.cap_style = cap_style;
}

twin_cap_t
twin_path_current_cap_style (twin_path_t *path)
{
    return path->state.cap_style;
}

void
twin_path_empty (twin_path_t *path)
{
    path->npoints = 0;
    path->nsublen = 0;
}

void
twin_path_bounds (twin_path_t *path, twin_rect_t *rect)
{
    twin_sfixed_t   left = TWIN_SFIXED_MAX;
    twin_sfixed_t   top = TWIN_SFIXED_MAX;
    twin_sfixed_t   right = TWIN_SFIXED_MIN;
    twin_sfixed_t   bottom = TWIN_SFIXED_MIN;
    int		    i;

    for (i = 0; i < path->npoints; i++)
    {
	twin_sfixed_t	x = path->points[i].x;
	twin_sfixed_t	y = path->points[i].y;
	if (x < left) left = x;
	if (x > right) right = x;
	if (y < top) top = y;
	if (y > bottom) bottom = y;
    }
    if (left >= right || top >= bottom)
	left = right = top = bottom = 0;
    rect->left = twin_sfixed_trunc (left);
    rect->top = twin_sfixed_trunc (top);
    rect->right = twin_sfixed_trunc (twin_sfixed_ceil (right));
    rect->bottom = twin_sfixed_trunc (twin_sfixed_ceil (bottom));
}

void
twin_path_append (twin_path_t *dst, twin_path_t *src)
{
    int	    p;
    int	    s = 0;

    for (p = 0; p < src->npoints; p++)
    {
	if (s < src->nsublen && p == src->sublen[s])
	{
	    _twin_path_sfinish (dst);
	    s++;
	}
	_twin_path_sdraw (dst, src->points[p].x, src->points[p].y);
    }
}

twin_state_t
twin_path_save (twin_path_t *path)
{
    return path->state;
}

void
twin_path_restore (twin_path_t *path, twin_state_t *state)
{
    path->state = *state;
}

twin_path_t *
twin_path_create (void)
{
    twin_path_t	*path;

    path = malloc (sizeof (twin_path_t));
    path->npoints = path->size_points = 0;
    path->nsublen = path->size_sublen = 0;
    path->points = 0;
    path->sublen = 0;
    twin_matrix_identity (&path->state.matrix);
    path->state.font_size = TWIN_FIXED_ONE * 15;
    path->state.font_style = TWIN_TEXT_ROMAN;
    path->state.cap_style = TwinCapRound;
    return path;
}

void
twin_path_destroy (twin_path_t *path)
{
    if (path->points)
	free (path->points);
    if (path->sublen)
	free (path->sublen);
    free (path);
}

void
twin_composite_path (twin_pixmap_t	*dst,
		     twin_operand_t	*src,
		     twin_coord_t	src_x,
		     twin_coord_t	src_y,
		     twin_path_t	*path,
		     twin_operator_t	operator)
{
    twin_rect_t	    bounds;
    twin_pixmap_t   *mask;
    twin_operand_t  msk;
    twin_coord_t    width, height;

    twin_path_bounds (path, &bounds);
    if (bounds.left >= bounds.right || bounds.top >= bounds.bottom)
	return;
    width = bounds.right - bounds.left;
    height = bounds.bottom - bounds.top;
    mask = twin_pixmap_create (TWIN_A8, width, height);
			       
    if (!mask)
	return;
    twin_fill_path (mask, path, -bounds.left, -bounds.top);
    msk.source_kind = TWIN_PIXMAP;
    msk.u.pixmap = mask;
    twin_composite (dst, bounds.left, bounds.top, 
		    src, src_x + bounds.left, src_y + bounds.top,
		    &msk, 0, 0, operator, width, height);
    twin_pixmap_destroy (mask);
}

void
twin_paint_path (twin_pixmap_t	*dst,
		 twin_argb32_t	argb,
		 twin_path_t	*path)
{
    twin_operand_t  src;

    src.source_kind = TWIN_SOLID;
    src.u.argb = argb;
    twin_composite_path (dst, &src, 0, 0, path, TWIN_OVER);
}

void
twin_composite_stroke (twin_pixmap_t	*dst,
		       twin_operand_t	*src,
		       twin_coord_t	src_x,
		       twin_coord_t	src_y,
		       twin_path_t	*stroke,
		       twin_fixed_t	pen_width,
		       twin_operator_t	operator)
{
    twin_path_t	    *pen = twin_path_create ();
    twin_path_t	    *path = twin_path_create ();
    twin_matrix_t   m = twin_path_current_matrix (stroke);
    
    m.m[2][0] = 0;
    m.m[2][1] = 0;
    twin_path_set_matrix (pen, m);
    twin_path_set_cap_style (path, twin_path_current_cap_style (stroke));
    twin_path_circle (pen, 0, 0, pen_width / 2);
    twin_path_convolve (path, stroke, pen);
    twin_composite_path (dst, src, src_x, src_y, path, operator);
    twin_path_destroy (path);
    twin_path_destroy (pen);
}

void
twin_paint_stroke (twin_pixmap_t    *dst,
		   twin_argb32_t    argb,
		   twin_path_t	    *stroke,
		   twin_fixed_t	    pen_width)
{
    twin_operand_t  src;

    src.source_kind = TWIN_SOLID;
    src.u.argb = argb;
    twin_composite_stroke (dst, &src, 0, 0, stroke, pen_width, TWIN_OVER);
}