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/*
* Copyright © 2022 Behdad Esfahbod
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#ifndef HB_PAINT_EXTENTS_HH
#define HB_PAINT_EXTENTS_HH
#include "hb.hh"
#include "hb-paint.h"
typedef struct hb_extents_t
{
hb_extents_t () {}
hb_extents_t (float xmin, float ymin, float xmax, float ymax) :
xmin (xmin), ymin (ymin), xmax (xmax), ymax (ymax) {}
bool is_empty () const { return xmin >= xmax || ymin >= ymax; }
bool is_void () const { return xmin > xmax; }
void union_ (const hb_extents_t &o)
{
xmin = hb_min (xmin, o.xmin);
ymin = hb_min (ymin, o.ymin);
xmax = hb_max (xmax, o.xmax);
ymax = hb_max (ymax, o.ymax);
}
void intersect (const hb_extents_t &o)
{
xmin = hb_max (xmin, o.xmin);
ymin = hb_max (ymin, o.ymin);
xmax = hb_min (xmax, o.xmax);
ymax = hb_min (ymax, o.ymax);
}
void
add_point (float x, float y)
{
if (unlikely (is_void ()))
{
xmin = xmax = x;
ymin = ymax = y;
}
else
{
xmin = hb_min (xmin, x);
ymin = hb_min (ymin, y);
xmax = hb_max (xmax, x);
ymax = hb_max (ymax, y);
}
}
float xmin = 0.f;
float ymin = 0.f;
float xmax = -1.f;
float ymax = -1.f;
} hb_extents_t;
typedef struct hb_transform_t
{
hb_transform_t () {}
hb_transform_t (float xx, float yx,
float xy, float yy,
float x0, float y0) :
xx (xx), yx (yx), xy (xy), yy (yy), x0 (x0), y0 (y0) {}
void multiply (const hb_transform_t &o)
{
/* Copied from cairo, with "o" being "a" there and "this" being "b" there. */
hb_transform_t r;
r.xx = o.xx * xx + o.yx * xy;
r.yx = o.xx * yx + o.yx * yy;
r.xy = o.xy * xx + o.yy * xy;
r.yy = o.xy * yx + o.yy * yy;
r.x0 = o.x0 * xx + o.y0 * xy + x0;
r.y0 = o.x0 * yx + o.y0 * yy + y0;
*this = r;
}
void transform_distance (float &dx, float &dy) const
{
float new_x = xx * dx + xy * dy;
float new_y = yx * dx + yy * dy;
dx = new_x;
dy = new_y;
}
void transform_point (float &x, float &y) const
{
transform_distance (x, y);
x += x0;
y += y0;
}
void transform_extents (hb_extents_t &extents) const
{
float quad_x[4], quad_y[4];
quad_x[0] = extents.xmin;
quad_y[0] = extents.ymin;
quad_x[1] = extents.xmin;
quad_y[1] = extents.ymax;
quad_x[2] = extents.xmax;
quad_y[2] = extents.ymin;
quad_x[3] = extents.xmax;
quad_y[3] = extents.ymax;
extents = hb_extents_t {};
for (unsigned i = 0; i < 4; i++)
{
transform_point (quad_x[i], quad_y[i]);
extents.add_point (quad_x[i], quad_y[i]);
}
}
float xx = 1.f;
float yx = 0.f;
float xy = 0.f;
float yy = 1.f;
float x0 = 0.f;
float y0 = 0.f;
} hb_transform_t;
typedef struct hb_bounds_t
{
enum status_t {
UNBOUNDED,
BOUNDED,
EMPTY,
};
hb_bounds_t (status_t status) : status (status) {}
hb_bounds_t (const hb_extents_t &extents) :
status (extents.is_empty () ? EMPTY : BOUNDED), extents (extents) {}
void union_ (const hb_bounds_t &o)
{
if (o.status == UNBOUNDED)
status = UNBOUNDED;
else if (o.status == BOUNDED)
{
if (status == EMPTY)
*this = o;
else if (status == BOUNDED)
extents.union_ (o.extents);
}
}
void intersect (const hb_bounds_t &o)
{
if (o.status == EMPTY)
status = EMPTY;
else if (o.status == BOUNDED)
{
if (status == UNBOUNDED)
*this = o;
else if (status == BOUNDED)
{
extents.intersect (o.extents);
if (extents.is_empty ())
status = EMPTY;
}
}
}
status_t status;
hb_extents_t extents;
} hb_bounds_t;
typedef struct hb_paint_extents_context_t hb_paint_extents_context_t;
struct hb_paint_extents_context_t
{
hb_paint_extents_context_t ()
{
transforms.push (hb_transform_t{});
clips.push (hb_bounds_t{hb_bounds_t::UNBOUNDED});
groups.push (hb_bounds_t{hb_bounds_t::EMPTY});
}
hb_extents_t get_extents ()
{
return groups.tail().extents;
}
bool is_bounded ()
{
return groups.tail().status != hb_bounds_t::UNBOUNDED;
}
void push_transform (const hb_transform_t &trans)
{
hb_transform_t t = transforms.tail ();
t.multiply (trans);
transforms.push (t);
}
void pop_transform ()
{
transforms.pop ();
}
void push_clip (hb_extents_t extents)
{
/* Transform extents and push a new clip. */
const hb_transform_t &t = transforms.tail ();
t.transform_extents (extents);
clips.push (hb_bounds_t {extents});
}
void pop_clip ()
{
clips.pop ();
}
void push_group ()
{
groups.push (hb_bounds_t {hb_bounds_t::EMPTY});
}
void pop_group (hb_paint_composite_mode_t mode)
{
const hb_bounds_t src_bounds = groups.pop ();
hb_bounds_t &backdrop_bounds = groups.tail ();
switch ((int) mode)
{
case HB_PAINT_COMPOSITE_MODE_CLEAR:
backdrop_bounds.status = hb_bounds_t::EMPTY;
break;
case HB_PAINT_COMPOSITE_MODE_SRC:
case HB_PAINT_COMPOSITE_MODE_SRC_OUT:
backdrop_bounds = src_bounds;
break;
case HB_PAINT_COMPOSITE_MODE_DEST:
case HB_PAINT_COMPOSITE_MODE_DEST_OUT:
break;
case HB_PAINT_COMPOSITE_MODE_SRC_IN:
case HB_PAINT_COMPOSITE_MODE_DEST_IN:
backdrop_bounds.intersect (src_bounds);
break;
default:
backdrop_bounds.union_ (src_bounds);
break;
}
}
void paint ()
{
const hb_bounds_t &clip = clips.tail ();
hb_bounds_t &group = groups.tail ();
group.union_ (clip);
}
protected:
hb_vector_t<hb_transform_t> transforms;
hb_vector_t<hb_bounds_t> clips;
hb_vector_t<hb_bounds_t> groups;
};
HB_INTERNAL hb_paint_funcs_t *
hb_paint_extents_get_funcs ();
#endif /* HB_PAINT_EXTENTS_HH */