AuroraMiddleware/gtk
1
0
Fork 1
mirror of https://gitlab.gnome.org/GNOME/gtk.git synced 2024-09-19 21:40:22 +00:00
Code Issues Projects Releases Wiki Activity

Merge branch 'matthiasc/for-main' into 'main'

Browse Source 
curve: Add a vfunc for get_at_length

See merge request GNOME/gtk!6366
This commit is contained in:
Matthias Clasen 2023-08-30 02:42:54 +00:00
commit 39a8c64624
1 changed files with 84 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

110
gsk/gskcurve.c
View File

@ -84,6 +84,9 @@ struct _GskCurveClass
const graphene_point_t *point);
float (* get_length_to) (const GskCurve *curve,
float t);
float (* get_at_length) (const GskCurve *curve,
float distance,
float epsilon);
};
/* {{{ Utilities */
@ -208,6 +211,41 @@ get_length_by_approximation (const GskCurve *curve,
return z * sum;
}
/* Compute the inverse of the arclength using bisection,
* to a given precision
*/
static float
get_t_by_bisection (const GskCurve *curve,
float length,
float epsilon)
{
float t1, t2, t, l;
GskCurve c1;
g_assert (epsilon >= FLT_EPSILON);
t1 = 0;
t2 = 1;
while (t1 < t2)
{
t = (t1 + t2) / 2;
if (t == t1 || t == t2)
break;
gsk_curve_split (curve, t, &c1, NULL);
l = gsk_curve_get_length (&c1);
if (fabsf (length - l) < epsilon)
break;
else if (l < length)
t1 = t;
else
t2 = t;
}
return t;
}
/* }}} */
/* {{{ Line */
@ -426,6 +464,23 @@ gsk_line_curve_get_length_to (const GskCurve *curve,
return t * graphene_point_distance (&pts[0], &pts[1], NULL, NULL);
}
static float
gsk_line_curve_get_at_length (const GskCurve *curve,
float distance,
float epsilon)
{
const GskLineCurve *self = &curve->line;
const graphene_point_t *pts = self->points;
float length;
length = graphene_point_distance (&pts[0], &pts[1], NULL, NULL);
if (length == 0)
return 0;
return CLAMP (distance / length, 0, 1);
}
static const GskCurveClass GSK_LINE_CURVE_CLASS = {
gsk_line_curve_init,
gsk_line_curve_init_foreach,
@ -448,6 +503,7 @@ static const GskCurveClass GSK_LINE_CURVE_CLASS = {
gsk_line_curve_get_derivative_at,
gsk_line_curve_get_crossing,
gsk_line_curve_get_length_to,
gsk_line_curve_get_at_length,
};
/* }}} */
@ -841,6 +897,14 @@ gsk_quad_curve_get_length_to (const GskCurve *curve,
return get_length_by_approximation (curve, t);
}
static float
gsk_quad_curve_get_at_length (const GskCurve *curve,
float t,
float epsilon)
{
return get_t_by_bisection (curve, t, epsilon);
}
static const GskCurveClass GSK_QUAD_CURVE_CLASS = {
gsk_quad_curve_init,
gsk_quad_curve_init_foreach,
@ -863,6 +927,7 @@ static const GskCurveClass GSK_QUAD_CURVE_CLASS = {
gsk_quad_curve_get_derivative_at,
gsk_quad_curve_get_crossing,
gsk_quad_curve_get_length_to,
gsk_quad_curve_get_at_length,
};
/* }}} */
@ -1311,6 +1376,14 @@ gsk_cubic_curve_get_length_to (const GskCurve *curve,
return get_length_by_approximation (curve, t);
}
static float
gsk_cubic_curve_get_at_length (const GskCurve *curve,
float t,
float epsilon)
{
return get_t_by_bisection (curve, t, epsilon);
}
static const GskCurveClass GSK_CUBIC_CURVE_CLASS = {
gsk_cubic_curve_init,
gsk_cubic_curve_init_foreach,
@ -1333,6 +1406,7 @@ static const GskCurveClass GSK_CUBIC_CURVE_CLASS = {
gsk_cubic_curve_get_derivative_at,
gsk_cubic_curve_get_crossing,
gsk_cubic_curve_get_length_to,
gsk_cubic_curve_get_at_length,
};
/* }}} */
@ -2018,6 +2092,14 @@ gsk_conic_curve_get_length_to (const GskCurve *curve,
return get_length_by_approximation (curve, t);
}
static float
gsk_conic_curve_get_at_length (const GskCurve *curve,
float t,
float epsilon)
{
return get_t_by_bisection (curve, t, epsilon);
}
static const GskCurveClass GSK_CONIC_CURVE_CLASS = {
gsk_conic_curve_init,
gsk_conic_curve_init_foreach,
@ -2040,6 +2122,7 @@ static const GskCurveClass GSK_CONIC_CURVE_CLASS = {
gsk_conic_curve_get_derivative_at,
gsk_conic_curve_get_crossing,
gsk_conic_curve_get_length_to,
gsk_conic_curve_get_at_length,
};
/* }}} */
@ -2389,32 +2472,7 @@ gsk_curve_at_length (const GskCurve *curve,
float length,
float epsilon)
{
float t1, t2, t, l;
GskCurve c1;
g_assert (epsilon >= FLT_EPSILON);
t1 = 0;
t2 = 1;
while (t1 < t2)
{
t = (t1 + t2) / 2;
if (t == t1 || t == t2)
break;
gsk_curve_split (curve, t, &c1, NULL);
l = gsk_curve_get_length (&c1);
if (fabsf (length - l) < epsilon)
break;
else if (l < length)
t1 = t;
else
t2 = t;
}
return t;
return get_class (curve->op)->get_at_length (curve, length, epsilon);
}
static inline void