/**
* cpml_segment_offset:
* @segment: a #CpmlSegment
* @offset: the offset distance
*
* Offsets a segment of the specified amount, that is builds a "parallel"
* segment at the @offset distance from the original one and returns the
* result by replacing the original @segment.
*
* <important>
* <title>TODO</title>
* <itemizedlist>
* <listitem>Closed path are not yet managed: an elegant solution is not
* so obvious: use <function>cpml_close_offset</function> when
* will be available.</listitem>
* <listitem>Degenerated primitives, such as lines of length 0, are not
* managed properly.</listitem>
* </itemizedlist>
* </important>
*
* Since: 1.0
**/
void
cpml_segment_offset(CpmlSegment *segment, double offset)
{
CpmlPrimitive primitive;
CpmlPrimitive last_primitive;
CpmlPair old_end;
cairo_path_data_t org, *old_org;
int first_cycle;
cpml_primitive_from_segment(&primitive, segment);
first_cycle = 1;
do {
if (! first_cycle) {
cpml_pair_to_cairo(&old_end, &org);
old_org = primitive.org;
primitive.org = &org;
}
cpml_primitive_put_point(&primitive, -1, &old_end);
cpml_primitive_offset(&primitive, offset);
if (! first_cycle) {
cpml_primitive_join(&last_primitive, &primitive);
primitive.org = old_org;
}
cpml_primitive_copy(&last_primitive, &primitive);
first_cycle = 0;
} while (cpml_primitive_next(&primitive));
}
static void
_cpml_sanity_join(gint i)
{
CpmlSegment segment;
CpmlPrimitive primitive;
cpml_segment_from_cairo(&segment, (cairo_path_t *) adg_test_path());
cpml_primitive_from_segment(&primitive, &segment);
switch (i) {
case 1:
cpml_primitive_join(NULL, &primitive);
break;
case 2:
cpml_primitive_join(&primitive, NULL);
break;
default:
g_test_trap_assert_failed();
break;
}
}
cairo_path_t path = {
CAIRO_STATUS_SUCCESS,
path_data,
G_N_ELEMENTS(path_data)
};
CpmlSegment segment;
CpmlPrimitive primitive1, primitive2;
cpml_segment_from_cairo(&segment, &path);
cpml_primitive_from_segment(&primitive1, &segment);
cpml_primitive_copy(&primitive2, &primitive1);
cpml_primitive_next(&primitive2);
/* primitive1 and primitive2 are already joint */
g_assert_cmpint(cpml_primitive_join(&primitive1, &primitive2), ==, 1);
adg_assert_isapprox((primitive2.org)->point.x, 2);
adg_assert_isapprox((primitive2.org)->point.y, 0);
cpml_primitive_next(&primitive2);
/* Now primitive1 and primitive2 are divergent,
* hence cannot be joined */
g_assert_cmpint(cpml_primitive_join(&primitive1, &primitive2), ==, 0);
cpml_primitive_next(&primitive2);
g_assert_cmpint(cpml_primitive_join(&primitive1, &primitive2), ==, 1);
adg_assert_isapprox((primitive2.org)->point.x, 1);
adg_assert_isapprox((primitive2.org)->point.y, 0);
}
static void
