static cairo_status_t
_cairo_skia_context_rel_curve_to (void *abstract_cr,
double dx1, double dy1,
double dx2, double dy2,
double dx3, double dy3)
{
cairo_skia_context_t *cr = (cairo_skia_context_t *) abstract_cr;
user_to_device_distance (cr, &dx1, &dy1);
user_to_device_distance (cr, &dx2, &dy2);
user_to_device_distance (cr, &dx3, &dy3);
cr->path->rCubicTo (SkFloatToScalar (dx1), SkFloatToScalar (dy1),
SkFloatToScalar (dx2), SkFloatToScalar (dy2),
SkFloatToScalar (dx3), SkFloatToScalar (dy3));
return CAIRO_STATUS_SUCCESS;
}
void snap_line_width(std::shared_ptr< cairo_t>& cr) {
double x_width = line_width(cr);
double y_width = x_width;
user_to_device_distance(cr, x_width, y_width);
/* If the line width is less than 1 then it will round to 0 and
* disappear. Instead, we clamp it to 1.0, but we must preserve
* its sign for the case of a reflecting transformation. */
double x_width_snapped = floor(x_width + 0.5);
if (fabs(x_width_snapped) < 1.0) {
if (x_width > 0)
x_width_snapped = 1.0;
else
x_width_snapped = -1.0;
}
double y_width_snapped = floor(y_width + 0.5);
if (fabs(y_width_snapped) < 1.0) {
if (y_width > 0)
y_width_snapped = 1.0;
else
y_width_snapped = -1.0;
}
double x_error = fabs(x_width - x_width_snapped);
double y_error = fabs(y_width - y_width_snapped);
device_to_user_distance(cr, x_width_snapped, y_width_snapped);
if (x_error > y_error)
line_width(cr, x_width_snapped);
else
line_width(cr, y_width_snapped);
}
static cairo_status_t
_cairo_skia_context_rel_line_to (void *abstract_cr, double dx, double dy)
{
cairo_skia_context_t *cr = (cairo_skia_context_t *) abstract_cr;
user_to_device_distance (cr, &dx, &dy);
cr->path->rLineTo (SkFloatToScalar (dx), SkFloatToScalar (dy));
return CAIRO_STATUS_SUCCESS;
}
static cairo_status_t
_cairo_skia_context_rel_arc_to (void *abstract_cr,
double dx1, double dy1,
double dx2, double dy2,
double radius)
{
cairo_skia_context_t *cr = (cairo_skia_context_t *) abstract_cr;
#if 0
user_to_device_point (cr, &x1, &y1);
user_to_device_point (cr, &x2, &y2);
user_to_device_distance (cr, &radius, &radius);
#endif
cr->path->arcTo (SkFloatToScalar (dx1), SkFloatToScalar (dy1),
SkFloatToScalar (dx2), SkFloatToScalar (dy2),
SkFloatToScalar (radius));
return CAIRO_STATUS_SUCCESS;
}
void snap_point_for_stroke(std::shared_ptr< cairo_t>& cr, double& x, double& y) {
/*
* Round in device space after adding the fractional portion of
* one-half the (device space) line width.
*/
double x_width_dev_2 = line_width(cr);
double y_width_dev_2 = x_width_dev_2;
user_to_device_distance(cr, x_width_dev_2, y_width_dev_2);
x_width_dev_2 *= 0.5;
y_width_dev_2 *= 0.5;
double x_offset = x_width_dev_2 - (int)(x_width_dev_2);
double y_offset = y_width_dev_2 - (int)(y_width_dev_2);
user_to_device(cr, x, y);
x = floor(x + x_offset + 0.5);
y = floor(y + y_offset + 0.5);
x -= x_offset;
y -= y_offset;
device_to_user(cr, x, y);
}