index 93c3f5b7b410a15c83204283d93b9907cb34f57f..08c4d167b2c1672be331110a0df3e0a736618ace 100644 (file)
}
/*
-** Returns the matrix you need to apply to an object with given bbox and strokewidth to
-scale/move it to the new box x0/y0/x1/y1. Takes into account the "scale stroke"
+** Returns the matrix you need to apply to an object with given visual bbox and strokewidth to
+scale/move it to the new visual bbox x0/y0/x1/y1. Takes into account the "scale stroke"
preference value passed to it. Has to solve a quadratic equation to make sure
the goal is met exactly and the stroke scaling is obeyed.
*/
@@ -133,7 +133,7 @@ get_scale_transform_with_stroke (NR::Rect &bbox_param, gdouble strokewidth, bool
// These coefficients are obtained from the assumption that scaling applies to the
// non-stroked "shape proper" and that stroke scale is scaled by the expansion of that
// matrix. We're trying to solve this equation:
- // r1 = r0 * sqrt (((w1-r0)/(w0-r0))*((h1-r1)/(h0-r0)))
+ // r1 = r0 * sqrt (((w1-r0)/(w0-r0))*((h1-r0)/(h0-r0)))
// The operant of the sqrt() must be positive, which is ensured by the fabs() a few lines above
gdouble A = -w0*h0 + r0*(w0 + h0);
gdouble B = -(w1 + h1) * r0*r0;
@@ -165,6 +165,38 @@ get_scale_transform_with_stroke (NR::Rect &bbox_param, gdouble strokewidth, bool
return (p2o * scale * unbudge * o2n);
}
+NR::Rect
+get_visual_bbox (NR::Maybe<NR::Rect> const &initial_geom_bbox, NR::Matrix const &abs_affine, gdouble const initial_strokewidth, bool const transform_stroke)
+{
+
+ g_assert(initial_geom_bbox);
+
+ // Find the new geometric bounding box; Do this by transforming each corner of
+ // the initial geometric bounding box individually and fitting a new boundingbox
+ // around the transformerd corners
+ NR::Point const p0 = initial_geom_bbox->corner(0) * abs_affine;
+ NR::Rect new_geom_bbox = NR::Rect(p0, p0);
+ for (unsigned i = 1 ; i < 4 ; i++) {
+ new_geom_bbox.expandTo(initial_geom_bbox->corner(i) * abs_affine);
+ }
+
+ NR::Rect new_visual_bbox = new_geom_bbox;
+ if (initial_strokewidth > 0 && initial_strokewidth < NR_HUGE) {
+ if (transform_stroke) {
+ // scale stroke by: sqrt (((w1-r0)/(w0-r0))*((h1-r0)/(h0-r0))) (for visual bboxes, see get_scale_transform_with_stroke)
+ // equals scaling by: sqrt ((w1/w0)*(h1/h0)) for geometrical bboxes
+ // equals scaling by: sqrt (area1/area0) for geometrical bboxes
+ gdouble const new_strokewidth = initial_strokewidth * sqrt (new_geom_bbox.area() / initial_geom_bbox->area());
+ new_visual_bbox.growBy(0.5 * new_strokewidth);
+ } else {
+ // Do not transform the stroke
+ new_visual_bbox.growBy(0.5 * initial_strokewidth);
+ }
+ }
+
+ return new_visual_bbox;
+}
+
/*
Local Variables:
mode:c++