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diff --git a/src/line-geometry.cpp b/src/line-geometry.cpp
index d36b1b63d3e507081c293d7b8d39ec65676ab29d..2e528f3afe5b555e64c459f02ef58e5d76a16836 100644 (file)
--- a/src/line-geometry.cpp
+++ b/src/line-geometry.cpp
#include "line-geometry.h"
#include "inkscape.h"
+#include "desktop.h"
#include "desktop-style.h"
#include "desktop-handles.h"
#include "display/sp-canvas.h"
#include "display/sodipodi-ctrl.h"
-//#include "display/curve.cpp"
namespace Box3D {
* of the segment. Otherwise interpret it as the direction of the line.
* FIXME: Think of a better way to distinguish between the two constructors of lines.
*/
-Line::Line(NR::Point const &start, NR::Point const &vec, bool is_endpoint) {
+Line::Line(Geom::Point const &start, Geom::Point const &vec, bool is_endpoint) {
pt = start;
if (is_endpoint)
v_dir = vec - start;
else
v_dir = vec;
normal = v_dir.ccw();
- d0 = NR::dot(normal, pt);
+ d0 = Geom::dot(normal, pt);
}
Line::Line(Line const &line) {
return *this;
}
-NR::Maybe<NR::Point> Line::intersect(Line const &line) {
- NR::Coord denom = NR::dot(v_dir, line.normal);
- g_return_val_if_fail(fabs(denom) > 1e-6, NR::Nothing());
+boost::optional<Geom::Point> Line::intersect(Line const &line) {
+ Geom::Coord denom = Geom::dot(v_dir, line.normal);
+ boost::optional<Geom::Point> no_point;
+ if (fabs(denom) < 1e-6)
+ return no_point;
- NR::Coord lambda = (line.d0 - NR::dot(pt, line.normal)) / denom;
+ Geom::Coord lambda = (line.d0 - Geom::dot(pt, line.normal)) / denom;
return pt + lambda * v_dir;
}
-void Line::set_direction(NR::Point const &dir)
+void Line::set_direction(Geom::Point const &dir)
{
v_dir = dir;
normal = v_dir.ccw();
- d0 = NR::dot(normal, pt);
+ d0 = Geom::dot(normal, pt);
}
-NR::Point Line::closest_to(NR::Point const &pt)
+Geom::Point Line::closest_to(Geom::Point const &pt)
{
/* return the intersection of this line with a perpendicular line passing through pt */
- NR::Maybe<NR::Point> result = this->intersect(Line(pt, (this->v_dir).ccw(), false));
- g_return_val_if_fail (result, NR::Point (0.0, 0.0));
+ boost::optional<Geom::Point> result = this->intersect(Line(pt, (this->v_dir).ccw(), false));
+ g_return_val_if_fail (result, Geom::Point (0.0, 0.0));
return *result;
}
-void create_canvas_point(NR::Point const &pos, double size, guint32 rgba)
+double Line::lambda (Geom::Point const pt)
+{
+ double sign = (Geom::dot (pt - this->pt, this->v_dir) > 0) ? 1.0 : -1.0;
+ double lambda = sign * Geom::L2 (pt - this->pt);
+ // FIXME: It may speed things up (but how much?) if we assume that
+ // pt lies on the line and thus skip the following test
+ Geom::Point test = point_from_lambda (lambda);
+ if (!pts_coincide (pt, test)) {
+ g_warning ("Point does not lie on line.\n");
+ return 0;
+ }
+ return lambda;
+}
+
+/* The coordinates of w with respect to the basis {v1, v2} */
+std::pair<double, double> coordinates (Geom::Point const &v1, Geom::Point const &v2, Geom::Point const &w)
+{
+ double det = determinant (v1, v2);;
+ if (fabs (det) < epsilon) {
+ // vectors are not linearly independent; we indicate this in the return value(s)
+ return std::make_pair (HUGE_VAL, HUGE_VAL);
+ }
+
+ double lambda1 = determinant (w, v2) / det;
+ double lambda2 = determinant (v1, w) / det;
+ return std::make_pair (lambda1, lambda2);
+}
+
+/* whether w lies inside the sector spanned by v1 and v2 */
+bool lies_in_sector (Geom::Point const &v1, Geom::Point const &v2, Geom::Point const &w)
+{
+ std::pair<double, double> coords = coordinates (v1, v2, w);
+ if (coords.first == HUGE_VAL) {
+ // catch the case that the vectors are not linearly independent
+ // FIXME: Can we assume that it's safe to return true if the vectors point in different directions?
+ return (Geom::dot (v1, v2) < 0);
+ }
+ return (coords.first >= 0 and coords.second >= 0);
+}
+
+bool lies_in_quadrangle (Geom::Point const &A, Geom::Point const &B, Geom::Point const &C, Geom::Point const &D, Geom::Point const &pt)
+{
+ return (lies_in_sector (D - A, B - A, pt - A) && lies_in_sector (D - C, B - C, pt - C));
+}
+
+static double pos_angle (Geom::Point v, Geom::Point w)
+{
+ return fabs (Geom::atan2 (v) - Geom::atan2 (w));
+}
+
+/*
+ * Returns the two corners of the quadrangle A, B, C, D spanning the edge that is hit by a semiline
+ * starting at pt and going into direction dir.
+ * If none of the sides is hit, it returns a pair containing two identical points.
+ */
+std::pair<Geom::Point, Geom::Point>
+side_of_intersection (Geom::Point const &A, Geom::Point const &B, Geom::Point const &C, Geom::Point const &D,
+ Geom::Point const &pt, Geom::Point const &dir)
+{
+ Geom::Point dir_A (A - pt);
+ Geom::Point dir_B (B - pt);
+ Geom::Point dir_C (C - pt);
+ Geom::Point dir_D (D - pt);
+
+ std::pair<Geom::Point, Geom::Point> result;
+ double angle = -1;
+ double tmp_angle;
+
+ if (lies_in_sector (dir_A, dir_B, dir)) {
+ result = std::make_pair (A, B);
+ angle = pos_angle (dir_A, dir_B);
+ }
+ if (lies_in_sector (dir_B, dir_C, dir)) {
+ tmp_angle = pos_angle (dir_B, dir_C);
+ if (tmp_angle > angle) {
+ angle = tmp_angle;
+ result = std::make_pair (B, C);
+ }
+ }
+ if (lies_in_sector (dir_C, dir_D, dir)) {
+ tmp_angle = pos_angle (dir_C, dir_D);
+ if (tmp_angle > angle) {
+ angle = tmp_angle;
+ result = std::make_pair (C, D);
+ }
+ }
+ if (lies_in_sector (dir_D, dir_A, dir)) {
+ tmp_angle = pos_angle (dir_D, dir_A);
+ if (tmp_angle > angle) {
+ angle = tmp_angle;
+ result = std::make_pair (D, A);
+ }
+ }
+ if (angle == -1) {
+ // no intersection found; return a pair containing two identical points
+ return std::make_pair (A, A);
+ } else {
+ return result;
+ }
+}
+
+boost::optional<Geom::Point> Line::intersection_with_viewbox (SPDesktop *desktop)
+{
+ Geom::Rect vb = desktop->get_display_area();
+ /* remaining viewbox corners */
+ Geom::Point ul (vb.min()[Geom::X], vb.max()[Geom::Y]);
+ Geom::Point lr (vb.max()[Geom::X], vb.min()[Geom::Y]);
+
+ std::pair <Geom::Point, Geom::Point> e = side_of_intersection (vb.min(), lr, vb.max(), ul, this->pt, this->v_dir);
+ if (e.first == e.second) {
+ // perspective line lies outside the canvas
+ return boost::optional<Geom::Point>();
+ }
+
+ Line line (e.first, e.second);
+ return this->intersect (line);
+}
+
+void create_canvas_point(Geom::Point const &pos, double size, guint32 rgba)
{
SPDesktop *desktop = inkscape_active_desktop();
SPCanvasItem * canvas_pt = sp_canvas_item_new(sp_desktop_controls(desktop), SP_TYPE_CTRL,
SP_CTRL(canvas_pt)->moveto(pos);
}
-void create_canvas_line(NR::Point const &p1, NR::Point const &p2, guint32 rgba)
+void create_canvas_line(Geom::Point const &p1, Geom::Point const &p2, guint32 rgba)
{
SPDesktop *desktop = inkscape_active_desktop();
SPCanvasItem *line = sp_canvas_item_new(sp_desktop_controls(desktop),
fill-column:99
End:
*/
-// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :