index 158ddd47bd2a2b7be83a0c77a51704622d3cc600..90857e6d5ecd10fac2ee887f5db8dfda20068e66 100644 (file)
--- a/src/perspective-line.cpp
+++ b/src/perspective-line.cpp
*/
#include "perspective-line.h"
+#include "desktop.h"
namespace Box3D {
Line (pt, *(perspective->get_vanishing_point(axis)), true)
{
g_assert (perspective != NULL);
+ g_assert (Box3D::is_single_axis_direction (axis));
if (perspective->get_vanishing_point(axis)->state == VP_INFINITE) {
this->set_direction(perspective->get_vanishing_point(axis)->v_dir);
return *intersect(line); // works since intersect() does not return NR::Nothing()
}
+NR::Point PerspectiveLine::pt_with_given_cross_ratio (NR::Point const &C, NR::Point const &D, double gamma)
+{
+ if (persp->get_vanishing_point (vp_dir)->is_finite()) {
+ NR::Point V (*persp->get_vanishing_point (vp_dir));
+ return fourth_pt_with_given_cross_ratio (V, C, D, gamma);
+ } else {
+ if (fabs (gamma - 1) < epsilon) {
+ g_warning ("Cannot compute point with given cross ratio.\n");
+ return NR::Point (0.0, 0.0);
+ }
+ Line line (C, D);
+ double lambda_C = line.lambda (C);
+ double lambda_D = line.lambda (D);
+ return line.point_from_lambda ((lambda_D - gamma * lambda_C) / (1 - gamma));
+ }
+}
+
+NR::Maybe<NR::Point> PerspectiveLine::intersection_with_viewbox (SPDesktop *desktop)
+{
+ NR::Rect vb = desktop->get_display_area();
+ /* remaining viewbox corners */
+ NR::Point ul (vb.min()[NR::X], vb.max()[NR::Y]);
+ NR::Point lr (vb.max()[NR::X], vb.min()[NR::Y]);
+
+ std::pair <NR::Point, NR::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 NR::Nothing();
+ }
+
+ Line line (e.first, e.second);
+ return this->intersect (line);
+}
+
} // namespace Box3D
/*