| #include "CurveIntersection.h" |
| #include "LineUtilities.h" |
| |
| bool implicitLine(const _Line& line, double& slope, double& axisIntercept) { |
| _Point delta; |
| tangent(line, delta); |
| bool moreHorizontal = fabs(delta.x) > fabs(delta.y); |
| if (moreHorizontal) { |
| slope = delta.y / delta.x; |
| axisIntercept = line[0].y - slope * line[0].x; |
| } else { |
| slope = delta.x / delta.y; |
| axisIntercept = line[0].x - slope * line[0].y; |
| } |
| return moreHorizontal; |
| } |
| |
| int reduceOrder(const _Line& line, _Line& reduced) { |
| reduced[0] = line[0]; |
| int different = line[0] != line[1]; |
| reduced[1] = line[different]; |
| return 1 + different; |
| } |
| |
| void sub_divide(const _Line& line, double t1, double t2, _Line& dst) { |
| _Point delta; |
| tangent(line, delta); |
| dst[0].x = line[0].x - t1 * delta.x; |
| dst[0].y = line[0].y - t1 * delta.y; |
| dst[1].x = line[0].x - t2 * delta.x; |
| dst[1].y = line[0].y - t2 * delta.y; |
| } |
| |
| // may have this below somewhere else already: |
| // copying here because I thought it was clever |
| |
| // Copyright 2001, softSurfer (www.softsurfer.com) |
| // This code may be freely used and modified for any purpose |
| // providing that this copyright notice is included with it. |
| // SoftSurfer makes no warranty for this code, and cannot be held |
| // liable for any real or imagined damage resulting from its use. |
| // Users of this code must verify correctness for their application. |
| |
| // Assume that a class is already given for the object: |
| // Point with coordinates {float x, y;} |
| //=================================================================== |
| |
| // isLeft(): tests if a point is Left|On|Right of an infinite line. |
| // Input: three points P0, P1, and P2 |
| // Return: >0 for P2 left of the line through P0 and P1 |
| // =0 for P2 on the line |
| // <0 for P2 right of the line |
| // See: the January 2001 Algorithm on Area of Triangles |
| #if 0 |
| float isLeft( _Point P0, _Point P1, _Point P2 ) |
| { |
| return (float) ((P1.x - P0.x)*(P2.y - P0.y) - (P2.x - P0.x)*(P1.y - P0.y)); |
| } |
| #endif |
| |