diff options
Diffstat (limited to 'src/utils/SkInsetConvexPolygon.h')
-rwxr-xr-x | src/utils/SkInsetConvexPolygon.h | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/src/utils/SkInsetConvexPolygon.h b/src/utils/SkInsetConvexPolygon.h index 3ab7558a25..1d5a19c176 100755 --- a/src/utils/SkInsetConvexPolygon.h +++ b/src/utils/SkInsetConvexPolygon.h @@ -8,20 +8,49 @@ #ifndef SkInsetConvexPolygon_DEFINED #define SkInsetConvexPolygon_DEFINED +#include <functional> + #include "SkTDArray.h" #include "SkPoint.h" - /** +/** * Generates a polygon that is inset a given distance from the boundary of a given convex polygon. * * @param inputPolygonVerts Array of points representing the vertices of the original polygon. * It should be convex and have no coincident points. * @param inputPolygonSize Number of vertices in the original polygon. - * @param insetDistance How far we wish to inset the polygon. This should be a positive value. + * @param insetDistanceFunc How far we wish to inset the polygon for a given index in the array. + * This should return a positive value. * @param insetPolygon The resulting inset polygon, if any. * @return true if an inset polygon exists, false otherwise. */ bool SkInsetConvexPolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize, - SkScalar insetDistance, SkTDArray<SkPoint>* insetPolygon); + std::function<SkScalar(int index)> insetDistanceFunc, + SkTDArray<SkPoint>* insetPolygon); + +inline bool SkInsetConvexPolygon(const SkPoint* inputPolygonVerts, int inputPolygonSize, + SkScalar inset, + SkTDArray<SkPoint>* insetPolygon) { + return SkInsetConvexPolygon(inputPolygonVerts, inputPolygonSize, + [inset](int) { return inset; }, + insetPolygon); +} + +/** + * Offset a segment by the given distance at each point. + * Uses the outer tangents of two circles centered on each endpoint. + * See: https://en.wikipedia.org/wiki/Tangent_lines_to_circles + * + * @param p0 First endpoint. + * @param p1 Second endpoint. + * @param d0 Offset distance from first endpoint. + * @param d1 Offset distance from second endpoint. + * @param side Indicates whether we want to offset to the left (1) or right (-1) side of segment. + * @param offset0 First endpoint of offset segment. + * @param offset1 Second endpoint of offset segment. + * @return true if an offset segment exists, false otherwise. + */ +bool SkOffsetSegment(const SkPoint& p0, const SkPoint& p1, SkScalar d0, SkScalar d1, + int side, SkPoint* offset0, SkPoint* offset1); #endif |