diff options
Diffstat (limited to 'basegfx/source/polygon/b2dpolygonclipper.cxx')
| -rw-r--r-- | basegfx/source/polygon/b2dpolygonclipper.cxx | 36 |
1 files changed, 14 insertions, 22 deletions
diff --git a/basegfx/source/polygon/b2dpolygonclipper.cxx b/basegfx/source/polygon/b2dpolygonclipper.cxx index 2cf7c30eb1de..817a43955900 100644 --- a/basegfx/source/polygon/b2dpolygonclipper.cxx +++ b/basegfx/source/polygon/b2dpolygonclipper.cxx @@ -29,7 +29,7 @@ #include <basegfx/tools/rectcliptools.hxx> #include <basegfx/matrix/b2dhommatrixtools.hxx> -////////////////////////////////////////////////////////////////////////////// + namespace basegfx { @@ -337,7 +337,7 @@ namespace basegfx return aRetval; } - ////////////////////////////////////////////////////////////////////////////// + B2DPolyPolygon clipPolyPolygonOnPolyPolygon(const B2DPolyPolygon& rCandidate, const B2DPolyPolygon& rClip, bool bInside, bool bStroke) { @@ -461,7 +461,7 @@ namespace basegfx return aRetval; } - ////////////////////////////////////////////////////////////////////////////// + B2DPolyPolygon clipPolygonOnPolyPolygon(const B2DPolygon& rCandidate, const B2DPolyPolygon& rClip, bool bInside, bool bStroke) { @@ -475,7 +475,7 @@ namespace basegfx return aRetval; } - ////////////////////////////////////////////////////////////////////////////// + /* * let a plane be defined as @@ -619,16 +619,12 @@ namespace basegfx if(nVertexCount) { - //////////////////////////////////////////////////////////////////////// - //////////////////////////////////////////////////////////////////////// - //////////////////////////////////////////////////////////////////////// - // // Upper bound for the maximal number of vertices when intersecting an // axis-aligned rectangle with a triangle in E2 - // + // The rectangle and the triangle are in general position, and have 4 and 3 // vertices, respectively. - // + // Lemma: Since the rectangle is a convex polygon ( see // http://mathworld.wolfram.com/ConvexPolygon.html for a definition), and // has no holes, it follows that any straight line will intersect the @@ -640,7 +636,7 @@ namespace basegfx // other 'outside') will at utmost add _one_ vertex to the resulting // intersection polygon (adding two intersection vertices, and removing at // least one rectangle vertex): - // + // * // +--+-----------------+ // | * | @@ -649,7 +645,7 @@ namespace basegfx // *| | // * | | // +--------------------+ - // + // Proof: If the straight line intersects the rectangle two // times, it does so for distinct edges, i.e. the intersection has // minimally one of the rectangle's vertices on either side of the straight @@ -657,17 +653,17 @@ namespace basegfx // minimally _one_ rectangle vertex removed from the resulting clip // polygon, and therefore, a clip against a half-plane has the net effect // of adding at utmost _one_ vertex to the resulting clip polygon. - // + // Theorem: The intersection of a rectangle and a triangle results in a // polygon with at utmost 7 vertices. - // + // Proof: The inside of the triangle can be described as the consecutive // intersection with three half-planes. Together with the lemma above, this // results in at utmost 3 additional vertices added to the already existing 4 // rectangle vertices. - // + // This upper bound is attained with the following example configuration: - // + // * // *** // ** * @@ -689,7 +685,7 @@ namespace basegfx // --*6-----5----- // ** * // ** - // + // As we need to scissor all triangles against the // output rectangle we employ an output buffer for the // resulting vertices. the question is how large this @@ -707,10 +703,6 @@ namespace basegfx // fan. for the maximum number of 7 vertices of // resulting triangle fans we therefore need 15 times // the number of original vertices. - // - //////////////////////////////////////////////////////////////////////// - //////////////////////////////////////////////////////////////////////// - //////////////////////////////////////////////////////////////////////// //const size_t nBufferSize = sizeof(vertex)*(nVertexCount*16); //vertex *pVertices = (vertex*)alloca(nBufferSize); @@ -787,7 +779,7 @@ namespace basegfx return aResult; } - ////////////////////////////////////////////////////////////////////////////// + } // end of namespace tools } // end of namespace basegfx |