mirror of https://github.com/axmolengine/axmol.git
111 lines
4.1 KiB
C++
111 lines
4.1 KiB
C++
/*
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Copyright 2010 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#ifndef GrPathIter_DEFINED
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#define GrPathIter_DEFINED
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#include "GrTypes.h"
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struct GrPoint;
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/**
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2D Path iterator. Porting layer creates a subclass of this. It allows Ganesh to
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parse the top-level API's 2D paths. Supports lines, quadratics, and cubic
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pieces and moves (multi-part paths).
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*/
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class GrPathIter {
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public:
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/**
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Returned by next(). Indicates the next piece of the path.
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*/
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enum Command {
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kMove_Command, //!< next() returns 1 pt
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// Starts a new subpath at
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// at the returned point
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kLine_Command, //!< next() returns 2 pts
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// Adds a line segment
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kQuadratic_Command, //!< next() returns 3 pts
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// Adds a quadratic segment
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kCubic_Command, //!< next() returns 4 pts
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// Adds a cubic segment
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kClose_Command, //!< next() returns 0 pts
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kEnd_Command //!< next() returns 0 pts
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// Implictly closes the last
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// point
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};
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enum ConvexHint {
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kNone_ConvexHint, //<! No hint about convexity
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// of the path
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kConvex_ConvexHint, //<! Path is one convex piece
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kNonOverlappingConvexPieces_ConvexHint, //<! Multiple convex pieces,
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// pieces are known to be
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// disjoint
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kSameWindingConvexPieces_ConvexHint, //<! Multiple convex pieces,
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// may or may not intersect,
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// either all wind cw or all
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// wind ccw.
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kConcave_ConvexHint //<! Path is known to be
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// concave
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};
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static int NumCommandPoints(Command cmd) {
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static const int numPoints[] = {
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1, 2, 3, 4, 0, 0
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};
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return numPoints[cmd];
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}
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virtual ~GrPathIter() {};
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/**
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Iterates through the path. Should not be called after
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kEnd_Command has been returned once. This version retrieves the
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points for the command.
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@param points The points relevant to returned commend. See Command
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enum for number of points valid for each command.
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@return The next command of the path.
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*/
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virtual Command next(GrPoint points[4]) = 0;
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/**
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* If the host API has knowledge of the convexity of the path
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* it can be communicated by this hint. Ganesh can make these
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* determinations itself. So it is not necessary to compute
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* convexity status if it isn't already determined.
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*
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* @return a hint about the convexity of the path.
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*/
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virtual ConvexHint hint() const { return kNone_ConvexHint; }
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/**
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Iterates through the path. Should not be called after
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kEnd_Command has been returned once. This version does not retrieve the
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points for the command.
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@return The next command of the path.
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*/
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virtual Command next() = 0;
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/**
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Restarts iteration from the beginning.
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*/
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virtual void rewind() = 0;
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};
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#endif
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