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Diffstat (limited to 'include/core/SkGeometry.h')
| -rw-r--r-- | include/core/SkGeometry.h | 316 |
1 files changed, 0 insertions, 316 deletions
diff --git a/include/core/SkGeometry.h b/include/core/SkGeometry.h deleted file mode 100644 index 119cfc68db..0000000000 --- a/include/core/SkGeometry.h +++ /dev/null @@ -1,316 +0,0 @@ - -/* - * Copyright 2006 The Android Open Source Project - * - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - */ - - -#ifndef SkGeometry_DEFINED -#define SkGeometry_DEFINED - -#include "SkMatrix.h" - -/** An XRay is a half-line that runs from the specific point/origin to - +infinity in the X direction. e.g. XRay(3,5) is the half-line - (3,5)....(infinity, 5) - */ -typedef SkPoint SkXRay; - -/** Given a line segment from pts[0] to pts[1], and an xray, return true if - they intersect. Optional outgoing "ambiguous" argument indicates - whether the answer is ambiguous because the query occurred exactly at - one of the endpoints' y coordinates, indicating that another query y - coordinate is preferred for robustness. -*/ -bool SkXRayCrossesLine(const SkXRay& pt, const SkPoint pts[2], - bool* ambiguous = NULL); - -/** Given a quadratic equation Ax^2 + Bx + C = 0, return 0, 1, 2 roots for the - equation. -*/ -int SkFindUnitQuadRoots(SkScalar A, SkScalar B, SkScalar C, SkScalar roots[2]); - -/////////////////////////////////////////////////////////////////////////////// - -/** Set pt to the point on the src quadratic specified by t. t must be - 0 <= t <= 1.0 -*/ -void SkEvalQuadAt(const SkPoint src[3], SkScalar t, SkPoint* pt, - SkVector* tangent = NULL); -void SkEvalQuadAtHalf(const SkPoint src[3], SkPoint* pt, - SkVector* tangent = NULL); - -/** Given a src quadratic bezier, chop it at the specified t value, - where 0 < t < 1, and return the two new quadratics in dst: - dst[0..2] and dst[2..4] -*/ -void SkChopQuadAt(const SkPoint src[3], SkPoint dst[5], SkScalar t); - -/** Given a src quadratic bezier, chop it at the specified t == 1/2, - The new quads are returned in dst[0..2] and dst[2..4] -*/ -void SkChopQuadAtHalf(const SkPoint src[3], SkPoint dst[5]); - -/** Given the 3 coefficients for a quadratic bezier (either X or Y values), look - for extrema, and return the number of t-values that are found that represent - these extrema. If the quadratic has no extrema betwee (0..1) exclusive, the - function returns 0. - Returned count tValues[] - 0 ignored - 1 0 < tValues[0] < 1 -*/ -int SkFindQuadExtrema(SkScalar a, SkScalar b, SkScalar c, SkScalar tValues[1]); - -/** Given 3 points on a quadratic bezier, chop it into 1, 2 beziers such that - the resulting beziers are monotonic in Y. This is called by the scan converter. - Depending on what is returned, dst[] is treated as follows - 0 dst[0..2] is the original quad - 1 dst[0..2] and dst[2..4] are the two new quads -*/ -int SkChopQuadAtYExtrema(const SkPoint src[3], SkPoint dst[5]); -int SkChopQuadAtXExtrema(const SkPoint src[3], SkPoint dst[5]); - -/** Given 3 points on a quadratic bezier, if the point of maximum - curvature exists on the segment, returns the t value for this - point along the curve. Otherwise it will return a value of 0. -*/ -float SkFindQuadMaxCurvature(const SkPoint src[3]); - -/** Given 3 points on a quadratic bezier, divide it into 2 quadratics - if the point of maximum curvature exists on the quad segment. - Depending on what is returned, dst[] is treated as follows - 1 dst[0..2] is the original quad - 2 dst[0..2] and dst[2..4] are the two new quads - If dst == null, it is ignored and only the count is returned. -*/ -int SkChopQuadAtMaxCurvature(const SkPoint src[3], SkPoint dst[5]); - -/** Given 3 points on a quadratic bezier, use degree elevation to - convert it into the cubic fitting the same curve. The new cubic - curve is returned in dst[0..3]. -*/ -SK_API void SkConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]); - -/////////////////////////////////////////////////////////////////////////////// - -/** Convert from parametric from (pts) to polynomial coefficients - coeff[0]*T^3 + coeff[1]*T^2 + coeff[2]*T + coeff[3] -*/ -void SkGetCubicCoeff(const SkPoint pts[4], SkScalar cx[4], SkScalar cy[4]); - -/** Set pt to the point on the src cubic specified by t. t must be - 0 <= t <= 1.0 -*/ -void SkEvalCubicAt(const SkPoint src[4], SkScalar t, SkPoint* locOrNull, - SkVector* tangentOrNull, SkVector* curvatureOrNull); - -/** Given a src cubic bezier, chop it at the specified t value, - where 0 < t < 1, and return the two new cubics in dst: - dst[0..3] and dst[3..6] -*/ -void SkChopCubicAt(const SkPoint src[4], SkPoint dst[7], SkScalar t); -/** Given a src cubic bezier, chop it at the specified t values, - where 0 < t < 1, and return the new cubics in dst: - dst[0..3],dst[3..6],...,dst[3*t_count..3*(t_count+1)] -*/ -void SkChopCubicAt(const SkPoint src[4], SkPoint dst[], const SkScalar t[], - int t_count); - -/** Given a src cubic bezier, chop it at the specified t == 1/2, - The new cubics are returned in dst[0..3] and dst[3..6] -*/ -void SkChopCubicAtHalf(const SkPoint src[4], SkPoint dst[7]); - -/** Given the 4 coefficients for a cubic bezier (either X or Y values), look - for extrema, and return the number of t-values that are found that represent - these extrema. If the cubic has no extrema betwee (0..1) exclusive, the - function returns 0. - Returned count tValues[] - 0 ignored - 1 0 < tValues[0] < 1 - 2 0 < tValues[0] < tValues[1] < 1 -*/ -int SkFindCubicExtrema(SkScalar a, SkScalar b, SkScalar c, SkScalar d, - SkScalar tValues[2]); - -/** Given 4 points on a cubic bezier, chop it into 1, 2, 3 beziers such that - the resulting beziers are monotonic in Y. This is called by the scan converter. - Depending on what is returned, dst[] is treated as follows - 0 dst[0..3] is the original cubic - 1 dst[0..3] and dst[3..6] are the two new cubics - 2 dst[0..3], dst[3..6], dst[6..9] are the three new cubics - If dst == null, it is ignored and only the count is returned. -*/ -int SkChopCubicAtYExtrema(const SkPoint src[4], SkPoint dst[10]); -int SkChopCubicAtXExtrema(const SkPoint src[4], SkPoint dst[10]); - -/** Given a cubic bezier, return 0, 1, or 2 t-values that represent the - inflection points. -*/ -int SkFindCubicInflections(const SkPoint src[4], SkScalar tValues[2]); - -/** Return 1 for no chop, 2 for having chopped the cubic at a single - inflection point, 3 for having chopped at 2 inflection points. - dst will hold the resulting 1, 2, or 3 cubics. -*/ -int SkChopCubicAtInflections(const SkPoint src[4], SkPoint dst[10]); - -int SkFindCubicMaxCurvature(const SkPoint src[4], SkScalar tValues[3]); -int SkChopCubicAtMaxCurvature(const SkPoint src[4], SkPoint dst[13], - SkScalar tValues[3] = NULL); - -/** Given a monotonic cubic bezier, determine whether an xray intersects the - cubic. - By definition the cubic is open at the starting point; in other - words, if pt.fY is equivalent to cubic[0].fY, and pt.fX is to the - left of the curve, the line is not considered to cross the curve, - but if it is equal to cubic[3].fY then it is considered to - cross. - Optional outgoing "ambiguous" argument indicates whether the answer is - ambiguous because the query occurred exactly at one of the endpoints' y - coordinates, indicating that another query y coordinate is preferred - for robustness. - */ -bool SkXRayCrossesMonotonicCubic(const SkXRay& pt, const SkPoint cubic[4], - bool* ambiguous = NULL); - -/** Given an arbitrary cubic bezier, return the number of times an xray crosses - the cubic. Valid return values are [0..3] - By definition the cubic is open at the starting point; in other - words, if pt.fY is equivalent to cubic[0].fY, and pt.fX is to the - left of the curve, the line is not considered to cross the curve, - but if it is equal to cubic[3].fY then it is considered to - cross. - Optional outgoing "ambiguous" argument indicates whether the answer is - ambiguous because the query occurred exactly at one of the endpoints' y - coordinates or at a tangent point, indicating that another query y - coordinate is preferred for robustness. - */ -int SkNumXRayCrossingsForCubic(const SkXRay& pt, const SkPoint cubic[4], - bool* ambiguous = NULL); - -/////////////////////////////////////////////////////////////////////////////// - -enum SkRotationDirection { - kCW_SkRotationDirection, - kCCW_SkRotationDirection -}; - -/** Maximum number of points needed in the quadPoints[] parameter for - SkBuildQuadArc() -*/ -#define kSkBuildQuadArcStorage 17 - -/** Given 2 unit vectors and a rotation direction, fill out the specified - array of points with quadratic segments. Return is the number of points - written to, which will be { 0, 3, 5, 7, ... kSkBuildQuadArcStorage } - - matrix, if not null, is appled to the points before they are returned. -*/ -int SkBuildQuadArc(const SkVector& unitStart, const SkVector& unitStop, - SkRotationDirection, const SkMatrix*, SkPoint quadPoints[]); - -// experimental -struct SkConic { - SkPoint fPts[3]; - SkScalar fW; - - void set(const SkPoint pts[3], SkScalar w) { - memcpy(fPts, pts, 3 * sizeof(SkPoint)); - fW = w; - } - - /** - * Given a t-value [0...1] return its position and/or tangent. - * If pos is not null, return its position at the t-value. - * If tangent is not null, return its tangent at the t-value. NOTE the - * tangent value's length is arbitrary, and only its direction should - * be used. - */ - void evalAt(SkScalar t, SkPoint* pos, SkVector* tangent = NULL) const; - void chopAt(SkScalar t, SkConic dst[2]) const; - void chop(SkConic dst[2]) const; - - void computeAsQuadError(SkVector* err) const; - bool asQuadTol(SkScalar tol) const; - - /** - * return the power-of-2 number of quads needed to approximate this conic - * with a sequence of quads. Will be >= 0. - */ - int computeQuadPOW2(SkScalar tol) const; - - /** - * Chop this conic into N quads, stored continguously in pts[], where - * N = 1 << pow2. The amount of storage needed is (1 + 2 * N) - */ - int chopIntoQuadsPOW2(SkPoint pts[], int pow2) const; - - bool findXExtrema(SkScalar* t) const; - bool findYExtrema(SkScalar* t) const; - bool chopAtXExtrema(SkConic dst[2]) const; - bool chopAtYExtrema(SkConic dst[2]) const; - - void computeTightBounds(SkRect* bounds) const; - void computeFastBounds(SkRect* bounds) const; - - /** Find the parameter value where the conic takes on its maximum curvature. - * - * @param t output scalar for max curvature. Will be unchanged if - * max curvature outside 0..1 range. - * - * @return true if max curvature found inside 0..1 range, false otherwise - */ - bool findMaxCurvature(SkScalar* t) const; -}; - -#include "SkTemplates.h" - -/** - * Help class to allocate storage for approximating a conic with N quads. - */ -class SkAutoConicToQuads { -public: - SkAutoConicToQuads() : fQuadCount(0) {} - - /** - * Given a conic and a tolerance, return the array of points for the - * approximating quad(s). Call countQuads() to know the number of quads - * represented in these points. - * - * The quads are allocated to share end-points. e.g. if there are 4 quads, - * there will be 9 points allocated as follows - * quad[0] == pts[0..2] - * quad[1] == pts[2..4] - * quad[2] == pts[4..6] - * quad[3] == pts[6..8] - */ - const SkPoint* computeQuads(const SkConic& conic, SkScalar tol) { - int pow2 = conic.computeQuadPOW2(tol); - fQuadCount = 1 << pow2; - SkPoint* pts = fStorage.reset(1 + 2 * fQuadCount); - conic.chopIntoQuadsPOW2(pts, pow2); - return pts; - } - - const SkPoint* computeQuads(const SkPoint pts[3], SkScalar weight, - SkScalar tol) { - SkConic conic; - conic.set(pts, weight); - return computeQuads(conic, tol); - } - - int countQuads() const { return fQuadCount; } - -private: - enum { - kQuadCount = 8, // should handle most conics - kPointCount = 1 + 2 * kQuadCount, - }; - SkAutoSTMalloc<kPointCount, SkPoint> fStorage; - int fQuadCount; // #quads for current usage -}; - -#endif |