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Diffstat (limited to 'libsgl/animator/SkSVGPath.cpp')
| -rw-r--r-- | libsgl/animator/SkSVGPath.cpp | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/libsgl/animator/SkSVGPath.cpp b/libsgl/animator/SkSVGPath.cpp new file mode 100644 index 0000000..86eeee8 --- /dev/null +++ b/libsgl/animator/SkSVGPath.cpp @@ -0,0 +1,243 @@ +/* libs/graphics/animator/SkSVGPath.cpp +** +** Copyright 2006, The Android Open Source Project +** +** Licensed under the Apache License, Version 2.0 (the "License"); +** you may not use this file except in compliance with the License. +** You may obtain a copy of the License at +** +** http://www.apache.org/licenses/LICENSE-2.0 +** +** Unless required by applicable law or agreed to in writing, software +** distributed under the License is distributed on an "AS IS" BASIS, +** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +** See the License for the specific language governing permissions and +** limitations under the License. +*/ + +#include <ctype.h> +#include "SkDrawPath.h" +#include "SkParse.h" +#include "SkPoint.h" +#include "SkUtils.h" +#define QUADRATIC_APPROXIMATION 1 + +#if QUADRATIC_APPROXIMATION +//////////////////////////////////////////////////////////////////////////////////// +//functions to approximate a cubic using two quadratics + +// midPt sets the first argument to be the midpoint of the other two +// it is used by quadApprox +static inline void midPt(SkPoint& dest,const SkPoint& a,const SkPoint& b) +{ + dest.set(SkScalarAve(a.fX, b.fX),SkScalarAve(a.fY, b.fY)); +} +// quadApprox - makes an approximation, which we hope is faster +static void quadApprox(SkPath &fPath, const SkPoint &p0, const SkPoint &p1, const SkPoint &p2) +{ + //divide the cubic up into two cubics, then convert them into quadratics + //define our points + SkPoint c,j,k,l,m,n,o,p,q, mid; + fPath.getLastPt(&c); + midPt(j, p0, c); + midPt(k, p0, p1); + midPt(l, p1, p2); + midPt(o, j, k); + midPt(p, k, l); + midPt(q, o, p); + //compute the first half + m.set(SkScalarHalf(3*j.fX - c.fX), SkScalarHalf(3*j.fY - c.fY)); + n.set(SkScalarHalf(3*o.fX -q.fX), SkScalarHalf(3*o.fY - q.fY)); + midPt(mid,m,n); + fPath.quadTo(mid,q); + c = q; + //compute the second half + m.set(SkScalarHalf(3*p.fX - c.fX), SkScalarHalf(3*p.fY - c.fY)); + n.set(SkScalarHalf(3*l.fX -p2.fX),SkScalarHalf(3*l.fY -p2.fY)); + midPt(mid,m,n); + fPath.quadTo(mid,p2); +} +#endif + + +static inline bool is_between(int c, int min, int max) +{ + return (unsigned)(c - min) <= (unsigned)(max - min); +} + +static inline bool is_ws(int c) +{ + return is_between(c, 1, 32); +} + +static inline bool is_digit(int c) +{ + return is_between(c, '0', '9'); +} + +static inline bool is_sep(int c) +{ + return is_ws(c) || c == ','; +} + +static const char* skip_ws(const char str[]) +{ + SkASSERT(str); + while (is_ws(*str)) + str++; + return str; +} + +static const char* skip_sep(const char str[]) +{ + SkASSERT(str); + while (is_sep(*str)) + str++; + return str; +} + +static const char* find_points(const char str[], SkPoint value[], int count, + bool isRelative, SkPoint* relative) +{ + str = SkParse::FindScalars(str, &value[0].fX, count * 2); + if (isRelative) { + for (int index = 0; index < count; index++) { + value[index].fX += relative->fX; + value[index].fY += relative->fY; + } + } + return str; +} + +static const char* find_scalar(const char str[], SkScalar* value, + bool isRelative, SkScalar relative) +{ + str = SkParse::FindScalar(str, value); + if (isRelative) + *value += relative; + return str; +} + +void SkDrawPath::parseSVG() { + fPath.reset(); + const char* data = d.c_str(); + SkPoint f = {0, 0}; + SkPoint c = {0, 0}; + SkPoint lastc = {0, 0}; + SkPoint points[3]; + char op = '\0'; + char previousOp = '\0'; + bool relative = false; + do { + data = skip_ws(data); + if (data[0] == '\0') + break; + char ch = data[0]; + if (is_digit(ch) || ch == '-' || ch == '+') { + if (op == '\0') + return; + } + else { + op = ch; + relative = false; + if (islower(op)) { + op = (char) toupper(op); + relative = true; + } + data++; + data = skip_sep(data); + } + switch (op) { + case 'M': + data = find_points(data, points, 1, relative, &c); + fPath.moveTo(points[0]); + op = 'L'; + c = points[0]; + break; + case 'L': + data = find_points(data, points, 1, relative, &c); + fPath.lineTo(points[0]); + c = points[0]; + break; + case 'H': { + SkScalar x; + data = find_scalar(data, &x, relative, c.fX); + fPath.lineTo(x, c.fY); + c.fX = x; + } + break; + case 'V': { + SkScalar y; + data = find_scalar(data, &y, relative, c.fY); + fPath.lineTo(c.fX, y); + c.fY = y; + } + break; + case 'C': + data = find_points(data, points, 3, relative, &c); + goto cubicCommon; + case 'S': + data = find_points(data, &points[1], 2, relative, &c); + points[0] = c; + if (previousOp == 'C' || previousOp == 'S') { + points[0].fX -= lastc.fX - c.fX; + points[0].fY -= lastc.fY - c.fY; + } + cubicCommon: + // if (data[0] == '\0') + // return; +#if QUADRATIC_APPROXIMATION + quadApprox(fPath, points[0], points[1], points[2]); +#else //this way just does a boring, slow old cubic + fPath.cubicTo(points[0], points[1], points[2]); +#endif + //if we are using the quadApprox, lastc is what it would have been if we had used + //cubicTo + lastc = points[1]; + c = points[2]; + break; + case 'Q': // Quadratic Bezier Curve + data = find_points(data, points, 2, relative, &c); + goto quadraticCommon; + case 'T': + data = find_points(data, &points[1], 1, relative, &c); + points[0] = points[1]; + if (previousOp == 'Q' || previousOp == 'T') { + points[0].fX = c.fX * 2 - lastc.fX; + points[0].fY = c.fY * 2 - lastc.fY; + } + quadraticCommon: + fPath.quadTo(points[0], points[1]); + lastc = points[0]; + c = points[1]; + break; + case 'Z': + fPath.close(); +#if 0 // !!! still a bug? + if (fPath.isEmpty() && (f.fX != 0 || f.fY != 0)) { + c.fX -= SkScalar.Epsilon; // !!! enough? + fPath.moveTo(c); + fPath.lineTo(f); + fPath.close(); + } +#endif + c = f; + op = '\0'; + break; + case '~': { + SkPoint args[2]; + data = find_points(data, args, 2, false, NULL); + fPath.moveTo(args[0].fX, args[0].fY); + fPath.lineTo(args[1].fX, args[1].fY); + } + break; + default: + SkASSERT(0); + return; + } + if (previousOp == 0) + f = c; + previousOp = op; + } while (data[0] > 0); +} + |