The Tor Browser: comparison gfx/skia/trunk/src/core/SkPoint.cpp

--1:000000000000
+:48b719788c9d
+/*
+* Copyright 2008 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.
+*/
+#include "SkPoint.h"
+void SkIPoint::rotateCW(SkIPoint* dst) const {
+SkASSERT(dst);
+// use a tmp in case this == dst
+int32_t tmp = fX;
+dst->fX = -fY;
+dst->fY = tmp;
+}
+void SkIPoint::rotateCCW(SkIPoint* dst) const {
+SkASSERT(dst);
+// use a tmp in case this == dst
+int32_t tmp = fX;
+dst->fX = fY;
+dst->fY = -tmp;
+}
+///////////////////////////////////////////////////////////////////////////////
+void SkPoint::setIRectFan(int l, int t, int r, int b, size_t stride) {
+SkASSERT(stride >= sizeof(SkPoint));
+((SkPoint*)((intptr_t)this + 0 * stride))->set(SkIntToScalar(l),
+SkIntToScalar(t));
+((SkPoint*)((intptr_t)this + 1 * stride))->set(SkIntToScalar(l),
+SkIntToScalar(b));
+((SkPoint*)((intptr_t)this + 2 * stride))->set(SkIntToScalar(r),
+SkIntToScalar(b));
+((SkPoint*)((intptr_t)this + 3 * stride))->set(SkIntToScalar(r),
+SkIntToScalar(t));
+}
+void SkPoint::setRectFan(SkScalar l, SkScalar t, SkScalar r, SkScalar b,
+size_t stride) {
+SkASSERT(stride >= sizeof(SkPoint));
+((SkPoint*)((intptr_t)this + 0 * stride))->set(l, t);
+((SkPoint*)((intptr_t)this + 1 * stride))->set(l, b);
+((SkPoint*)((intptr_t)this + 2 * stride))->set(r, b);
+((SkPoint*)((intptr_t)this + 3 * stride))->set(r, t);
+}
+void SkPoint::rotateCW(SkPoint* dst) const {
+SkASSERT(dst);
+// use a tmp in case this == dst
+SkScalar tmp = fX;
+dst->fX = -fY;
+dst->fY = tmp;
+}
+void SkPoint::rotateCCW(SkPoint* dst) const {
+SkASSERT(dst);
+// use a tmp in case this == dst
+SkScalar tmp = fX;
+dst->fX = fY;
+dst->fY = -tmp;
+}
+void SkPoint::scale(SkScalar scale, SkPoint* dst) const {
+SkASSERT(dst);
+dst->set(SkScalarMul(fX, scale), SkScalarMul(fY, scale));
+}
+bool SkPoint::normalize() {
+return this->setLength(fX, fY, SK_Scalar1);
+}
+bool SkPoint::setNormalize(SkScalar x, SkScalar y) {
+return this->setLength(x, y, SK_Scalar1);
+}
+bool SkPoint::setLength(SkScalar length) {
+return this->setLength(fX, fY, length);
+}
+// Returns the square of the Euclidian distance to (dx,dy).
+static inline float getLengthSquared(float dx, float dy) {
+return dx * dx + dy * dy;
+}
+// Calculates the square of the Euclidian distance to (dx,dy) and stores it in
+// *lengthSquared.  Returns true if the distance is judged to be "nearly zero".
+//
+// This logic is encapsulated in a helper method to make it explicit that we
+// always perform this check in the same manner, to avoid inconsistencies
+// (see http://code.google.com/p/skia/issues/detail?id=560 ).
+static inline bool isLengthNearlyZero(float dx, float dy,
+float *lengthSquared) {
+*lengthSquared = getLengthSquared(dx, dy);
+return *lengthSquared <= (SK_ScalarNearlyZero * SK_ScalarNearlyZero);
+}
+SkScalar SkPoint::Normalize(SkPoint* pt) {
+float x = pt->fX;
+float y = pt->fY;
+float mag2;
+if (isLengthNearlyZero(x, y, &mag2)) {
+return 0;
+}
+float mag, scale;
+if (SkScalarIsFinite(mag2)) {
+mag = sk_float_sqrt(mag2);
+scale = 1 / mag;
+} else {
+// our mag2 step overflowed to infinity, so use doubles instead.
+// much slower, but needed when x or y are very large, other wise we
+// divide by inf. and return (0,0) vector.
+double xx = x;
+double yy = y;
+double magmag = sqrt(xx * xx + yy * yy);
+mag = (float)magmag;
+// we perform the divide with the double magmag, to stay exactly the
+// same as setLength. It would be faster to perform the divide with
+// mag, but it is possible that mag has overflowed to inf. but still
+// have a non-zero value for scale (thanks to denormalized numbers).
+scale = (float)(1 / magmag);
+}
+pt->set(x * scale, y * scale);
+return mag;
+}
+SkScalar SkPoint::Length(SkScalar dx, SkScalar dy) {
+float mag2 = dx * dx + dy * dy;
+if (SkScalarIsFinite(mag2)) {
+return sk_float_sqrt(mag2);
+} else {
+double xx = dx;
+double yy = dy;
+return (float)sqrt(xx * xx + yy * yy);
+}
+}
+/*
+*  We have to worry about 2 tricky conditions:
+*  1. underflow of mag2 (compared against nearlyzero^2)
+*  2. overflow of mag2 (compared w/ isfinite)
+*
+*  If we underflow, we return false. If we overflow, we compute again using
+*  doubles, which is much slower (3x in a desktop test) but will not overflow.
+*/
+bool SkPoint::setLength(float x, float y, float length) {
+float mag2;
+if (isLengthNearlyZero(x, y, &mag2)) {
+return false;
+}
+float scale;
+if (SkScalarIsFinite(mag2)) {
+scale = length / sk_float_sqrt(mag2);
+} else {
+// our mag2 step overflowed to infinity, so use doubles instead.
+// much slower, but needed when x or y are very large, other wise we
+// divide by inf. and return (0,0) vector.
+double xx = x;
+double yy = y;
+scale = (float)(length / sqrt(xx * xx + yy * yy));
+}
+fX = x * scale;
+fY = y * scale;
+return true;
+}
+bool SkPoint::setLengthFast(float length) {
+return this->setLengthFast(fX, fY, length);
+}
+bool SkPoint::setLengthFast(float x, float y, float length) {
+float mag2;
+if (isLengthNearlyZero(x, y, &mag2)) {
+return false;
+}
+float scale;
+if (SkScalarIsFinite(mag2)) {
+scale = length * sk_float_rsqrt(mag2);  // <--- this is the difference
+} else {
+// our mag2 step overflowed to infinity, so use doubles instead.
+// much slower, but needed when x or y are very large, other wise we
+// divide by inf. and return (0,0) vector.
+double xx = x;
+double yy = y;
+scale = (float)(length / sqrt(xx * xx + yy * yy));
+}
+fX = x * scale;
+fY = y * scale;
+return true;
+}
+///////////////////////////////////////////////////////////////////////////////
+SkScalar SkPoint::distanceToLineBetweenSqd(const SkPoint& a,
+const SkPoint& b,
+Side* side) const {
+SkVector u = b - a;
+SkVector v = *this - a;
+SkScalar uLengthSqd = u.lengthSqd();
+SkScalar det = u.cross(v);
+if (NULL != side) {
+SkASSERT(-1 == SkPoint::kLeft_Side &&
+0 == SkPoint::kOn_Side &&
+1 == kRight_Side);
+*side = (Side) SkScalarSignAsInt(det);
+}
+return SkScalarMulDiv(det, det, uLengthSqd);
+}
+SkScalar SkPoint::distanceToLineSegmentBetweenSqd(const SkPoint& a,
+const SkPoint& b) const {
+// See comments to distanceToLineBetweenSqd. If the projection of c onto
+// u is between a and b then this returns the same result as that
+// function. Otherwise, it returns the distance to the closer of a and
+// b. Let the projection of v onto u be v'.  There are three cases:
+//    1. v' points opposite to u. c is not between a and b and is closer
+//       to a than b.
+//    2. v' points along u and has magnitude less than y. c is between
+//       a and b and the distance to the segment is the same as distance
+//       to the line ab.
+//    3. v' points along u and has greater magnitude than u. c is not
+//       not between a and b and is closer to b than a.
+// v' = (u dot v) * u / |u|. So if (u dot v)/|u| is less than zero we're
+// in case 1. If (u dot v)/|u| is > |u| we are in case 3. Otherwise
+// we're in case 2. We actually compare (u dot v) to 0 and |u|^2 to
+// avoid a sqrt to compute |u|.
+SkVector u = b - a;
+SkVector v = *this - a;
+SkScalar uLengthSqd = u.lengthSqd();
+SkScalar uDotV = SkPoint::DotProduct(u, v);
+if (uDotV <= 0) {
+return v.lengthSqd();
+} else if (uDotV > uLengthSqd) {
+return b.distanceToSqd(*this);
+} else {
+SkScalar det = u.cross(v);
+return SkScalarMulDiv(det, det, uLengthSqd);
+}
+}

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comparison: gfx/skia/trunk/src/core/SkPoint.cpp

gfx/skia/trunk/src/core/SkPoint.cpp