| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| #include "src/pathops/SkPathOpsLine.h" |
| |
| #include "src/pathops/SkPathOpsTypes.h" |
| |
| #include <cmath> |
| #include <algorithm> |
| |
| SkDPoint SkDLine::ptAtT(double t) const { |
| if (0 == t) { |
| return fPts[0]; |
| } |
| if (1 == t) { |
| return fPts[1]; |
| } |
| double one_t = 1 - t; |
| SkDPoint result = { one_t * fPts[0].fX + t * fPts[1].fX, one_t * fPts[0].fY + t * fPts[1].fY }; |
| return result; |
| } |
| |
| double SkDLine::exactPoint(const SkDPoint& xy) const { |
| if (xy == fPts[0]) { // do cheapest test first |
| return 0; |
| } |
| if (xy == fPts[1]) { |
| return 1; |
| } |
| return -1; |
| } |
| |
| double SkDLine::nearPoint(const SkDPoint& xy, bool* unequal) const { |
| if (!AlmostBetweenUlps(fPts[0].fX, xy.fX, fPts[1].fX) |
| || !AlmostBetweenUlps(fPts[0].fY, xy.fY, fPts[1].fY)) { |
| return -1; |
| } |
| // project a perpendicular ray from the point to the line; find the T on the line |
| SkDVector len = fPts[1] - fPts[0]; // the x/y magnitudes of the line |
| double denom = len.fX * len.fX + len.fY * len.fY; // see DLine intersectRay |
| SkDVector ab0 = xy - fPts[0]; |
| double numer = len.fX * ab0.fX + ab0.fY * len.fY; |
| if (!between(0, numer, denom)) { |
| return -1; |
| } |
| if (!denom) { |
| return 0; |
| } |
| double t = numer / denom; |
| SkDPoint realPt = ptAtT(t); |
| double dist = realPt.distance(xy); // OPTIMIZATION: can we compare against distSq instead ? |
| // find the ordinal in the original line with the largest unsigned exponent |
| double tiniest = std::min(std::min(std::min(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY); |
| double largest = std::max(std::max(std::max(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY); |
| largest = std::max(largest, -tiniest); |
| if (!AlmostEqualUlps_Pin(largest, largest + dist)) { // is the dist within ULPS tolerance? |
| return -1; |
| } |
| if (unequal) { |
| *unequal = (float) largest != (float) (largest + dist); |
| } |
| t = SkPinT(t); // a looser pin breaks skpwww_lptemp_com_3 |
| SkASSERT(between(0, t, 1)); |
| return t; |
| } |
| |
| bool SkDLine::nearRay(const SkDPoint& xy) const { |
| // project a perpendicular ray from the point to the line; find the T on the line |
| SkDVector len = fPts[1] - fPts[0]; // the x/y magnitudes of the line |
| double denom = len.fX * len.fX + len.fY * len.fY; // see DLine intersectRay |
| SkDVector ab0 = xy - fPts[0]; |
| double numer = len.fX * ab0.fX + ab0.fY * len.fY; |
| double t = numer / denom; |
| SkDPoint realPt = ptAtT(t); |
| double dist = realPt.distance(xy); // OPTIMIZATION: can we compare against distSq instead ? |
| // find the ordinal in the original line with the largest unsigned exponent |
| double tiniest = std::min(std::min(std::min(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY); |
| double largest = std::max(std::max(std::max(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY); |
| largest = std::max(largest, -tiniest); |
| return RoughlyEqualUlps(largest, largest + dist); // is the dist within ULPS tolerance? |
| } |
| |
| double SkDLine::ExactPointH(const SkDPoint& xy, double left, double right, double y) { |
| if (xy.fY == y) { |
| if (xy.fX == left) { |
| return 0; |
| } |
| if (xy.fX == right) { |
| return 1; |
| } |
| } |
| return -1; |
| } |
| |
| double SkDLine::NearPointH(const SkDPoint& xy, double left, double right, double y) { |
| if (!AlmostBequalUlps(xy.fY, y)) { |
| return -1; |
| } |
| if (!AlmostBetweenUlps(left, xy.fX, right)) { |
| return -1; |
| } |
| double t = (xy.fX - left) / (right - left); |
| t = SkPinT(t); |
| SkASSERT(between(0, t, 1)); |
| double realPtX = (1 - t) * left + t * right; |
| SkDVector distU = {xy.fY - y, xy.fX - realPtX}; |
| double distSq = distU.fX * distU.fX + distU.fY * distU.fY; |
| double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ? |
| double tiniest = std::min(std::min(y, left), right); |
| double largest = std::max(std::max(y, left), right); |
| largest = std::max(largest, -tiniest); |
| if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance? |
| return -1; |
| } |
| return t; |
| } |
| |
| double SkDLine::ExactPointV(const SkDPoint& xy, double top, double bottom, double x) { |
| if (xy.fX == x) { |
| if (xy.fY == top) { |
| return 0; |
| } |
| if (xy.fY == bottom) { |
| return 1; |
| } |
| } |
| return -1; |
| } |
| |
| double SkDLine::NearPointV(const SkDPoint& xy, double top, double bottom, double x) { |
| if (!AlmostBequalUlps(xy.fX, x)) { |
| return -1; |
| } |
| if (!AlmostBetweenUlps(top, xy.fY, bottom)) { |
| return -1; |
| } |
| double t = (xy.fY - top) / (bottom - top); |
| t = SkPinT(t); |
| SkASSERT(between(0, t, 1)); |
| double realPtY = (1 - t) * top + t * bottom; |
| SkDVector distU = {xy.fX - x, xy.fY - realPtY}; |
| double distSq = distU.fX * distU.fX + distU.fY * distU.fY; |
| double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ? |
| double tiniest = std::min(std::min(x, top), bottom); |
| double largest = std::max(std::max(x, top), bottom); |
| largest = std::max(largest, -tiniest); |
| if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance? |
| return -1; |
| } |
| return t; |
| } |