示例#1
0
bool isLinear(const Cubic& cubic, int startIndex, int endIndex) {
    LineParameters lineParameters;
    lineParameters.cubicEndPoints(cubic, startIndex, endIndex);
    double normalSquared = lineParameters.normalSquared();
    double distance[2]; // distance is not normalized
    int mask = other_two(startIndex, endIndex);
    int inner1 = startIndex ^ mask;
    int inner2 = endIndex ^ mask;
    lineParameters.controlPtDistance(cubic, inner1, inner2, distance);
    double limit = normalSquared;
    int index;
    for (index = 0; index < 2; ++index) {
        double distSq = distance[index];
        distSq *= distSq;
        if (approximately_greater(distSq, limit)) {
            return false;
        }
    }
    return true;
}
示例#2
0
void LineParameter_Test() {
    for (size_t index = firstLineParameterTest; index < tests_count; ++index) {
        LineParameters lineParameters;
        const Cubic& cubic = tests[index];
        lineParameters.cubicEndPoints(cubic);
        double denormalizedDistance[2];
        denormalizedDistance[0] = lineParameters.controlPtDistance(cubic, 1);
        denormalizedDistance[1] = lineParameters.controlPtDistance(cubic, 2);
        double normalSquared = lineParameters.normalSquared();
        size_t inner;
        for (inner = 0; inner < 2; ++inner) {
            double distSq = denormalizedDistance[inner];
            distSq *= distSq;
            double answersSq = answers[index][inner];
            answersSq *= answersSq;
            if (AlmostEqualUlps(distSq, normalSquared * answersSq)) {
                continue;
            }
            SkDebugf("%s [%d,%d] denormalizedDistance:%g != answer:%g"
                    " distSq:%g answerSq:%g normalSquared:%g\n",
                    __FUNCTION__, (int)index, (int)inner,
                    denormalizedDistance[inner], answers[index][inner],
                    distSq, answersSq, normalSquared);
        }
        lineParameters.normalize();
        double normalizedDistance[2];
        normalizedDistance[0] = lineParameters.controlPtDistance(cubic, 1);
        normalizedDistance[1] = lineParameters.controlPtDistance(cubic, 2);
        for (inner = 0; inner < 2; ++inner) {
            if (AlmostEqualUlps(fabs(normalizedDistance[inner]), answers[index][inner])) {
                continue;
            }
            SkDebugf("%s [%d,%d] normalizedDistance:%1.10g != answer:%g\n",
                    __FUNCTION__, (int)index, (int)inner,
                    normalizedDistance[inner], answers[index][inner]);
        }
    }
}
示例#3
0
static int check_linear(const Cubic& cubic, Cubic& reduction,
        int minX, int maxX, int minY, int maxY) {
    int startIndex = 0;
    int endIndex = 3;
    while (cubic[startIndex].approximatelyEqual(cubic[endIndex])) {
        --endIndex;
        if (endIndex == 0) {
            printf("%s shouldn't get here if all four points are about equal", __FUNCTION__);
            assert(0);
        }
    }
    LineParameters lineParameters;
    lineParameters.cubicEndPoints(cubic, startIndex, endIndex);
    double normalSquared = lineParameters.normalSquared();
    double distance[2]; // distance is not normalized
    int mask = other_two(startIndex, endIndex);
    int inner1 = startIndex ^ mask;
    int inner2 = endIndex ^ mask;
    lineParameters.controlPtDistance(cubic, inner1, inner2, distance);
    double limit = normalSquared * SquaredEpsilon;
    int index;
    for (index = 0; index < 2; ++index) {
        double distSq = distance[index];
        distSq *= distSq;
        if (distSq > limit) {
            return 0;
        }
    }
    // four are colinear: return line formed by outside
    reduction[0] = cubic[0];
    reduction[1] = cubic[3];
    int sameSide1;
    int sameSide2;
    bool useX = cubic[maxX].x - cubic[minX].x >= cubic[maxY].y - cubic[minY].y;
    if (useX) {
        sameSide1 = sign(cubic[0].x - cubic[1].x) + sign(cubic[3].x - cubic[1].x);
        sameSide2 = sign(cubic[0].x - cubic[2].x) + sign(cubic[3].x - cubic[2].x);
    } else {
        sameSide1 = sign(cubic[0].y - cubic[1].y) + sign(cubic[3].y - cubic[1].y);
        sameSide2 = sign(cubic[0].y - cubic[2].y) + sign(cubic[3].y - cubic[2].y);
    }
    if (sameSide1 == sameSide2 && (sameSide1 & 3) != 2) {
        return 2;
    }
    double tValues[2];
    int roots;
    if (useX) {
        roots = SkFindCubicExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
    } else {
        roots = SkFindCubicExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, tValues);
    }
    for (index = 0; index < roots; ++index) {
        _Point extrema;
        extrema.x = interp_cubic_coords(&cubic[0].x, tValues[index]);
        extrema.y = interp_cubic_coords(&cubic[0].y, tValues[index]);
        // sameSide > 0 means mid is smaller than either [0] or [3], so replace smaller
        int replace;
        if (useX) {
            if (extrema.x < cubic[0].x ^ extrema.x < cubic[3].x) {
                continue;
            }
            replace = (extrema.x < cubic[0].x | extrema.x < cubic[3].x)
                    ^ cubic[0].x < cubic[3].x;
        } else {
            if (extrema.y < cubic[0].y ^ extrema.y < cubic[3].y) {
                continue;
            }
            replace = (extrema.y < cubic[0].y | extrema.y < cubic[3].y)
                    ^ cubic[0].y < cubic[3].y;
        }
        reduction[replace] = extrema;
    }
    return 2;
}