C++ SkMatrix::setSinCos方法代码示例

void Matrix::NativeSetSinCos(
    /* [in] */ Int64 nObj,
    /* [in] */ Float sinValue,
    /* [in] */ Float cosValue)
{
    SkMatrix* obj = reinterpret_cast<SkMatrix*>(nObj);
    obj->setSinCos(sinValue, cosValue);
}

static SkMatrix pts_to_unit_matrix(const SkPoint pts[2]) {
    SkVector    vec = pts[1] - pts[0];
    SkScalar    mag = vec.length();
    SkScalar    inv = mag ? SkScalarInvert(mag) : 0;

    vec.scale(inv);
    SkMatrix matrix;
    matrix.setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
    matrix.postTranslate(-pts[0].fX, -pts[0].fY);
    matrix.postScale(inv, inv);
    return matrix;
}

void draw(SkCanvas* canvas) {
    SkPaint paint;
    paint.setColor(SK_ColorGRAY);
    paint.setAntiAlias(true);
    SkRect rect = {20, 20, 100, 100};
    canvas->drawRect(rect, paint);
    paint.setColor(SK_ColorRED);
    SkMatrix matrix;
    matrix.setSinCos(.25f, .85f);
    matrix.postTranslate(rect.centerX(), rect.centerY());
    canvas->concat(matrix);
    canvas->translate(-rect.centerX(), -rect.centerY());
    canvas->drawRect(rect, paint);
}

static void morphpoints(SkPoint dst[], const SkPoint src[], int count,
                        SkPathMeasure& meas, SkScalar dist) {
    for (int i = 0; i < count; i++) {
        SkPoint pos;
        SkVector tangent;
        
        SkScalar sx = src[i].fX;
        SkScalar sy = src[i].fY;
        
        meas.getPosTan(dist + sx, &pos, &tangent);
        
        SkMatrix    matrix;
        SkPoint     pt;
        
        pt.set(sx, sy);
        matrix.setSinCos(tangent.fY, tangent.fX, 0, 0);
        matrix.preTranslate(-sx, 0);
        matrix.postTranslate(pos.fX, pos.fY);
        matrix.mapPoints(&dst[i], &pt, 1);
    }
}

int SkBuildQuadArc(const SkVector& uStart, const SkVector& uStop,
                   SkRotationDirection dir, const SkMatrix* userMatrix,
                   SkPoint quadPoints[])
{
    // rotate by x,y so that uStart is (1.0)
    SkScalar x = SkPoint::DotProduct(uStart, uStop);
    SkScalar y = SkPoint::CrossProduct(uStart, uStop);

    SkScalar absX = SkScalarAbs(x);
    SkScalar absY = SkScalarAbs(y);

    int pointCount;

    // check for (effectively) coincident vectors
    // this can happen if our angle is nearly 0 or nearly 180 (y == 0)
    // ... we use the dot-prod to distinguish between 0 and 180 (x > 0)
    if (absY <= SK_ScalarNearlyZero && x > 0 &&
        ((y >= 0 && kCW_SkRotationDirection == dir) ||
         (y <= 0 && kCCW_SkRotationDirection == dir))) {
            
        // just return the start-point
        quadPoints[0].set(SK_Scalar1, 0);
        pointCount = 1;
    } else {
        if (dir == kCCW_SkRotationDirection)
            y = -y;

        // what octant (quadratic curve) is [xy] in?
        int oct = 0;
        bool sameSign = true;

        if (0 == y)
        {
            oct = 4;        // 180
            SkASSERT(SkScalarAbs(x + SK_Scalar1) <= SK_ScalarNearlyZero);
        }
        else if (0 == x)
        {
            SkASSERT(absY - SK_Scalar1 <= SK_ScalarNearlyZero);
            if (y > 0)
                oct = 2;    // 90
            else
                oct = 6;    // 270
        }
        else
        {
            if (y < 0)
                oct += 4;
            if ((x < 0) != (y < 0))
            {
                oct += 2;
                sameSign = false;
            }
            if ((absX < absY) == sameSign)
                oct += 1;
        }

        int wholeCount = oct << 1;
        memcpy(quadPoints, gQuadCirclePts, (wholeCount + 1) * sizeof(SkPoint));

        const SkPoint* arc = &gQuadCirclePts[wholeCount];
        if (quad_pt2OffCurve(arc, x, y, &quadPoints[wholeCount + 1]))
        {
            quadPoints[wholeCount + 2].set(x, y);
            wholeCount += 2;
        }
        pointCount = wholeCount + 1;
    }

    // now handle counter-clockwise and the initial unitStart rotation
    SkMatrix    matrix;
    matrix.setSinCos(uStart.fY, uStart.fX);
    if (dir == kCCW_SkRotationDirection) {
        matrix.preScale(SK_Scalar1, -SK_Scalar1);
    }
    if (userMatrix) {
        matrix.postConcat(*userMatrix);
    }
    matrix.mapPoints(quadPoints, pointCount);
    return pointCount;
}

  static void setSinCos__FF(JNIEnv* env, jobject clazz, jlong objHandle, jfloat sinValue, jfloat cosValue) {
     SkMatrix* obj = reinterpret_cast<SkMatrix*>(objHandle);
     obj->setSinCos(sinValue, cosValue);
 }