Example usage for android.graphics Matrix mapVectors

Introduction

In this page you can find the example usage for android.graphics Matrix mapVectors.

Prototype

public void mapVectors(float[] vecs) 

Source Link

Document

Apply this matrix to the array of 2D vectors, and write the transformed vectors back into the array.

Usage

From source file:Main.java

private static float transformAngle(Matrix m, float angleRadians) {
    // Construct and transform a vector oriented at the specified clockwise
    // angle from vertical.  Coordinate system: down is increasing Y, right is
    // increasing X.
    float[] v = new float[2];
    v[0] = (float) Math.sin(angleRadians);
    v[1] = (float) Math.cos(angleRadians);
    m.mapVectors(v);
    // Derive the transformed vector's clockwise angle from vertical.
    float result = (float) Math.atan2(v[0], -v[1]);
    if (result < -Math.PI / 2) {
        result += Math.PI;//from  w w w  . j  av a  2 s  .c  o  m
    } else if (result > Math.PI / 2) {
        result -= Math.PI;
    }
    return result;
}

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From source file:Main.java

private static float transformAngle(Matrix m, float angleRadians) {
    // Construct and transform a vector oriented at the specified clockwise
    // angle from vertical.  Coordinate system: down is increasing Y, right is
    // increasing X.
    float[] v = new float[2];
    v[0] = (float) Math.sin(angleRadians);
    v[1] = (float) -Math.cos(angleRadians);
    m.mapVectors(v);

    // Derive the transformed vector's clockwise angle from vertical.
    float result = (float) Math.atan2(v[0], -v[1]);
    if (result < -Math.PI / 2) {
        result += Math.PI;/* w w  w . ja  v  a2  s . c  o m*/
    } else if (result > Math.PI / 2) {
        result -= Math.PI;
    }
    return result;
}

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