Get the new position object when scale with a given point via Matrix. - Android Graphics

Android examples for Graphics:Path Point

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Description

Get the new position object when scale with a given point via Matrix.

Demo Code


//package com.java2s;
import android.graphics.Matrix;
import android.graphics.PointF;

public class Main {
    /**/*from w  ww .j a va2 s.  com*/
     * Get the new position object when scale with a given point.
     * @param targetPointX the x position before scale
     * @param targetPointY the y position before scale
     * @param scaleCenterX the scale point ,x position
     * @param scaleCenterY the scale point ,y position
     * @param scale scale
     * @return the new position after scale
     */
    public static PointF scaleByPoint(float targetPointX,
            float targetPointY, float scaleCenterX, float scaleCenterY,
            float scale) {
        Matrix matrix = new Matrix();
        // move the matrix to target position
        // then, scale with the given point and scale.
        matrix.preTranslate(targetPointX, targetPointY);
        matrix.postScale(scale, scale, scaleCenterX, scaleCenterY);
        float[] values = new float[9];
        matrix.getValues(values);
        return new PointF(values[Matrix.MTRANS_X], values[Matrix.MTRANS_Y]);
    }
}

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