packages/SystemUI/src/com/android/systemui/BitmapHelper.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License
 */

package com.android.systemui;

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;

public class BitmapHelper {
    /**
     * Generate a new bitmap (width x height pixels, ARGB_8888) with the input bitmap scaled
     * to fit and clipped to an inscribed circle.
     * @param input Bitmap to resize and clip
     * @param width Width of output bitmap (and diameter of circle)
     * @param height Height of output bitmap
     * @return A shiny new bitmap for you to use
     */
    public static Bitmap createCircularClip(Bitmap input, int width, int height) {
        if (input == null) return null;

        final int inWidth = input.getWidth();
        final int inHeight = input.getHeight();
        final Bitmap output = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        final Canvas canvas = new Canvas(output);
        final Paint paint = new Paint();
        paint.setShader(new BitmapShader(input, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
        paint.setAntiAlias(true);
        final RectF srcRect = new RectF(0, 0, inWidth, inHeight);
        final RectF dstRect = new RectF(0, 0, width, height);
        final Matrix m = new Matrix();
        m.setRectToRect(srcRect, dstRect, Matrix.ScaleToFit.CENTER);
        canvas.setMatrix(m);
        canvas.drawCircle(inWidth / 2, inHeight / 2, inWidth / 2, paint);
        return output;
    }
}