ImageUtils.java 文件源码

public static Bitmap scaleImage(Bitmap bitmap, int boxSize){
    if (boxSize == 0)
        return null;

    // Determine how much to scale: the dimension requiring less scaling is
    // closer to the its side. This way the image always stays inside your
    // bounding box AND either x/y axis touches it.
    float xScale = ((float) boxSize) / bitmap.getWidth();
    float yScale = ((float) boxSize) / bitmap.getHeight();
    float scale = (xScale <= yScale) ? xScale : yScale;

    // Create a matrix for the scaling and add the scaling data
    Matrix matrix = new Matrix();
    matrix.postScale(scale, scale);

    // Create a new bitmap and convert it to a format understood by the ImageView
    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}