根据现有Bitmap生成相同图案指定大小的新Bitmap

通过一张现有的Bitmap，画出一张同样的但是大小使我们指定的Bitmap

需求：直接createBitmap的话不允许生成的bitmap的宽高大于原始的，因此需要特定方法来将一张Bitmap的大小进行调整

crossImage为一张现有的bitmap

Bitmap target = Bitmap.createBitmap(MIDDLE_LINE_WIDTH, MIDDLE_LINE_WIDTH, crossImage.getConfig());

Canvas temp_canvas = new Canvas(target);

temp_canvas.drawBitmap(crossImage, null, new Rect(0, 0, target.getWidth(), target.getHeight()), null);

此时的target就是一张指定大小，但是内容和crossImage一样的bitmap了。

//使用Bitmap加Matrix来缩放

public static Drawable resizeImage(Bitmap bitmap, int w, int h)

{

Bitmap BitmapOrg = bitmap;

int width = BitmapOrg.getWidth();

int height = BitmapOrg.getHeight();

int newWidth = w;

int newHeight = h;

    float scaleWidth = ((float) newWidth) / width;

    float scaleHeight = ((float) newHeight) / height;  

    Matrix matrix = new Matrix();

    matrix.postScale(scaleWidth, scaleHeight);

    // if you want to rotate the Bitmap

    // matrix.postRotate(45);

    Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,

                    height, matrix, true);

    return new BitmapDrawable(resizedBitmap);

}

//使用BitmapFactory.Options的inSampleSize参数来缩放

public static Drawable resizeImage2(String path,

int width,int height)

{

BitmapFactory.Options options = new BitmapFactory.Options();

options.inJustDecodeBounds = true;//不加载bitmap到内存中

BitmapFactory.decodeFile(path,options);

int outWidth = options.outWidth;

int outHeight = options.outHeight;

options.inDither = false;

options.inPreferredConfig = Bitmap.Config.ARGB_8888;

options.inSampleSize = 1;

    if (outWidth != 0 && outHeight != 0 && width != 0 && height != 0)

    {

        int sampleSize=(outWidth/width+outHeight/height)/2;

        Log.d(tag, "sampleSize = " + sampleSize);

        options.inSampleSize = sampleSize;

    }

    options.inJustDecodeBounds = false;

    return new BitmapDrawable(BitmapFactory.decodeFile(path, options));

}