遇寻笔记

如何从当前View获取到Bitmap

v.setDrawingCacheEnabled(true);
v.buildDrawingCache();
Bitmap bitmap = v.getDrawingCache();

如何从TextureView中获取Bitmap

mTextureView.getBitmap();

如何压缩Bitmap

压缩成适配目标宽、高的Bitmap

/**
 * get a scaled bitmap from a file located in path, adjust to destWidth and destHeight
 * @param path the bitmap's file location
 * @param destWidth destination width
 * @param destHeight destination height
 * @return a scaled bitmap
 */
public static Bitmap getScaledBitmap(String path, int destWidth, int destHeight){
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(path, options);

    float srcWidth = options.outWidth;
    float srcHeight = options.outHeight;

    int inSampleSize = 1;
    if (srcHeight > destHeight || srcWidth > destWidth){
        float heightScale = srcHeight / destHeight;
        float widthScale = srcWidth / destWidth;

        inSampleSize = Math.round(heightScale > widthScale ? heightScale : widthScale);
    }

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

    return BitmapFactory.decodeFile(path, options);
}

如何将Bitmap与byte[]相互转换

从Bitmap到byte[]

int bytes = bmp.getByteCount();
ByteBuffer buf = ByteBuffer.allocate(bytes);
bmp.copyPixelsToBuffer(buf);
byte[] byteArray = buf.array();

从byte[]到Bitmap

Bitmap stitchBmp = Bitmap.createBitmap(width, height, type);
stitchBmp.copyPixelsFromBuffer(ByteBuffer.wrap(byteArray));
imageView.setImageBitmap(stitchBmp);

缩略图相关

理解ThumbnaiUtils