解决Glide4.x之后transform和centerCrop同时使用不能显示圆角的问题

项目中使用到一个imageview上面是两个圆角，下面是两个直角，如图

网上找了一波类似的控件，找到了这个

public class OvalImageView extends ImageView {  


    /*圆角的半径，依次为左上角xy半径，右上角，右下角，左下角*/  
    private float[] rids = {10.0f, 10.0f, 10.0f, 10.0f, 0.0f, 0.0f, 0.0f, 0.0f,};  


    public OvalImageView(Context context) {  
        super(context);  
    }  


    public OvalImageView(Context context, AttributeSet attrs) {  
        super(context, attrs);  
    }  


    public OvalImageView(Context context, AttributeSet attrs, int defStyleAttr) {  
        super(context, attrs, defStyleAttr);  
    }  




    /** 
     * 画图 
     * by Hankkin at:2015-08-30 21:15:53 
     * 
     * @param canvas 
     */  
    protected void onDraw(Canvas canvas) {  
        Path path = new Path();  
        int w = this.getWidth();  
        int h = this.getHeight();    
        /*向路径中添加圆角矩形。radii数组定义圆角矩形的四个圆角的x,y半径。radii长度必须为8*/  
        path.addRoundRect(new RectF(0, 0, w, h), rids, Path.Direction.CW);  
        canvas.clipPath(path);  
        super.onDraw(canvas);  
    }  
}   

但是使用过程中会出现有点卡顿的问题，采用这种裁剪的方式性能显然不是很好
然后我又想到glide可以显示圆角，并且项目中集成了glide，那就用glide来试试

但是glide4.x和3.x使用的方式很不一样，导致centerCrop()和transform并不能共存
最开始直接使用transform继承BitmapTransformation

 class GlideRoundedCornersTransform extends BitmapTransformation {}

显然这样是用不了的
然后查阅了下资料
需要继承CenterCrop

class GlideRoundedCornersTransform extends CenterCrop {}

并且下面重写方法的这个位置很关键
就是先调用super的CenterCrop处理，得到的结果再在自己的roundCrop里处理

 @Override
    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        Bitmap transform = super.transform(pool, toTransform, outWidth, outHeight);
        return roundCrop(pool, transform);
    }

这样设置进去就可以了

        val options = RequestOptions()
        options.optionalTransform(GlideRoundedCornersTransform(5f, GlideRoundedCornersTransform.CornerType.TOP))
        Glide.with(mContext).load(url).apply(options).into(imageView)

贴下transform代码，完美显示

public class GlideRoundedCornersTransform extends CenterCrop {
    private float mRadius;
    private CornerType mCornerType;
    private static final int VERSION = 1;
    private static final String ID = BuildConfig.APPLICATION_ID+"GlideRoundedCornersTransform." + VERSION;
    private static final byte[] ID_BYTES = ID.getBytes(CHARSET);


    public enum CornerType {
        ALL,
        TOP_LEFT, TOP_RIGHT, BOTTOM_LEFT, BOTTOM_RIGHT,
        TOP, BOTTOM, LEFT, RIGHT,
        TOP_LEFT_BOTTOM_RIGHT,
        TOP_RIGHT_BOTTOM_LEFT,
        TOP_LEFT_TOP_RIGHT_BOTTOM_RIGHT,
        TOP_RIGHT_BOTTOM_RIGHT_BOTTOM_LEFT,
    }

    public GlideRoundedCornersTransform(float radius, CornerType cornerType) {
        super();
        mRadius = UIUtils.dp2px(radius);//dp ->px
        mCornerType = cornerType;
    }

    @Override
    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        Bitmap transform = super.transform(pool, toTransform, outWidth, outHeight);
        return roundCrop(pool, transform);
    }

    private Bitmap roundCrop(BitmapPool pool, Bitmap source) {
        if (source == null) {
            return null;
        }
        int width = source.getWidth();
        int height = source.getHeight();
        Bitmap result = pool.get(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);


        if (result == null) {
            result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config
                    .ARGB_8888);
        }
        Canvas canvas = new Canvas(result);
        Paint paint = new Paint();
        paint.setShader(new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader
                .TileMode.CLAMP));
        paint.setAntiAlias(true);



        Path path = new Path();
        drawRoundRect(canvas, paint, path, width, height);

        return result;
    }

    private void drawRoundRect(Canvas canvas, Paint paint, Path path, int width, int height) {
         float[] rids ;
        switch (mCornerType) {
            case ALL:
                rids = new float[]{mRadius,mRadius,mRadius,mRadius,mRadius,mRadius,mRadius,mRadius};
                drawPath(rids,canvas, paint, path, width, height);
                break;
            case TOP_LEFT:
                rids = new float[]{mRadius,mRadius,0.0f,0.0f,0.0f,0.0f,0.0f,0.0f};
                drawPath(rids,canvas, paint, path, width, height);
                break;
            case TOP_RIGHT:
                rids  = new float[]{0.0f,0.0f,mRadius,mRadius,0.0f,0.0f,0.0f,0.0f};
                drawPath(rids,canvas, paint, path, width, height);
                break;
            case BOTTOM_RIGHT:
                rids  = new float[]{0.0f,0.0f,0.0f,0.0f,mRadius,mRadius,0.0f,0.0f};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case BOTTOM_LEFT:
                rids  = new float[]{0.0f,0.0f,0.0f,0.0f,0.0f,0.0f,mRadius,mRadius};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case TOP:
                rids = new float[]{mRadius,mRadius,mRadius,mRadius,0.0f,0.0f,0.0f,0.0f};
                drawPath(rids,canvas,  paint,  path,width, height);
                break;
            case BOTTOM:
                rids  = new float[]{0.0f,0.0f,0.0f,0.0f,mRadius,mRadius,mRadius,mRadius};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case LEFT:
                rids = new float[]{mRadius,mRadius,0.0f,0.0f,0.0f,0.0f,mRadius,mRadius};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case RIGHT:
                rids  = new float[]{0.0f,0.0f,mRadius,mRadius,mRadius,mRadius,0.0f,0.0f};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case TOP_LEFT_BOTTOM_RIGHT:
                rids  = new float[]{mRadius,mRadius,0.0f,0.0f,mRadius,mRadius,0.0f,0.0f};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case TOP_RIGHT_BOTTOM_LEFT:
                rids  = new float[]{0.0f,0.0f,mRadius,mRadius,0.0f,0.0f,mRadius,mRadius};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case TOP_LEFT_TOP_RIGHT_BOTTOM_RIGHT:
                rids  = new float[]{mRadius,mRadius,mRadius,mRadius,mRadius,mRadius,0.0f,0.0f};
                drawPath(rids,canvas,  paint, path, width, height);
                break;
            case TOP_RIGHT_BOTTOM_RIGHT_BOTTOM_LEFT:
                rids  = new float[]{0.0f,0.0f,mRadius,mRadius,mRadius,mRadius,mRadius,mRadius};
                drawPath(rids,canvas,  paint,  path,width, height);
                break;
            default:
                throw new RuntimeException("RoundedCorners type not belong to CornerType");
        }
    }


    /**@param rids 圆角的半径，依次为左上角xy半径，右上角，右下角，左下角*/
    private void drawPath(float[] rids,Canvas canvas,Paint paint,Path path, int width, int height) {
        path.addRoundRect(new RectF(0, 0, width, height), rids, Path.Direction.CW);
//        canvas.clipPath(path);
        canvas.drawPath(path,paint);
    }


    @Override
    public boolean equals(Object o) {
        return o instanceof GlideRoundedCornersTransform;
    }


    @Override
    public int hashCode() {
        return ID.hashCode();
    }


    @Override
    public void updateDiskCacheKey(MessageDigest messageDigest) {
        messageDigest.update(ID_BYTES);
    }
}