Android开发imageview实现上面两个圆角下面两个直角的效果

效果图：

实现代码：

RequestOptions options1 = new RequestOptions()
        .centerCrop()
        .placeholder(R.drawable.error)
        .error(R.drawable.error)
        .transform(new GlideRoundTransform(10));

Glide.with(mContext).load(url).apply(options1).into(iv_icon);

GlideRoundTransform类：

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.support.annotation.NonNull;

import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.resource.bitmap.BitmapTransformation;
import com.bumptech.glide.load.resource.bitmap.TransformationUtils;

import java.security.MessageDigest;

public class GlideRoundTransform extends BitmapTransformation {
    private static float radius = 0f;

    public GlideRoundTransform() {
        this(4);
    }

    public GlideRoundTransform(int dp) {
        super();
        this.radius = Resources.getSystem().getDisplayMetrics().density * dp;
    }


    @Override
    protected Bitmap transform(@NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
        //变换的时候裁切
        Bitmap bitmap = TransformationUtils.centerCrop(pool, toTransform, outWidth, outHeight);
        return roundCrop(pool, bitmap);
    }

    @Override
    public void updateDiskCacheKey(MessageDigest messageDigest) {

    }


    private static Bitmap roundCrop(BitmapPool pool, Bitmap source) {
        if (source == null) {
            return null;
        }
        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);
   
        RectF rectF = new RectF(0f, 0f, source.getWidth(), source.getHeight());
        canvas.drawRoundRect(rectF, radius, radius, paint);
        //上边圆角 下边直角 (注释掉下边这两行代码 全是圆角)
        RectF rectRound = new RectF(0f, 100f, source.getWidth(), source.getHeight());
        canvas.drawRect(rectRound, paint);
        return result;
    }

}