import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.View;



public class CustomImageView extends View {

    private Paint mPaint;

    private RectF mRectF;



    public CustomImageView(Context context) {

        super(context);

        init();

    }



    public CustomImageView(Context context, AttributeSet attrs) {

        super(context, attrs);

        init();

    }



    public CustomImageView(Context context, AttributeSet attrs, int defStyleAttr) {

        super(context, attrs, defStyleAttr);

        init();

    }



    private void init() {

        mPaint = new Paint();

        mPaint.setAntiAlias(true);

        mPaint.setDither(true);

        mPaint.setColor(Color.WHITE);

        mPaint.setTextSize(20);

        mRectF = new RectF();

    }



    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        if (mPaint != null && mRectF != null) {

            // 计算高度

            int height = getResources().getDimensionPixelSize(R.dimen.height_custom_imageview);

            // 设置高度

            canvas.translate(mRectF.left, mRectF.top);

            canvas.scale(1, -height / getWidth());

            canvas.drawBitmap(getBitmap(), mRectF, mRectF, mPaint);

            canvas.restore();

        }

    }



    private Bitmap getBitmap() {

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

        options.inPreferredConfig = Bitmap.Config.ARGB_8888;

        return BitmapFactory.decodeResource(getResources(), R.drawable.your_image, options);

    }

}