三种方式的圆形视图

package com.ahtelit.zbv.myapplication.View;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;

import com.ahtelit.zbv.myapplication.R;

/**
 * Created by Administrator on 2018/5/17.
 * qzx
 * 三种方式的圆形图片绘制
 */

public class CustomeCircleView extends View {

    private Paint mPaint;
    private int minRadius;

    public CustomeCircleView(Context context) {
        this(context, null);
    }

    public CustomeCircleView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CustomeCircleView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //消除抗锯齿以及过滤图片边缘锯齿
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setColor(Color.BLACK);

    }

    @Override
    protected void onDraw(Canvas canvas) {

        //PorterDuffXfermode-------------------------------------------------------------
//        //如果Config的配置是RGB_565是绘制不出来圆形的,一般都会设置为ARGB_8888
//        //创建一个画布，在这个画布上绘制PorterDuffXfermode
//        //最后把画布中绘制好的Bitmap让View的Canvas绘制出来
//
//        //所要绘制的图片
//        Bitmap wantDraw=getBitmapFromDrawable(getResources().getDrawable(R.drawable.dragandzoombase));
//        //要知道画布的大小---这里配置设置ARGB_8888
//        Bitmap bitmap=Bitmap.createBitmap(wantDraw.getWidth(),wantDraw.getHeight(), Bitmap.Config.ARGB_8888);
//        Canvas mCanvas=new Canvas(bitmap);
//        //简单以minRadius为宽高从左上角算起开画
//        mCanvas.drawCircle(minRadius,minRadius,minRadius,mPaint);
//        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
//        mCanvas.drawBitmap(wantDraw,0,0,mPaint);
//        mPaint.setXfermode(null);
//        canvas.drawBitmap(bitmap,0,0,mPaint);
        //PorterDuffXfermode------------------------------------------------------------

        //BitmapShader-----------------------------------------------------------
//        Bitmap wantDraw=BitmapFactory.decodeResource(getResources(),R.drawable.dragandzoombase);
//        /*
//        * BitmapShader---Tile瓦片
//        * CLAMP---宽度最后像素和高度最后像素拉伸
//        * REPEAT
//        * MIRROR
//        * */
//        BitmapShader bmShader=new BitmapShader(wantDraw, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
//        //Matrix缩放---要让图片的宽高大于我们View的宽高这样不至于拉伸变形
//        // bmShader.setLocalMatrix(Matrix);
//        mPaint.setShader(bmShader);
//        canvas.drawCircle(minRadius,minRadius,minRadius,mPaint);
        //BitmapShader-----------------------------------------------------------


        //ClipPath---》无法消除抗锯齿--------------------------------------------
        //之所以使用save和restore是因为裁剪效果会影响到后续的canvas
        canvas.save();
        //一般消除抗锯齿---这里对clippath无效
        //Android中，Canvas的抗锯齿功能必须使用到画笔Paint。
        canvas.setDrawFilter(new PaintFlagsDrawFilter(0,Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG));
        Bitmap wantDraw=BitmapFactory.decodeResource(getResources(),R.drawable.dragandzoombase);
        Path mPath=new Path();
        //CCW是逆时针，CW是顺时针
        mPath.addCircle(minRadius,minRadius,minRadius, Path.Direction.CCW);
        canvas.clipPath(mPath);
        canvas.drawBitmap(wantDraw,0,0,null);
        canvas.restore();
        //ClipPath---------------------------------------------------------

    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        Log.d("zbv", "onLayout");
        super.onLayout(changed, left, top, right, bottom);
    }

    /*
        * 被多次测量即多次调用
        * */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.d("zbv", "onMeasure"+"   ;measureWidth="+getMeasuredWidth()+";measureHeight="+getMeasuredHeight());
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int minW_H=getMeasuredWidth()>=getMeasuredHeight()?getMeasuredHeight():getMeasuredWidth();

        minRadius=minW_H/2;

        setMeasuredDimension(minW_H,minW_H);
    }

    /*
    * 这个onSizeChanged的函数在测量之后布局之前调用一次，以后尺寸改变会调用
    * 所以可以在这里拿到视图的宽度和高度
    * */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Log.d("zbv", "onSizeChanged"+"   ;w="+w+";h="+h);
        super.onSizeChanged(w, h, oldw, oldh);
    }

    /**
     * 将drawable转变成bitmap
     * */
    private Bitmap getBitmapFromDrawable(Drawable drawable) {

        Bitmap bitmap;
        if (drawable instanceof BitmapDrawable) {
            bitmap = ((BitmapDrawable) drawable).getBitmap();
        } else {
            int width = drawable.getIntrinsicWidth();
            int height = drawable.getIntrinsicHeight();
            bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
            drawable.draw(canvas);
        }
        return bitmap;
    }
}

继续完善中……