import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BitmapShader;

import android.graphics.Canvas;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.Shader;

import android.util.AttributeSet;

import android.util.Log;

import android.view.View;

//自己导包以及R引入

public class ShaderView extends View {

Paint paint;

private int width;

private int height;

private int centerX;

private int centerY;

Bitmap bitmap;

BitmapShader shader;

BitmapFactory.Options options;

//自定义view的限制宽高

private static final int MOST_WIDTH = 800;

private static final int MOST_HEIGHT = MOST_WIDTH;

public ShaderView(Context context) {

this(context, null);

}

public ShaderView(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

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

super(context, attrs, defStyleAttr);

paint = new Paint();

paint.setAntiAlias(true);

paint.setDither(true);

bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.tt);

options = new BitmapFactory.Options();

BitmapFactory.decodeResource(context.getResources(), R.drawable.tt, options);

shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.MIRROR);

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

int wMode = MeasureSpec.getMode(widthMeasureSpec);

int wSize = MeasureSpec.getSize(widthMeasureSpec); //parent给的参考值， AT_MOST下不能超过改值

int hMode = MeasureSpec.getMode(heightMeasureSpec);

int hSize = MeasureSpec.getSize(heightMeasureSpec); //parent给的参考值， AT_MOST下不能超过改值

Log.d("szx", "onLayout, wSize=" + wSize + ",hSize=" + hSize);

if (wMode == MeasureSpec.EXACTLY) { //match_parent或者精确值

width = wSize;

} else if (wMode == MeasureSpec.AT_MOST) { //wrap_content, UNSPECIFIED不考虑

width = Math.min(wSize, MOST_WIDTH);

}

if (hMode == MeasureSpec.EXACTLY) { //match_parent或者精确值

height = hSize;

} else if (hMode == MeasureSpec.AT_MOST) { //wrap_content, UNSPECIFIED不考虑

height = Math.min(hSize, MOST_HEIGHT);

}

width = height = Math.min(width, height);

Log.d("szx", "onLayout, width=" + width + ",height=" + height);

centerX = width / 2;

centerY = height / 2;

setMeasuredDimension(width, height);

}

@Override

protected void onLayout(boolean changed, int left, int top, int right, int bottom) {

super.onLayout(changed, left, top, right, bottom);

//

float wScale = (float)width / (float)options.outWidth;

float hScame = (float)height / (float)options.outHeight;

float scale = Math.min(wScale, hScame);

Log.d("szx", "width="+width+",height="+height);

Log.d("szx", "options.outWidth="+options.outWidth+",options.outWidth="+options.outWidth);

Log.d("szx", "wScale="+wScale+",hScame="+hScame+",scale="+scale);

Matrix matrix = new Matrix();

matrix.setScale(scale, scale);

shader.setLocalMatrix(matrix);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

Log.d("szx","onDraw");

paint.setShader(shader);

canvas.drawCircle(centerX, centerY, width/2, paint);

}

}