android图片底部波浪,Android-Canvas.drawBitmapMesh给照片底部添加波浪效果

实现的效果是酱紫的：

使用方式跟普通的ImageView是一样的，代码：

/**

* 参考：http://blog.youkuaiyun.com/lee576/article/details/7900228

* */

public class WaveBottomImageView extends ImageView{

private Bitmap mBitmap;

private boolean inited;

// 定义两个常量,这两个常量指定该图片横向,纵向上都被划分为100格

private final int WIDTH = 100;

private final int HEIGHT = 100;

// 记录该图片上包含10201个顶点

private final int COUNT = (WIDTH + 1) * (HEIGHT + 1);

// 定义一个数组,记录Bitmap上的101*101个点的坐标

private final float[] orig = new float[COUNT * 2];

// 定义一个数组,记录Bitmap上的101*101个点经过扭曲后的坐标

// 对图片扭曲的关键就是修改该数组里元素的值

private final float[] verts = new float[COUNT * 2];

private int bitmapWidth;

private int bitmapHeight;

private float boxHeigtht;

public WaveBottomImageView(Context context) {

this(context, null);

}

public WaveBottomImageView(Context context, AttributeSet attrs) {

super(context, attrs);

mBitmap = ((BitmapDrawable)this.getDrawable()).getBitmap();

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

// 获取图片宽度和高度

bitmapWidth = getMeasuredWidth();

bitmapHeight = getMeasuredHeight();

boxHeigtht = bitmapHeight / HEIGHT;

setMeasuredDimension(bitmapWidth, (int)(bitmapHeight + boxHeigtht));

if(!inited){

init();

inited = true;

}

}

protected void onDraw(Canvas canvas) {

canvas.drawBitmapMesh(mBitmap, WIDTH, HEIGHT, verts, 0, null, 0, null);

}

private void init(){

//初始化

int index = 0;

for (int y = 0; y <= HEIGHT; y++) {

float fy = bitmapHeight * y / HEIGHT;

for (int x = 0; x <= WIDTH; x++) {

float fx = bitmapWidth * x / WIDTH;

// 初始化orig,verts数组

// 初始化,orig,verts两个数组均匀地保存了101*101个点的x,y坐标

orig[index * 2 + 0] = verts[index * 2 + 0] = fx;

orig[index * 2 + 1] = verts[index * 2 + 1] = fy;

if(y == HEIGHT){

// 修改最后一行的y坐标

float oldY = orig[index * 2 + 1];

float newY = (float) (oldY + boxHeigtht * Math.sin(Math.PI / 4 * (x % 5)));

verts[index * 2 + 1] = newY;

}

index += 1;

}

}

}

//private void wave() {

//int index = (WIDTH + 1) * HEIGHT;

//for (int x = 0; x <= WIDTH; x++) {

//float oldY = orig[index * 2 + 1];

//float newY = (float) (oldY + boxHeigtht * Math.sin(Math.PI / 4 * (x % 5)));

//verts[index * 2 + 1] = newY;

//index += 1;

//}

//}

}

最开始没有重写onMeasure，导致波浪效果怎么也出不来，妈蛋的！

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原文：http://blog.youkuaiyun.com/goldenfish1919/article/details/47126691