Android Xfermode 实战 实现圆形、圆角图片(1)

3、onMeasure

---

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)

{

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

/**

• 如果类型是圆形，则强制改变view的宽高一致，以小值为准

*/

if (type == TYPE_CIRCLE)

{

int width = Math.min(getMeasuredWidth(), getMeasuredHeight());

setMeasuredDimension(width, width);

}

}

在onMeasure中，如果是圆形则重新设置view大小。

4、onDraw

---

@SuppressLint(“DrawAllocation”)

@Override

protected void onDraw(Canvas canvas)

{

//在缓存中取出bitmap

Bitmap bitmap = mWeakBitmap == null ? null : mWeakBitmap.get();

if (null == bitmap || bitmap.isRecycled())

{

//拿到Drawable

Drawable drawable = getDrawable();

//获取drawable的宽和高

int dWidth = drawable.getIntrinsicWidth();

int dHeight = drawable.getIntrinsicHeight();

if (drawable != null)

{

//创建bitmap

bitmap = Bitmap.createBitmap(getWidth(), getHeight(),

Config.ARGB_8888);

float scale = 1.0f;

//创建画布

Canvas drawCanvas = new Canvas(bitmap);

//按照bitmap的宽高，以及view的宽高，计算缩放比例；因为设置的src宽高比例可能和imageview的宽高比例不同，这里我们不希望图片失真；

if (type == TYPE_ROUND)

{

// 如果图片的宽或者高与view的宽高不匹配，计算出需要缩放的比例；缩放后的图片的宽高，一定要大于我们view的宽高；所以我们这里取大值；

scale = Math.max(getWidth() * 1.0f / dWidth, getHeight()

• 1.0f / dHeight);

} else

{

scale = getWidth() * 1.0F / Math.min(dWidth, dHeight);

}

//根据缩放比例，设置bounds，相当于缩放图片了

drawable.setBounds(0, 0, (int) (scale * dWidth),

(int) (scale * dHeight));

drawable.draw(drawCanvas);

if (mMaskBitmap == null || mMaskBitmap.isRecycled())

{

mMaskBitmap = getBitmap();