Android裁剪图片为圆形图片的实现原理与代码
作者：
这个方法是根据传入的图片的高度（height）和宽度（width）决定的，如果是 width <= height时，则会裁剪高度，裁剪的区域是宽度不变高度从顶部到宽度width的长度
以前在eoe论坛中找过裁剪图片为圆形图片的方法，但是效果都不是很理想，这几天因为公司业务的要求，需要对头像进行裁剪以圆形的方式显示，这个方法是根据传入的图片的高度（height）和宽度（width）决定的，如果是 width <= height时，则会裁剪高度，裁剪的区域是宽度不变高度从顶部到宽度width的长度；如果 width > height，则会裁剪宽度，裁剪的区域是高度不变，宽度是取的图片宽度的中心区域，不过不同的业务需求，对裁剪图片要求不一样，可以根据业务的需求来调整裁剪的区域。
好了，不多说了，直接上代码
/**
* 转换图片成圆形
* @param bitmap 传入Bitmap对象
* @return
*/
public Bitmap toRoundBitmap(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float roundPx;
float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;
if (width <= height) {
roundPx = width / 2;
top = 0;
bottom = width;
left = 0;
right = width;
height = width;
dst_left = 0;
dst_top = 0;
dst_right = width;
dst_bottom = width;
} else {
roundPx = height / 2;
float clip = (width - height) / 2;
left = clip;
right = width - clip;
top = 0;
bottom = height;
width = height;
dst_left = 0;
dst_top = 0;
dst_right = height;
dst_bottom = height;
}
Bitmap output = Bitmap.createBitmap(width,
height, Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);
final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);
final RectF rectF = new RectF(dst);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, src, dst, paint);
return output;
}
好了，不多说了，直接上代码
复制代码 代码如下:
/**
* 转换图片成圆形
* @param bitmap 传入Bitmap对象
* @return
*/
public Bitmap toRoundBitmap(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float roundPx;
float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;
if (width <= height) {
roundPx = width / 2;
top = 0;
bottom = width;
left = 0;
right = width;
height = width;
dst_left = 0;
dst_top = 0;
dst_right = width;
dst_bottom = width;
} else {
roundPx = height / 2;
float clip = (width - height) / 2;
left = clip;
right = width - clip;
top = 0;
bottom = height;
width = height;
dst_left = 0;
dst_top = 0;
dst_right = height;
dst_bottom = height;
}
Bitmap output = Bitmap.createBitmap(width,
height, Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);
final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);
final RectF rectF = new RectF(dst);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, src, dst, paint);
return output;
}