Android图片转换类 1. Bitmap去色,转换为黑白的灰度图, 2. Bitmap图片加圆角效果

/**
* 处理图片的工具类.
*
*/
public class ImageTools {

/***//**
* 图片去色,返回灰度图片
* @param bmpOriginal 传入的图片
* @return 去色后的图片
*/
public static Bitmap toGrayscale(Bitmap bmpOriginal) {
int width, height;
height = bmpOriginal.getHeight();
width = bmpOriginal.getWidth();

Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
Canvas c = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
c.drawBitmap(bmpOriginal, 0, 0, paint);
return bmpGrayscale;
}

/***//**
* 去色同时加圆角
* @param bmpOriginal 原图
* @param pixels 圆角弧度
* @return 修改后的图片
*/
public static Bitmap toGrayscale(Bitmap bmpOriginal, int pixels) {
return toRoundCorner(toGrayscale(bmpOriginal), pixels);
}

/***//**
* 把图片变成圆角
* @param bitmap 需要修改的图片
* @param pixels 圆角的弧度
* @return 圆角图片
*/
public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) {

Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);

final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;

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, rect, rect, paint);

return output;
}

/***//**
* 使圆角功能支持BitampDrawable
* @param bitmapDrawable
* @param pixels
* @return
*/
public static BitmapDrawable toRoundCorner(BitmapDrawable bitmapDrawable, int pixels) {
Bitmap bitmap = bitmapDrawable.getBitmap();
bitmapDrawable = new BitmapDrawable(toRoundCorner(bitmap, pixels));
return bitmapDrawable;
}
}