微信分享图片变黑

/**
* bitmap中的透明色用白色替换
*
* @param bitmap
* @return
*/
public static Bitmap changeColor(Bitmap bitmap) {
if (bitmap == null) {
return null;
}
int w = bitmap.getWidth();
int h = bitmap.getHeight();
int[] colorArray = new int[w * h];
int n = 0;
for (int i = 0; i < h; i++) {
for (int j = 0; j < w; j++) {
int color = getMixtureWhite(bitmap.getPixel(j, i));
colorArray[n++] = color;
}
}
return Bitmap.createBitmap(colorArray, w, h, Bitmap.Config.ARGB_8888);
}

/**
* 获取和白色混合颜色
*
* @return
*/
private static int getMixtureWhite(int color) {
int alpha = Color.alpha(color);
int red = Color.red(color);
int green = Color.green(color);
int blue = Color.blue(color);
return Color.rgb(getSingleMixtureWhite(red, alpha), getSingleMixtureWhite

(green, alpha),
getSingleMixtureWhite(blue, alpha));
}

/**
* 获取单色的混合值
*
* @param color
* @param alpha
* @return
*/
private static int getSingleMixtureWhite(int color, int alpha) {
int newColor = color * alpha / 255 + 255 - alpha;
return newColor > 255 ? 255 : newColor;
}