工作中遇到图片转灰度数组的须要，经过研究和大神的指导。终于得到例如以下两个方法。能够实现位图转灰度数组
简单的位图转灰度数组就是：得到位图中的每一个像素点，然后依据像素点得到RGB值，最后对RGB值，依据灰度算法得到灰度值就可以
/*如一张480*800的图片，终于得到一个byte[480*800/2]的灰度数组，由于函数把每两个相邻高的像素灰度转化为一个灰度*/
private byte[] java_convertIMG2GreyArray(Bitmap img) {
byte[] theBytes = null;/* 得到位图的宽高 */
int width = img.getWidth();
int height = img.getHeight();
/* 取得位图的像素点 */
int[] pixels = new int[width * height];
img.getPixels(pixels, 0, width, 0, 0, width, height);
/* 定义结果数据数组 */
theBytes = new byte[width * height / 2];
/*定义循环中用到的变量，节约内存和时间*/
int x, y, k;
int pixel, r, g, b;
for (y = 0; y < height; y++) {
for (x = 0, k = 0; x < width; x++) {
//依次取得像素点
pixel = pixels[y * width + x];
//得到rgb
r = (pixel >> 16) & 0xFF;
g = (pixel >> 8) & 0xFF;
b = pixel & 0xFF;
/*每两行存为一行*/
if (x % 2 == 1) {
theBytes[k + y * width / 2] = (byte) (theBytes[k + y
* width / 2] | ((r * 299 + g * 587 + b * 114 + 500) / 1000) & 0xf0);
k++;
} else {
theBytes[k + y * width / 2] = (byte) (theBytes[k + y
* width / 2] | (((r * 299 + g * 587 + b * 114 + 500) / 1000) >> 4) & 0x0f);
}
}
}
return theBytes;
}
/*灰度依次转换 如：480 * 800最后得到一个byte[480*800]的灰度数组*/
private void java_convertIMGtoGreyArray(Bitmap img) {
boolean usedebug = true;
if (debugImage == null || debugUihandler == null)
usedebug = false;
int width = img.getWidth(); // 获取位图的宽
int height = img.getHeight(); // 获取位图的高
theBytes = null;
theBytes = new byte[width * height];
int[] pixels = new int[width * height]; // 通过位图的大小创建像素点数组
img.getPixels(pixels, 0, width, 0, 0, width, height);
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
int colorAtPixel = pixels[width * i + j];
int alpha = (colorAtPixel >> 24) & 0xFF;
int red = (colorAtPixel >> 16) & 0xFF;
int green = (colorAtPixel >> 8) & 0xFF;
int blue = colorAtPixel & 0xFF;
theBytes[width * i + j] = (byte) ((red + green + blue) / 3);
int theb = (0xff & theBytes[width * i + j]);
pixels[width * i + j] = alpha << 24 | theb << 16 | theb << 8
| theb;
}
}
bmo = img;
bmo.setPixels(pixels, 0, width, 0, 0, width, height);
pixels = null;
if (debugUihandler != null)
debugUihandler.post(new Runnable() {
@Override
public void run() {
if (debugImage != null && bmo != null)
debugImage.setImageBitmap(bmo);
}
});
}