我想知道在Android中,将从互联网上下载的彩色图像转换为黑白图像并显示给用户的方法。 您是否在您的Android工作中遇到过此需求?请告诉我。
谢谢 Lakshman
使用内置方法:
public static Bitmap toGrayscale(Bitmap srcImage) {
Bitmap bmpGrayscale = Bitmap.createBitmap(srcImage.getWidth(), srcImage.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
paint.setColorFilter(new ColorMatrixColorFilter(cm));
canvas.drawBitmap(srcImage, 0, 0, paint);
return bmpGrayscale;
}
嗨,您可以使用对比度将图像变为黑白。
看看这段代码..
public static Bitmap createContrast(Bitmap src, double value) {
// image size
int width = src.getWidth();
int height = src.getHeight();
// create output bitmap
Bitmap bmOut = Bitmap.createBitmap(width, height, src.getConfig());
// color information
int A, R, G, B;
int pixel;
// get contrast value
double contrast = Math.pow((100 + value) / 100, 2);
// scan through all pixels
for(int x = 0; x < width; ++x) {
for(int y = 0; y < height; ++y) {
// get pixel color
pixel = src.getPixel(x, y);
A = Color.alpha(pixel);
// apply filter contrast for every channel R, G, B
R = Color.red(pixel);
R = (int)(((((R / 255.0) - 0.5) * contrast) + 0.5) * 255.0);
if(R < 0) { R = 0; }
else if(R > 255) { R = 255; }
G = Color.red(pixel);
G = (int)(((((G / 255.0) - 0.5) * contrast) + 0.5) * 255.0);
if(G < 0) { G = 0; }
else if(G > 255) { G = 255; }
B = Color.red(pixel);
B = (int)(((((B / 255.0) - 0.5) * contrast) + 0.5) * 255.0);
if(B < 0) { B = 0; }
else if(B > 255) { B = 255; }
// set new pixel color to output bitmap
bmOut.setPixel(x, y, Color.argb(A, R, G, B));
}
}
return bmOut;
}
在调用该方法时将double值设置为50。例如:createContrast(Bitmap src, 50)