检测我的位图是黑白还是颜色图像

Question

我有一个图像URI，我使用以下代码从该URI获取bitmap：

Bitmap bitmap = null;
    try {
       bitmap = MediaStore.Images.Media.getBitmap(getContext().getContentResolver(), uri);
    } catch (IOException e) {
        e.printStackTrace();
    }

现在我想检查bitmap是黑色和白色还是颜色图像。

（要么有黑色/白色图像或彩色图像）

我该怎么做？ 我在Android上使用Java。

Answer 1

我在Kotlin中创建了一个扩展功能，您可以使用此功能或在Java中以相同逻辑制作类似的函数

fun Bitmap.isColored(): Boolean{
for (x in 0 until this.width){
    for (y in 0 until this.height){
        val color = this.getColor(x,y)
        val blue = color.blue()
        val red = color.red()
        val green = color.green()

        if(blue!=red || blue!=green || red!=green){
            return true
        }
    }
}

return false
}

来使用扩展功能，只需调用iScolored = yourbitmap.iscolored（）

edit：java函数

@RequiresApi(Build.VERSION_CODES.Q)
boolean isColored(Bitmap bitmap){
    for (int x = 0; x< bitmap.getWidth(); x++){
        for (int y = 0 ;y < bitmap.getHeight(); y++){
            Color color = bitmap.getColor(x,y);
            float blue = color.blue();
            float red = color.red();
            float green = color.green();

            Log.d( "blue: " , Float.toString(blue));
            Log.d( "red: " , Float.toString(red));
            Log.d( "green: " , Float.toString(green));


            if(blue!=red || blue!=green || red!=green){
                return true;
            }
        }
    }

    return false;
}

编辑： Java的主要活动显示其使用

public class MainActivity2 extends AppCompatActivity {

@RequiresApi(api = Build.VERSION_CODES.Q)
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);

    InputStream ins= getResources().openRawResource(
            getResources().getIdentifier(
                    "image",
                    "raw", getPackageName()
            )
    );

    Bitmap bitmap = BitmapFactory.decodeStream(ins);

    Log.d( "isColored: ", "" + isColored(bitmap));
}

@RequiresApi(Build.VERSION_CODES.Q)
boolean isColored(Bitmap bitmap){
    for (int x = 0; x< bitmap.getWidth(); x++){
        for (int y = 0 ;y < bitmap.getHeight(); y++){
            Color color = bitmap.getColor(x,y);
            float blue = color.blue();
            float red = color.red();
            float green = color.green();

            Log.d( "blue: " , Float.toString(blue));
            Log.d( "red: " , Float.toString(red));
            Log.d( "green: " , Float.toString(green));


            if(blue!=red || blue!=green || red!=green){
                return true;
            }
        }
    }

    return false;
}
}