效果图

原图

过滤蓝光

反色

主要代码

class MainActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_main)

filterBlueLightBtn.setOnClickListener { filterBlueLight() }

reverseColorBtn.setOnClickListener { reverseColor() }

resumeBtn.setOnClickListener { resumeColor() }

}

/**

* 反色

*/

private fun reverseColor() {

val paint = Paint()

val cm = ColorMatrix(floatArrayOf(

-1f, 0f, 0f, 0f, 255f,

0f, -1f, 0f, 0f, 255f,

0f, 0f, -1f, 0f, 255f,

0f, 0f, 0f, 1f, 0f))

paint.colorFilter = ColorMatrixColorFilter(cm)

window.decorView.setLayerType(View.LAYER_TYPE_HARDWARE, paint)

}

/**

* 过滤蓝光

*/

private fun filterBlueLight() {

val paint = Paint()

// 把蓝色减弱为原来的0.7

val cm = ColorMatrix(floatArrayOf(

1f, 0f, 0f, 0f, 0f,

0f, 1f, 0f, 0f, 0f,

0f, 0f, 0.7f, 0f, 0f,

0f, 0f, 0f, 1f, 0f))

paint.colorFilter = ColorMatrixColorFilter(cm)

window.decorView.setLayerType(View.LAYER_TYPE_HARDWARE, paint)

}

/**

* 恢复

*/

private fun resumeColor() {

window.decorView.setLayerType(View.LAYER_TYPE_HARDWARE, Paint())

}

}

完整源代码

附录

这种方式是基于view做的修改,也可直接针对ImageView设置颜色过滤器,详见:https://www.jianshu.com/p/f1f93a37738b