android开发笔记之多媒体—图片的颜色处理

た入场券 2022-07-24 05:25 216阅读 0赞

1.拿到原图

baseBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pre);

2.拿到一张与原图同样大小的纸

copyBitmap = Bitmap.createBitmap(baseBitmap.getWidth(), baseBitmap.getHeight(), baseBitmap.getConfig());

3.把画纸固定在画布上

canvas = new Canvas(copyBitmap);

4.拿到画笔

paint = new Paint();

5.给画笔设置颜色过滤器

//vactor的取值范围0-2
            float[] colors = new float[]{
                red_vactor ,0 ,0 ,0 ,0,   
                0 ,green_vactor ,0 ,0 ,0,   
                0 ,0 ,blue_vactor ,0 ,0,   
                0 ,0 ,0 ,1 ,0
            };
            //给画笔设置颜色过滤器
            paint.setColorFilter(new ColorMatrixColorFilter(colors));

6.处理规则

Matrix matrix = new Matrix();

7.照着原图画

canvas.drawBitmap(baseBitmap, matrix, paint);

8.把图片显示在ImageView组件上

iv.setImageBitmap(copyBitmap);

效果图：

![这里写图片描述][20160514194501091]

核心代码：

public class MainActivity extends Activity implements OnSeekBarChangeListener{ 
    
        private Bitmap baseBitmap,copyBitmap;//原图和复制的图
        private Canvas canvas;              //画布
        private Paint paint;                //画笔
        private SeekBar red_seekbar,blue_seekbar,green_seekbar; //拖动条
        private ImageView iv;                   
        private float red_vactor,blue_vactor,green_vactor;//用来记录RGB三种颜色的量的
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            red_seekbar = (SeekBar) findViewById(R.id.red_seekbar);
            blue_seekbar = (SeekBar) findViewById(R.id.blue_seekbar);
            green_seekbar = (SeekBar) findViewById(R.id.green_seekbar);
            iv = (ImageView) findViewById(R.id.iv);
            red_seekbar.setOnSeekBarChangeListener(this);
            blue_seekbar.setOnSeekBarChangeListener(this);
            green_seekbar.setOnSeekBarChangeListener(this);
        }
        //进度改变的时候调用
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,
                boolean fromUser) {
    
        }
        //开始拖动的时候调用
        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
    
        }
        //停止拖动的时候调用
        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            float progress = seekBar.getProgress(); 
            float count = progress / 50f;       //使拖动条的值为0f-2f
            switch (seekBar.getId()) {
            case R.id.red_seekbar:
                this.red_vactor = count;
                break;
            case R.id.green_seekbar:
                this.green_vactor = count;
                break;
            case R.id.blue_seekbar:
                this.blue_vactor = count;
                break;
            default:
                break;
            }
            //主体代码
            //1.拿到原图
            baseBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pre);
            //2.拿到一张与原图一样大小的纸
            copyBitmap = Bitmap.createBitmap(baseBitmap.getWidth(), baseBitmap.getHeight(), baseBitmap.getConfig());
            //3.把画纸固定在画板上
            canvas = new Canvas(copyBitmap);
            //4.拿到画笔
            paint = new Paint();
            //vactor的取值范围0-2
            float[] colors = new float[]{
                red_vactor ,0 ,0 ,0 ,0,   
                0 ,green_vactor ,0 ,0 ,0,   
                0 ,0 ,blue_vactor ,0 ,0,   
                0 ,0 ,0 ,1 ,0
            };
            //5.给画笔设置颜色过滤器
            paint.setColorFilter(new ColorMatrixColorFilter(colors));
            //6.处理规则
            Matrix matrix = new Matrix();
            //7.照着原图画
            canvas.drawBitmap(baseBitmap, matrix, paint);
            //8.把画好的图显示在ImageView组件上
            iv.setImageBitmap(copyBitmap);
        }
    }

[20160514194501091]: /images/20220722/3d45f82bfb104755827336d8a41b153f.png