ImageView设置背景图片后置灰探究

最新推荐文章于 2021-11-16 17:14:44 发布

_逆水寒_

最新推荐文章于 2021-11-16 17:14:44 发布

阅读量469

点赞数

CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/rrrraa/article/details/50773100

本文介绍了一种使用Android平台实现图片灰度效果的方法。通过自定义View并覆盖draw方法，利用Bitmap.Config.ARGB_8888配置来创建Bitmap，再通过Canvas和Paint结合ColorMatrixColorFilter实现将彩色图片转换为灰度图片的功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

直接上代码

public void change(View v) {
    Drawable drawAble = img.getBackground();
    img.setImageBitmap(toGrayscale(drawableToBitmap(img.getDrawable())));
}
//置灰 RGB_565会使整个背景都变黑
private Bitmap drawableToBitmap(Drawable drawable) {
    //Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight(),drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888: Bitmap.Config.RGB_565);
    Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight(),Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight());
    drawable.draw(canvas);
    return bitmap;
}

private Bitmap toGrayscale(Bitmap bmpOriginal) {
    int width, height;
    height = bmpOriginal.getHeight();
    width = bmpOriginal.getWidth();

    Bitmap bmpGrayscale = Bitmap.createBitmap(width, height,Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(bmpGrayscale);
    Paint paint = new Paint();
    ColorMatrix cm = new ColorMatrix();
    cm.setSaturation(0);
    ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
    paint.setColorFilter(f);
    c.drawBitmap(bmpOriginal, 0, 0, paint);
    return bmpGrayscale;
}