android - Android:滚动搜寻栏时更改图像对比度和亮度

我想设置图像视图的对比度和亮度。参考How to programmatically change contrast of a bitmap in android?，这应该是最快和最有效的方法，我实现了如下代码：
代码：

final SeekBar SeekBar_contrast = (SeekBar) dialog_preview.findViewById(R.id.SeekBar_contrast);
        final SeekBar SeekBar_brightness = (SeekBar) dialog_preview.findViewById(R.id.SeekBar_brightness);
        SeekBar_contrast.setMax(10);
        SeekBar_brightness.setMax(510);
        SeekBar_contrast.setProgress((1));
        SeekBar_brightness.setProgress((255));
        SeekBar_contrast.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
        {
             @Override
             public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
             {
                    new_bm = changeBitmapContrastBrightness(bimap, (float)(progress-1),(float)(SeekBar_brightness.getProgress()-255));
                    cropImageView.setImageBitmap(new_bm);
             }

             @Override
             public void onStartTrackingTouch(SeekBar seekBar)
             {
             }

             @Override
             public void onStopTrackingTouch(SeekBar seekBar)
             {
             }
        });
        SeekBar_brightness.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
        {
             @Override
             public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
             {
                    new_bm = changeBitmapContrastBrightness(bimap, (float)(SeekBar_contrast.getProgress()-1), (float)(progress-255));
                    cropImageView.setImageBitmap(new_bm);
             }

             @Override
             public void onStartTrackingTouch(SeekBar seekBar)
             {
             }

             @Override
             public void onStopTrackingTouch(SeekBar seekBar)
             {

             }
        });

方法：

public static Bitmap changeBitmapContrastBrightness(Bitmap bmp, float contrast, float brightness)
{
    ColorMatrix cm = new ColorMatrix(new float[]
            {
                contrast, 0, 0, 0, brightness,
                0, contrast, 0, 0, brightness,
                0, 0, contrast, 0, brightness,
                0, 0, 0, 1, 0
            });

    Bitmap ret = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

    Canvas canvas = new Canvas(ret);

    Paint paint = new Paint();
    paint.setColorFilter(new ColorMatrixColorFilter(cm));
    canvas.drawBitmap(bmp, 0, 0, paint);

    return ret;
}

参数如下：

 @param bmp input bitmap
 * @param contrast 0..10 1 is default
 * @param brightness -255..255 0 is default
 * @return new bitmap

问题：
虽然亮度默认值是0，这是范围的中间值，因此滚动亮度seekbar它工作得很好，但我想问一下如何设置seekbar max值以及对比度的进度更改，因为默认值是1，不在范围的中间。
在滚动seekbar_对比度时，上面的代码将使图像在progress=0时显示“负颜色”，同时向右滚动（seekbar的较大值）将生成白色图像。

最佳答案

首先，在对比度seekbar的侦听器中，必须对seekbark的亮度值执行-255。
为了使对比度的默认值位于中间，请执行以下代码：

    SeekBar_contrast.setMax(10);
    SeekBar_contrast.setProgress((5));
         @Override
         public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (progress <= 5) {
                    progress = 1 - progress / 5;
                } else {
                    progress = 1 + (progress / 10) * 9
                }
                new_bm = changeBitmapContrastBrightness(bimap, (float)(progress-1),(float)SeekBar_brightness.getProgress() - 255);
                cropImageView.setImageBitmap(new_bm);
         }

如果你想增加对比度平滑-尝试使用任何非线性函数。