android 高斯模糊

BaseRender

import android.graphics.Bitmap;

public interface BaseRender {
    public abstract void blur(float radius, Bitmap in, Bitmap out);
    public abstract void destory();
}

Blur

public class Blur {

    private static final float BITMAP_SCALE_NOMAL = 0.8f;
    private static final float BLUR_RADIUS_NOMAL = 12.0f;
    
    public  static final float BITMAP_SCALE_FAST = 0.2f;
    public static final float BLUR_RADIUS_FAST = 5.0f;
    
    private boolean USE_JNI = false;
    
    private BaseRender mRender;
    
    private static Blur instance;
    
    public static Blur getInstance(Context context) {
        if(instance == null)
            instance = new Blur(context);
        return instance;
    }
    
    private Blur(Context context) {
            mRender = new ScriptIntrinsicBlurRender(context);
    }
    
    public Bitmap blur(Bitmap image, boolean fast) {
        float scale = BITMAP_SCALE_NOMAL;
        float radius = BLUR_RADIUS_NOMAL;
        
        if (fast) {
            scale = BITMAP_SCALE_FAST;
            radius = BLUR_RADIUS_FAST;
        }
        
        int width = Math.round(image.getWidth() * scale);
        int height = Math.round(image.getHeight() * scale);
        
        Bitmap bitmap = Bitmap.createScaledBitmap(image, width, height, true);
        Bitmap outputBitmap = bitmap.copy(bitmap.getConfig(), true);
        mRender.blur(radius, bitmap, outputBitmap);
        bitmap.recycle();
        
        return outputBitmap;
    }
    
    public void destory() {
        if (mRender != null) {
            mRender.destory();
        }
    }
    
}

RSRender

public abstract class RSRender implements BaseRender {

    protected RenderScript rs;
    
    public RSRender(Context ctx) {
        rs = RenderScript.create(ctx);
    }
    
    @Override
    public void blur(float radius, Bitmap in, Bitmap out) {
        Allocation tmpIn = Allocation.createFromBitmap(rs, in);
        Allocation tmpOut = Allocation.createFromBitmap(rs, out);
        blur(radius, tmpIn, tmpOut);
        tmpOut.copyTo(out);
        tmpIn.destroy();
        tmpOut.destroy();
    }

    public abstract void blur(float radius, Allocation tmpIn, Allocation tmpOut);
    
    @Override
    public void destory() {
        if (rs != null) rs.destroy();
    }

}

ScriptIntrinsicBlurRender

public class ScriptIntrinsicBlurRender extends RSRender {

    private ScriptIntrinsicBlur theIntrinsic;
    
    public ScriptIntrinsicBlurRender(Context context) {
        super(context);
        theIntrinsic = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
    }

    @Override
    public void blur(float radius, Allocation tmpIn, Allocation tmpOut) {
        theIntrinsic.setRadius(radius);
        theIntrinsic.setInput(tmpIn);
        theIntrinsic.forEach(tmpOut);
    }
    
    @Override
    public void destory() {
        super.destory();
        theIntrinsic.destroy();
    }

}

调用方式

 Bitmap bitmap = Blur.getInstance(context).blur(bitmap, false);