The realization of Gaussian blur _android with Android Renderscript

Yesterday read the official document of Renderscript, found that renderscript this fellow is a bit of a kick. Accidentally found Scriptintrinsic this abstract class, some very useful subclasses. One of them is called the Scriptintrinsicblur class, which is basically the image to achieve a Gaussian blur.

Scriptintrinsic's statement:

Scriptintrinsicblur the declaration of the class:

Coupled with a look at the next SDK in the samples, he wrote a Gaussian blur.
(The exact location of sample is:
SDK Directory/samples/android-19/renderscript/renderscriptintrinsic/renderscriptintrinsicsample/
）。

First figure. The effect is as follows:

"Attention!! Before we start, we need to import the required support packs.
The specific path to the support package is: SDK directory/buildtools/any version number/renderscript/lib/renderscript-v8.jar
In addition: In order to prevent the emergence of a model compatibility problem, it is best to renderscript-v8.jar the same directory under the packaged directory of all libraries are also copied to the Lib folder.

For example:

All right. Start writing code.

1. Declare the common member variable first.

Private SeekBar blurseekbar;//Drag bar
private ImageView img_blur;//show blur bitmap ImageView
// The original Bitmap and Gauss Fuzzy Bitmap
private Bitmap bitmap_original, Bitmap_blur;
Gauss fuzzy processing asynctask
private renderscripttask mlatesttask = null;
Renderscript object (Google's High-performance parallel computing class, he can use equipment such as GPU/CPU computing resources)
private renderscript MRS;
Here are two renderscript incoming parameter objects
private allocation minallocation;
private allocation moutallocation;
Gaussian fuzzy processing instance
private Scriptintrinsicblur Mscriptblur;

2, loading two copies of bitmap, and initializing Gaussian blur related objects.

@Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);
  Setcontentview (R.layout.activity_main);
  Blurseekbar = (SeekBar) Findviewbyid (R.id.aty_main_seekbar);

  Img_blur = (ImageView) Findviewbyid (R.id.aty_main_img_blur);
  Bitmap_original = LoadBitmap (r.drawable.meet_entry_guide_3); Copies a copy of Bitmap_blur = Bitmap.createbitmap (Bitmap_original.getwidth (), Bitmap_original.getheight (), bitmap_original
  . GetConfig ());
  Createblurescript (); Setseekbarlistening ()///For Seekbar settings drag-and-drop listening}/** * Helper to load Bitmap from resource/private Bitmap LoadBitmap (int res
  Ource) {final bitmapfactory.options Options = new Bitmapfactory.options ();
  Options.inpreferredconfig = Bitmap.Config.ARGB_8888;
Return Bitmapfactory.decoderesource (Getresources (), Resource, options);
  /** * Create script/private void Createblurescript () {MRS = Renderscript.create (this);
  Minallocation = Allocation.createfrombitmap (MRS, bitmap_original); Moutallocation = Allocation.createfrombitmap (MRS, Bitmap_blur); * * Create intrinsics. Renderscript has built-in features such as Blur, * convolve filter etc. These intrinsics are handy for specific * operations without writing renderscript.
   In the sample, it ' s * creating blur, Convolve and Matrix intrinsics.
* * Mscriptblur = scriptintrinsicblur.create (Mrs, Element.u8_4 (Mrs));

 }

3, the completion of the Gauss Fuzzy processing code.

private void Performfilter (allocation inallocation,
      allocation outallocation, Bitmap bitmapout, float value) {
   * * Set the degree of ambiguity. Range between the 0~25. Otherwise there will be an error
   * *
  Mscriptblur.setradius (value);
   * * Invoke Filter Kernel * *
  mscriptblur.setinput (inallocation);
  Mscriptblur.foreach (outallocation);

  Outallocation.copyto (bitmapout);
}

4, the processing of the bitmap set to the ImageView.

Request UI update
img_blur.setimagebitmap (bitmap_blur);
Img_blur.invalidate ();

The basic work is done. The rest is the code calling each other.

Summary
in fact, the use of renderscript for Gaussian Blur is mainly divided into three steps:

1. Create and initialize the objects you need (once initialization is OK).

MRS = Renderscript.create (this);
Mscriptblur = Scriptintrinsicblur.create (Mrs, Element.u8_4 (Mrs));
Renderscript input and output parameter object
minallocation = Allocation.createfrombitmap (MRS, bitmap_original);
Moutallocation = Allocation.createfrombitmap (MRS, Bitmap_blur);

2, the implementation of Gaussian blur, and copy the results.

 * * Set the degree of ambiguity. Range between the 0~25. Otherwise there will be an error (this can be set only once)/
Mscriptblur.setradius (value);
 * * Invoke Filter Kernel * *
mscriptblur.setinput (inallocation);
Mscriptblur.foreach (outallocation);
Copy the results and copy them to the Bitmapout object
outallocation.copyto (bitmapout);

3, Recycling Renderscript objects

Mrs.destory ();
MRs = null; 

The article ends here.

By convention: Here is my complete code implementation.

public class Mainactivity extends activity {private SeekBar Blurseekbar;
  Private ImageView Img_blur;

  Private Bitmap bitmap_original, Bitmap_blur;

  Private Renderscripttask mlatesttask = null;
  Private Renderscript MRS;
  private allocation minallocation;
  private allocation moutallocation;

  Private Scriptintrinsicblur Mscriptblur;
    @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);
    Setcontentview (R.layout.activity_main);
    Blurseekbar = (SeekBar) Findviewbyid (R.id.aty_main_seekbar);
    Img_blur = (ImageView) Findviewbyid (R.id.aty_main_img_blur);
    Bitmap_original = LoadBitmap (r.drawable.meet_entry_guide_3); Copies a copy of Bitmap_blur = Bitmap.createbitmap (Bitmap_original.getwidth (), Bitmap_original.getheight (), Bitmap_orig
    Inal.getconfig ());
    Createblurescript ();
  Setseekbarlistening (); /** * Set Seekbar monitor/private void setseekbarlistening () {Blurseekbar.setonseekbarchangeListener (New Onseekbarchangelistener () {@Override public void Onstoptrackingtouch (SeekBar SeekBar) {} @Override public void Onstarttrackingtouch (SeekBar SeekBar) {} @Override public void on
      ProgressChanged (SeekBar SeekBar, int progress, Boolean fromuser) {updateimage (progress);
  }
    });
    /** * Create script/private void Createblurescript () {MRS = Renderscript.create (this);
    Minallocation = Allocation.createfrombitmap (MRS, bitmap_original);

    Moutallocation = Allocation.createfrombitmap (MRS, Bitmap_blur); * * Create intrinsics. Renderscript has built-in features such as Blur, * convolve filter etc. These intrinsics are handy for specific * operations without writing renderscript.
     In the sample, it ' s * creating blur, Convolve and Matrix intrinsics.
  * * Mscriptblur = scriptintrinsicblur.create (Mrs, Element.u8_4 (Mrs)); } private void Performfilter (allocation inallocation, allocation outallocation, Bitmap bitmapout, float value) {/* * Set Blur Kerne

    L Size */Mscriptblur.setradius (value);
    * * Invoke Filter Kernel * * Mscriptblur.setinput (inallocation);

    Mscriptblur.foreach (outallocation);
  Outallocation.copyto (bitmapout);
   } * * In the Asynctask, it invokes Renderscript intrinsics to do a filtering. * After the filtering was done, a operation blocks at Allication.copyto () * in Asynctask thread.
   Once all operation are finished at OnPostExecute () in * UI thread, it can invalidate and update ImageView UI.

    * * Private class Renderscripttask extends Asynctask<float, Integer, integer> {Boolean issued = false;
        Protected Integer doinbackground (Float ... values) {if (iscancelled () = = False) {issued = true;
      Performfilter (Minallocation, Moutallocation, Bitmap_blur, values[0]);
    return 0; } void UPdateview (Integer result) {//Request UI update Img_blur.setimagebitmap (Bitmap_blur);
    Img_blur.invalidate ();
    } protected void OnPostExecute (Integer result) {Updateview (result);
      } protected void oncancelled (Integer result) {if (issued) {Updateview (result); }}/* Invoke Asynchtask and cancel previous task.  When asynctasks are piled up * (typically in slow device with heavy kernel), only the latest (and * already started)
   Task invokes Renderscript operation.

    * * private void UpdateImage (int progress) {float F = getblureparam (progress);
    if (mlatesttask!= null) Mlatesttask.cancel (FALSE);
    Mlatesttask = new Renderscripttask ();
  Mlatesttask.execute (f); /** * Fuzzy value between 1 ~ 25 * * @param progress * Seekbar Progress value (0 ~) * @return Fuzzy value/Private Flo
    at Getblureparam (int progress) {final float max = 25.0f;
    Final float min = 1.f; Return (float) ((max-min) * (progress/100.0) + min); }/** * Helper to load Bitmap from resource/private Bitmap LoadBitmap (int resource) {final bitmapfactor
    Y.options Options = new Bitmapfactory.options ();
    Options.inpreferredconfig = Bitmap.Config.ARGB_8888;
  Return Bitmapfactory.decoderesource (Getresources (), Resource, options);

 }
}

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