add filter of Gaussian blur

add filter of Gaussian blur

app/src/main/java/com/frank/ffmpeg/activity/FilterActivity.java

@@ -52,6 +52,8 @@ public class FilterActivity extends BaseActivity implements SurfaceHolder.Callba
             "colorbalance=bs=0.3",
             "drawbox=x=100:y=100:w=100:h=100:color=red@0.5'",
             "hflip",
+            //adjust the coefficient of sigma to control the blur
+            "gblur=sigma=2:steps=1:planes=1:sigmaV=1",
             "rotate=180*PI/180",
             "unsharp"
     };
@@ -64,6 +66,7 @@ public class FilterActivity extends BaseActivity implements SurfaceHolder.Callba
             FFmpegApplication.getInstance().getString(R.string.filter_equalize),
             FFmpegApplication.getInstance().getString(R.string.filter_rectangle),
             FFmpegApplication.getInstance().getString(R.string.filter_flip),
+            FFmpegApplication.getInstance().getString(R.string.filter_blur),
             FFmpegApplication.getInstance().getString(R.string.filter_rotate),
             FFmpegApplication.getInstance().getString(R.string.filter_sharpening)
     };

app/src/main/res/layout/activity_filter.xml

@@ -5,8 +5,8 @@
 
     <SurfaceView
         android:id="@+id/surface_filter"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent" />
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content" />
 
     <androidx.recyclerview.widget.RecyclerView
         android:id="@+id/recycler_view"

app/src/main/res/values-en/strings.xml

@@ -81,6 +81,7 @@
     <string name="filter_equalize">equalize</string>
     <string name="filter_rectangle">rectangle</string>
     <string name="filter_flip">flip</string>
+    <string name="filter_blur">blur</string>
     <string name="filter_rotate">rotate</string>
     <string name="filter_sharpening">sharpen</string>
 

app/src/main/res/values/strings.xml

@@ -81,6 +81,7 @@
     <string name="filter_equalize">均衡</string>
     <string name="filter_rectangle">矩形</string>
     <string name="filter_flip">镜像</string>
+    <string name="filter_blur">模糊</string>
     <string name="filter_rotate">旋转</string>
     <string name="filter_sharpening">锐化</string>