Added RaiseFromCenter, RotateAboutTop and RotateAboutBottom Transformers

Author: kungfucat

app/src/main/java/me/kungfucat/pagetransformerslibrary/MainActivity.java

@@ -10,10 +10,9 @@
 
 import java.util.ArrayList;
 
-import me.kungfucat.viewpagertransformers.DepthPageTransformer;
-import me.kungfucat.viewpagertransformers.DrawerTransformer;
-import me.kungfucat.viewpagertransformers.WindmillTransformer;
-import me.kungfucat.viewpagertransformers.ZoomOutPageTransformer;
+import me.kungfucat.viewpagertransformers.RaiseFromCenterTransformer;
+import me.kungfucat.viewpagertransformers.RotateAboutBottomTransformer;
+import me.kungfucat.viewpagertransformers.RotateAboutTopTransformer;
 
 public class MainActivity extends AppCompatActivity {
 
@@ -43,7 +42,8 @@ protected void onCreate(Bundle savedInstanceState) {
 //        viewPager.setPageTransformer(true,new CubeOutTransformer());
 //        viewPager.setPageTransformer(true, new RandomTransformer());
 //        viewPager.setPageTransformer(true, new DepthPageTransformer());
-          viewPager.setPageTransformer(true, new DrawerTransformer());
+//        viewPager.setPageTransformer(true, new RotateAboutTopTransformer());
+        viewPager.setPageTransformer(true,new RaiseFromCenterTransformer());
     }
 
 

viewpagertransformers/src/main/java/me/kungfucat/viewpagertransformers/DrawerTransformer.java

@@ -7,12 +7,12 @@
 public class DrawerTransformer implements ViewPager.PageTransformer {
     @Override
     public void transformPage(@NonNull View page, float position) {
-        int width=page.getWidth();
+        int width = page.getWidth();
 
         if (position < -1) {
             page.setTranslationX(0);
         } else if (position > 0 && position <= 1) {
-            page.setTranslationX(-width/2*position);
+            page.setTranslationX(-width/2 * position);
         } else {
             page.setTranslationX(0);
         }

viewpagertransformers/src/main/java/me/kungfucat/viewpagertransformers/RaiseFromCenterTransformer.java

@@ -0,0 +1,36 @@
+package me.kungfucat.viewpagertransformers;
+
+import android.support.annotation.NonNull;
+import android.support.v4.view.ViewPager;
+import android.view.View;
+
+public class RaiseFromCenterTransformer implements ViewPager.PageTransformer {
+    @Override
+    public void transformPage(@NonNull View page, float position) {
+        int width = page.getWidth(), height = page.getHeight();
+
+        if (position < -1) {
+            page.setTranslationX(0);
+        } else if (position < 0) {
+
+            float scale = 1 + position;
+            page.setPivotX(width/2);
+            page.setPivotY(height/2);
+            page.setScaleY(scale);
+            page.setScaleX(scale);
+//            Counteract the default motion
+            page.setTranslationX(-position*width);
+        } else if (position < 1) {
+            float scale = 1 - position;
+            page.setPivotX(width/2);
+            page.setPivotY(height/2);
+            page.setScaleY(scale);
+            page.setScaleX(scale);
+//            Counteract the default motion
+            page.setTranslationX(-width * position);
+
+        } else {
+            page.setTranslationX(0);
+        }
+    }
+}

viewpagertransformers/src/main/java/me/kungfucat/viewpagertransformers/RotateAboutBottomTransformer.java

@@ -0,0 +1,21 @@
+package me.kungfucat.viewpagertransformers;
+
+import android.support.annotation.NonNull;
+import android.support.v4.view.ViewPager;
+import android.view.View;
+
+public class RotateAboutBottomTransformer implements ViewPager.PageTransformer {
+    @Override
+    public void transformPage(@NonNull View page, float position) {
+
+        final float width = page.getWidth(), height = page.getHeight();
+
+//        Rotate about centre bottom part
+        page.setPivotX(width / 2);
+        page.setPivotY(height);
+//        Rotate 20 degrees in anticlockwise
+//        If want to rotate clockwise, use negative sign
+        page.setRotation(position * 20);
+
+    }
+}

viewpagertransformers/src/main/java/me/kungfucat/viewpagertransformers/RotateAboutTopTransformer.java

@@ -0,0 +1,20 @@
+package me.kungfucat.viewpagertransformers;
+
+import android.support.annotation.NonNull;
+import android.support.v4.view.ViewPager;
+import android.view.View;
+
+public class RotateAboutTopTransformer implements ViewPager.PageTransformer {
+
+    @Override
+    public void transformPage(@NonNull View page, float position) {
+
+        final float width = page.getWidth();
+
+        //Rotate about top centre of screen, i.e pivoted at width/2 and 0
+        page.setPivotX(width/2);
+        page.setPivotY(0f);
+        page.setRotation(-position*20);
+
+    }
+}