use Picasso for loading fullscreen images

app/build.gradle

@@ -38,6 +38,7 @@ dependencies {
     compile 'com.google.code.gson:gson:2.8.0'
     compile 'com.github.chrisbanes:PhotoView:1.3.1'
     compile 'it.sephiroth.android.exif:library:1.0.1'
+    compile 'com.squareup.picasso:picasso:2.5.2'
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 }
 

app/proguard-rules.pro

@@ -1,19 +1,2 @@
-# Add project specific ProGuard rules here.
-# By default, the flags in this file are appended to flags specified
-# in $ANDROID_HOME/tools/proguard/proguard-android.txt
-# You can edit the include path and order by changing the proguardFiles
-# directive in build.gradle.
-#
-# For more details, see
-#   http://developer.android.com/guide/developing/tools/proguard.html
-
-# Add any project specific keep options here:
-
-# If your project uses WebView with JS, uncomment the following
-# and specify the fully qualified class name to the JavaScript interface
-# class:
-#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
-#   public *;
-#}
 -keep class com.simplemobiletools.** { *; }
 -dontwarn com.simplemobiletools.**

app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt

@@ -160,6 +160,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         val pagerAdapter = MyPagerAdapter(this, supportFragmentManager, mMedia)
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && !isDestroyed) {
             view_pager?.apply {
+                offscreenPageLimit = 2
                 adapter = pagerAdapter
                 currentItem = mPos
                 addOnPageChangeListener(this@ViewPagerActivity)

app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt

@@ -6,19 +6,20 @@ import android.graphics.BitmapFactory
 import android.graphics.Matrix
 import android.net.Uri
 import android.os.Bundle
+import android.util.DisplayMetrics
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import com.bumptech.glide.Glide
-import com.bumptech.glide.load.DecodeFormat
 import com.bumptech.glide.load.engine.DiskCacheStrategy
 import com.simplemobiletools.commons.extensions.beGone
+import com.simplemobiletools.commons.extensions.beVisible
 import com.simplemobiletools.commons.extensions.toast
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.extensions.getRealPathFromURI
-import com.simplemobiletools.gallery.helpers.GlideRotateTransformation
 import com.simplemobiletools.gallery.helpers.MEDIUM
 import com.simplemobiletools.gallery.models.Medium
+import com.squareup.picasso.Picasso
 import it.sephiroth.android.library.exif2.ExifInterface
 import kotlinx.android.synthetic.main.pager_photo_item.view.*
 import uk.co.senab.photoview.PhotoViewAttacher
@@ -118,6 +119,7 @@ class PhotoFragment : ViewPagerFragment() {
     private fun loadImage() {
         if (medium.isGif()) {
             view.photo_view.beGone()
+            view.gif_holder.beVisible()
             Glide.with(this)
                     .load(medium.path)
                     .asGif()
@@ -130,13 +132,12 @@ class PhotoFragment : ViewPagerFragment() {
     }
 
     private fun loadBitmap(degrees: Float = 0f) {
-        Glide.with(this)
-                .load(medium.path)
-                .asBitmap()
-                .transform(GlideRotateTransformation(context, degrees))
-                .format(if (medium.isPng()) DecodeFormat.PREFER_ARGB_8888 else DecodeFormat.PREFER_RGB_565)
-                .thumbnail(0.2f)
-                .diskCacheStrategy(DiskCacheStrategy.NONE)
+        val metrics = DisplayMetrics()
+        activity.windowManager.defaultDisplay.getMetrics(metrics)
+        Picasso.with(activity)
+                .load("file:${medium.path}")
+                .resize(metrics.widthPixels * 2, metrics.heightPixels * 2)
+                .centerInside()
                 .into(view.photo_view)
     }
 
@@ -146,7 +147,6 @@ class PhotoFragment : ViewPagerFragment() {
 
     override fun onDestroyView() {
         super.onDestroyView()
-        Glide.clear(view.photo_view)
         Glide.clear(view.gif_holder)
     }
 

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

@@ -8,7 +8,8 @@
     <ImageView
         android:id="@+id/gif_holder"
         android:layout_width="match_parent"
-        android:layout_height="match_parent"/>
+        android:layout_height="match_parent"
+        android:visibility="gone"/>
 
     <uk.co.senab.photoview.PhotoView
         android:id="@+id/photo_view"