From adeed37b06c80c8955c80c4f1cb7ede181a8af37 Mon Sep 17 00:00:00 2001
From: Markus Ressel <mail@markusressel.de>
Date: Fri, 12 Jun 2020 20:34:47 +0200
Subject: [PATCH] Bugfix/#152 pan to center (#158)

* added boolean return value to callback function for easier delegation

* respect realZoom when calculating transformationPan
---
 .../java/com/otaliastudios/zoom/ZoomEngine.kt | 21 +++++++++----------
 .../zoom/internal/matrix/MatrixController.kt  | 12 ++++-------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/library/src/main/java/com/otaliastudios/zoom/ZoomEngine.kt b/library/src/main/java/com/otaliastudios/zoom/ZoomEngine.kt
index e0856c9..ee2fa90 100644
--- a/library/src/main/java/com/otaliastudios/zoom/ZoomEngine.kt
+++ b/library/src/main/java/com/otaliastudios/zoom/ZoomEngine.kt
@@ -4,13 +4,16 @@ import android.annotation.SuppressLint
 import android.content.Context
 import android.graphics.Matrix
 import android.graphics.RectF
-import android.view.*
+import android.view.Gravity
+import android.view.MotionEvent
+import android.view.View
+import android.view.ViewTreeObserver
 import com.otaliastudios.zoom.ZoomApi.*
-import com.otaliastudios.zoom.internal.UpdatesDispatcher
-import com.otaliastudios.zoom.internal.matrix.MatrixController
 import com.otaliastudios.zoom.internal.StateController
+import com.otaliastudios.zoom.internal.UpdatesDispatcher
 import com.otaliastudios.zoom.internal.gestures.PinchDetector
 import com.otaliastudios.zoom.internal.gestures.ScrollFlingDetector
+import com.otaliastudios.zoom.internal.matrix.MatrixController
 import com.otaliastudios.zoom.internal.matrix.MatrixUpdate
 import com.otaliastudios.zoom.internal.movement.PanManager
 import com.otaliastudios.zoom.internal.movement.ZoomManager
@@ -76,13 +79,9 @@ internal constructor(context: Context) : ZoomApi {
 
         // Post utilities
 
-        override fun post(action: Runnable) {
-            container.post(action)
-        }
+        override fun post(action: Runnable): Boolean = container.post(action)
 
-        override fun postOnAnimation(action: Runnable) {
-            container.postOnAnimation(action)
-        }
+        override fun postOnAnimation(action: Runnable) = container.postOnAnimation(action)
 
         // Matrix callbacks
 
@@ -607,8 +606,8 @@ internal constructor(context: Context) : ZoomApi {
      * dimensions. This means applying the transformation gravity.
      */
     private fun computeTransformationPan(): ScaledPoint {
-        val extraWidth = contentWidth - containerWidth
-        val extraHeight = contentHeight - containerHeight
+        val extraWidth = contentWidth * realZoom - containerWidth
+        val extraHeight = contentHeight * realZoom - containerHeight
         val gravity = computeTransformationGravity(transformationGravity)
         val x = -panManager.applyGravity(gravity, extraWidth, true)
         val y = -panManager.applyGravity(gravity, extraHeight, false)
diff --git a/library/src/main/java/com/otaliastudios/zoom/internal/matrix/MatrixController.kt b/library/src/main/java/com/otaliastudios/zoom/internal/matrix/MatrixController.kt
index 4138fab..74d96ca 100644
--- a/library/src/main/java/com/otaliastudios/zoom/internal/matrix/MatrixController.kt
+++ b/library/src/main/java/com/otaliastudios/zoom/internal/matrix/MatrixController.kt
@@ -26,7 +26,7 @@ internal class MatrixController(
     internal interface Callback {
         fun onMatrixUpdate()
         fun onMatrixSizeChanged(oldZoom: Float, firstTime: Boolean)
-        fun post(action: Runnable)
+        fun post(action: Runnable): Boolean
         fun postOnAnimation(action: Runnable)
     }
 
@@ -151,13 +151,9 @@ internal class MatrixController(
         }
 
 
-    internal fun post(action: Runnable) {
-        callback.post(action)
-    }
+    internal fun post(action: Runnable) = callback.post(action)
 
-    internal fun postOnAnimation(action: Runnable) {
-        callback.postOnAnimation(action)
-    }
+    internal fun postOnAnimation(action: Runnable) = callback.postOnAnimation(action)
 
     /**
      * Clears our state.
@@ -213,7 +209,7 @@ internal class MatrixController(
     private fun sync() {
         stub.mapRect(contentScaledRect, contentRect)
     }
-    
+
     private fun dispatch() {
         callback.onMatrixUpdate()
     }