From 30d17197c169d7dc1c8b210e6c43fbfd698cdad6 Mon Sep 17 00:00:00 2001
From: "Jakob L. Kreuze" <jakob@memeware.net>
Date: Thu, 20 Dec 2018 09:42:05 -0500
Subject: Initial pinch-to-zoom and tile revealing

---
 .../main/java/space/jakob/mines/GameActivity.kt    | 60 +++++++++++++++++++---
 1 file changed, 54 insertions(+), 6 deletions(-)

(limited to 'app/src/main/java/space/jakob')

diff --git a/app/src/main/java/space/jakob/mines/GameActivity.kt b/app/src/main/java/space/jakob/mines/GameActivity.kt
index 49b301e..7e8313c 100644
--- a/app/src/main/java/space/jakob/mines/GameActivity.kt
+++ b/app/src/main/java/space/jakob/mines/GameActivity.kt
@@ -16,33 +16,80 @@ import android.support.v7.app.AppCompatActivity
 import android.support.v4.view.GestureDetectorCompat
 import android.os.Bundle
 import android.view.GestureDetector
+import android.view.ScaleGestureDetector
 import android.view.MotionEvent
 import android.util.Log
 
 class GameActivity : AppCompatActivity() {
     lateinit var gameView: GameView
     lateinit var gestureDetector: GestureDetectorCompat
+    lateinit var scaleGestureDetector: ScaleGestureDetector
 
     // Implements the callbacks for gestureDetector.
     val gestureListener = object : GestureDetector.SimpleOnGestureListener() {
+        override fun onDown(e: MotionEvent): Boolean {
+            with (gameView) {
+                grid?.let {
+                    val (x, y) = toGridCoordinates(e.x.toInt(), e.y.toInt())
+                    it.reveal(x, y)
+                    invalidate()
+                }
+            }
+            return false
+        }
+
         override fun onScroll(e1: MotionEvent, e2: MotionEvent, dx: Float, dy: Float): Boolean {
             with (gameView) {
                 cameraX = (cameraX + dx / 100.0).coerceIn(0.0, gameView.maxCameraX)
                 cameraY = (cameraY + dy / 100.0).coerceIn(0.0, gameView.maxCameraY)
+                invalidate()
             }
-            gameView.invalidate()
             return false
         }
     }
 
-    override fun onTouchEvent(event: MotionEvent): Boolean {
-        return if (gestureDetector.onTouchEvent(event)) {
-            true
-        } else {
-            super.onTouchEvent(event)
+    // Implements the callbacks for scaleGestureDetector.
+    val scaleListener = object : ScaleGestureDetector.SimpleOnScaleGestureListener() {
+        override fun onScale(scaleGestureDetector: ScaleGestureDetector) : Boolean {
+            with (gameView) {
+                grid?.let {
+                    val factor = scaleGestureDetector.getScaleFactor()
+
+                    var currentDistance = sightX - cameraX
+                    var desiredDistance = currentDistance / factor
+                    var deltaDistance = Math.abs(desiredDistance - currentDistance) / 2
+
+                    if (factor < 1.0) {
+                        cameraX = (cameraX - deltaDistance).coerceAtLeast(0.0)
+                        sightX = (sightX + deltaDistance).coerceAtMost(it.width.toDouble() - cameraX)
+                    } else {
+                        cameraX = cameraX + deltaDistance
+                        sightX = sightX - deltaDistance
+                    }
+
+                    currentDistance = sightY - cameraY
+                    desiredDistance = currentDistance / factor
+                    deltaDistance = Math.abs(desiredDistance - currentDistance) / 2
+
+                    if (factor < 1.0) {
+                        cameraY = (cameraY - deltaDistance).coerceAtLeast(0.0)
+                        sightY = (sightY + deltaDistance).coerceAtMost(it.height.toDouble() - cameraY)
+                    } else {
+                        cameraY = cameraY + deltaDistance
+                        sightY = sightY - deltaDistance
+                    }
+                }
+            }
+            return false
         }
     }
 
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        return gestureDetector.onTouchEvent(event)
+            || scaleGestureDetector.onTouchEvent(event)
+            || super.onTouchEvent(event)
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_game)
@@ -61,5 +108,6 @@ class GameActivity : AppCompatActivity() {
         gameView.grid = Grid(width, height, mines)
 
         gestureDetector = GestureDetectorCompat(this, gestureListener)
+        scaleGestureDetector = ScaleGestureDetector(this, scaleListener)
     }
 }
-- 
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