From c49fe4d6a05bd32a0e2816bbd5887122027a1ba6 Mon Sep 17 00:00:00 2001
From: Julian Descottes <julian.descottes@gmail.com>
Date: Thu, 9 Jun 2016 11:05:59 +0200
Subject: [PATCH] Issue #483 - limit zoom to have 10 sprite pixels displayed on
 screen

---
 src/js/Constants.js                     | 2 --
 src/js/rendering/frame/FrameRenderer.js | 9 ++++++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/js/Constants.js b/src/js/Constants.js
index 90f0fd01..f6ac4519 100644
--- a/src/js/Constants.js
+++ b/src/js/Constants.js
@@ -14,8 +14,6 @@ var Constants = {
 
   MAX_PALETTE_COLORS : 100,
 
-  MINIMUM_ZOOM : 1,
-
   PREVIEW_FILM_SIZE : 96,
   ANIMATED_PREVIEW_WIDTH : 200,
 
diff --git a/src/js/rendering/frame/FrameRenderer.js b/src/js/rendering/frame/FrameRenderer.js
index 0ea7723b..c9b610ce 100644
--- a/src/js/rendering/frame/FrameRenderer.js
+++ b/src/js/rendering/frame/FrameRenderer.js
@@ -75,9 +75,12 @@
   };
 
   ns.FrameRenderer.prototype.setZoom = function (zoom) {
-    if (zoom < Constants.MINIMUM_ZOOM) {
-      zoom = Constants.MINIMUM_ZOOM;
-    }
+    // Minimum zoom is one to ensure one sprite pixel occupies at least one pixel on screen.
+    var minimumZoom = 1;
+    // Maximum zoom is relative to the display dimensions to ensure at least 10 pixels can
+    // be drawn on screen.
+    var maximumZoom = Math.min(this.displayWidth, this.displayHeight) / 10;
+    zoom = pskl.utils.Math.minmax(zoom, minimumZoom, maximumZoom);
 
     if (zoom == this.zoom) {
       return;