fixed pixel-manipulation distortions on newly imported hi-res images

by normalizing (de-retinizing) costume thumbnails

HISTORY.md

@@ -12,6 +12,7 @@
     * changed default name for new costumes created with STRETCH etc. to localized 'costume'
 * **Notable Fixes:**
     * loading a project that fires STOP ALL from a WHEN hat block no longer "hangs" Snap
+    * fixed pixel-manipulation distortions on newly imported hi-res images
     * assert that dimensions given for STRETCH are finite numbers (avoid crash)
     * fixed occasional "dead clicks" on buttons and menu items
 * **Translation Updates:**
@@ -21,6 +22,7 @@
 ### 2019-10-22
 * morphic: url-clicking fix by @brollb, updated morphic documentation
 * pushed dev version to release-candidate status
+* objects: normalized (de-retinized) costume thumbnails, fixed pixel-manipulation distortions on newly imported hi-res images
 
 ### 2019-10-21
 * blocks, threads: new experimental entry for "green flag pressed" in the BROADCAST block's dropdown when the shift key is pressed

snap.html

@@ -8,7 +8,7 @@
         <script type="text/javascript" src="src/widgets.js?version=2019-10-16"></script>
         <script type="text/javascript" src="src/blocks.js?version=2019-10-21"></script>
         <script type="text/javascript" src="src/threads.js?version=2019-10-21"></script>
-        <script type="text/javascript" src="src/objects.js?version=2019-10-21"></script>
+        <script type="text/javascript" src="src/objects.js?version=2019-10-22"></script>
         <script type="text/javascript" src="src/gui.js?version=2019-10-22"></script>
         <script type="text/javascript" src="src/paint.js?version=2019-06-27"></script>
         <script type="text/javascript" src="src/lists.js?version=2019-07-01"></script>

src/objects.js

@@ -84,7 +84,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph,  BooleanSlotMorph,
 localize, TableMorph, TableFrameMorph, normalizeCanvas, VectorPaintEditorMorph,
 HandleMorph, AlignmentMorph, Process, XML_Element, WorldMap*/
 
-modules.objects = '2019-October-21';
+modules.objects = '2019-October-22';
 
 var SpriteMorph;
 var StageMorph;
@@ -9789,7 +9789,7 @@ Costume.prototype.thumbnail = function (extentPoint) {
         ),
         xOffset = (extentPoint.x - (src.width * scale)) / 2,
         yOffset = (extentPoint.y - (src.height * scale)) / 2,
-        trg = newCanvas(extentPoint),
+        trg = newCanvas(extentPoint, true),
         ctx = trg.getContext('2d');
 
     if (!src || src.width + src.height === 0) {return trg; }