Merge pull request #965 from MrP/master

Fix issue #890 in applyConstraints

src/viewport.js

@@ -495,51 +495,40 @@ $.Viewport.prototype = {
                 bounds.width,
                 bounds.height);
 
-        var horizontalThreshold = this.visibilityRatio * newBounds.width;
-        var verticalThreshold   = this.visibilityRatio * newBounds.height;
-
         if (this.wrapHorizontal) {
             //do nothing
         } else {
-            var dx = 0;
+            var horizontalThreshold = this.visibilityRatio * newBounds.width;
-            var thresholdLeft = newBounds.x + (newBounds.width - horizontalThreshold);
+            var boundsRight = newBounds.x + newBounds.width;
-            if (this._contentBoundsNoRotate.x > thresholdLeft) {
-                dx = this._contentBoundsNoRotate.x - thresholdLeft;
-            }
-
             var contentRight = this._contentBoundsNoRotate.x + this._contentBoundsNoRotate.width;
-            var thresholdRight = newBounds.x + horizontalThreshold;
+            var leftDx = this._contentBoundsNoRotate.x - boundsRight + horizontalThreshold;
-            if (contentRight < thresholdRight) {
+            var rightDx = contentRight - newBounds.x - horizontalThreshold;
-                var newDx = contentRight - thresholdRight;
+
-                if (dx) {
+            if (horizontalThreshold > this._contentBoundsNoRotate.width) {
-                    dx = (dx + newDx) / 2;
+                newBounds.x += (leftDx + rightDx) / 2;
-                } else {
+            } else if (rightDx < 0) {
-                    dx = newDx;
+                newBounds.x += rightDx;
-                }
+            } else if (leftDx > 0) {
+                newBounds.x += leftDx;
             }
-            newBounds.x += dx;
         }
 
         if (this.wrapVertical) {
             //do nothing
         } else {
-            var dy = 0;
+            var verticalThreshold   = this.visibilityRatio * newBounds.height;
-            var thresholdTop = newBounds.y + (newBounds.height - verticalThreshold);
+            var boundsBottom = newBounds.y + newBounds.height;
-            if (this._contentBoundsNoRotate.y > thresholdTop) {
-                dy = this._contentBoundsNoRotate.y - thresholdTop;
-            }
-
             var contentBottom = this._contentBoundsNoRotate.y + this._contentBoundsNoRotate.height;
-            var thresholdBottom = newBounds.y + verticalThreshold;
+            var topDy = this._contentBoundsNoRotate.y - boundsBottom + verticalThreshold;
-            if (contentBottom < thresholdBottom) {
+            var bottomDy = contentBottom - newBounds.y - verticalThreshold;
-                var newDy = contentBottom - thresholdBottom;
+
-                if (dy) {
+            if (verticalThreshold > this._contentBoundsNoRotate.height) {
-                    dy = (dy + newDy) / 2;
+                newBounds.y += (topDy + bottomDy) / 2;
-                } else {
+            } else if (bottomDy < 0) {
-                    dy = newDy;
+                newBounds.y += bottomDy;
-                }
+            } else if (topDy > 0) {
+                newBounds.y += topDy;
             }
-            newBounds.y += dy;
         }
 
         if (this.viewer) {

test/modules/events.js

@@ -820,8 +820,8 @@
             Util.assessNumericValue(zoom, 0.002, epsilon,
                 "Zoom should not be prevented");
             Util.assertRectangleEquals(
+                new OpenSeadragon.Rect(-249.5, -0.25, 500, 0.5),
                 bounds,
-                new OpenSeadragon.Rect(-250, -0.25, 500, 0.5),
                 epsilon,
                 'Pan should not be prevented');
 

test/modules/viewport.js

@@ -437,8 +437,8 @@
             viewport.applyConstraints(true);
             var bounds = viewport.getBounds();
             Util.assertRectangleEquals(
-                bounds,
                 new OpenSeadragon.Rect(0.7, 0.7, 1, 1),
+                bounds,
                 EPSILON,
                 "Viewport.applyConstraints should move viewport.");
             start();
@@ -447,6 +447,27 @@
         viewer.open(DZI_PATH);
     });
 
+    asyncTest('applyConstraints with visibilityRatio = 1 shouldn\'t bounce around', function() {
+        var openHandler = function() {
+            viewer.removeHandler('open', openHandler);
+            var viewport = viewer.viewport;
+
+            viewport.visibilityRatio = 1;
+            viewport.zoomTo(0.5, undefined, true);
+            viewport.panBy(new OpenSeadragon.Point(0.75, 0), true);
+            viewport.applyConstraints(true);
+            var bounds = viewport.getBounds();
+            Util.assertRectangleEquals(
+                new OpenSeadragon.Rect(-0.5, 1, 2, 2),
+                bounds,
+                EPSILON,
+                "Viewport.applyConstraints should move viewport to the center, not to a side.");
+            start();
+        };
+        viewer.addHandler('open', openHandler);
+        viewer.open(TALL_PATH);
+    });
+
     asyncTest('applyConstraints with rotation', function() {
         var openHandler = function() {
             viewer.removeHandler('open', openHandler);