Fixes #1450: a scroll view with non hiding legacy scrollbars would cr…

…ash if the document view had a size of 0 pixels in either dimension.
cappuccino · Feb 8, 2012 · fe70a55 · fe70a55 · Me1000 · Feb 8, 2012
1 parent c9d4089
commit fe70a55
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 2 deletions.
diff --git a/AppKit/CPScrollView.j b/AppKit/CPScrollView.j
@@ -1138,8 +1138,9 @@ var CPScrollerStyleGlobal                       = CPScrollerStyleOverlay,
         if (_scrollerStyle === CPScrollerStyleOverlay && hasHorizontalScroll)
             verticalScrollerHeight -= horizontalScrollerHeight;
 
+        var documentHeight = _CGRectGetHeight(documentFrame);
         [_verticalScroller setFloatValue:(difference.height <= 0.0) ? 0.0 : scrollPoint.y / difference.height];
-        [_verticalScroller setKnobProportion:_CGRectGetHeight(contentFrame) / _CGRectGetHeight(documentFrame)];
+        [_verticalScroller setKnobProportion:documentHeight > 0 ? _CGRectGetHeight(contentFrame) / documentHeight : 1.0];
         [_verticalScroller setFrame:_CGRectMake(_CGRectGetMaxX(contentFrame) - overlay, verticalScrollerY, verticalScrollerWidth, verticalScrollerHeight)];
     }
     else if (wasShowingVerticalScroller)
@@ -1155,8 +1156,10 @@ var CPScrollerStyleGlobal                       = CPScrollerStyleOverlay,
         if (_scrollerStyle === CPScrollerStyleOverlay && hasVerticalScroll)
             horizontalScrollerWidth -= verticalScrollerWidth;
 
+        var documentWidth = _CGRectGetWidth(documentFrame);
+
         [_horizontalScroller setFloatValue:(difference.width <= 0.0) ? 0.0 : scrollPoint.x / difference.width];
-        [_horizontalScroller setKnobProportion:_CGRectGetWidth(contentFrame) / _CGRectGetWidth(documentFrame)];
+        [_horizontalScroller setKnobProportion:documentWidth > 0 ? _CGRectGetWidth(contentFrame) / documentWidth : 1.0];
         [_horizontalScroller setFrame:_CGRectMake(_CGRectGetMinX(contentFrame), _CGRectGetMaxY(contentFrame) - overlay, horizontalScrollerWidth, horizontalScrollerHeight)];
     }
     else if (wasShowingHorizontalScroller)

diff --git a/Tests/AppKit/CPScrollViewTest.j b/Tests/AppKit/CPScrollViewTest.j
@@ -4,6 +4,21 @@
 {
 }
 
+/*!
+    Test that scroll views don't generate bad layouts when very small.
+*/
+- (void)testZeroSize
+{
+    var scrollView = [[CPScrollView alloc] initWithFrame:CGRectMakeZero()],
+        documentView = [[CPView alloc] initWithFrame:CGRectMake(0, 0, 0, 0)];
+    [scrollView setAutohidesScrollers:NO];
+    [scrollView setDocumentView:documentView];
+    [scrollView setScrollerStyle:CPScrollerStyleLegacy];
+    // If the layout operation leads to setKnobProportion:0/0 this will crash.
+    [[scrollView horizontalScroller] layoutSubviews];
+    [[scrollView verticalScroller] layoutSubviews];
+}
+
 - (void)testBothScrollersVisible
 {
     var scrollView = [[CPScrollView alloc] initWithFrame:CGRectMake(0.0, 0.0, 100.0, 100.0)];
@@ -200,3 +215,4 @@
 }
 
 @end
+