Changed calculation of x position in grid view to avoid position jitter

JNWCollectionView/JNWCollectionViewCell.m

@@ -157,15 +157,13 @@ - (NSImage *)backgroundImage {
 	return self.backgroundView.image;
 }
 
-- (void)mouseDown:(NSEvent *)theEvent {
-	[super mouseDown:theEvent];
-
+- (void)mouseDown:(NSEvent *)theEvent
+{
 	[self.collectionView mouseDownInCollectionViewCell:self withEvent:theEvent];
 }
 
-- (void)mouseUp:(NSEvent *)theEvent {
-	[super mouseUp:theEvent];
-
+- (void)mouseUp:(NSEvent *)theEvent
+{
 	[self.collectionView mouseUpInCollectionViewCell:self withEvent:theEvent];
 
 	if (theEvent.clickCount == 2) {

JNWCollectionView/JNWCollectionViewFramework.h

@@ -114,10 +114,16 @@ typedef NS_ENUM(NSInteger, JNWCollectionViewScrollPosition) {
 /// Tells the delegate that the specified index path has been scrolled to.
 - (void)collectionView:(JNWCollectionView *)collectionView didScrollToItemAtIndexPath:(NSIndexPath *)indexPath;
 
+- (void)collectionView:(JNWCollectionView *)collectionView willDisplayCell:(JNWCollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath;
+
 /// Tells the delegate that the cell for the specified index path has been put
 /// back into the reuse queue.
 - (void)collectionView:(JNWCollectionView *)collectionView didEndDisplayingCell:(JNWCollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath;
 
+/// Tells the delegate that the collection view is about to reload the cells,
+/// view size has already been calculated,
+/// gives the delegate the chance the update the scroll position
+- (void)collectionViewWillRelayoutCells:(JNWCollectionView *)collectionView;
 @end
 
 #pragma mark Reloading and customizing
@@ -184,18 +190,6 @@ typedef NS_ENUM(NSInteger, JNWCollectionViewScrollPosition) {
 /// Defaults to nil.
 @property (nonatomic, strong) JNWCollectionViewLayout *collectionViewLayout;
 
-/// The background color determines what is drawn underneath any cells that might be visible
-/// at the time. If this is a repeating pattern image, it will scroll along with the content.
-///
-/// Defaults to a white color.
-@property (nonatomic, strong) NSColor *backgroundColor;
-
-/// Whether or not the collection view draws the background color. If the collection view
-/// background color needs to be transparent, this should be disabled.
-///
-/// Defaults to YES.
-@property (nonatomic, assign) BOOL drawsBackground;
-
 #pragma mark - Information
 
 /// Returns the total number of sections.
@@ -267,6 +261,11 @@ typedef NS_ENUM(NSInteger, JNWCollectionViewScrollPosition) {
 /// Defaults to YES.
 @property (nonatomic, assign) BOOL allowsEmptySelection;
 
+/// If set to NO, the collection view will not extend the selection when using command and shift modifier keys
+///
+/// Defaults to YES.
+@property (nonatomic, assign) BOOL allowsMultipleSelection;
+
 /// Scrolls the collection view to the item at the specified path, optionally animated. The scroll position determines
 /// where the item is positioned on the screen.
 - (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(JNWCollectionViewScrollPosition)scrollPosition animated:(BOOL)animated;
@@ -276,6 +275,12 @@ typedef NS_ENUM(NSInteger, JNWCollectionViewScrollPosition) {
 /// desired, pass in JNWCollectionViewScrollPositionNone to prevent the scroll..
 - (void)selectItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(JNWCollectionViewScrollPosition)scrollPosition animated:(BOOL)animated;
 
+/// Selects the item at the specified index path, deselecting any other selected items in the process, optionally animated.
+/// The collection view will then scroll to that item in the position as determined by scrollPosition. If no scroll is
+/// desired, pass in JNWCollectionViewScrollPositionNone to prevent the scroll..
+/// extendSelection: A BOOL value that specifies whether to extend the current selection. Pass YES to extends the selection; NO replaces the current selection.
+- (void)selectItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(JNWCollectionViewScrollPosition)scrollPosition byExtendingSelection:(BOOL)extendSelection animated:(BOOL)animated;
+
 /// Selects all items in the collection view.
 - (void)selectAllItems;