Merge branch 'release/0.9'

CHTCollectionViewWaterfallLayout.h

@@ -186,6 +186,25 @@ extern NSString *const CHTCollectionElementKindSectionFooter;
  */
 - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section;
 
+/**
+ * Asks the delegate for the minimum spacing between colums in a secified section. If this method is not implemented, the
+ * minimumColumnSpacing property is used for all sections.
+ *
+ * @param collectionView
+ *   The collection view object displaying the waterfall layout.
+ * @param collectionViewLayout
+ *   The layout object requesting the information.
+ * @param section
+ *   The index of the section whose minimum interitem spacing is being requested.
+ *
+ * @discussion
+ *   If you do not implement this method, the waterfall layout uses the value in its minimumColumnSpacing property to determine the amount of space between columns in each section.
+ *
+ * @return
+ *   The minimum spacing between each column.
+ */
+- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumColumnSpacingForSectionAtIndex:(NSInteger)section;
+
 @end
 
 #pragma mark - CHTCollectionViewWaterfallLayout
@@ -287,6 +306,15 @@ extern NSString *const CHTCollectionElementKindSectionFooter;
  */
 @property (nonatomic, assign) CHTCollectionViewWaterfallLayoutItemRenderDirection itemRenderDirection;
 
+/**
+ *  @brief The minimum height of the collection view's content.
+ *  @discussion
+ *    The minimum height of the collection view's content. This could be used to allow hidden headers with no content.
+ *
+ *    Default: 0.f
+ */
+@property (nonatomic, assign) CGFloat minimumContentHeight;
+
 /**
  *  @brief The calculated width of an item in the specified section.
  *  @discussion

CHTCollectionViewWaterfallLayout.m

@@ -6,6 +6,7 @@
 //
 
 #import "CHTCollectionViewWaterfallLayout.h"
+#import "tgmath.h"
 
 NSString *const CHTCollectionElementKindSectionHeader = @"CHTCollectionElementKindSectionHeader";
 NSString *const CHTCollectionElementKindSectionFooter = @"CHTCollectionElementKindSectionFooter";
@@ -30,7 +31,12 @@ @interface CHTCollectionViewWaterfallLayout ()
 @implementation CHTCollectionViewWaterfallLayout
 
 /// How many items to be union into a single rectangle
-const NSInteger unionSize = 20;
+static const NSInteger unionSize = 20;
+
+static CGFloat CHTFloorCGFloat(CGFloat value) {
+  CGFloat scale = [UIScreen mainScreen].scale;
+  return floor(value * scale) / scale;
+}
 
 #pragma mark - Public Accessors
 - (void)setColumnCount:(NSInteger)columnCount {
@@ -113,7 +119,13 @@ - (CGFloat)itemWidthInSectionAtIndex:(NSInteger)section {
   }
   CGFloat width = self.collectionView.frame.size.width - sectionInset.left - sectionInset.right;
   NSInteger columnCount = [self columnCountForSection:section];
-  return floorf((width - (columnCount - 1) * self.minimumColumnSpacing) / columnCount);
+
+  CGFloat columnSpacing = self.minimumColumnSpacing;
+  if ([self.delegate respondsToSelector:@selector(collectionView:layout:minimumColumnSpacingForSectionAtIndex:)]) {
+    columnSpacing = [self.delegate collectionView:self.collectionView layout:self minimumColumnSpacingForSectionAtIndex:section];
+  }
+
+  return CHTFloorCGFloat((width - (columnCount - 1) * columnSpacing) / columnCount);
 }
 
 #pragma mark - Private Accessors
@@ -194,6 +206,13 @@ - (id)initWithCoder:(NSCoder *)aDecoder {
 - (void)prepareLayout {
   [super prepareLayout];
 
+  [self.headersAttribute removeAllObjects];
+  [self.footersAttribute removeAllObjects];
+  [self.unionRects removeAllObjects];
+  [self.columnHeights removeAllObjects];
+  [self.allItemAttributes removeAllObjects];
+  [self.sectionItemAttributes removeAllObjects];
+
   NSInteger numberOfSections = [self.collectionView numberOfSections];
   if (numberOfSections == 0) {
     return;
@@ -205,13 +224,6 @@ - (void)prepareLayout {
   // Initialize variables
   NSInteger idx = 0;
 
-  [self.headersAttribute removeAllObjects];
-  [self.footersAttribute removeAllObjects];
-  [self.unionRects removeAllObjects];
-  [self.columnHeights removeAllObjects];
-  [self.allItemAttributes removeAllObjects];
-  [self.sectionItemAttributes removeAllObjects];
-
   for (NSInteger section = 0; section < numberOfSections; section++) {
     NSInteger columnCount = [self columnCountForSection:section];
     NSMutableArray *sectionColumnHeights = [NSMutableArray arrayWithCapacity:columnCount];
@@ -235,6 +247,11 @@ - (void)prepareLayout {
       minimumInteritemSpacing = self.minimumInteritemSpacing;
     }
 
+    CGFloat columnSpacing = self.minimumColumnSpacing;
+    if ([self.delegate respondsToSelector:@selector(collectionView:layout:minimumColumnSpacingForSectionAtIndex:)]) {
+      columnSpacing = [self.delegate collectionView:self.collectionView layout:self minimumColumnSpacingForSectionAtIndex:section];
+    }
+
     UIEdgeInsets sectionInset;
     if ([self.delegate respondsToSelector:@selector(collectionView:layout:insetForSectionAtIndex:)]) {
       sectionInset = [self.delegate collectionView:self.collectionView layout:self insetForSectionAtIndex:section];
@@ -244,7 +261,7 @@ - (void)prepareLayout {
 
     CGFloat width = self.collectionView.frame.size.width - sectionInset.left - sectionInset.right;
     NSInteger columnCount = [self columnCountForSection:section];
-    CGFloat itemWidth = floorf((width - (columnCount - 1) * self.minimumColumnSpacing) / columnCount);
+    CGFloat itemWidth = CHTFloorCGFloat((width - (columnCount - 1) * columnSpacing) / columnCount);
 
     /*
      * 2. Section header
@@ -293,12 +310,12 @@ - (void)prepareLayout {
     for (idx = 0; idx < itemCount; idx++) {
       NSIndexPath *indexPath = [NSIndexPath indexPathForItem:idx inSection:section];
       NSUInteger columnIndex = [self nextColumnIndexForItem:idx inSection:section];
-      CGFloat xOffset = sectionInset.left + (itemWidth + self.minimumColumnSpacing) * columnIndex;
+      CGFloat xOffset = sectionInset.left + (itemWidth + columnSpacing) * columnIndex;
       CGFloat yOffset = [self.columnHeights[section][columnIndex] floatValue];
       CGSize itemSize = [self.delegate collectionView:self.collectionView layout:self sizeForItemAtIndexPath:indexPath];
       CGFloat itemHeight = 0;
       if (itemSize.height > 0 && itemSize.width > 0) {
-        itemHeight = floorf(itemSize.height * itemWidth / itemSize.width);
+        itemHeight = CHTFloorCGFloat(itemSize.height * itemWidth / itemSize.width);
       }
 
       attributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
@@ -354,11 +371,16 @@ - (void)prepareLayout {
   idx = 0;
   NSInteger itemCounts = [self.allItemAttributes count];
   while (idx < itemCounts) {
-    CGRect rect1 = ((UICollectionViewLayoutAttributes *)self.allItemAttributes[idx]).frame;
-    idx = MIN(idx + unionSize, itemCounts) - 1;
-    CGRect rect2 = ((UICollectionViewLayoutAttributes *)self.allItemAttributes[idx]).frame;
-    [self.unionRects addObject:[NSValue valueWithCGRect:CGRectUnion(rect1, rect2)]];
-    idx++;
+    CGRect unionRect = ((UICollectionViewLayoutAttributes *)self.allItemAttributes[idx]).frame;
+    NSInteger rectEndIndex = MIN(idx + unionSize, itemCounts);
+
+    for (NSInteger i = idx + 1; i < rectEndIndex; i++) {
+      unionRect = CGRectUnion(unionRect, ((UICollectionViewLayoutAttributes *)self.allItemAttributes[i]).frame);
+    }
+
+    idx = rectEndIndex;
+
+    [self.unionRects addObject:[NSValue valueWithCGRect:unionRect]];
   }
 }
 
@@ -371,6 +393,10 @@ - (CGSize)collectionViewContentSize {
   CGSize contentSize = self.collectionView.bounds.size;
   contentSize.height = [[[self.columnHeights lastObject] firstObject] floatValue];
 
+  if (contentSize.height < self.minimumContentHeight) {
+    contentSize.height = self.minimumContentHeight;
+  }
+
   return contentSize;
 }
 

CHTCollectionViewWaterfallLayout.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "CHTCollectionViewWaterfallLayout"
-  s.version      = "0.8"
+  s.version      = "0.9"
   s.summary      = "The waterfall (i.e., Pinterest-like) layout for UICollectionView."
   s.homepage     = "https://github.com/chiahsien/CHTCollectionViewWaterfallLayout"
   s.screenshots  = "https://raw.github.com/chiahsien/UICollectionViewWaterfallLayout/master/Screenshots/2-columns.png"

CHTCollectionViewWaterfallLayout.swift

@@ -11,19 +11,19 @@ import UIKit
 
 @objc protocol CHTCollectionViewDelegateWaterfallLayout: UICollectionViewDelegate{
 
-    func collectionView (collectionView: UICollectionView!,layout collectionViewLayout: UICollectionViewLayout,
+    func collectionView (collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,
         sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
 
-    optional func colletionView (collectionView: UICollectionView!, layout collectionViewLayout: UICollectionViewLayout,
+    optional func colletionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
         heightForHeaderInSection section: NSInteger) -> CGFloat
 
-    optional func colletionView (collectionView: UICollectionView!, layout collectionViewLayout: UICollectionViewLayout,
+    optional func colletionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
         heightForFooterInSection section: NSInteger) -> CGFloat
 
-    optional func colletionView (collectionView: UICollectionView!, layout collectionViewLayout: UICollectionViewLayout,
+    optional func colletionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
         insetForSectionAtIndex section: NSInteger) -> UIEdgeInsets
 
-    optional func colletionView (collectionView: UICollectionView!, layout collectionViewLayout: UICollectionViewLayout,
+    optional func colletionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
         minimumInteritemSpacingForSectionAtIndex section: NSInteger) -> CGFloat
 }
 
@@ -186,11 +186,11 @@ class CHTCollectionViewWaterfallLayout : UICollectionViewLayout{
                 self.headersAttributes.setObject(attributes, forKey: (section))
                 self.allItemAttributes.addObject(attributes)
 
-                top = CGRectGetMaxX(attributes.frame)
+                top = CGRectGetMaxY(attributes.frame)
             }
             top += sectionInset.top
             for var idx = 0; idx < self.columnCount; idx++ {
-                self.columnHeights.setObject(top, atIndexedSubscript: idx)
+                self.columnHeights[idx]=top;
             }
 
             /*
@@ -216,7 +216,7 @@ class CHTCollectionViewWaterfallLayout : UICollectionViewLayout{
                 attributes.frame = CGRectMake(xOffset, CGFloat(yOffset), itemWidth, itemHeight)
                 itemAttributes.addObject(attributes)
                 self.allItemAttributes.addObject(attributes)
-                self.columnHeights.setObject(CGRectGetMaxY(attributes.frame) + minimumInteritemSpacing, atIndexedSubscript: columnIndex)
+                self.columnHeights[columnIndex]=CGRectGetMaxY(attributes.frame) + minimumInteritemSpacing;
             }
             self.sectionItemAttributes.addObject(itemAttributes)
 
@@ -242,7 +242,7 @@ class CHTCollectionViewWaterfallLayout : UICollectionViewLayout{
             }
 
             for var idx = 0; idx < self.columnCount; idx++ {
-                self.columnHeights.setObject(top, atIndexedSubscript: idx)
+                self.columnHeights[idx] = top
             }
         }
 
@@ -280,7 +280,7 @@ class CHTCollectionViewWaterfallLayout : UICollectionViewLayout{
         return list.objectAtIndex(indexPath.item) as UICollectionViewLayoutAttributes
     }
 
-    override func layoutAttributesForSupplementaryViewOfKind(elementKind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes!{
+    override func layoutAttributesForSupplementaryViewOfKind(elementKind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes{
         var attribute = UICollectionViewLayoutAttributes()
         if elementKind == CHTCollectionElementKindSectionHeader{
             attribute = self.headersAttributes.objectForKey(indexPath.section) as UICollectionViewLayoutAttributes

README.md

@@ -80,6 +80,8 @@ Please let me know if your app is using this library. I'm glad to put your app o
 F3PiX is a series of apps which gives you a concise, curated collection of pictures by professional (Dutch) photographers according to a specific theme. You can use the pictures freely for your own work.
 * [GroupMe for iOS](https://itunes.apple.com/us/app/groupme/id392796698?mt=8)  
 GroupMe - A Home for All the Groups in Your Life.
+* [Flickr](https://itunes.apple.com/us/app/id328407587)  
+Access and organize your photos from anywhere.
 
 License
 -------