Add new API variants to distribute views with optional insets to thei…

…r superview This commit also merges pull request #12 by @rahul-malik.
smileyborg · Apr 21, 2014 · 37b43ee · 37b43ee
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diff --git a/Example/Example/ALViewController.m b/Example/Example/ALViewController.m
@@ -88,7 +88,7 @@ - (void)setupDemo1
 
     [self.orangeView autoAlignAxisToSuperviewAxis:ALAxisVertical];
 
-    [subviews autoDistributeViewsAlongAxis:ALAxisVertical withFixedSize:30.0f alignment:NSLayoutFormatAlignAllCenterX];
+    [subviews autoDistributeViewsAlongAxis:ALAxisVertical withFixedSize:30.0f insetSpacing:YES alignment:NSLayoutFormatAlignAllCenterX];
 }
 
 /**
@@ -106,7 +106,7 @@ - (void)setupDemo2
 
     [self.orangeView autoAlignAxisToSuperviewAxis:ALAxisHorizontal];
 
-    [subviews autoDistributeViewsAlongAxis:ALAxisHorizontal withFixedSpacing:10.0f alignment:NSLayoutFormatAlignAllCenterY];
+    [subviews autoDistributeViewsAlongAxis:ALAxisHorizontal withFixedSpacing:10.0f insetSpacing:NO alignment:NSLayoutFormatAlignAllCenterY];
 }
 
 /**

diff --git a/README.md b/README.md
@@ -37,8 +37,8 @@ This is just a handy overview of the core API methods. Check out the [header fil
     - autoAlignViewsToAxis:
     - autoMatchViewsDimension:
     - autoSetViewsDimension:toSize:
-    - autoDistributeViewsAlongAxis:withFixedSpacing:alignment:
-    - autoDistributeViewsAlongAxis:withFixedSize:alignment:
+    - autoDistributeViewsAlongAxis:withFixedSpacing:(insetSpacing:)alignment:
+    - autoDistributeViewsAlongAxis:withFixedSize:(insetSpacing:)alignment:
 
 **`NSLayoutConstraint`**
 
@@ -115,6 +115,8 @@ Problems, Suggestions, Pull Requests?
 
 Bring 'em on! :)
 
+It's always a good idea to reach out before taking on any significant amount of changes or additions to the project. This allows everyone to get onboard with upcoming changes, ensures that changes align with the project's design philosophy, and avoids duplicated work.
+
 I'm especially interested in hearing about any common use cases that this API does not currently address. Feel free to add feature requests (and view current work in progress) on the [Feature Requests](https://github.com/smileyborg/UIView-AutoLayout/wiki/Feature-Requests) page of the wiki for this project.
 
 Meta

diff --git a/Source/UIView+AutoLayout.h b/Source/UIView+AutoLayout.h
@@ -266,9 +266,15 @@ typedef void(^ALConstraintsBlock)(void);    // a block of method calls to the UI
 /** Distributes the views in this array equally along the selected axis in their superview. Views will be the same size (variable) in the dimension along the axis and will have spacing (fixed) between them. */
 - (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat)spacing alignment:(NSLayoutFormatOptions)alignment;
 
+/** Distributes the views in this array equally along the selected axis in their superview. Views will be the same size (variable) in the dimension along the axis and will have spacing (fixed) between them, with optional insets from the first and last views to their superview. */
+- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat)spacing insetSpacing:(BOOL)shouldSpaceInsets alignment:(NSLayoutFormatOptions)alignment;
+
 /** Distributes the views in this array equally along the selected axis in their superview. Views will be the same size (fixed) in the dimension along the axis and will have spacing (variable) between them. */
 - (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSize:(CGFloat)size alignment:(NSLayoutFormatOptions)alignment;
 
+/** Distributes the views in this array equally along the selected axis in their superview. Views will be the same size (fixed) in the dimension along the axis and will have spacing (variable) between them, with optional insets from the first and last views to their superview. */
+- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSize:(CGFloat)size insetSpacing:(BOOL)shouldSpaceInsets alignment:(NSLayoutFormatOptions)alignment;
+
 @end
 
 

diff --git a/Source/UIView+AutoLayout.m b/Source/UIView+AutoLayout.m
@@ -1129,16 +1129,33 @@ - (NSArray *)autoSetViewsDimension:(ALDimension)dimension toSize:(CGFloat)size
 
 #pragma mark Distribute Multiple Views
 
+/**
+ Distributes the views in this array equally along the selected axis in their superview.
+ Views will be the same size (variable) in the dimension along the axis and will have spacing (fixed) between them,
+ including from the first and last views to their superview.
+ 
+ @param axis The axis along which to distribute the subviews.
+ @param spacing The fixed amount of spacing between each subview, before the first subview and after the last subview.
+ @param alignment The way in which the subviews will be aligned.
+ @return An array of constraints added.
+ */
+- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat)spacing alignment:(NSLayoutFormatOptions)alignment
+{
+    return [self autoDistributeViewsAlongAxis:axis withFixedSpacing:spacing insetSpacing:YES alignment:alignment];
+}
+
 /**
  Distributes the views in this array equally along the selected axis in their superview.
  Views will be the same size (variable) in the dimension along the axis and will have spacing (fixed) between them.
+ The first and last views can optionally be inset from their superview by the same amount of spacing as between views.
  
  @param axis The axis along which to distribute the subviews.
  @param spacing The fixed amount of spacing between each subview.
+ @param shouldSpaceInsets Whether the first and last views should be equally inset from their superview.
  @param alignment The way in which the subviews will be aligned.
  @return An array of constraints added.
  */
-- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat)spacing alignment:(NSLayoutFormatOptions)alignment
+- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat)spacing insetSpacing:(BOOL)shouldSpaceInsets alignment:(NSLayoutFormatOptions)alignment
 {
     NSAssert([self al_containsMinimumNumberOfViews:2], @"This array must contain at least 2 views to distribute.");
     ALDimension matchedDimension;
@@ -1159,39 +1176,61 @@ - (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSpacing:(CGFloat
             NSAssert(nil, @"Not a valid axis.");
             return nil;
     }
+    CGFloat leadingSpacing = shouldSpaceInsets ? spacing : 0.0;
+    CGFloat trailingSpacing = shouldSpaceInsets ? spacing : 0.0;
 
     NSMutableArray *constraints = [NSMutableArray new];
     UIView *previousView = nil;
     for (id object in self) {
         if ([object isKindOfClass:[UIView class]]) {
             UIView *view = (UIView *)object;
             if (previousView) {
+                // Second, Third, ... View
                 [constraints addObject:[view autoPinEdge:firstEdge toEdge:lastEdge ofView:previousView withOffset:spacing]];
                 [constraints addObject:[view autoMatchDimension:matchedDimension toDimension:matchedDimension ofView:previousView]];
                 [constraints addObject:[view al_alignToView:previousView withOption:alignment forAxis:axis]];
             }
             else {
-                [constraints addObject:[view autoPinEdgeToSuperviewEdge:firstEdge withInset:spacing]];
+                // First view
+                [constraints addObject:[view autoPinEdgeToSuperviewEdge:firstEdge withInset:leadingSpacing]];
             }
             previousView = view;
         }
     }
     if (previousView) {
-        [constraints addObject:[previousView autoPinEdgeToSuperviewEdge:lastEdge withInset:spacing]];
+        // Last View
+        [constraints addObject:[previousView autoPinEdgeToSuperviewEdge:lastEdge withInset:trailingSpacing]];
     }
     return constraints;
 }
 
 /**
  Distributes the views in this array equally along the selected axis in their superview.
- Views will be the same size (fixed) in the dimension along the axis and will have spacing (variable) between them.
+ Views will be the same size (fixed) in the dimension along the axis and will have spacing (variable) between them,
+ including from the first and last views to their superview.
  
  @param axis The axis along which to distribute the subviews.
  @param size The fixed size of each subview in the dimension along the given axis.
  @param alignment The way in which the subviews will be aligned.
  @return An array of constraints added.
  */
 - (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSize:(CGFloat)size alignment:(NSLayoutFormatOptions)alignment
+{
+    return [self autoDistributeViewsAlongAxis:axis withFixedSize:size insetSpacing:YES alignment:alignment];
+}
+
+/**
+ Distributes the views in this array equally along the selected axis in their superview.
+ Views will be the same size (fixed) in the dimension along the axis and will have spacing (variable) between them.
+ The first and last views can optionally be inset from their superview by the same amount of spacing as between views.
+ 
+ @param axis The axis along which to distribute the subviews.
+ @param size The fixed size of each subview in the dimension along the given axis.
+ @param shouldSpaceInsets Whether the first and last views should be equally inset from their superview.
+ @param alignment The way in which the subviews will be aligned.
+ @return An array of constraints added.
+ */
+- (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSize:(CGFloat)size insetSpacing:(BOOL)shouldSpaceInsets alignment:(NSLayoutFormatOptions)alignment
 {
     NSAssert([self al_containsMinimumNumberOfViews:2], @"This array must contain at least 2 views to distribute.");
     ALDimension fixedDimension;
@@ -1221,8 +1260,14 @@ - (NSArray *)autoDistributeViewsAlongAxis:(ALAxis)axis withFixedSize:(CGFloat)si
     for (NSInteger i = 0; i < numberOfViews; i++) {
         UIView *view = shouldFlipOrder ? views[numberOfViews - i - 1] : views[i];
         [constraints addObject:[view autoSetDimension:fixedDimension toSize:size]];
-        CGFloat multiplier = (i * 2.0f + 2.0f) / (numberOfViews + 1.0f);
-        CGFloat constant = (multiplier - 1.0f) * size / 2.0f;
+        CGFloat multiplier, constant;
+        if (shouldSpaceInsets) {
+            multiplier = (i * 2.0f + 2.0f) / (numberOfViews + 1.0f);
+            constant = (multiplier - 1.0f) * size / 2.0f;
+        } else {
+            multiplier = (i * 2.0f) / (numberOfViews - 1.0f);
+            constant = (-multiplier + 1.0f) * size / 2.0f;
+        }
         NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:view attribute:attribute relatedBy:NSLayoutRelationEqual toItem:commonSuperview attribute:attribute multiplier:multiplier constant:constant];
         [commonSuperview al_addConstraintUsingGlobalPriority:constraint];
         [constraints addObject:constraint];