Initial version

.gitignore

@@ -1,6 +1,6 @@
 # Xcode
 #
-build/
+Demo/build/
 *.pbxuser
 !default.pbxuser
 *.mode1v3

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2015 mattga
+Copyright (c) 2015 Matthew Gardner
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

MGCollapsibleHeader.podspec

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+#
+#  Be sure to run `pod spec lint MGCollapsibleHeader.podspec' to ensure this is a
+#  valid spec and to remove all comments including this before submitting the spec.
+#
+#  To learn more about Podspec attributes see http://docs.cocoapods.org/specification.html
+#  To see working Podspecs in the CocoaPods repo see https://github.com/CocoaPods/Specs/
+#
+@version = "1.0.1"
+
+Pod::Spec.new do |s|
+
+  # ―――  Spec Metadata  ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  These will help people to find your library, and whilst it
+  #  can feel like a chore to fill in it's definitely to your advantage. The
+  #  summary should be tweet-length, and the description more in depth.
+  #
+
+  s.name         = "MGCollapsibleHeader"
+  s.version      = @version
+  s.summary      = "A short description of MGCollapsibleHeader."
+
+  # This description is used to generate tags and improve search results.
+  #   * Think: What does it do? Why did you write it? What is the focus?
+  #   * Try to keep it short, snappy and to the point.
+  #   * Write the description between the DESC delimiters below.
+  #   * Finally, don't worry about the indent, CocoaPods strips it!
+  s.description  = <<-DESC
+                   DESC
+
+  s.homepage     = "https://github.com/mattga/MGCollapsibleHeader"
+  s.screenshots  = "https://github.com/mattga/MGCollapsibleHeader/raw/master/Screenshots/mgcollapsibleheader_demo.gif"
+
+
+  # ―――  Spec License  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  Licensing your code is important. See http://choosealicense.com for more info.
+  #  CocoaPods will detect a license file if there is a named LICENSE*
+  #  Popular ones are 'MIT', 'BSD' and 'Apache License, Version 2.0'.
+  #
+
+  s.license      = { :type => "MIT", :file => "LICENSE" }
+
+
+  # ――― Author Metadata  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  Specify the authors of the library, with email addresses. Email addresses
+  #  of the authors are extracted from the SCM log. E.g. $ git log. CocoaPods also
+  #  accepts just a name if you'd rather not provide an email address.
+  #
+  #  Specify a social_media_url where others can refer to, for example a twitter
+  #  profile URL.
+  #
+
+  s.author             = { "Matthew Gardner" => "[email protected]" }
+  # Or just: s.author    = "Matthew Gardner"
+  # s.authors            = { "Matthew Gardner" => "[email protected]" }
+  # s.social_media_url   = "http://twitter.com/Matthew Gardner"
+
+  # ――― Platform Specifics ――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  If this Pod runs only on iOS or OS X, then specify the platform and
+  #  the deployment target. You can optionally include the target after the platform.
+  #
+
+  s.platform     = :ios
+  # s.platform     = :ios, "7.0"
+
+  #  When using multiple platforms
+  # s.ios.deployment_target = "5.0"
+  # s.osx.deployment_target = "10.7"
+  # s.watchos.deployment_target = "2.0"
+  # s.tvos.deployment_target = "9.0"
+
+
+  # ――― Source Location ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  Specify the location from where the source should be retrieved.
+  #  Supports git, hg, bzr, svn and HTTP.
+  #
+
+  s.source       = { :git => "https://github.com/mattga/MGCollapsibleHeader.git", :tag => "v#{s.version}" }
+
+
+  # ――― Source Code ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  CocoaPods is smart about how it includes source code. For source files
+  #  giving a folder will include any swift, h, m, mm, c & cpp files.
+  #  For header files it will include any header in the folder.
+  #  Not including the public_header_files will make all headers public.
+  #
+
+  s.header_mappings_dir = "Source"
+  s.source_files  = "Source/**/*.{h,m}"
+
+  # s.public_header_files = "Classes/**/*.h"
+
+
+  # ――― Resources ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  A list of resources included with the Pod. These are copied into the
+  #  target bundle with a build phase script. Anything else will be cleaned.
+  #  You can preserve files from being cleaned, please don't preserve
+  #  non-essential files like tests, examples and documentation.
+  #
+
+  # s.resource  = "icon.png"
+  # s.resources = "Resources/*.png"
+
+  # s.preserve_paths = "FilesToSave", "MoreFilesToSave"
+
+
+  # ――― Project Linking ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  Link your library with frameworks, or libraries. Libraries do not include
+  #  the lib prefix of their name.
+  #
+
+  # s.framework  = "SomeFramework"
+  # s.frameworks = "SomeFramework", "AnotherFramework"
+
+  # s.library   = "iconv"
+  # s.libraries = "iconv", "xml2"
+
+
+  # ――― Project Settings ――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
+  #
+  #  If your library depends on compiler flags you can set them in the xcconfig hash
+  #  where they will only apply to your library. If you depend on other Podspecs
+  #  you can include multiple dependencies to ensure it works.
+
+  # s.requires_arc = true
+
+  # s.xcconfig = { "HEADER_SEARCH_PATHS" => "$(SDKROOT)/usr/include/libxml2" }
+  # s.dependency "JSONKit", "~> 1.4"
+
+end

MGCollapsibleHeader/MGCollapsibleHeaderView.h

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+//
+//  The MIT License (MIT)
+//
+//  Copyright (c) 2015 Matthew Gardner
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+
+#import <UIKit/UIKit.h>
+
+@protocol MGCollapsibleHeaderDelegate <NSObject>
+
+- (void)headerDidCollapse;
+- (void)headerDidFinishCollapsing;
+- (void)headerDidExpand;
+- (void)headerDidFinishExpanding;
+
+@end
+
+// TODO: Transform Functions
+typedef enum : NSUInteger {
+    MGTransformCurveLinear = 0,
+    MGTransformCurveEaseIn,
+    MGTransformCurveEaseOut,
+    MGTransformCurveEaseInOut,
+} MGTransformCurve;
+
+/*!
+ * @typedef MGAttribute
+ * @brief Enumeration of attributes that can be transformed when scrolling.
+ * @constant MGAttributeX x-value of a view's origin.
+ * @constant MGAttributeY y-value of a view's origin.
+ * @constant MGAttributeWidth Width of a view.
+ * @constant MGAttributeHeight Height of a view.
+ * @constant MGAttributeAlpha Apha value of a view.
+ * @constant MGAttributeCornerRadius Corner radius of a view.
+ * @constant MGAttributeShadowRadius Shadow radius of a view.
+ * @constant MGAttributeCornerRadius Shadow opacity of a view.
+ */
+typedef enum : NSUInteger {
+    MGAttributeX = 1,
+    MGAttributeY,
+    MGAttributeWidth,
+    MGAttributeHeight,
+    MGAttributeAlpha,
+    MGAttributeCornerRadius,
+    MGAttributeShadowRadius,
+    MGAttributeShadowOpacity
+} MGAttribute;
+
+/*!
+ * @brief Defines an attribute to be transformed when scrolling.
+ */
+@interface MGTransformAttribute : NSObject
+
+@property (nonatomic) MGAttribute attribute;
+@property (nonatomic) MGTransformCurve curve;
+@property (nonatomic) CGFloat value, origValue, dValue;
+
++ (instancetype)attribute:(MGAttribute)attr value:(CGFloat)val;
+
+@end
+
+/*!
+ * @brief Subclass of UIView that manages collapsing and expanding.
+ */
+@interface MGCollapsibleHeaderView : UIView {
+    NSMutableArray *transfViews, *fadeViews;
+    NSMutableDictionary *constrs, *constrVals, *transfAttrs, *alphaRatios;
+    CGFloat lastOffset;
+    CGFloat header_ht, scroll_ht, offset_max;
+    NSLayoutConstraint *headerTop;
+}
+
+@property (nonatomic) CGFloat minimumHeaderHeight;
+
+@property (strong, nonatomic) NSLayoutConstraint *scrollViewTop;
+
+/*!
+ * @discussion Adds a subview of the header that transforms as the user scrolls.
+ * @param view The view to transform.
+ * @param attrs A dictionary of attributes that describe the view in it's condensed form.
+ Keys must be a MGAttribute; Values must be a double.
+ * @return Boolean identifying if the transform was successfully added.
+ */
+- (BOOL)addTransformingSubview:(UIView *)view attributes:(NSArray *)attrs;
+
+/*!
+ * @discussion Adds a subview of the header that fades as the user scrolls.
+ * @param view The view to fade away.
+ * @param ratio The ratio of collapsing at which the subview will finish fading away.
+ * @return Boolean identifying if the fading subview was successfully added.
+ */
+- (BOOL)addFadingSubview:(UIView *)view fadeBy:(CGFloat)ratio;
+
+/*!
+ * @discussion Tells the header to collapse with some offset. This should be called from
+ a scrollViewDidScroll call.
+ * @param offset The content offset of the scroll view.
+ */
+- (void)collapseToOffset:(CGPoint)offset;
+
+@end