UIImage Class

Definition

Image representation in UIKit, with support for loading, saving and manipulating images.

[Foundation.Register("UIImage", true)]
public class UIImage : Foundation.NSObject, Foundation.INSItemProviderReading, Foundation.INSItemProviderWriting, Foundation.INSSecureCoding, IDisposable, UIKit.IUIAccessibilityIdentification, UIKit.IUIItemProviderPresentationSizeProviding
type UIImage = class
    inherit NSObject
    interface INSCoding
    interface INativeObject
    interface IDisposable
    interface INSItemProviderReading
    interface INSItemProviderWriting
    interface INSSecureCoding
    interface IUIAccessibilityIdentification
    interface IUIItemProviderPresentationSizeProviding
Inheritance
UIImage
Attributes
Implements

Remarks

Image objects do not provide direct access to the underlying image - they are immutable. The methods M:UIKit.UIImage.AsJPEG() or AsPNG() will provide the underlying image data as a JPEG or PNG.

To avoid issues with excessive memory use, UIImages objects should not be larger than 1024x1024 in size. Code-based manipulations such as resizing are not subject to this restriction.

It is possible that the system may purge UIImage objects to free up memory. If the UIImage is required later on by an application, it will be loaded again from its source file.

The following image formats are supported by the UIImage class:

  • .tiff:
  • .jpg, .jpeg:
  • .gif:
  • .bmp:
  • .ico:
  • .cur:
  • .xbm:

Starting with iOS 8, the M:UIKIt.UIImage.FromBundle(System.String,Foundation.NSBundle,UIKIt.UITraitCollection) method can be used to load a UIImage that takes into consideration a UITraitCollection. This can automatically load the proper image for the specified resolution.

Most of the members of this class can be used from a background thread, with a couple of exceptions (FromBundle methods that retrieve images from the bundle and use the built-in memory cache).

Constructors

UIImage()

Default constructor that initializes a new instance of this class with no parameters.

UIImage(CGImage)

Creates a new UIImage from the provided Core Graphics image.

UIImage(CGImage, nfloat, UIImageOrientation)
UIImage(CIImage)

Creates a new UIImage from the provided Core Image image.

UIImage(CIImage, nfloat, UIImageOrientation)

Constructs a new UIImage backed by the , scaled and oriented as specified.

UIImage(IntPtr)

A constructor used when creating managed representations of unmanaged objects; Called by the runtime.

UIImage(NSCoder)

A constructor that initializes the object from the data stored in the unarchiver object.

UIImage(NSData)

Creates a new UIImage from the provided image data.

UIImage(NSData, nfloat)

Constructs a UIImage from the provided data, scaled by the scale factor.

UIImage(NSObjectFlag)

Constructor to call on derived classes to skip initialization and merely allocate the object.

UIImage(String)

Creates a UIImage by loading from the provided file name.

Properties

AccessibilityActivationPoint

Gets or sets the screen coordinates of the activation point for this IUIAccessibilityIdentification element.

AccessibilityAttributedHint

Gets or sets the NSAttributedString for the accessibility hint.

AccessibilityAttributedLabel

Gets or sets the NSAttributedString used for the accessibility label.

AccessibilityAttributedValue

Gets or sets the NSAttributedString used for the accessibility value.

AccessibilityElementsHidden

Gets or sets whether accessibility elements contained in this IUIAccessibilityIdentification element are hidden.

AccessibilityFrame

Gets or sets the screen coordinates of the frame of this IUIAccessibilityIdentification element.

AccessibilityHint

Gets or sets a localized string that describes the result of an action.

AccessibilityIdentifier

Gets or sets an identifier that identifies this IUIAccessibilityIdentification element.

AccessibilityLabel

Gets or sets a localized string to identify this IUIAccessibilityIdentification element.

AccessibilityLanguage

Gets or sets the language for the AccessibilityLabel, AccessibilityValue, and AccessibilityHint of this IUIAccessibilityIdentification element.

AccessibilityNavigationStyle

Gets or sets the navigation style.

AccessibilityPath

Specifies screen coordinates for the path of an element that is used to highlight the element.

AccessibilityTraits

Gets or sets the accessibility traits that best characterize this IUIAccessibilityIdentification element.

AccessibilityValue

Specifies a localized string that contains the value of this IUIAccessibilityIdentification element.

AccessibilityViewIsModal

Gets or sets whether VoiceOver ignores elements in sibling views of this image object.

AlignmentRectInsets

Alignment metadata that provides hints for aligning the UIImage content.

AnnouncementDidFinishNotification

Notification constant for AnnouncementDidFinish

AnnouncementNotification

Gets the notification posted by an application that an announcement requires assistive technology.

AssistiveTechnologyKey

The string "UIAccessibilityAssistiveTechnologyKey" which can be used to distinguish accessibility notifications..

AssistiveTouchStatusDidChangeNotification

Notification constant for AssistiveTouchStatusDidChange

BoldTextStatusDidChangeNotification

Notification constant for BoldTextStatusDidChange

CapInsets

The portions of a image that are not resized when the image is stretched. Read-only.

CGImage

The underlying image data. Read-only.

CIImage

The underlying CIImage data. Read-only.

Class (Inherited from NSObject)
ClassHandle

The handle for this class.

ClosedCaptioningStatusDidChangeNotification

Notification constant for ClosedCaptioningStatusDidChange

CurrentScale

The scale of the image.

DarkerSystemColorsStatusDidChangeNotification

Notification constant for DarkerSystemColorsStatusDidChange

DebugDescription

A developer-meaningful description of this object.

(Inherited from NSObject)
Description

Description of the object, the Objective-C version of ToString.

(Inherited from NSObject)
Duration

The time interval to display the animated image. Read-only.

ElementFocusedNotification

Notification constant for ElementFocused

FlipsForRightToLeftLayoutDirection

Whether this image is mirrored when layout is right-to-left.

FocusedElementKey

A string constant used by accessibility APIs (see FocusedElement(String)) to identify the focused element.

GrayscaleStatusDidChangeNotification

Notification constant for GrayscaleStatusDidChange

GuidedAccessStatusDidChangeNotification

Notification constant for GuidedAccessStatusDidChange

Handle

Handle (pointer) to the unmanaged object representation.

(Inherited from NSObject)
HearingDevicePairedEarDidChangeNotification

Notification constant for HearingDevicePairedEarDidChange

ImageAsset

Gets an image asset with which the image is associated.

ImageRendererFormat

Gets the best UIGraphicsImageRendererFormat for the UIImage.

Images

An array of UIImage objects that make up an animated iamge.

InvertColorsStatusDidChangeNotification

Notification constant for InvertColorsStatusDidChange

IsAccessibilityElement

Gets or sets whether this image is an accessibility object that an assistive app can access.

IsDirectBinding (Inherited from NSObject)
IsProxy (Inherited from NSObject)
LayoutChangedNotification

Gets the notification posted by an application that the layout of a screen has changed.

LeftCapWidth

The width of the left cap.

MonoAudioStatusDidChangeNotification

Notification constant for MonoAudioStatusDidChange

NotificationSwitchControlIdentifier

Notification constant for NotificationSwitchContr

NotificationVoiceOverIdentifier

Notification constant for NotificationVoiceOv

Orientation

The orienation of the image. Read-only.

PageScrolledNotification

Gets the notification posted by an application that a scroll action has finished.

PauseAssistiveTechnologyNotification

Pauses assistive technology notifications.

PreferredPresentationSizeForItemProvider
ReadableTypeIdentifiers

Gets the array of Uniform Type Identifiers (UTIs) for the image.

ReduceMotionStatusDidChangeNotification

Notification constant for ReduceMotionStatusDidChange

ReduceTransparencyStatusDidChangeNotification

Notification constant for ReduceTransparencyStatusDidChange

RenderingMode

The default value is Automatic.

ResizingMode

The resizing mode used by the image.

ResumeAssistiveTechnologyNotification

Resumes assistive technology notifications.

RetainCount

Returns the current Objective-C retain count for the object.

(Inherited from NSObject)
ScreenChangedNotification

Gets the notification posted by an application that a new view appears that includes a major portion of the screen.

Self (Inherited from NSObject)
ShakeToUndoDidChangeNotification

Notification constant for ShakeToUndoDidChange

ShouldGroupAccessibilityChildren

Gets or sets whether VoiceOver groups elements that are children of this object regardless of their positions.

Size

The dimensions of the image. Read-only.

SpeakScreenStatusDidChangeNotification

Notification constant for SpeakScreenStatusDidChange

SpeakSelectionStatusDidChangeNotification

Notification constant for SpeakSelectionStatusDidChange

SpeechAttributeIpaNotation

Returns the IPA notation for the accessibility attributed string.

SpeechAttributeLanguage

Gets a BCP-47 language code.

SpeechAttributePitch

Gets the value from 0.0 to 2.0 that determines the pitch for a spoken string.

SpeechAttributePunctuation

Gets a value to be interpreted as a bool that determines whether the punctuation in a string is pronounced.

SpeechAttributeQueueAnnouncement

Key for option that spoken text interrupt existing spoken content.

Superclass (Inherited from NSObject)
SuperHandle

Handle used to represent the methods in the base class for this NSObject.

(Inherited from NSObject)
SwitchControlStatusDidChangeNotification

Notification constant for SwitchControlStatusDidChange

TextAttributeCustom

Key for option that custom attributes be applied to the accessibility text.

TextAttributeHeadingLevel

Key for option of the accessibility text's heading level.

TopCapHeight

The height of the top cap (non-resizable area).

TraitAdjustable

Gets a trait that allows continuous adjustment of an accessibility element through a range of values.

TraitAllowsDirectInteraction

Gets a trait that allows direct touch interaction for users.

TraitButton

Gets a trait that indicates that this IUIAccessibilityIdentification element should be treated as a button.

TraitCausesPageTurn

Gets a trait that indicates that this IUIAccessibilityIdentification element should turn the page when VoiceOver finishes that page.

TraitCollection

Returns a trait collection.

TraitHeader

Gets a trait that indicates that this IUIAccessibilityIdentification element is a header that divides content into sections.

TraitImage

Gets a trait that indicates that this IUIAccessibilityIdentification element should be treated as an image.

TraitKeyboardKey

Gets a trait that indicates that this IUIAccessibilityIdentification element acts like a keyboard key.

TraitLink

Gets a trait that indicates that this IUIAccessibilityIdentification element should be considered a link.

TraitNone

Gets a trait that indicates that this IUIAccessibilityIdentification element has no traits.

TraitNotEnabled

Gets a trait that indicates that this IUIAccessibilityIdentification element is not enabled.

TraitPlaysSound

Gets a trait that indicates that this IUIAccessibilityIdentification elements plays its own sound when activated.

TraitSearchField

Gets a trait that indicates that this IUIAccessibilityIdentification element should be considered a search field.

TraitSelected

Gets a trait that indicates that this IUIAccessibilityIdentification element is selected.

TraitStartsMediaSession

Gets a trait that indicates that this IUIAccessibilityIdentification element starts a media session when it is activated.

TraitStaticText

Gets a trait that indicates that this IUIAccessibilityIdentification element should be treated as static text.

TraitSummaryElement

Gets a trait that provides summary information when an application starts.

TraitTabBar
TraitUpdatesFrequently

Gets a trait that indicates that this IUIAccessibilityIdentification element updates its AccessibilityLabel or AccessibilityValue.

UnfocusedElementKey

A string constant used by accessibility APIs (see FocusedElement(String)) to identify the previously focused element.

VoiceOverStatusChanged

Developers should not use this deprecated property. Developers should use 'VoiceOverStatusDidChangeNotification' instead.

VoiceOverStatusDidChangeNotification

Notification constant for VoiceOverStatusDidChange

WritableTypeIdentifiers

Gets the array of uniform type identifiers that specify which data types can be loaded into a color.

WritableTypeIdentifiersForItemProvider

Gets the array of uniform type identifiers that specify which data types can be loaded into a color.

Zone (Inherited from NSObject)

Methods

AccessibilityActivate()

Activates accessibility for this UIImage, returning true on success.

AddObserver(NSObject, NSString, NSKeyValueObservingOptions, IntPtr)

Registers an object for being observed externally (using NSString keyPath).   Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method.

(Inherited from NSObject)
AddObserver(NSObject, String, NSKeyValueObservingOptions, IntPtr)

Registers an object for being observed externally (using string keyPath).   Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method.

(Inherited from NSObject)
AddObserver(NSString, NSKeyValueObservingOptions, Action<NSObservedChange>)

Registers an object for being observed externally using an arbitrary method.

(Inherited from NSObject)
AddObserver(String, NSKeyValueObservingOptions, Action<NSObservedChange>)

Registers an object for being observed externally using an arbitrary method.

(Inherited from NSObject)
AsJPEG()

Encodes the image with minimal compression (maximum quality) into a NSData byte blob using the JPEG encoding.

AsJPEG(nfloat)

Encodes the image into a NSData byte blob using the JPEG encoding.

AsPNG()

Encodes the image into a NSData byte blob using the PNG encoding.

AwakeFromNib()

Called after the object has been loaded from the nib file. Overriders must call base.AwakeFromNib().

(Inherited from NSObject)
BeginInvokeOnMainThread(Action) (Inherited from NSObject)
BeginInvokeOnMainThread(Selector, NSObject)

Invokes asynchrously the specified code on the main UI thread.

(Inherited from NSObject)
Bind(NSString, NSObject, String, NSDictionary) (Inherited from NSObject)
Bind(String, NSObject, String, NSDictionary)
Obsolete.
(Inherited from NSObject)
BindingInfo(String)
Obsolete.
(Inherited from NSObject)
BindingOptionDescriptions(String)
Obsolete.
(Inherited from NSObject)
BindingValueClass(String)
Obsolete.
(Inherited from NSObject)
CommitEditing() (Inherited from NSObject)
CommitEditing(NSObject, Selector, IntPtr) (Inherited from NSObject)
ConformsToProtocol(IntPtr)

Invoked to determine if this object implements the specified protocol.

(Inherited from NSObject)
Copy()

Performs a copy of the underlying Objective-C object.

(Inherited from NSObject)
CreateAnimatedImage(String, Double)

Creates an animated image from a series of files.

CreateAnimatedImage(String, UIEdgeInsets, Double)

Creates a new animated image by loading a set of identically sized and scaled image files that have names that begin with name and that have sequential numerical suffixes.

CreateAnimatedImage(String, UIEdgeInsets, UIImageResizingMode, Double)

Factory method to create an animated image with end caps and the specified resizingMode.

CreateAnimatedImage(UIImage[], Double)

This method will create a animated image from a collection of images.

CreateResizableImage(UIEdgeInsets)

Creates a new image from the current instance and applies the specified cap insets.

CreateResizableImage(UIEdgeInsets, UIImageResizingMode)

Creates a new image, based on the current, with the specified capInsets and resizingMode.

DangerousAutorelease() (Inherited from NSObject)
DangerousRelease() (Inherited from NSObject)
DangerousRetain() (Inherited from NSObject)
DidChange(NSKeyValueChange, NSIndexSet, NSString)

Indicates a change occurred to the indexes for a to-many relationship.

(Inherited from NSObject)
DidChange(NSString, NSKeyValueSetMutationKind, NSSet) (Inherited from NSObject)
DidChangeValue(String)

Indicates that a change occurred on the specified key.

(Inherited from NSObject)
Dispose()

Releases the resources used by the NSObject object.

(Inherited from NSObject)
Dispose(Boolean)

Releases the resources used by the NSObject object.

(Inherited from NSObject)
DoesNotRecognizeSelector(Selector)

Indicates that this object does not recognize the specified selector.

(Inherited from NSObject)
Draw(CGPoint)

Draws the image at the specified position.

Draw(CGPoint, CGBlendMode, nfloat)

Draws the UIImage into the current graphics context at the specified , with blending mode and alpha as specified.

Draw(CGRect)

This method will draw the image (scaling as necessary) in the rectangle specified.

Draw(CGRect, CGBlendMode, nfloat)

Draws the UIImage into the current graphics context in the specified , with blending mode and alpha as specified.

DrawAsPatternInRect(CGRect)

This method will draw an image in the specified rectangle.

EncodeTo(NSCoder)

Encodes the state of the object on the provided encoder

Equals(NSObject) (Inherited from NSObject)
Equals(Object) (Inherited from NSObject)
ExposedBindings() (Inherited from NSObject)
FromBundle(String)

Loads an image relative to the application bundle, and caches its result.

FromBundle(String, NSBundle, UITraitCollection)

Gets an image from the specified bundle that is compatible with the specified trait collection.

FromFile(String)

Create an image object from the specified file.

FromImage(CGImage)

Creates a new image oject from a Quartz image.

FromImage(CGImage, nfloat, UIImageOrientation)

Static factory method to create a UIImage backed by the specified , scaled and oriented as specified.

FromImage(CIImage)

Factory method to create a UIImage from a Core Image CIImage.

FromImage(CIImage, nfloat, UIImageOrientation)

Static factory method to create a UIImage backed by the specified , scaled and oriented as specified.

FromResource(Assembly, String)

Loads an image from a resource embedded in the assembly.

GetBindingInfo(NSString) (Inherited from NSObject)
GetBindingOptionDescriptions(NSString) (Inherited from NSObject)
GetBindingValueClass(NSString) (Inherited from NSObject)
GetDictionaryOfValuesFromKeys(NSString[])

Retrieves the values of the specified keys.

(Inherited from NSObject)
GetHashCode()

Generates a hash code for the current instance.

(Inherited from NSObject)
GetImageFlippedForRightToLeftLayoutDirection()

Developers can override this method to provide an appropriate image for left-to-right layouts.

GetImageWithHorizontallyFlippedOrientation()

Returns a mirror-image copy of this UIImage.

GetItemProviderVisibilityForTypeIdentifier(String)

Gets the default representation visibility for the UTI .

GetMethodForSelector(Selector) (Inherited from NSObject)
GetNativeField(String)
Obsolete.
(Inherited from NSObject)
GetNativeHash() (Inherited from NSObject)
GetObject(NSData, String, NSError)

Static factory method to create a UIImage from , with being the appropriate UTI.

ImageWithAlignmentRectInsets(UIEdgeInsets)

Creates a UIImage based on this, with the specified alignmentInsets.

ImageWithRenderingMode(UIImageRenderingMode)

Creates a UIImage based on the current one, with the specified renderingMode.

Init() (Inherited from NSObject)
InitializeHandle(IntPtr) (Inherited from NSObject)
InitializeHandle(IntPtr, String) (Inherited from NSObject)
Invoke(Action, Double) (Inherited from NSObject)
Invoke(Action, TimeSpan) (Inherited from NSObject)
InvokeOnMainThread(Action) (Inherited from NSObject)
InvokeOnMainThread(Selector, NSObject)

Invokes synchrously the specified code on the main UI thread.

(Inherited from NSObject)
IsEqual(NSObject) (Inherited from NSObject)
IsKindOfClass(Class) (Inherited from NSObject)
IsMemberOfClass(Class) (Inherited from NSObject)
LoadData(String, Action<NSData,NSError>)

Loads data for the identified type from an item provider.

LoadDataAsync(String)

Asynchronously loads data for the identified type from an item provider, returning a task that contains the data.

LoadDataAsync(String, NSProgress)

Asynchronously loads data for the identified type from an item provider, returning a task that contains the data, and storing the data in result.

LoadFromData(NSData)

Will create an image from data that originated from a file or was programmatically created.

LoadFromData(NSData, nfloat)

Factory method to create a UIImage from the provided data, at the specified scale.

MarkDirty()

Promotes a regular peer object (IsDirectBinding is true) into a toggleref object.

(Inherited from NSObject)
MutableCopy()

Creates a mutable copy of the specified NSObject.

(Inherited from NSObject)
ObjectDidEndEditing(NSObject) (Inherited from NSObject)
ObserveValue(NSString, NSObject, NSDictionary, IntPtr)

Indicates that the value at the specified keyPath relative to this object has changed.

(Inherited from NSObject)
PerformSelector(Selector) (Inherited from NSObject)
PerformSelector(Selector, NSObject) (Inherited from NSObject)
PerformSelector(Selector, NSObject, Double)

Invokes the selector on the current instance and if the obj is not null, it passes this as its single parameter.

(Inherited from NSObject)
PerformSelector(Selector, NSObject, Double, NSString[]) (Inherited from NSObject)
PerformSelector(Selector, NSObject, NSObject) (Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean) (Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean, NSString[]) (Inherited from NSObject)
PrepareForInterfaceBuilder() (Inherited from NSObject)
RemoveObserver(NSObject, NSString)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath.

(Inherited from NSObject)
RemoveObserver(NSObject, NSString, IntPtr)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context.

(Inherited from NSObject)
RemoveObserver(NSObject, String)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath.

(Inherited from NSObject)
RemoveObserver(NSObject, String, IntPtr)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context.

(Inherited from NSObject)
RespondsToSelector(Selector)

Whether this object recognizes the specified selector.

(Inherited from NSObject)
SaveToPhotosAlbum(UIImage+SaveStatus)

Saves the specified image into the Photos Album.

Scale(CGSize)

Scales the image up or down.

Scale(CGSize, nfloat)

Scales the image up or down.

SetNativeField(String, NSObject)
Obsolete.
(Inherited from NSObject)
SetNilValueForKey(NSString)

Sets the value of the specified key to null.

(Inherited from NSObject)
SetValueForKey(NSObject, NSString)

Sets the value of the property specified by the key to the specified value.

(Inherited from NSObject)
SetValueForKeyPath(IntPtr, NSString)

A constructor used when creating managed representations of unmanaged objects; Called by the runtime.

(Inherited from NSObject)
SetValueForKeyPath(NSObject, NSString)

Sets the value of a property that can be reached using a keypath.

(Inherited from NSObject)
SetValueForUndefinedKey(NSObject, NSString)

Indicates an attempt to write a value to an undefined key. If not overridden, raises an NSUndefinedKeyException.

(Inherited from NSObject)
SetValuesForKeysWithDictionary(NSDictionary)

Sets the values of this NSObject to those in the specified dictionary.

(Inherited from NSObject)
StretchableImage(nint, nint)

Creates a stretchable image with the specified parameters. Deprecated in iOS 5, but still useful since the replacement is known to have bugs.

ToString()

Returns a string representation of the value of the current instance.

(Inherited from NSObject)
Unbind(NSString) (Inherited from NSObject)
Unbind(String)
Obsolete.
(Inherited from NSObject)
ValueForKey(NSString)

Returns the value of the property associated with the specified key.

(Inherited from NSObject)
ValueForKeyPath(NSString)

Returns the value of a property that can be reached using a keypath.

(Inherited from NSObject)
ValueForUndefinedKey(NSString)

Indicates an attempt to read a value of an undefined key. If not overridden, raises an NSUndefinedKeyException.

(Inherited from NSObject)
WillChange(NSKeyValueChange, NSIndexSet, NSString)

Indicates that the values of the specified indices in the specified key are about to change.

(Inherited from NSObject)
WillChange(NSString, NSKeyValueSetMutationKind, NSSet) (Inherited from NSObject)
WillChangeValue(String)

Indicates that the value of the specified key is about to change.

(Inherited from NSObject)

Extension Methods

GetItemProviderVisibilityForTypeIdentifier(INSItemProviderWriting, String)
GetWritableTypeIdentifiersForItemProvider(INSItemProviderWriting)
LoadDataAsync(INSItemProviderWriting, String)
LoadDataAsync(INSItemProviderWriting, String, NSProgress)
GetDebugDescription(INSObjectProtocol)
GetAccessibilityCustomRotors(NSObject)

Gets the array of UIAccessibilityCustomRotor objects appropriate for this object.

SetAccessibilityCustomRotors(NSObject, UIAccessibilityCustomRotor[])

Sets the array of UIAccessibilityCustomRotor objects appropriate for this object.

Applies to

See also