UIGraphicsImageRenderer Class

Reference

Definition

Namespace:: UIKit

Assembly:: Xamarin.iOS.dll

Important

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A UIGraphicsRenderer that produces images (see UIGraphicsPdfRendererFormat).

[Foundation.Register("UIGraphicsImageRenderer", true)]
[ObjCRuntime.Introduced(ObjCRuntime.PlatformName.iOS, 10, 0, ObjCRuntime.PlatformArchitecture.All, null)]
[ObjCRuntime.Introduced(ObjCRuntime.PlatformName.TvOS, 10, 0, ObjCRuntime.PlatformArchitecture.All, null)]
public class UIGraphicsImageRenderer : UIKit.UIGraphicsRenderer

type UIGraphicsImageRenderer = class
    inherit UIGraphicsRenderer

Inheritance: Object

NSObject

UIGraphicsRenderer
UIGraphicsImageRenderer

Attributes: RegisterAttribute IntroducedAttribute

Remarks

Introduced in iOS 10, the UIGraphicsImageRenderer allows custom drawing code that utilitizes wide color.

In versions prior to iOS 10, custom drawing was done by retrieving a CGContext, manipulating its state, and then retrieving the custom image. Now, the standard technique is to use CreateImage(Action<UIGraphicsImageRendererContext>), which takes an Action as an argument, allowing the developer to either pass in drawing code or use a lambda expression:

// Pre-iOS 10 drawing pattern
var size = new CGSize (100, 100);
UIGraphics.BeginImageContext (size);

// ... drawing statements here ...

UIGraphics.EndImageContext ();
image = UIGraphics.GetImageFromCurrentImageContext ();

// iOS 10 drawing model:

var r = new UIGraphicsImageRenderer(new CGSize(100, 100));

var img = r.CreateImage((UIGraphicsImageRendererContext ctxt) => 
    {
        var superRed = UIColor.FromDisplayP3(1.358f, -0.074f, -0.012f, 1.0f);
        superRed.SetFill();

        UIColor.Black.SetStroke();

        var path = new UIBezierPath();
        path.MoveTo(new CGPoint(10,10));
        path.AddLineTo(new CGPoint(90, 10));
        path.AddLineTo(new CGPoint(45, 90));
        path.ClosePath();
        path.Stroke();
        path.Fill();
    });

The new drawing method is still based on manipulating the state of a "current context" but instead of a CGContext it is now a subclass of UIGraphicsRendererContext (either UIGraphicsImageRendererContext or UIGraphicsPdfRendererContext). If necessary, developers can retrieve the current context as a CGContext using GetContext(UIGraphicsRendererFormat).

Constructors

UIGraphicsImageRenderer()	Default constructor, initializes a new instance of this class.
UIGraphicsImageRenderer(CGRect, UIGraphicsImageRendererFormat)
UIGraphicsImageRenderer(CGSize, UIGraphicsImageRendererFormat)
UIGraphicsImageRenderer(CGSize)
UIGraphicsImageRenderer(IntPtr)	A constructor used when creating managed representations of unmanaged objects; Called by the runtime.
UIGraphicsImageRenderer(NSObjectFlag)	Constructor to call on derived classes to skip initialization and merely allocate the object.

Properties

AllowsImageOutput	Whether this renderer outputs an image. (Inherited from UIGraphicsRenderer)
Class	(Inherited from NSObject)
ClassHandle	The handle for this class.
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)
Format	Gets the UIGraphicsRendererFormat used to create the renderer. (Inherited from UIGraphicsRenderer)
Handle	Handle (pointer) to the unmanaged object representation. (Inherited from NSObject)
IsDirectBinding	(Inherited from NSObject)
IsProxy	(Inherited from NSObject)
RetainCount	Returns the current Objective-C retain count for the object. (Inherited from NSObject)
Self	(Inherited from NSObject)
Superclass	(Inherited from NSObject)
SuperHandle	Handle used to represent the methods in the base class for this NSObject. (Inherited from NSObject)
Zone	(Inherited from NSObject)

Methods

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)
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)
CreateImage(Action<UIGraphicsImageRendererContext>)	Renders the `actions`UIGraphicsImageRenderer context as a UIImage
CreateJpeg(nfloat, Action<UIGraphicsImageRendererContext>)	Returns NSData whose content is a JPEG representation of the current graphics context.
CreatePng(Action<UIGraphicsImageRendererContext>)	Renders the `actions`UIGraphicsImageRenderer context as a PNG image.
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)
Equals(NSObject)	(Inherited from NSObject)
Equals(Object)	(Inherited from NSObject)
ExposedBindings()	(Inherited from NSObject)
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)
GetMethodForSelector(Selector)	(Inherited from NSObject)
GetNativeField(String)	Obsolete. (Inherited from NSObject)
GetNativeHash()	(Inherited from NSObject)
Init()	(Inherited from NSObject)
InitializeHandle(IntPtr, String)	(Inherited from NSObject)
InitializeHandle(IntPtr)	(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)
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, NSObject, Double, NSString[])	(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, NSObject)	(Inherited from NSObject)
PerformSelector(Selector, NSObject)	(Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean, NSString[])	(Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean)	(Inherited from NSObject)
PerformSelector(Selector)	(Inherited from NSObject)
PrepareForInterfaceBuilder()	(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, NSString)	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)
RemoveObserver(NSObject, String)	Stops the specified observer from receiving further notifications of changed values for the specified keyPath. (Inherited from NSObject)
RespondsToSelector(Selector)	Whether this object recognizes the specified selector. (Inherited from NSObject)
Run(Action<UIGraphicsRendererContext>, Action<UIGraphicsRendererContext>, NSError)	Performs the on the renderer's context and then runs . (Inherited from UIGraphicsRenderer)
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)
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

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

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