Home > Articles > Mobile Application Development & Programming

iOS Developer's Cookbook: Painting Sprite Kit

Don't waste time wallpapering your Sprite Kit scenes. Focus your time on actual game design and debugging. Simple class extensions enable you to apply UIKit pattern colors and images to your Sprite Kit nodes.
Like this article? We recommend

Sprite Kit lives in a country of its own. It sports its own currency, customs, and language. It's not exactly UIKit. It's not exactly AppKit. It's something different. Although certain classes and macros appear familiar, they often present unexpected difficulties. For example, consider SKColor. The SKColor macro resolves to UIColor on iOS and NSColor on OS X. It provides a convenient way to simplify cross-platform development. But (you knew there was a "but" coming) this cross-platform support works only with solid colors in the RGBA device color space.

#define SKColor UIColor
#define SKColor NSColor

So what happens when you want to paint in paisley? Many Sprite Kit node classes support some sort of color attribute, but to leverage UIColor's colorWithPatternImage: API (as in Figure 1) requires a little work.

Figure 1 To paint using a UIColor pattern involves a sprite-based workaround

Before showing the solution, take a quick look at the code that generated the right scene in Figure 1. In particular, notice how the color is applied. The paintedBackgroundColor property belongs to a custom SKNode category.

- (void) setup
    SKScene *scene = [SKScene sceneWithSize:skview.frame.size];
    UIImage *pattern = [UIImage imageNamed:@"Purple Paisley"];
    scene.paintedBackgroundColor = [UIColor colorWithPatternImage:pattern];
    ShadowLabelNode *label = [ShadowLabelNode labelNodeWithText:@"I am an SKScene"];
    label.fontSize = 20;
    label.fontColor = [UIColor purpleColor];
    [scene addChild:label];
    [label centerNodeInScene];
    [skview presentScene:scene];

Leveraging UIKit Drawing

Behind this property is the following code. It consists of a helper function that draws an image, creates a child sprite node with that image, and matches it to the size of the parent node.

NSString *const SceneryBackdrop = @"SceneryBackdrop";

- (void) updateBackgroundWithBlock: (void (^)()) block
    // Remove any existing background
    SKNode *background = [self childNodeWithName:SceneryBackdrop];
    if (background) [background removeFromParent];
    // Paint or draw
    UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0);
    if (block) block();
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    // Build a sprite node to present the texture
    SKTexture *texture = [SKTexture textureWithImage:image];
    SKSpriteNode *node = [SKSpriteNode spriteNodeWithTexture:texture size:image.size];
    node.name = SceneryBackdrop;
    node.anchorPoint = CGPointMake(0, 0);
    node.position = CGPointZero;

    // Add it at the back
    [self insertChild:node atIndex:0];
    node.zposition = -1; // adjust if you want it further back

- (void) setPaintedBackgroundColor:(UIColor *)SceneryBackdropColor
    [self updateBackgroundWithBlock:^(){
        [SceneryBackdropColor set];
        UIRectFill((CGRect){.size = self.frame.size});

To paint the background color, the setPaintedBackgroundColor: method passes a block with drawing instructions. The block sets the UIKit color and draws it using the UIKit UIRectFill() function. When drawn, the method converts the UIKit image to a Sprite Kit texture and creates a sprite node, making sure to name it with the reserved scenery backdrop keyword. The backdrop is always added at index 0, so it floats behind any other children in the node.

Keep in mind that Sprite Kit textures do not use screen-scale coding. A retina image produces a texture twice as big as its 1x scale sibling. This method uses the image size to scale the sprite node, ensuring that the point size of the sprite matches the point size of the source node. Although nodes offer xScale and yScale properties (and you can retrieve the calculateAccumulatedFrame property) I generally find it easier to work directly with the expected size.

The block-based approach used here makes it easy to add other drawn properties using UIKit calls. The following methods assign an image to be centered in the background (setBackgroundImage:) and one that fills the node's background (setScenery:). The node creation work is done by the helper method, so these methods concern themselves only with drawing operations. Because these blocks are quickly run and then disposed, they do not use any self-capture workarounds.

- (void) setScenery:(UIImage *)scenery
    [self updateBackgroundWithBlock:^() {
        CGRect rect = (CGRect){.size = scenery.size};
        CGRect bounds = (CGRect){.size = self.frame.size};
        rect = SKRectByFillingRect(rect, bounds);
        [scenery drawInRect:rect];

- (void) setBackgroundImage:(UIImage *)backgroundImage
    [self updateBackgroundWithBlock:^() {
        CGFloat screenScale = UIScreen.mainScreen.scale;
        CGFloat imageScale = backgroundImage.scale;
        CGSize size = backgroundImage.size;
        if ((imageScale == 1) && (screenScale != imageScale))
            size = CGSizeMake(backgroundImage.size.width / screenScale, 
                backgroundImage.size.height / screenScale);
        CGRect rect = SKRectCenteredInRect((CGRect){.size = size}, 
            (CGRect){.size = self.frame.size});
        [backgroundImage drawInRect:rect];

Painting Shape Nodes

You tweak this approach slightly to account for the SKShapeNode class. The first modification in the following method retrieves the instance's path. It uses it to clip its drawing, as in the first of the two screen shots in Figure 1. Clipping to the path enables the drawing to take place only within its edges. When working with complex shapes, remember to enable the path's even-odd fill rule for best results. (Tangentially, I did consider using a crop node here instead but found it wasn't really worth the extra effort.)

The second modification is specific to the way I personally create shape nodes. My shapes always center around CGPointZero. This ensures that position properties correspond to the center of the drawn shape. Updating the sprite node's anchor point to (0.5, 0.5) ensures the drawn image remains centered in its parent.

I use background drawing almost exclusively for SKScene and SKShapeNode instances, so this method might need adapting for other classes.

- (void) updateBackgroundWithBlock: (void (^)()) block
    // Remove any existing background
    SKNode *background = [self childNodeWithName:SceneryBackdrop];
    if (background) [background removeFromParent];
    // Paint or draw
    UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0);
    if ([self isKindOfClass:[SKShapeNode class]])
        SKShapeNode *node = (SKShapeNode *) self;
        // Fetch a drawing path
        UIBezierPath *path = [UIBezierPath bezierPathWithCGPath:node.path];
        [path applyTransform:CGAffineTransformMakeTranslation(
            -path.bounds.origin.x, -path.bounds.origin.y)];
        [path addClip];
    if (block) block();
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    // Build a sprite node to present the texture
    SKTexture *texture = [SKTexture textureWithImage:image];
    SKSpriteNode *node = [SKSpriteNode spriteNodeWithTexture:texture size:image.size];
    node.name = SceneryBackdrop;
    node.anchorPoint = CGPointMake(0, 0);
    if ([self isKindOfClass:[SKShapeNode class]]) node.anchorPoint = CGPointMake(0.5, 0.5);
    node.position = CGPointZero;
    // Add it at the back
    [self insertChild:node atIndex:0];
    node.zposition = -1; // adjust if you want it further back

Building a Debugging Backdrop

Figure 2 shows my standard debugging backdrop. It consists of two grids. A fine grid lays out 8-point texture blocks, enabling easy (if not exact) measurements to edges and between sprites. A second overlay, the 2-by-2 gray blocks, splits the SKScene into quadrants. This helps focus position checks on boundaries and centerlines.

Figure 2 A gridded backdrop enables you to check alignment and estimate point positions

The following method draws this placement backdrop. It uses the custom scenery property defined earlier in this write-up to add it to the SKScene instance. As you can see, this method takes advantage of UIKit drawing to produce an artifact that's quite useful for the Sprite Kit world.

- (void) drawPlacementBackdrop
    CGRect rect = self.frame;
    CGSize size = rect.size;
    CGSize small = CGSizeMake(16, 16);
    CGSize smaller = CGSizeMake(8, 8);
    // Create 8x8 grid pattern color
    UIGraphicsBeginImageContextWithOptions(small, NO, 0);
    [[UIColor whiteColor] set];
    UIRectFill((CGRect){.size = small});
    [[UIColor lightGrayColor] set];
    UIRectFill((CGRect){.size = smaller});
    UIRectFill((CGRect){.size = smaller, .origin = CGPointMake(smaller.width, smaller.height)});
    UIColor *patternColor = [UIColor colorWithPatternImage:

    // Draw backdrop
    UIGraphicsBeginImageContextWithOptions(size, NO, 0);
    UIColor *light = [[UIColor lightGrayColor] colorWithAlphaComponent:0.25];
    UIColor *dark = [[UIColor grayColor] colorWithAlphaComponent:0.25];
    // Fill bg with white
    [[UIColor whiteColor] set];
    // Lightly draw pattern over it
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:rect];
    [[patternColor colorWithAlphaComponent:0.15] set];
    [path fill];
    // Add left backsplash
    path = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, size.width / 2, size.height)];
    [light set];
    [path fill];
    // Add right backsplash
    path = [UIBezierPath bezierPathWithRect:
        CGRectMake(0, size.height / 2, size.width, size.height / 2)];
    [dark set];
    [path fill];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    self.scenery = image;


Applying patterns and easily drawing backdrops simplifies basic Sprite Kit development. Building this object category enabled me to move away from the fussy details of wallpapering my world to help focus on actual game design and debugging.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020