Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Multithreaded Drawing by Eric Lanz
Search
Triangle Cocoa
August 23, 2012
Programming
3
190
Multithreaded Drawing by Eric Lanz
Eric discusses multithreaded drawing with Core Graphics at CocoaHeads August in Raleigh
Triangle Cocoa
August 23, 2012
Tweet
Share
More Decks by Triangle Cocoa
See All by Triangle Cocoa
App Store Secrets by Lawrence Ingraham
trianglecocoa
1
250
iPhone 5 and You! by Ameir Al-Zoubi
trianglecocoa
0
160
Grand Central Dispatch by Jody Hagins
trianglecocoa
2
460
Instruments: Leaks by Trevor Brown
trianglecocoa
5
130
Foundation Collections by Kevin Conner
trianglecocoa
3
230
Unburdened ViewControllers by Jay Thrash
trianglecocoa
9
11k
Automated Acceptance Testing by Josh Johnson
trianglecocoa
4
160
Understanding UIResponder by Dirk Smith
trianglecocoa
5
280
Taming Xcode by Jay Thrash
trianglecocoa
3
130
Other Decks in Programming
See All in Programming
Writing documentation can be fun with plugin system
okuramasafumi
0
120
プログラミング言語学習のススメ / why-do-i-learn-programming-language
yashi8484
0
120
Pythonでもちょっとリッチな見た目のアプリを設計してみる
ueponx
1
480
ARA Ansible for the teams
kksat
0
150
SwiftUI Viewの責務分離
elmetal
PRO
0
140
Unity Android XR入門
sakutama_11
0
140
Rails アプリ地図考 Flush Cut
makicamel
1
110
JavaScriptツール群「UnJS」を5分で一気に駆け巡る!
k1tikurisu
10
1.8k
XStateを用いた堅牢なReact Components設計~複雑なClient Stateをシンプルに~ @React Tokyo ミートアップ #2
kfurusho
1
770
パスキーのすべて ── 導入・UX設計・実装の紹介 / 20250213 パスキー開発者の集い
kuralab
3
670
Software Architecture
hschwentner
6
2.1k
お前もAI鬼にならないか?👹Bolt & Cursor & Supabase & Vercelで人間をやめるぞ、ジョジョー!👺
taishiyade
5
3.8k
Featured
See All Featured
What's in a price? How to price your products and services
michaelherold
244
12k
What’s in a name? Adding method to the madness
productmarketing
PRO
22
3.3k
How to Ace a Technical Interview
jacobian
276
23k
Cheating the UX When There Is Nothing More to Optimize - PixelPioneers
stephaniewalter
280
13k
The Web Performance Landscape in 2024 [PerfNow 2024]
tammyeverts
4
400
[Rails World 2023 - Day 1 Closing Keynote] - The Magic of Rails
eileencodes
33
2.1k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
3
310
Thoughts on Productivity
jonyablonski
69
4.5k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
31
2.1k
Optimizing for Happiness
mojombo
376
70k
Scaling GitHub
holman
459
140k
Designing for Performance
lara
604
68k
Transcript
Multithreaded Drawing with core graphics Eric.Lanz @OrgBook.com
What you should do • Get an artist to make
all your graphics up front • Use tools like GraphicsMagick, OptiPng and PVRTC (OpenGL) • Use built in cache mechanisms • UIKit -> Core Animation -> OpenGL
What if you can’t • User defined image data at
run-time • Continuous animation responding to user interaction • Too much image data to pre-process and ship with the app
Know when to draw View Controllers Drawables Drawables Drawables Drawables
User Input • User triggers redraw • View controllers determine layout • Don’t directly call draw on a drawable
Synchronous Data API View Controllers Drawables Drawables Drawables Drawables Data
Controller User Input Core Data No Local Copy? Return a fake object while you wait for the API
Asynchronous Draw API View Controllers Drawables Drawables Drawables Drawables Data
Controller User Input Core Data Targeted NSNotifications: @”ObjectUpdate_XYZ”
Drawing Pipeline Render Controller Drawable • Drawable asks to be
drawn using some template • Entire operation contained in a block
Direct Draw Controller Drawable Direct Template Core Graphics Cache 1
Dispatch Serial Queue Draw Controller Drawable Dispatch_Serial Template Core Graphics
Cache 2 Create a serial dispatch queue, this will run one task at a time on a worker thread.
Dispatch Global Queue Draw Controller Drawable Dispatch_Global Template Core Graphics
Cache 3 Use the Global dispatch queue, this runs tasks concurrently on multiple worker threads.
All Together Now Draw Controller Drawable Dispatch_Global Template Core Graphics
Cache 3 Dispatch_Serial Template Core Graphics Cache 2 Direct Template Core Graphics Cache 1
Dispatch Serial Queue UIGraphicsPushContext(c); [[UIColor blackColor] setFill]; [@"Sample" drawInRect:CGRectMake(0, 4,
width, height) withFont:[UIFont fontWithName:@"Helvetica" size:fontSize] lineBreakMode:UILineBreakModeTailTruncation alignment:UITextAlignmentCenter]; UIGraphicsPopContext(); CGContextRelease(c); CGColorSpaceRelease(genericRGBColorspace); GLubyte *imageData = (GLubyte *) calloc(1, width * height * 4); CGColorSpaceRef genericRGBColorspace = CGColorSpaceCreateDeviceRGB(); CGContextRef c = CGBitmapContextCreate(imageData, width, height, 8, width * 4, genericRGBColorspace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
Dispatch Global CGContextScaleCTM(c, 1.0, -1.0); CGContextTranslateCTM(c, 0, -height); CGMutablePathRef circlePath
= CGPathCreateMutable(); CGPathAddEllipseInRect( circlePath , NULL , CGRectMake(1, 1, width-2, height-2) ); CGContextAddPath(c, circlePath); CGContextClip(c); UIImage * personImage = [UIImage imageWithContentsOfFile:path]; CGContextDrawImage(c, CGRectMake(0, 0, width, height), personImage.CGImage); CGContextRelease(c); CGColorSpaceRelease(genericRGBColorspace); GLubyte *imageData = (GLubyte *) calloc(1, width * height * 4); CGColorSpaceRef genericRGBColorspace = CGColorSpaceCreateDeviceRGB(); CGContextRef c = CGBitmapContextCreate(imageData, width, height, 8, width * 4, genericRGBColorspace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
Final Thoughts • No architecture is perfect • Maintain balance
• Make it easy to tweak • Don’t get lost in the details
Questions