Fluid User Interface with Hardware Acceleration

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Fluid User Interface with Hardware Acceleration Ariya Hidayat San Francisco
Feb 22, 2013 @ariyahidayat 1

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Magical Advice Use translate3d for hardware acceleration 3

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whoami 4

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CSS3 5

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Web Browser from 10,000 ft 6

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Browser: High Level User Interface Browser Engine Graphics Stack Data
Persistence Render Engine JavaScript Engine Networking I/O 7

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From Contents to Pixels HTML Parser DOM CSS Parser HTML
Style Sheets DOM Tree Style Rules Render Tree Render Layout Paint http://www.html5rocks.com/en/tutorials/internals/howbrowserswork 8

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DOM Tree <html><body><p>Hello</p></body></html> HTMLDocument HTMLBodyElement HTMLParagraphElement attributes, children, contents 9

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DOM Tree vs Render Tree HTMLDocument HTMLBodyElement HTMLParagraphElement RenderRoot RenderBody
RenderText tree structure/navigation metrics (box model) hit testing RenderStyle computed style many:1 10

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Style Recalc vs Layout document.getElementById('box').style.top = '100px'; Aggregated “dirty” area
document.getElementById('box').style.backgroundColor = 'red'; No layout necessary, metrics are not ﬂagged as “changed” 11

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Minimizing Layout http://gent.ilcore.com/2011/03/how-not-to-trigger-layout-in-webkit.html http://code.google.com/p/chromium/source/search?q=%22-%3EupdateLayoutIgnorePendingStylesheets()%22 clientHeight clientLeft clientTop clientWidth offsetHeight offsetLeft
offsetParent offsetTop offsetWidth scrollLeft scrollTop scrollWidth innerText outerText Element focus() getBoundingClientRect() getClientRects() scrollByLines() scrollByPages() scrollHeight scrollIntoView() scrollIntoViewIfNeeded() 12

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CSS Painting: 10 Stages http://www.w3.org/TR/CSS2/zindex.html Appendix E. Elaborate description of
Stacking Contexts • Background • Floats • Foreground • Selection • Outline Done by the render objects (in the render tree) 13

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Graphics Stack: Crash Course 14

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Path is Everything 15

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Stroke = Outline Solid Dashed Dotted Textured 16

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Brush = Fill Solid None Gradient Textured 17

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Path Approximation Curves Polygon 18

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Antialiasing 19

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Transformation Scaling Rotation Perspective 20

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Graphics Processing Unit “Fixed” geometry Transformation Textured triangles Parallelism 21

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Optimized for Games http://epicgames.com/technology/epic-citadel http://www.rage.com/ 22

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GPU Workﬂow Vertices Rendered Textured Matrix 23

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Web Page Rendering 24

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Game vs Web Page Predictable contents (assets) ✔ Mostly text
✔ Mostly images ✔ immediate Initial response 25

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GPU Physical Limitations • Memory: Can’t store too much stuff
• Speed: Quad-core CPU can do certain operations better • Bandwidth: Data transfer can be the bottleneck • Power: Electrons always need energy 26

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Fluid Animation At the beginning, push as many resources as
possible to the GPU During the animation, minimize the interaction between CPU-GPU 1 2 27

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Immediate vs Retained draw the shape at (x, y) x
= x + 10 blit the buffer at (x, y) x = x + 10 For every animation tick... At the beginning... draw the shape onto a buffer Off main thread 28

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Animation Mechanics Initialization Animation step “Hey, this is good stuff.
Cache it as texture #42.” “Apply [operation] to texture #42.” Animation loop 29

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Element = Layer http://www.webkit.org/blog-ﬁles/leaves/ 30

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Compositing: “Logical” 3-D Compositor Tweening Actual operation 31

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By Force transform: translateZ(0) Not needed for CSS animation! .someid
{ animation-name: somekeyframeanimation; animation-duration: 7s; transform: translateZ(0); } Don’t do that 32

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Tools & Examples 33

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Debugging in Safari defaults write com.apple.Safari IncludeInternalDebugMenu 1 https://developer.apple.com/videos/wwdc/2012/?id=601 34

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Compositing Indicator Composited layer Container layer No associated texture Overﬂow
Texture (number = upload) 35

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Texture Upload No reupload Upload Opacity Position Size Filter Everything
else! “Hardware accelerated CSS” 36

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Constant Upload = Bad http://codepen.io/ariya/full/xuwgy translate3d ??? 37

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Transformation http://ariya.github.com/css/spinningcube/ http://dev.sencha.com/animator/demos/cogs/ 38

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Fade In/Out http://dev.sencha.com/animator/demos/ions/ http://codepen.io/ariya/full/spzad 39

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three.js Periodic Table http://mrdoob.github.com/three.js/examples/css3d_periodictable.html 40

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Montage MovieShow http://montagejs.github.com/montage/samples/popcorn/ 41

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Photon CSS Lighting http://photon.attasi.com 42

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FPS View http://www.keithclark.co.uk/labs/css3-fps/ 43

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Filter http://html.adobe.com/webstandards/csscustomﬁlters/cssﬁlterlab/ 44

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Hacks & Tricks 45

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Trafﬁc Congestion The speed of the car vs the trafﬁc
condition 46

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Avoid Overcapacity .... .... Texture upload Think of the GPU
memory like a cache. 47

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Prepare and Reuse Hide the poster (=layer) offscreen Viewport 48

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Color Transition @keyframes box { 0% { transform: background-color: blue;
} 100% { transform: background-color: green; } } Need a new texture uploaded to the GPU for every in-between color 49

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Color Transition Trick Blended with http://codepen.io/ariya/full/ofDIh 50

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Timer Latency Depending on user reaction Animation end triggers the
JavaScript callback JavaScript code kicks the next animation Prepare both animation and hide the “wrong” one 51

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More Stuff Jank Busters: http://www.youtube.com/watch?v=hAzhayTnhEI Continuous painting: http://updates.html5rocks.com/2013/02/Proﬁling-Long-Paint-Times-with- DevTools-Continuous-Painting-Mode Chrome
GPU rendering benchmark (Telemetry): http://www.chromium.org/developers/design-documents/rendering-benchmarks Skia debugger: http://wesleyhales.com/blog/2013/02/18/Adventures-With-the-Skia-Debugger/ 52

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Final Words 53

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http://www.trollquotes.org/619-super-spider-bat-troll-quote/ 54

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Use CSS3 animation & transition Be advised of texture uploads
Never assume, always measure 55

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There is No Silver Bullet Traditional graphics programming has been
always full of tricks. It will always be. 56

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Thank You ariya.hidayat@gmail.com @AriyaHidayat ariya.oﬁlabs.com Background artwork from http://kde-look.org/content/show.php/Sin+Flow?content=139751 CC
BY-NC-SA speakerdeck.com/ariya 57

Fluid User Interface with Hardware Acceleration

Fluid User Interface with Hardware Acceleration

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