Fluid User Interface with Hardware Acceleration

Talk at W3Conf 2013, San Francisco.

Transcript

1. Fluid User Interface with Hardware Acceleration Ariya Hidayat San Francisco Feb 22, 2013 @ariyahidayat 1
3. Magical Advice Use translate3d for hardware acceleration 3
4. whoami 4
5. CSS3 5
6. Web Browser from 10,000 ft 6
7. Browser: High Level User Interface Browser Engine Graphics Stack Data Persistence Render Engine JavaScript Engine Networking I/O 7
8. 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
9. DOM Tree <html><body><p>Hello</p></body></html> HTMLDocument HTMLBodyElement HTMLParagraphElement attributes, children, contents 9
10. 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
11. 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
12. 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
13. 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
14. Graphics Stack: Crash Course 14
15. Path is Everything 15
16. Stroke = Outline Solid Dashed Dotted Textured 16
17. Brush = Fill Solid None Gradient Textured 17
18. Path Approximation Curves Polygon 18
19. Antialiasing 19
20. Transformation Scaling Rotation Perspective 20
21. Graphics Processing Unit “Fixed” geometry Transformation Textured triangles Parallelism 21
22. Optimized for Games http://epicgames.com/technology/epic-citadel http://www.rage.com/ 22
23. GPU Workflow Vertices Rendered Textured Matrix 23
24. Web Page Rendering 24
25. Game vs Web Page Predictable contents (assets) ✔ Mostly text ✔ Mostly images ✔ immediate Initial response 25
26. 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
27. 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
28. 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
29. Animation Mechanics Initialization Animation step “Hey, this is good stuff. Cache it as texture #42.” “Apply [operation] to texture #42.” Animation loop 29
30. Element = Layer http://www.webkit.org/blog-files/leaves/ 30
31. Compositing: “Logical” 3-D Compositor Tweening Actual operation 31
32. 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
33. Tools & Examples 33
34. Debugging in Safari defaults write com.apple.Safari IncludeInternalDebugMenu 1 https://developer.apple.com/videos/wwdc/2012/?id=601 34
35. Compositing Indicator Composited layer Container layer No associated texture Overflow Texture (number = upload) 35
36. Texture Upload No reupload Upload Opacity Position Size Filter Everything else! “Hardware accelerated CSS” 36
37. Constant Upload = Bad http://codepen.io/ariya/full/xuwgy translate3d ??? 37
38. Transformation http://ariya.github.com/css/spinningcube/ http://dev.sencha.com/animator/demos/cogs/ 38
39. Fade In/Out http://dev.sencha.com/animator/demos/ions/ http://codepen.io/ariya/full/spzad 39
40. three.js Periodic Table http://mrdoob.github.com/three.js/examples/css3d_periodictable.html 40
41. Montage MovieShow http://montagejs.github.com/montage/samples/popcorn/ 41
42. Photon CSS Lighting http://photon.attasi.com 42
43. FPS View http://www.keithclark.co.uk/labs/css3-fps/ 43
44. Filter http://html.adobe.com/webstandards/csscustomfilters/cssfilterlab/ 44
45. Hacks & Tricks 45
46. Traffic Congestion The speed of the car vs the traffic condition 46
47. Avoid Overcapacity .... .... Texture upload Think of the GPU memory like a cache. 47
48. Prepare and Reuse Hide the poster (=layer) offscreen Viewport 48
49. 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
50. Color Transition Trick Blended with http://codepen.io/ariya/full/ofDIh 50
51. 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
52. 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
53. Final Words 53
54. http://www.trollquotes.org/619-super-spider-bat-troll-quote/ 54
55. Use CSS3 animation & transition Be advised of texture uploads Never assume, always measure 55
56. There is No Silver Bullet Traditional graphics programming has been always full of tricks. It will always be. 56
57. 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