Canvasでピアノロールを作る Canvasでスクロールを扱う際の
座標計算と苦労 / ng-kyoto Angular Meetup #9

Transcript

1. $BOWBTͰϐΞϊϩʔϧΛ࡞Δ
   $BOWBTͰεΫϩʔϧΛѻ͏ࡍͷ
 ࠲ඪܭࢉͱۤ࿑ +BO
   
   
   
   OHLZPUP
   "OHVMBS
   .FFUVQ
   
   !PLVOPLFOUBSP

2. ୭ w Ԟ໺ݡଠ࿠
   !PLVOPLFOUBSP
   w ΫϨε΢ΣΞ୅ද
   w ΞϓϦέʔγϣϯ ɾ ΤϯδχΞ

3. ࠷ۙ΍ͬͨ͜ͱ w 8FC
   .VTJDͰ͸Կ͕Ͱ͖Δͷ͔
 
   '30/5&/%
   $0/'&3&/$&
   
   w ೔ͷ τϥΠΤϥʔ͔Βੜ·Εͨେن໛ઃܭϊ΢ϋ΢
 
   'SPOUFOE
   $POGFSFODF
   'VLVPLB
   
   w ࣍ੈ୅8FCΧϯϑΝϨϯε
   8FC
   .VTJDηογϣϯ


   
   ࣍ੈ୅8FCΧϯϑΝϨϯε

4. ࠓ೔࿩͢͜ͱ w $BOWBTͰϐΞϊϩʔϧΛ࣮૷͢Δ
   w 3FBDU
   )PPLTͱ͸Կ͔
   w $BOWBTΛѻ͏্Ͱͷۤ࿑

5. ϐΞϊϩʔϧͱ͸

6. ϐΞϊϩʔϧ ͍͍ͩͨͲͷԻ੍ָ࡞༻ͷιϑ τ΢ΣΞʹ΋࣮૷͞Ε͍ͯΔ
 ϝϩσΟ Λೖྗ͢ΔͨΊͷΤσΟ λը໘

7. %FNP

8. Ͱ͖Δ͜ͱ Ϋ Ϧ οΫͰͷԻූͷೖྗ
 υϥ οάͰͷԻූ௕ͷมߋ
 ϐΞϊϩʔϧදࣔͷ9ํ޲ɺ :ํ޲ͷ֦େॖখɺ εΫϩʔϧ
 ʢσϞͯ͠ͳ͍͚Ͳɺ

   Իූͷίϐϖ΍࡟আ΋౰ͨΓલʹͰ͖Δʣ

9. ͳʹ͛ʹߴػೳ w Ի੍ָ࡞༻ιϑ τ
   %"8
   ͸ઐ໳ੑ͕ߴ͍ͨΊಛԽͨ͠ػೳ͕ଟ͍
   w ςΩε τΤσΟ λʹൺ΂Δͱང͔ʹಛघͳ࣮૷
   

   w (6*࣮૷Λੜۀͱ͢Δϑϩϯ τΤϯ υ ɾ ΤϯδχΞͱͯ͠
 ͜ΕΛͪΌΜͱ࣮૷Ͱ͖ΔͱεΩϧΞοϓ͢ΔͷͰ͸

10. ΍ͬͯΈͨ

11. 3FBDU
    
    $BOWBT w OHLZPUP
    "OHVMBS
    .FFUVQͰൃදͯ͠Δ͚Ͳ3FBDUΛ࢖ͬͨ
    w $BOWBTΛ࢖͏͚ͩͳͷͰ7BOJMMB
    +4Ͱ΋͍͍͕3FBDUΛ࢖ͬͨ
    w )PPLTͷ࿅श΋͔ͨͬͨ͠ͷͰ3FBDUΛ࢖ͬͨ

12. 3FBDU
    )PPLT w ೥݄ɺ 3FBDU
    $POG
    ʹͯൃද͞Εͨ3FBDUͷ৽͍͠"1*܈
    w 4UBCMFͰ͸࢖͏ ͜ͱ͕Ͱ͖ͣ
    npm i react@next
    ͢Δ͜ͱͰ
 ࣮૷ࡁΈϦ

    ϦʔεΛΠϯε τʔϧͰ͖Δ

13. 3FBDU
    )PPLT w ͔ͭͯ3FBDUͷίϯϙʔωϯ τ͸
 class Something extends React.Component
 ͷΑ ͏ʹΫϥεͱ

    ͯ͠هड़͢Δ͔
 SFDPNQPTFΛ࢖ͬͯ)JHIFSPSEFS
    $PNQPOFOU
    )0$ ͱͯ͠هड़ͨ͠
    w )0$ͱ͸ίϯϙʔωϯ τΛҾ਺ͱ ͯ͠ίϯϙʔωϯ τΛฦؔ͢਺ͷ͜ͱ
    w ͭ· Γ Ϋϥεͱͯ͠Ͱ͸ͳ͘ɺ ؔ਺ͱ ͯ͠هड़͢Δͱ͍͏ ͜ͱ

14. 3FBDU
    )PPLT w SFDPNQPTFͷ࡞ऀ͕'BDFCPPLʹࢀՃͨ͠
    w SFDPNQPTF͕ղܾ͠Α ͏ ͱ ͍ͯͨ͠໰୊Λ
 3FBDUຊମͰ׬݁ͯ͠վળͰ͖ΔΑ ͏ʹͳͬͨ
    

    w ͦ͏΍ͬͯੜ·Εͨͷ͕)PPLT
    w SFDPNQPTF͸σΟ είϯͱͳͬͨ

15. ͳͥΫϥεͰ͸μϝ͔ w Ϋϥε͸UIJTʹঢ়ଶΛ࣋ͨͤΔ͜ͱ͕Ͱ͖Δ ʢεςʔ τϑϧɺ ෭࡞༻ʣ
    w componentDidMount
    componentDidUpdateͱ͍ͬͨ


    ϥΠ ϑαΠΫϧϝ ιο υʹΑͬͯUIJT಺͕ॻ͖׵͑ΒΕ֎෦͔Βͷςε τ͕ࠔ೉
    w ϥΠ ϑαΠΫϧϝ ιο υʹɺ ίϯϙʔωϯ τͷ ʮ஋Λඳը͢Δʯ ͱ͍͏੹຿Λ௒͑ͨ ෳࡶͳॲཧ͕ॻ͔Ε͕ͪ ʢGFUDIॲཧͱ͔ʣ
    w ෳࡶੑ͕૿͢ͱݕূ͕ࠔ೉ʹͳΓόά͕૿͑Δ 3FBDUυΩϡϝϯ τͷϞνϕʔγϣϯͷทΑ Γҙ༁ͯ͠Ҿ༻

16. 'VODUJPOBM
    $PNQPOFOU w 3FBDU
    )PPLTΛ࢖͏ ͜ͱͰίϯϙʔωϯ τΛؔ਺ͱͯ͠هड़ͭͭ͠
 ͞Βʹঢ়ଶΛѻ͏ ͜ͱ͕Ͱ͖ΔΑ ͏ʹͳΔ
    w 3FBDU
    IPPLT
    OPU
    NBHJD

    
    KVTU
    BSSBZT
 https://medium.com/@ryardley/react-hooks-not-magic-just-arrays-cd4f1857236e
    w ैདྷͷϥΠ ϑαΠΫϧϝ ιο υ΋
    useEffect() ͱ͍͏
 3FBDU
    )PPLTͷҰछΛ࢖͍ɺ ؔ਺ͱ ͯ͠هड़͢Δ

17. %FNP

18. ίʔ υͷߏ଄ export default function App() { // ͻͨ͢Β useState()

    const canvasRef = useRef < HTMLCanvasElement > null; useEffect(() => { // ॳظඳը࣌ॲཧ }, []); useEffect(() => { // Իූ௥Ճ࣌ͷॲཧ }, [notes]); useEffect(() => { // εΫϩʔϧҐஔมߋ࣌ͷॲཧ }, [scrollLeft, scrollTop]); const onDragHorizontalScrollBarKnob = useCallback((ev: React.MouseEvent) => { // ਫฏεΫϩʔϧόʔυϥοά࣌ͷϋϯυϦϯά }, [originXY, mediator]); const onDragVerticalScrollBarKnob = useCallback((ev: React.MouseEvent) => { // ਨ௚εΫϩʔϧόʔυϥοά࣌ͷϋϯυϦϯά }, [originXY, mediator]); const onDragScreen = useCallback((ev: React.MouseEvent) => { // Canvas಺υϥοά࣌ͷૢ࡞ʢԻූ௕ͷมߋʣ }, [scrollBarCoord, currentUuid, originXY, notes]); const onMouseDown = useCallback((ev: React.MouseEvent) => { // Canvas಺ͰͷmousedownϋϯυϦϯά }, [ currentUuid, originXY, notes, scrollBarCoord, isDraggingHorizontalScrollBarKnob, isDraggingVerticalScrollBarKnob ]); const onMouseMove = useCallback((ev: React.MouseEvent) => { // canvas಺ͰͷmousemoveϋϯυϦϯά }, [ currentUuid, originXY, notes, isDraggingHorizontalScrollBarKnob, isDraggingVerticalScrollBarKnob ]); return ( <div className="App"> <canvas onMouseDown={ev => onMouseDown(ev)} onMouseMove={ev => onMouseMove(ev)} ref={canvasRef} width="600" height="400" /> </div> ); }

19. υϥοάϋϯ υ Ϧ ϯάͷ࣮ݱ w Ϛ΢εΫ Ϧ οΫΛͯͦ͠ͷ··཭ͣ͞υϥ οάͱ͍͏࣮૷͕஍ຯʹ೉͍͠
    w

    ondrag͸ͦ͏͍࣮ͬͨ૷ͷͨΊͷΠϕϯ τͰ͸ͳ͍
    w onmousemoveͰev.button === 1ͷͱ͖ υϥοάͱ൑அ͢ΔΑ ͏ʹ෼ذ

20. εΫϩʔϧόʔͷϋϯ υ Ϧ ϯά w εΫϩʔϧόʔ͕Ϋ Ϧ οΫ͞Ε͍ͯΔ͔Ͳ͏͔͸ɺ શͯࣗྗͰ࠲ඪܭࢉ
 ͠ͳ͚Ε͹ͳΒͳ͍
    

    w ϊ ϒͷࠨ্࠲ඪͱӈԼ࠲ඪΛuseState()Ͱ
 ֨ೲ͓͖ͯ͠onmousedownͰ
 ຖճɺ ྖҬ಺͔൑ఆ͢Δ

21. ԻූͷઃஔͱԻූ௕ͷมߋ w Ϛ΢εͷ࠲ඪ͔Βx - 5, y - 10ͷҐஔΛج఺ʹۣܗ ʢԻූʣ Λඳը
    

    w Ϛ΢ε࠲ඪΛج఺ʹ͢ΔͱԻූ͕ΧʔιϧͰӅΕͯ͠·͍ඇ௚ײత
    w ຖճ66*%Λൃߦͯ͠Իූʹ෇༩
    w mousedown࣌ʹهԱͨ͠66*%͕mousemove࣌ʹ༗ޮͳΒ͹
 Իූ௕มߋͱ൑ఆ͢Δ
    w Ϣʔβʹ͸ී௨ʹΫ Ϧ οΫͯ͠ υϥ οάͯ͠Δײ֮

22. ॳظඳը w 3FBDU
    )PPLTʹuseRef()͕͋ΔͷͰͦΕΛ࢖ͬͯ$BOWBT3FGΛऔಘ
    w CanvasRef.currentͰωΠςΟ ϒͳ$BOWBTཁૉͷࢀরΛಘΔ
    w canvasEl.getContext('2d')ͰίϯςΩε τΛಘ͔ͯΒ͸$BOWBT
    "1* ௨ΓʹਐΊΕ͹0,

23. 3FUJOBରԠ w window.devicePixelRatioͰ3FUJOBͳͲͷഒ཰ΛऔಘՄೳ
    w canvasCtx.scale(dpr, dpr)Ͱഒ཰ઃఆ͕Մೳ
    w fillRect(x * dpr,

    y * dpr, width * dpr, height * dpr)
 ͱ͔ຖճॻ͔ͳ͘ ͯࡁΉ
    w ߴEQSදࣔ࣌ʹδϟΪʔ͕ग़ͳ͍Α ͏ʹɺ ຐ๏ͷߦΛ௥Ճ canvasEl.width *= dpr; canvasEl.height *= dpr; canvasEl.style.width = `${canvasEl.width / dpr}px`; canvasEl.style.height = `${canvasEl.height / dpr}px`;

24. εΫϩʔϧରԠ w Ϋ Ϧ οΫͰͷԻූඳը࣌ʹ
 ͋Β͔͡ΊxʹscrollLeftΛɺ yʹscrollTopΛ଍͢
    w εΫϩʔϧόʔͷ υϥ

    οά࣌ʹ࠶ඳըॲཧͰ
 ͢΂ͯͷԻූ࠲ඪ͔ΒscrollLeftͱscrollTopΛҾ͍ͯ࠶ඳը
    w ͨͿΜݱࡏͷ࣮૷ͷ··Ͱ͸·ͣ͘ ͯ
 ཧ૝తʹ͸Ϋ Ϧ οΫ͞Ε࣮ͨࡍͷ࠲ඪͱϐΞϊϩʔϧશମ͔ΒΈͨԾ૝࠲ඪΛ
 ܥ౷؅ཧ͠ͳ͍ͱɺ ॎԣ֦େॖখͳͲͰࢮ͵

25. ۤ࿑ͨ͠఺ ʢ3FBDUฤʣ w useEffect()͕૿͑Δ
    
    ๲ΒΉ
    w Πϕϯ τϋϯ υ Ϧ

    ϯάʹԠͨ͡࠶ඳըͷछྨ͕ଟ͍͍ͤ΋͋Δ͚Ͳ
 ෳ਺ͷuseEffect()ʹΑͬͯίϯϙʔωϯ τؔ਺͕ංେԽͨ͠
    w Իූυϥ οά࣌ͱεΫϩʔϧόʔ ɾ υϥ οά࣌Ͱ࠶ඳըॲཧ͕ҧ͏
    w useEffect(cb, [])ͷୈೋҾ਺ʹࢀরΛྻڍ͢Δ͜ͱͰ
 ͦͷࢀর͕มԽͨ͠ͱ͖ͷΈuseEffectΛ࣮ߦ͢Δ͜ͱ͕Ͱ͖Δ
 ʢuseEffect(() => {}, [scrollLeft]) ͳͲʣ

26. ۤ࿑ͨ͠఺ ʢ3FBDUฤʣ w 3FBDUͷϚ΢εૢ࡞࣌ͷϋϯ υ Ϧ ϯάҾ਺͸MouseEventܕͰ͸ͳ͍
    w 3FBDUख़࿅ऀʹ͸౰ͨΓલͷ࿩͔΋
    w

    SyntheticEventͱ͍͏ܗࣜͰ౉ΔͷͰnativeEventऔಘͷͨΊʹ͸
 ev.persist();
 const nativeEv = ev.nativeEvent;
 ͷΑ ͏ʹҰ୴persist͢Δඞཁ͕͋Δ
    w ͜͏ ͠ͳ͍ͱoffsetX
    offsetY͕औΕͳ͍ͷͰ஫ҙ

27. ۤ࿑ͨ͠఺ ʢ$BOWBTฤʣ w ͻͨ͢Β࠲ඪܭࢉͱͷઓ͍ͱͳΔ
    w fillRect()ͳͲ͢΂ͯͷඳըॲཧ͸ޙউͪͳͷͰίʔϧॱͰ݁Ռ͕มΘΔ
    w ։ൃத͸Իූ͕εΫϩʔϧόʔΛಥ͖ൈ͚Δͱ͔βϥ
    w ϨΠϠʔͳΜͯ֓೦͸ແ͍

    ʢؤு࣮ͬͯ૷͢Δ͔$BOWBTϥούʔϥΠ ϒϥ ϦʹཔΔʣ
    w ͻͨ͢ΒԚ͍ίʔ υͱ ϒϥ΢β্ͷखಈσόοάΛ܁Γฦͯ͠
 ͧ͜͜ͱ͍͏ ͱ͜ΖͰϦ ϑΝΫλ Ϧ ϯά

28. ۤ࿑ͨ͠఺ ʢ$BOWBTฤʣ w 3FBDUͷίϯϙʔωϯ τؔ਺͔Β$BOWBTʹؔ͢Δॲཧ͸͢΂ͯ௥͍ग़ͨ͠
    w CanvasMediatorͱ͍͏தؒҕৡ༻ͷγϯάϧ τϯΛ࡞ͬͯ
 ඳըܥͱ࠲ඪऔಘܥ͸͢΂ͯͦͬͪʹ࣮૷͢ΔΑ ͏

    Ϧ ϑΝΫλ Ϧ ϯά
    w Իූ͚ͩͳΒ؆୯ͩͬͨ
    w εΫϩʔϧόʔͷ࣮૷Λ࢝ΊͨลΓ͔Βࠞಱͱ ࢝͠Ίͯ
 ϒϥ΢βͷ΢Πϯ υ΢࣮૷ͷ࢓༷ͱ͔ړΓ࢝Ίͨ
    w 04ͷ΢Πϯ υ΢γεςϜΛ࣮૷ͨ͠ਓ͸ϚδͰҒେͩͱࢥ͏

29. ࠓޙ΍͍͖͍ͬͯͨػೳ w Ϋ Ϧ οΫͯ͠ஔ͍ͨԻූͷҠಈ ɾ ࡟আ
    w Ͳͷۣܗ͕Ϋ Ϧ

    οΫ͞Ε͔͕ͨऔΕͦ͏ʹͳ͍ͷͰ
 εΫϩʔϧόʔͱಉ͡Ͱɺ ͢΂ͯྖҬܭࢉͰදݱ͢Δ͔͠ͳ͍͔΋
    wυϥοάͨ͠··$BOWBT֎ʹϚ΢εΛಈ͔ͨ͠ΒࣗಈͰεΫϩʔϧ
    w ࠲ඪ͸औΕΔͬΆ͍ɺ ࠶ඳըܭࢉ͕΍ͨΒ໘౗ͬΆ͍
    w ࣮ࡍʹ࠶ੜϘλϯΛ෇͚ͯԻΛ໐Β͢
    w ເͷ·ͨເ

30. ͜͜·Ͱۤ࿑ͯ͠ࢥͬͨ͜ͱ w "OHVMBSͰେن໛ΞϓϦΛ࡞Εͯ΋$BOWBTશવ࡞Εͳ͍
    w 3FBDU͡Όͳ͘ ͍͍ͯ
    w $VTUPN
    &MFNFOUTͱ૬ੑΑͦ͞͏

31. 5IBOL
    ZPV %0.ʹײँ͠ͳ͕Β$BOWBTͰ(6*ͷԞਂ͞ʹ৮ΕΑ ͏ ʂ