글자를 편집으로 남기다

export type TextPath={path:PathShape;offset:number;end?:number;flip:boolean};
export function validateTextPath(t:TextPath){if(!t||!Number.isFinite(t.offset)||Math.abs(t.offset)>100000||typeof t.flip!=='boolean')throw Error('Invalid text path.');if(t.end!==undefined&&(!Number.isFinite(t.end)||t.end<0||t.end>100000))throw Error('Invalid text path end.');validatePaths([{id:'type',name:'Type',paths:[t.path]}]);if(t.path.knots.length<2)throw Error('Text needs at least two path anchors.');}
/** Adaptive subdivision preserves arc length on curved paths, rather than spacing by parameter t. */
export function flattenTextPath(path:PathShape){const points:Point[]=[],knots=path.knots;let length=0;const append=(p:Point)=>{if(points.length)length+=Math.hypot(p.x-points.at(-1)!.x,p.y-points.at(-1)!.y);points.push(p);distances.push(length);},distances:number[]=[];const pt=(a:number[],i:number)=>({x:a[i],y:a[i+1]}),mid=(a:Point,b:Point)=>({x:(a.x+b.x)/2,y:(a.y+b.y)/2});
 const subdivide=(a:Point,b:Point,c:Point,d:Point,depth:number)=>{const chord=Math.hypot(d.x-a.x,d.y-a.y),polygon=Math.hypot(b.x-a.x,b.y-a.y)+Math.hypot(c.x-b.x,c.y-b.y)+Math.hypot(d.x-c.x,d.y-c.y);if(depth>=12||polygon-chord<.025){append(d);return;}const ab=mid(a,b),bc=mid(b,c),cd=mid(c,d),abc=mid(ab,bc),bcd=mid(bc,cd),center=mid(abc,bcd);subdivide(a,ab,abc,center,depth+1);subdivide(center,bcd,cd,d,depth+1);};
 if(knots.length){append(pt(knots[0].points,2));for(let i=1;i<knots.length+(path.open?0:1);i++){const a=knots[(i-1)%knots.length].points,b=knots[i%knots.length].points;subdivide(pt(a,2),pt(a,4),pt(b,0),pt(b,2),0);}}
 const at=(distance:number)=>{if(!length||distance<0||distance>length)return;let lo=1,hi=distances.length-1;while(lo<hi){const m=(lo+hi)>>1;if(distances[m]<distance)lo=m+1;else hi=m;}const a=points[lo-1],b=points[lo],span=distances[lo]-distances[lo-1],t=span?(distance-distances[lo-1])/span:0;return {x:a.x+(b.x-a.x)*t,y:a.y+(b.y-a.y)*t,angle:Math.atan2(b.y-a.y,b.x-a.x)};};return {length,at};

export const warpNames={arc:'Arc',arcLower:'Arc Lower',arcUpper:'Arc Upper',arch:'Arch',bulge:'Bulge',shellLower:'Shell Lower',shellUpper:'Shell Upper',flag:'Flag',wave:'Wave',fish:'Fish',rise:'Rise',fisheye:'Fisheye',inflate:'Inflate',squeeze:'Squeeze',twist:'Twist'};
export type TextWarp={style:keyof typeof warpNames;bend:number;horizontal:number;vertical:number;orientation:'horizontal'|'vertical'};
export function validateTextWarp(w:TextWarp){if(!w||!Object.hasOwn(warpNames,w.style)||!['horizontal','vertical'].includes(w.orientation)||[w.bend,w.horizontal,w.vertical].some(n=>!Number.isFinite(n)||n< -100||n>100))throw Error('Invalid text warp.');}

export type OpenType={kerning?:boolean;ligatures?:boolean;discretionaryLigatures?:boolean;fractions?:boolean;ordinals?:boolean;alternates?:boolean;swash?:boolean;oldStyle?:boolean;tabular?:boolean;caps?:'normal'|'small-caps'|'all-small-caps'|'uppercase';position?:'normal'|'superscript'|'subscript'};
export const openTypeFlags=['kerning','ligatures','discretionaryLigatures','fractions','ordinals','alternates','swash','oldStyle','tabular'] as const;
export function validateOpenType(t:OpenType){if(!t||typeof t!=='object')throw Error('Invalid OpenType options.');for(const k of openTypeFlags)if(t[k]!==undefined&&typeof t[k]!=='boolean')throw Error('Invalid OpenType option.');if(t.caps!==undefined&&!['normal','small-caps','all-small-caps','uppercase'].includes(t.caps)||t.position!==undefined&&!['normal','superscript','subscript'].includes(t.position))throw Error('Invalid character variant.');}
export function openTypeStyle(t:OpenType={}){const pairs=[['kern',t.kerning??true],['liga',t.ligatures??true],['clig',t.ligatures??true],['dlig',!!t.discretionaryLigatures],['frac',!!t.fractions],['ordn',!!t.ordinals],['salt',!!t.alternates],['swsh',!!t.swash],['onum',!!t.oldStyle],['tnum',!!t.tabular],['smcp',t.caps==='small-caps'||t.caps==='all-small-caps'],['c2sc',t.caps==='all-small-caps']];return `font-feature-settings:${pairs.map(([k,v])=>`'${k}' ${v?1:0}`).join(',')};font-kerning:${t.kerning===false?'none':'normal'};text-transform:${t.caps==='uppercase'?'uppercase':'none'};`;}
export function openTypeToPsd(t:OpenType={}){return {autoKerning:t.kerning!==false,ligatures:t.ligatures!==false,dLigatures:!!t.discretionaryLigatures,fontCaps:t.caps==='uppercase'?2:t.caps==='small-caps'||t.caps==='all-small-caps'?1:0,fontBaseline:t.position==='superscript'?1:t.position==='subscript'?2:0};}
export function openTypeFromPsd(s:any):OpenType|undefined{if(!s)return;const t:OpenType={};if(s.autoKerning===false)t.kerning=false;if(s.ligatures===false)t.ligatures=false;if(s.dLigatures)t.discretionaryLigatures=true;if(s.fontCaps===2)t.caps='uppercase';else if(s.fontCaps===1)t.caps='small-caps';if(s.fontBaseline===1)t.position='superscript';else if(s.fontBaseline===2)t.position='subscript';return Object.keys(t).length?t:undefined;}