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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 | import type { EuclidViewportState } from '../types' import { CITATIONS } from '../engine/citations' const FLASH_DURATION = 1200 // ms total const FADE_IN_END = 100 // ms const FADE_OUT_START = 900 // ms const FLOAT_DISTANCE = 8 // px over lifetime const FONT_SIZE = 12 const COLOR = '#F0C75E' // ── Discriminated union ────────────────────────────────────────── export type CitationFlash = | { type: 'segment' startTime: number citation: string fromX: number fromY: number toX: number toY: number } | { type: 'circle' startTime: number citation: string centerX: number centerY: number radius: number } | { type: 'extend' startTime: number citation: string throughX: number throughY: number endX: number endY: number } | { type: 'point' startTime: number citation: string worldX: number worldY: number } /** Distributive Omit that works across union members */ export type CitationFlashInit = CitationFlash extends infer T ? T extends CitationFlash ? Omit<T, 'startTime'> : never : never // ── Coordinate conversion ──────────────────────────────────────── function toScreen( wx: number, wy: number, viewport: EuclidViewportState, w: number, h: number ): { sx: number; sy: number } { const sx = w / 2 + (wx - viewport.center.x) * viewport.pixelsPerUnit const sy = h / 2 - (wy - viewport.center.y) * viewport.pixelsPerUnit return { sx, sy } } // ── Shared rendering helpers (exported for tool overlay preview) ── /** * Render a label aligned parallel to a line segment. * `angle` is screen-space radians from atan2(dy, dx). * Text is offset perpendicular to the line so it doesn't overlap. */ export function renderLineAlignedLabel( ctx: CanvasRenderingContext2D, label: string, sx: number, sy: number, angle: number, alpha: number, fontSize: number, perpOffset: number ) { // Prevent upside-down text: flip by PI if needed let drawAngle = angle if (drawAngle > Math.PI / 2) drawAngle -= Math.PI else if (drawAngle < -Math.PI / 2) drawAngle += Math.PI // Perpendicular offset uses the ORIGINAL angle so the direction is // consistent regardless of the upside-down text flip const offX = -Math.sin(angle) * perpOffset const offY = Math.cos(angle) * perpOffset ctx.save() ctx.globalAlpha = alpha ctx.font = `${fontSize}px system-ui, sans-serif` ctx.textAlign = 'center' ctx.textBaseline = 'middle' ctx.shadowColor = 'rgba(0, 0, 0, 0.6)' ctx.shadowBlur = 3 ctx.shadowOffsetX = 0 ctx.shadowOffsetY = 1 ctx.fillStyle = COLOR ctx.translate(sx + offX, sy + offY) ctx.rotate(drawAngle) ctx.fillText(label, 0, 0) ctx.restore() } /** * Render a label curved along a circle's circumference. * Characters are placed individually along the arc, centered at the top. * Falls back to flat text above center for small circles (< 30px radius). */ export function renderArcLabel( ctx: CanvasRenderingContext2D, label: string, cx: number, cy: number, radius: number, alpha: number, fontSize: number ) { ctx.save() ctx.globalAlpha = alpha ctx.font = `${fontSize}px system-ui, sans-serif` ctx.textAlign = 'center' ctx.textBaseline = 'middle' ctx.shadowColor = 'rgba(0, 0, 0, 0.6)' ctx.shadowBlur = 3 ctx.shadowOffsetX = 0 ctx.shadowOffsetY = 1 ctx.fillStyle = COLOR // Small-circle fallback: flat text above center if (radius < 30) { ctx.fillText(label, cx, cy - radius - 10) ctx.restore() return } // Place characters along the arc at the top of the circle const textRadius = radius + 6 // Measure total angular width const charWidths: number[] = [] let totalAngularWidth = 0 for (const char of label) { const w = ctx.measureText(char).width const angularW = w / textRadius charWidths.push(angularW) totalAngularWidth += angularW } // Start angle: centered at top of circle (screen angle -PI/2) let currentAngle = -Math.PI / 2 - totalAngularWidth / 2 for (let i = 0; i < label.length; i++) { const charAngle = currentAngle + charWidths[i] / 2 ctx.save() ctx.translate(cx, cy) ctx.rotate(charAngle) ctx.translate(textRadius, 0) // move along radius to circumference ctx.rotate(Math.PI / 2) // align with tangent direction ctx.textBaseline = 'bottom' // text renders outside the circle ctx.fillText(label[i], 0, 0) ctx.restore() currentAngle += charWidths[i] } ctx.restore() } // ── Main flash renderer ────────────────────────────────────────── /** * Render citation flash labels on the canvas. * * Returns the subset of flashes that are still animating (caller should * replace its array with this return value to prune expired flashes). */ export function renderCitationFlashes( ctx: CanvasRenderingContext2D, flashes: CitationFlash[], viewport: EuclidViewportState, w: number, h: number, now: number ): CitationFlash[] { const surviving: CitationFlash[] = [] for (const flash of flashes) { const elapsed = now - flash.startTime if (elapsed >= FLASH_DURATION) continue surviving.push(flash) const t = elapsed / FLASH_DURATION // 0 -> 1 // Alpha: fade in 0->100ms, hold 100->900ms, fade out 900->1200ms let alpha: number if (elapsed < FADE_IN_END) { alpha = elapsed / FADE_IN_END } else if (elapsed < FADE_OUT_START) { alpha = 1 } else { alpha = 1 - (elapsed - FADE_OUT_START) / (FLASH_DURATION - FADE_OUT_START) } const label = CITATIONS[flash.citation]?.label ?? flash.citation switch (flash.type) { case 'segment': case 'extend': { const from = flash.type === 'segment' ? toScreen(flash.fromX, flash.fromY, viewport, w, h) : toScreen(flash.throughX, flash.throughY, viewport, w, h) const to = flash.type === 'segment' ? toScreen(flash.toX, flash.toY, viewport, w, h) : toScreen(flash.endX, flash.endY, viewport, w, h) const midX = (from.sx + to.sx) / 2 const midY = (from.sy + to.sy) / 2 const angle = Math.atan2(to.sy - from.sy, to.sx - from.sx) // Perpendicular float: offset grows over lifetime // Negative so label stays on the working-edge side (opposite the straightedge bar) const perpOffset = -(10 + t * FLOAT_DISTANCE) // Skip label for very short segments (< 40px) const segLen = Math.sqrt((to.sx - from.sx) ** 2 + (to.sy - from.sy) ** 2) if (segLen < 40) continue renderLineAlignedLabel(ctx, label, midX, midY, angle, alpha, FONT_SIZE, perpOffset) break } case 'circle': { const sc = toScreen(flash.centerX, flash.centerY, viewport, w, h) const radiusScreen = flash.radius * viewport.pixelsPerUnit // Radial float: text drifts outward over lifetime const driftRadius = radiusScreen + t * FLOAT_DISTANCE if (driftRadius < 30) { // Small circle fallback: flat text above ctx.save() ctx.globalAlpha = alpha ctx.font = `${FONT_SIZE}px system-ui, sans-serif` ctx.textAlign = 'center' ctx.textBaseline = 'middle' ctx.shadowColor = 'rgba(0, 0, 0, 0.6)' ctx.shadowBlur = 3 ctx.shadowOffsetX = 0 ctx.shadowOffsetY = 1 ctx.fillStyle = COLOR ctx.fillText(label, sc.sx, sc.sy - driftRadius - 10) ctx.restore() } else { renderArcLabel(ctx, label, sc.sx, sc.sy, driftRadius, alpha, FONT_SIZE) } break } case 'point': { const sp = toScreen(flash.worldX, flash.worldY, viewport, w, h) // Float upward over lifetime const floatOffset = t * FLOAT_DISTANCE ctx.save() ctx.globalAlpha = alpha ctx.font = `${FONT_SIZE}px system-ui, sans-serif` ctx.textAlign = 'center' ctx.textBaseline = 'middle' ctx.shadowColor = 'rgba(0, 0, 0, 0.6)' ctx.shadowBlur = 3 ctx.shadowOffsetX = 0 ctx.shadowOffsetY = 1 ctx.fillStyle = COLOR ctx.fillText(label, sp.sx, sp.sy - 28 - floatOffset) ctx.restore() break } } } return surviving } |