fix(ui): reduce badge width overestimation in fallback text measurement

server/api/registry/badge/[type]/[...pkg].get.ts

@@ -41,18 +41,87 @@ const COLORS = {
   white: '#ffffff',
 }
 
-const CHAR_WIDTH = 7
-const SHIELDS_CHAR_WIDTH = 6
-
 const BADGE_PADDING_X = 8
 const MIN_BADGE_TEXT_WIDTH = 40
+const FALLBACK_VALUE_EXTRA_PADDING_X = 8
 const SHIELDS_LABEL_PADDING_X = 5
 
 const BADGE_FONT_SHORTHAND = 'normal normal 400 11px Geist, system-ui, -apple-system, sans-serif'
 const SHIELDS_FONT_SHORTHAND = 'normal normal 400 11px Verdana, Geneva, DejaVu Sans, sans-serif'
 
 let cachedCanvasContext: SKRSContext2D | null | undefined
 
+const NARROW_CHARS = new Set([' ', '!', '"', "'", '(', ')', '*', ',', '-', '.', ':', ';', '|'])
+const MEDIUM_CHARS = new Set([
+  '#',
+  '$',
+  '+',
+  '/',
+  '<',
+  '=',
+  '>',
+  '?',
+  '@',
+  '[',
+  '\\',
+  ']',
+  '^',
+  '_',
+  '`',
+  '{',
+  '}',
+  '~',
+])
+
+const FALLBACK_WIDTHS = {
+  default: {
+    narrow: 3,
+    medium: 5,
+    digit: 6,
+    uppercase: 7,
+    other: 6,
+  },
+  shieldsio: {
+    narrow: 3,
+    medium: 5,
+    digit: 6,
+    uppercase: 7,
+    other: 5.5,
+  },
+} as const
+
+function estimateTextWidth(text: string, fallbackFont: 'default' | 'shieldsio'): number {
+  // Heuristic coefficients tuned to keep fallback rendering close to canvas metrics.
+  const widths = FALLBACK_WIDTHS[fallbackFont]
+  let totalWidth = 0
+
+  for (const character of text) {
+    if (NARROW_CHARS.has(character)) {
+      totalWidth += widths.narrow
+      continue
+    }
+
+    if (MEDIUM_CHARS.has(character)) {
+      totalWidth += widths.medium
+      continue
+    }
+
+    if (/\d/.test(character)) {
+      totalWidth += widths.digit
+      continue
+    }
+
+    if (/[A-Z]/.test(character)) {
+      totalWidth += widths.uppercase
+      continue
+    }
+
+    totalWidth += widths.other
+  }
+
+  return Math.max(1, Math.round(totalWidth))
+}
+
 function getCanvasContext(): SKRSContext2D | null {
   if (cachedCanvasContext !== undefined) {
     return cachedCanvasContext
@@ -83,14 +152,17 @@ function measureTextWidth(text: string, font: string): number | null {
   return null
 }
 
-function measureDefaultTextWidth(text: string): number {
+function measureDefaultTextWidth(text: string, fallbackExtraPadding = 0): number {
   const measuredWidth = measureTextWidth(text, BADGE_FONT_SHORTHAND)
 
   if (measuredWidth !== null) {
     return Math.max(MIN_BADGE_TEXT_WIDTH, measuredWidth + BADGE_PADDING_X * 2)
   }
 
-  return Math.max(MIN_BADGE_TEXT_WIDTH, Math.round(text.length * CHAR_WIDTH) + BADGE_PADDING_X * 2)
+  return Math.max(
+    MIN_BADGE_TEXT_WIDTH,
+    estimateTextWidth(text, 'default') + BADGE_PADDING_X * 2 + fallbackExtraPadding,
+  )
 }
 
 function escapeXML(str: string): string {
@@ -125,7 +197,7 @@ function measureShieldsTextLength(text: string): number {
     return Math.max(1, measuredWidth)
   }
 
-  return Math.max(1, Math.round(text.length * SHIELDS_CHAR_WIDTH))
+  return estimateTextWidth(text, 'shieldsio')
 }
 
 function renderDefaultBadgeSvg(params: {
@@ -139,7 +211,7 @@ function renderDefaultBadgeSvg(params: {
   const { finalColor, finalLabel, finalLabelColor, finalValue, labelTextColor, valueTextColor } =
     params
   const leftWidth = finalLabel.trim().length === 0 ? 0 : measureDefaultTextWidth(finalLabel)
-  const rightWidth = measureDefaultTextWidth(finalValue)
+  const rightWidth = measureDefaultTextWidth(finalValue, FALLBACK_VALUE_EXTRA_PADDING_X)
   const totalWidth = leftWidth + rightWidth
   const height = 20
   const escapedLabel = escapeXML(finalLabel)