1. 修复海报图片

vite-tailwindcss/src/composables/drawXiSeal.js

@@ -0,0 +1,46 @@
+/**
+ * 在 canvas 上绘制圆内「囍」印章。
+ * 用位图避免 html2canvas 对 CJK + transform/flex 居中错位。
+ */
+export function drawXiSeal(canvas, {
+  size = 28,
+  fontSize = 13,
+  color = '#d4af37',
+  borderColor = '#d4af37',
+  fill = 'rgba(0, 0, 0, 0.15)',
+  dpr = Math.min(3, window.devicePixelRatio || 2),
+} = {}) {
+  if (!canvas) return
+  const s = Math.max(12, Number(size) || 28)
+  const fs = Math.max(8, Number(fontSize) || Math.round(s * 0.46))
+  const ratio = Math.max(1, Number(dpr) || 2)
+
+  canvas.width = Math.round(s * ratio)
+  canvas.height = Math.round(s * ratio)
+  canvas.style.width = `${s}px`
+  canvas.style.height = `${s}px`
+
+  const ctx = canvas.getContext('2d')
+  if (!ctx) return
+  ctx.setTransform(ratio, 0, 0, ratio, 0, 0)
+  ctx.clearRect(0, 0, s, s)
+
+  const cx = s / 2
+  const cy = s / 2
+  const r = s / 2 - 0.75
+
+  ctx.beginPath()
+  ctx.arc(cx, cy, r, 0, Math.PI * 2)
+  ctx.fillStyle = fill
+  ctx.fill()
+  ctx.lineWidth = 1
+  ctx.strokeStyle = borderColor
+  ctx.stroke()
+
+  ctx.fillStyle = color
+  ctx.font = `700 ${fs}px "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif`
+  ctx.textAlign = 'center'
+  ctx.textBaseline = 'middle'
+  // 轻微上移做视觉光学居中（非 CSS transform，导出安全）
+  ctx.fillText('囍', cx, cy + fs * 0.04)
+}