cfc/cfc-frontend/components/ContentSharePoster.vue

<template>
  <view class="poster-overlay" v-if="show" @click.self="$emit('close')">
    <view class="poster-container">
      <canvas canvas-id="contentPosterCanvas" class="poster-canvas" id="contentPosterCanvas"></canvas>
      <view class="poster-actions">
        <button class="poster-btn save" @click="savePoster">保存到相册</button>
      </view>
    </view>
  </view>
</template>

<script>
export default {
  name: 'ContentSharePoster',
  props: {
    show: { type: Boolean, default: false },
    title: { type: String, default: '' },
    coverImage: { type: String, default: '' },
    qrCodeBase64: { type: String, default: '' },
    typeLabel: { type: String, default: '好物推荐' },
    dimensionCode: { type: String, default: '' },
    summary: { type: String, default: '' },
    priceText: { type: String, default: '' },
    ctaText: { type: String, default: '长按识别二维码 · 查看详情' },
    inviteText: { type: String, default: '' }
  },
  watch: {
    show(val) {
      if (val) {
        this.$nextTick(function() {
          setTimeout(this.drawPoster.bind(this), 300)
        }.bind(this))
      }
    }
  },
  methods: {
    getColors() {
      var map = {
        body: { main: '#FF8C42', dark: '#EA580C', light: '#FFF7ED' },
        mind: { main: '#FF6B9D', dark: '#DB2777', light: '#FDF2F8' },
        wisdom: { main: '#6366F1', dark: '#4F46E5', light: '#EEF2FF' },
        action: { main: '#10B981', dark: '#059669', light: '#ECFDF5' },
        wealth: { main: '#F59E0B', dark: '#D97706', light: '#FFFBEB' }
      }
      return map[this.dimensionCode] || { main: '#F97316', dark: '#EA580C', light: '#FFF7ED' }
    },
    drawPoster() {
      var self = this
      uni.createSelectorQuery().in(this)
        .select('#contentPosterCanvas')
        .boundingClientRect(function(rect) {
          var scaleX = 1
          var scaleY = 1
          if (rect && rect.width && rect.height) {
            scaleX = rect.width / 500
            scaleY = rect.height / 800
          }
          self._renderPoster(scaleX, scaleY)
        })
        .exec()
    },

    _renderPoster(scaleX, scaleY) {
      var ctx = uni.createCanvasContext('contentPosterCanvas', this)
      var w = 500
      var h = 800
      var colors = this.getColors()

      // 画布 CSS 用 rpx,实际像素随设备变化(375px 屏约 310x496),而绘制按 500x800 设计坐标;
      // 不缩放坐标系时右侧/底部内容(含二维码 y≈552-702)会被裁剪出画布,导致海报显示不全。
      if (scaleX !== 1 || scaleY !== 1) {
        ctx.scale(scaleX, scaleY)
      }

      var gradient = ctx.createLinearGradient(0, 0, w * 0.3, h)
      gradient.addColorStop(0, colors.main)
      gradient.addColorStop(0.55, colors.dark)
      gradient.addColorStop(1, colors.dark)
      ctx.setFillStyle(gradient)
      ctx.fillRect(0, 0, w, h)

      this._drawTopDecoration(ctx, w, colors)

      var cardX = 28
      var cardY = 112
      var cardW = 444
      var cardH = 600
      this._drawContentCard(ctx, cardX, cardY, cardW, cardH, colors)

      var coverY = cardY + 20
      var coverW = cardW - 40
      var coverH = 220
      var self = this

      if (this.coverImage) {
        uni.downloadFile({
          url: this.coverImage,
          success: function(res) {
            if (res.statusCode === 200) {
              ctx.drawImage(res.tempFilePath, cardX + 20, coverY, coverW, coverH)
            } else {
              self._drawCoverPlaceholder(ctx, cardX + 20, coverY, coverW, coverH)
            }
            self._drawContentAfterCover(ctx, w, h, cardX, cardW, coverY, coverH, colors)
          },
          fail: function() {
            self._drawCoverPlaceholder(ctx, cardX + 20, coverY, coverW, coverH)
            self._drawContentAfterCover(ctx, w, h, cardX, cardW, coverY, coverH, colors)
          }
        })
      } else {
        this._drawCoverPlaceholder(ctx, cardX + 20, coverY, coverW, coverH)
        this._drawContentAfterCover(ctx, w, h, cardX, cardW, coverY, coverH, colors)
      }
    },

    _drawTopDecoration(ctx, w, colors) {
      var centerX = w / 2
      var dotColors = ['#FF8C42', '#6366F1', '#F59E0B', '#10B981', '#FF6B9D']
      var dotY = 28
      var dotR = 5
      var dotSpacing = 26
      var i, offsetX, offsetY

      for (i = 0; i < 5; i++) {
        offsetX = (i - 2) * dotSpacing
        offsetY = Math.abs(i - 2) * 3
        ctx.setFillStyle(dotColors[i])
        ctx.beginPath()
        ctx.arc(centerX + offsetX, dotY + offsetY, dotR, 0, 2 * Math.PI)
        ctx.fill()
      }

      ctx.setFillStyle('#ffffff')
      ctx.setFontSize(20)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('top')
      ctx.fillText('浠艾福', centerX, 52)

      ctx.setFontSize(14)
      ctx.setFillStyle('rgba(255,255,255,0.8)')
      ctx.fillText('给全家的一站式幸福提案', centerX, 76)

      ctx.setStrokeStyle('rgba(255,255,255,0.25)')
      ctx.setLineWidth(1)
      ctx.beginPath()
      ctx.moveTo(80, 100)
      ctx.lineTo(w - 80, 100)
      ctx.stroke()
    },

    _drawContentCard(ctx, x, y, w, h, colors) {
      ctx.setFillStyle('rgba(0,0,0,0.04)')
      this._roundRect(ctx, x + 2, y + 3, w, h, 16)
      ctx.fill()

      ctx.setFillStyle(colors.light)
      this._roundRect(ctx, x, y, w, h, 16)
      ctx.fill()
    },

    _drawCoverPlaceholder(ctx, x, y, w, h) {
      ctx.setFillStyle('#FEF3C7')
      this._roundRect(ctx, x, y, w, h, 8)
      ctx.fill()

      ctx.setFillStyle('#F97316')
      ctx.setFontSize(16)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('middle')
      ctx.fillText('暂无封面图', x + w / 2, y + h / 2)
    },

    _drawContentAfterCover(ctx, w, h, cardX, cardW, coverY, coverH, colors) {
      var self = this

      var labelY = coverY + coverH + 16
      ctx.setFillStyle(colors.main)
      ctx.setFontSize(13)
      ctx.setTextAlign('left')
      ctx.setTextBaseline('top')
      ctx.fillText(this.typeLabel, cardX + 20, labelY)

      // 标题（2行截断）
      var titleY = labelY + 22
      ctx.setFillStyle('#1C1917')
      ctx.setFontSize(18)
      ctx.setTextAlign('left')
      ctx.setTextBaseline('top')
      this._drawWrappedText(ctx, this.title || '精彩内容', cardX + 20, titleY, cardW - 40, 24, 2)

      // 价格行（商品用；空则跳过）
      var priceY = titleY + 56
      if (this.priceText) {
        ctx.setFillStyle(colors.main)
        ctx.setFontSize(17)
        ctx.setTextAlign('left')
        ctx.setTextBaseline('top')
        ctx.fillText(this.priceText, cardX + 20, priceY)
      }

      // 简介（1-2行灰字；空则跳过）
      var summaryY = (this.priceText ? priceY + 34 : priceY)
      if (this.summary) {
        ctx.setFillStyle('#78716C')
        ctx.setFontSize(13)
        ctx.setTextAlign('left')
        ctx.setTextBaseline('top')
        this._drawWrappedText(ctx, this.summary, cardX + 20, summaryY, cardW - 40, 20, 2)
      }

      // 邀请语（二维码上方）
      var inviteY = (this.summary ? summaryY + 48 : summaryY)
      ctx.setFillStyle('#A8A29E')
      ctx.setFontSize(13)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('top')
      ctx.fillText(this.inviteText || '长按识别二维码 · 查看详情', w / 2, inviteY)

      // 二维码
      var qrSize = 150
      var qrX = (w - qrSize) / 2
      var qrY = inviteY + 24

      if (this.qrCodeBase64) {
        var base64Data = this.qrCodeBase64
        if (base64Data.indexOf('data:image') === 0) {
          var commaIdx = base64Data.indexOf(',')
          if (commaIdx > -1) {
            base64Data = base64Data.substring(commaIdx + 1)
          }
        }

        var fs = uni.getFileSystemManager()
        var filePath = wx.env.USER_DATA_PATH + '/content_share_qr_tmp.png'

        fs.writeFile({
          filePath: filePath,
          data: base64Data,
          encoding: 'base64',
          success: function() {
            ctx.setFillStyle('#ffffff')
            self._roundRect(ctx, qrX - 10, qrY - 10, qrSize + 20, qrSize + 20, 8)
            ctx.fill()

            ctx.setStrokeStyle('#E7E5E4')
            ctx.setLineWidth(0.5)
            self._roundRect(ctx, qrX - 10, qrY - 10, qrSize + 20, qrSize + 20, 8)
            ctx.stroke()

            ctx.drawImage(filePath, qrX, qrY, qrSize, qrSize)
            self._drawBottomDecoration(ctx, w, h, qrY, qrSize, colors)
          },
          fail: function() {
            self._drawQrPlaceholder(ctx, qrX, qrY, qrSize)
            self._drawBottomDecoration(ctx, w, h, qrY, qrSize, colors)
          }
        })
      } else {
        this._drawQrPlaceholder(ctx, qrX, qrY, qrSize)
        this._drawBottomDecoration(ctx, w, h, qrY, qrSize, colors)
      }
    },

    _drawWrappedText(ctx, text, x, y, maxWidth, lineHeight, maxLines) {
      var chars = (text || '').split('')
      var line = ''
      var lineCount = 0
      for (var i = 0; i < chars.length; i++) {
        var testLine = line + chars[i]
        var testWidth = this._textWidth(ctx, testLine)
        if (testWidth > maxWidth && line.length > 0) {
          ctx.fillText(line, x, y + lineCount * lineHeight)
          line = chars[i]
          lineCount++
          if (lineCount >= maxLines - 1) {
            var remaining = chars.slice(i).join('')
            var remainingLine = line + remaining
            while (this._textWidth(ctx, remainingLine + '..') > maxWidth && remainingLine.length > 2) {
              remainingLine = remainingLine.substring(0, remainingLine.length - 1)
            }
            ctx.fillText(remainingLine + '..', x, y + lineCount * lineHeight)
            return
          }
        } else {
          line = testLine
        }
      }
      ctx.fillText(line, x, y + lineCount * lineHeight)
    },

    _textWidth(ctx, text) {
      if (ctx.measureText) {
        try { return ctx.measureText(text).width } catch (e) { return (text || '').length * 18 }
      }
      return (text || '').length * 18
    },

    _drawQrPlaceholder(ctx, x, y, size) {
      ctx.setFillStyle('#ffffff')
      this._roundRect(ctx, x - 10, y - 10, size + 20, size + 20, 8)
      ctx.fill()

      ctx.setStrokeStyle('#E7E5E4')
      ctx.setLineWidth(0.5)
      this._roundRect(ctx, x - 10, y - 10, size + 20, size + 20, 8)
      ctx.stroke()

      ctx.setFillStyle('#A8A29E')
      ctx.setFontSize(16)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('middle')
      ctx.fillText('二维码加载中', x + size / 2, y + size / 2)
    },

    _drawBottomDecoration(ctx, w, h, qrY, qrSize, colors) {
      var centerX = w / 2
      var bottomY = qrY + qrSize + 16

      var diamondY = bottomY + 6
      ctx.setFillStyle('rgba(0,0,0,0.06)')
      ctx.beginPath()
      ctx.moveTo(centerX - 76, diamondY)
      ctx.lineTo(centerX - 72, diamondY - 4)
      ctx.lineTo(centerX - 68, diamondY)
      ctx.lineTo(centerX - 72, diamondY + 4)
      ctx.closePath()
      ctx.fill()
      ctx.beginPath()
      ctx.moveTo(centerX + 68, diamondY)
      ctx.lineTo(centerX + 72, diamondY - 4)
      ctx.lineTo(centerX + 76, diamondY)
      ctx.lineTo(centerX + 72, diamondY + 4)
      ctx.closePath()
      ctx.fill()

      ctx.setFillStyle(colors.main)
      ctx.setFontSize(18)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('top')
      ctx.fillText(this.ctaText || '长按识别二维码 · 查看详情', centerX, bottomY)

      var dotColors = ['#FF8C42', '#6366F1', '#F59E0B', '#10B981', '#FF6B9D']
      var dotY = h - 22
      var dotR = 4
      var dotSpacing = 20
      var i_b, offsetX_b

      for (i_b = 0; i_b < 5; i_b++) {
        offsetX_b = (i_b - 2) * dotSpacing
        ctx.setFillStyle(dotColors[i_b])
        ctx.beginPath()
        ctx.arc(centerX + offsetX_b, dotY, dotR, 0, 2 * Math.PI)
        ctx.fill()
      }

      ctx.setFillStyle('rgba(255,255,255,0.45)')
      ctx.setFontSize(12)
      ctx.setTextAlign('center')
      ctx.setTextBaseline('top')
      ctx.fillText('浠艾福 · 家庭健康俱乐部', centerX, dotY + 7)

      ctx.draw()
    },

    _roundRect(ctx, x, y, w, h, r) {
      ctx.beginPath()
      ctx.moveTo(x + r, y)
      ctx.arcTo(x + w, y, x + w, y + r, r)
      ctx.arcTo(x + w, y + h, x + w - r, y + h, r)
      ctx.arcTo(x, y + h, x, y + h - r, r)
      ctx.arcTo(x, y, x + r, y, r)
      ctx.closePath()
    },

    savePoster() {
      var self = this
      uni.canvasToTempFilePath({
        canvasId: 'contentPosterCanvas',
        destWidth: 500,
        destHeight: 800,
        success: function(res) {
          uni.saveImageToPhotosAlbum({
            filePath: res.tempFilePath,
            success: function() {
              uni.showToast({ title: '已保存到相册', icon: 'success' })
              self.$emit('close')
            },
            fail: function(err) {
              if (err && err.errMsg && (err.errMsg.indexOf('deny') > -1 || err.errMsg.indexOf('auth denied') > -1 || err.errMsg.indexOf('authorize') > -1)) {
                uni.showModal({
                  title: '提示',
                  content: '需要相册权限才能保存图片',
                  confirmText: '去设置',
                  success: function(modalRes) {
                    if (modalRes.confirm) {
                      uni.openSetting()
                    }
                  }
                })
              } else {
                uni.showToast({ title: '保存失败，请重试', icon: 'none' })
              }
            }
          })
        },
        fail: function() {
          uni.showToast({ title: '生成图片失败', icon: 'none' })
        }
      }, this)
    }
  }
}
</script>

<style scoped>
.poster-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
}
.poster-container {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.poster-canvas {
  width: 620rpx;
  height: 992rpx;
  border-radius: 16rpx;
}
.poster-actions {
  display: flex;
  flex-direction: column;
  width: 620rpx;
  margin-top: 30rpx;
}
.poster-btn {
  height: 80rpx;
  line-height: 80rpx;
  font-size: 30rpx;
  border-radius: 40rpx;
  text-align: center;
  border: none;
}
.poster-btn::after { border: none; }
.poster-btn.save {
  background: #ffffff;
  color: #F97316;
  font-weight: 600;
}
.poster-btn.save:active { opacity: 0.85; }
</style>