feat: 身份证打印支持裁剪旋转和 A5 版面

- ImageCropModal 裁剪弹窗新增左旋/右旋按钮，复用 cropperjs rotate
- 身份证模式新增 A4/A5 版面切换，选 A5 时自动联动纸张大小
- 后端 composeIdCard 支持 A5 尺寸（148×210mm）PDF 生成

Author: hanxi

cmd/server/compose_handler.go

@@ -39,7 +39,11 @@ func composeHandler(w http.ResponseWriter, r *http.Request) {
 	case "invoice":
 		outPath, cleanup, err = composeInvoice2Up(ctx, headers)
 	case "id_card":
-		outPath, cleanup, err = composeIdCard(ctx, headers)
+		paper := r.FormValue("paper")
+		if paper == "" {
+			paper = "A4"
+		}
+		outPath, cleanup, err = composeIdCard(ctx, headers, paper)
 	default:
 		writeJSONError(w, http.StatusBadRequest, "unsupported mode: "+mode)
 		return

cmd/server/pdf_compose.go

@@ -100,7 +100,7 @@ const (
 	idCardGapMM    = 30.0
 )
 
-func composeIdCard(ctx context.Context, fileHeaders []*multipart.FileHeader) (string, func(), error) {
+func composeIdCard(ctx context.Context, fileHeaders []*multipart.FileHeader, paper string) (string, func(), error) {
 	if len(fileHeaders) != 2 {
 		return "", nil, errors.New("id card mode requires exactly 2 files (front and back)")
 	}
@@ -131,14 +131,50 @@ func composeIdCard(ctx context.Context, fileHeaders []*multipart.FileHeader) (st
 		}
 	}
 
+	var pageW, pageH float64
+	if paper == "A5" {
+		pageW, pageH = 148.0, 210.0
+		pdf := gofpdf.NewCustom(&gofpdf.InitType{
+			OrientationStr: "P",
+			UnitStr:        "mm",
+			Size:           gofpdf.SizeType{Wd: pageW, Ht: pageH},
+		})
+		pdf.SetMargins(0, 0, 0)
+		pdf.SetAutoPageBreak(false, 0)
+		pdf.AddPage()
+
+		imp := gofpdi.NewImporter()
+
+		halfH := pageH / 2
+		cardX := (pageW - idCardWidthMM) / 2
+		card1Y := (halfH - idCardHeightMM) / 2
+		card2Y := halfH + (halfH-idCardHeightMM)/2
+
+		if err := placePageInSlot(pdf, imp, &pages[0], cardX, card1Y, idCardWidthMM, idCardHeightMM); err != nil {
+			cleanup()
+			return "", nil, fmt.Errorf("front: %w", err)
+		}
+		if err := placePageInSlot(pdf, imp, &pages[1], cardX, card2Y, idCardWidthMM, idCardHeightMM); err != nil {
+			cleanup()
+			return "", nil, fmt.Errorf("back: %w", err)
+		}
+
+		outPath := filepath.Join(tmpDir, "idcard_composed.pdf")
+		if err := pdf.OutputFileAndClose(outPath); err != nil {
+			cleanup()
+			return "", nil, err
+		}
+		return outPath, cleanup, nil
+	}
+
+	pageW, pageH = 210.0, 297.0
 	pdf := gofpdf.New("P", "mm", "A4", "")
 	pdf.SetMargins(0, 0, 0)
 	pdf.SetAutoPageBreak(false, 0)
 	pdf.AddPage()
 
 	imp := gofpdi.NewImporter()
 
-	pageW, pageH := 210.0, 297.0
 	halfH := pageH / 2
 	cardX := (pageW - idCardWidthMM) / 2
 	card1Y := (halfH - idCardHeightMM) / 2

frontend/src/components/print/ImageCropModal.vue

@@ -9,9 +9,15 @@
         <div class="relative bg-elevated rounded-lg overflow-hidden" style="max-height: 60vh;">
           <img ref="imgRef" :src="imageUrl" class="max-w-full block" />
         </div>
-        <div class="flex justify-end gap-2">
-          <UButton variant="ghost" @click="cancel">取消</UButton>
-          <UButton color="primary" icon="i-lucide-check" @click="confirm">确认裁剪</UButton>
+        <div class="flex items-center justify-between">
+          <div class="flex gap-1">
+            <UButton variant="outline" size="sm" icon="i-lucide-rotate-ccw" @click="rotateLeft">左旋</UButton>
+            <UButton variant="outline" size="sm" icon="i-lucide-rotate-cw" @click="rotateRight">右旋</UButton>
+          </div>
+          <div class="flex gap-2">
+            <UButton variant="ghost" @click="cancel">取消</UButton>
+            <UButton color="primary" icon="i-lucide-check" @click="confirm">确认裁剪</UButton>
+          </div>
         </div>
       </div>
     </template>
@@ -159,6 +165,9 @@ function confirm() {
   }, 'image/jpeg', 0.92)
 }
 
+function rotateLeft() { if (cropper) cropper.rotate(-90) }
+function rotateRight() { if (cropper) cropper.rotate(90) }
+
 function cancel() { isOpen.value = false }
 
 onBeforeUnmount(() => destroyCropper())

frontend/src/views/PrintView.vue

@@ -133,6 +133,20 @@
           @update:front="onIdCardFront"
           @update:back="onIdCardBack"
         />
+        <div v-if="printMode === 'id_card'" class="flex items-center gap-3">
+          <span class="text-sm text-muted shrink-0">版面</span>
+          <div class="flex rounded-lg border border-muted overflow-hidden">
+            <label
+              v-for="p in ['A4', 'A5']"
+              :key="p"
+              class="px-3 py-1 cursor-pointer text-sm transition"
+              :class="idCardPaper === p ? 'bg-primary text-white font-medium' : 'hover:bg-elevated'"
+            >
+              <input type="radio" :value="p" :checked="idCardPaper === p" class="sr-only" @change="setIdCardPaper(p)" />
+              {{ p }}
+            </label>
+          </div>
+        </div>
         <UButton
           v-if="printMode === 'id_card' && idCardFront && idCardBack"
           variant="outline"
@@ -284,6 +298,7 @@ const idCardFront = ref(null)
 const idCardBack = ref(null)
 const idCardFrontPreview = ref('')
 const idCardBackPreview = ref('')
+const idCardPaper = ref('A4')
 const composing = ref(false)
 
 // ─── 状态 ─────────────────────────────────────────────────
@@ -908,12 +923,18 @@ function switchMode(mode) {
   } else if (mode === 'id_card') {
     isColor.value = true
     printScaling.value = 'none'
+    paperSize.value = 'A4'
   } else {
     isColor.value = true
     printScaling.value = 'fit'
   }
 }
 
+function setIdCardPaper(p) {
+  idCardPaper.value = p
+  paperSize.value = p
+}
+
 function clearModeState() {
   invoiceFiles.value = []
   if (idCardFrontPreview.value) { try { URL.revokeObjectURL(idCardFrontPreview.value) } catch (_) {} }
@@ -922,6 +943,7 @@ function clearModeState() {
   idCardBack.value = null
   idCardFrontPreview.value = ''
   idCardBackPreview.value = ''
+  idCardPaper.value = 'A4'
   composing.value = false
 }
 
@@ -984,6 +1006,7 @@ async function composeAndPreview() {
       }
     } else if (printMode.value === 'id_card') {
       fd.append('mode', 'id_card')
+      fd.append('paper', idCardPaper.value)
       fd.append('files', idCardFront.value, idCardFront.value.name)
       fd.append('files', idCardBack.value, idCardBack.value.name)
     }