feat: add xmlsvg export option (#761)

* feat: add xmlsvg export option

* fix: avoid atob for xmlsvg export to prevent UTF-8 corruption

Pass the data URL directly (like PNG export) instead of decoding
with atob(). atob() + Blob([string]) double-encodes non-ASCII
characters (Chinese, Japanese, emoji), corrupting the output file.

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

components/save-dialog.tsx

@@ -20,7 +20,7 @@ import {
 } from "@/components/ui/select"
 import { useDictionary } from "@/hooks/use-dictionary"
 
-export type ExportFormat = "drawio" | "png" | "svg"
+export type ExportFormat = "drawio" | "png" | "svg" | "xmlsvg"
 
 interface SaveDialogProps {
     open: boolean
@@ -74,6 +74,11 @@ export function SaveDialog({
             label: dict.save.formats.svg,
             extension: ".svg",
         },
+        {
+            value: "xmlsvg" as const,
+            label: dict.save.formats.xmlsvg,
+            extension: ".drawio.svg",
+        },
     ]
 
     const currentFormat = FORMAT_OPTIONS.find((f) => f.value === format)

contexts/diagram-context.tsx

@@ -233,7 +233,8 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
             saveResolverRef.current = { resolver: null, format: null }
             // For non-xmlsvg formats, skip XML extraction as it will fail
             // Only drawio (which uses xmlsvg internally) has the content attribute
-            if (format === "png" || format === "svg") {
+            // xmlsvg is saved directly as SVG file, no need for extraction
+            if (format === "png" || format === "svg" || format === "xmlsvg") {
                 return
             }
         }
@@ -296,7 +297,8 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
         }
 
         // Map format to draw.io export format
-        const drawioFormat = format === "drawio" ? "xmlsvg" : format
+        const drawioFormat =
+            format === "drawio" || format === "xmlsvg" ? "xmlsvg" : format
 
         // Set up the resolver before triggering export
         saveResolverRef.current = {
@@ -320,8 +322,13 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
                     fileContent = exportData
                     mimeType = "image/png"
                     extension = ".png"
+                } else if (format === "xmlsvg") {
+                    // Editable SVG: pass data URL directly (like PNG)
+                    fileContent = exportData
+                    mimeType = "image/svg+xml"
+                    extension = ".drawio.svg"
                 } else {
-                    // SVG format
+                    // SVG format (view-only)
                     fileContent = exportData
                     mimeType = "image/svg+xml"
                     extension = ".svg"

lib/i18n/dictionaries/en.json

@@ -140,7 +140,8 @@
         "formats": {
             "drawio": "Draw.io XML",
             "png": "PNG Image",
-            "svg": "SVG Image"
+            "svg": "SVG Image",
+            "xmlsvg": "Editable SVG"
         },
         "savedSuccessfully": "Saved successfully!"
     },

lib/i18n/dictionaries/ja.json

@@ -140,7 +140,8 @@
         "formats": {
             "drawio": "Draw.io XML",
             "png": "PNG 画像",
-            "svg": "SVG 画像"
+            "svg": "SVG 画像",
+            "xmlsvg": "編集可能 SVG"
         },
         "savedSuccessfully": "保存完了！"
     },

lib/i18n/dictionaries/zh-Hant.json

@@ -140,7 +140,8 @@
         "formats": {
             "drawio": "Draw.io XML",
             "png": "PNG 圖片",
-            "svg": "SVG 圖片"
+            "svg": "SVG 圖片",
+            "xmlsvg": "可編輯 SVG"
         },
         "savedSuccessfully": "儲存成功！"
     },

lib/i18n/dictionaries/zh.json

@@ -140,7 +140,8 @@
         "formats": {
             "drawio": "Draw.io XML",
             "png": "PNG 图片",
-            "svg": "SVG 图片"
+            "svg": "SVG 图片",
+            "xmlsvg": "可编辑 SVG"
         },
         "savedSuccessfully": "保存成功！"
     },