export document:
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 
UnimplementedError: getSavePath() has not been implemented.
#0      FileSelectorPlatform.getSavePath 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:76)
#1      FileSelectorPlatform.getSaveLocation 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:87)
#2      getSaveLocation (package:file_selector/file_selector.dart:101)
#3      exportFile (package:butterfly/api/save_io.dart:26)
#4      exportFile (package:butterfly/api/save.dart:15)
#5      saveData (package:butterfly/api/save.dart:30)
#6      ExportAction.invoke (package:butterfly/actions/export.dart:20)
#7      Action._invoke (package:flutter/src/widgets/actions.dart:338)
#8      ActionDispatcher.invokeAction 
(package:flutter/src/widgets/actions.dart:641)
#9      Actions.maybeInvoke.<anonymous closure> 
(package:flutter/src/widgets/actions.dart:1011)
#10     Actions._visitActionsAncestors


export svg:
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 
UnimplementedError: getSavePath() has not been implemented.
#0      FileSelectorPlatform.getSavePath 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:76)
#1      FileSelectorPlatform.getSaveLocation 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:87)
#2      getSaveLocation (package:file_selector/file_selector.dart:101)
#3      exportFile (package:butterfly/api/save_io.dart:26)
#4      exportFile (package:butterfly/api/save.dart:15)
#5      exportSvg (package:butterfly/api/save.dart:19)
#6      _SvgExportDialogState._exportSvg 
(package:butterfly/dialogs/export/svg.dart:108)
#7      _SvgExportDialogState.build.<anonymous closure>.<anonymous 
closure> (package:butterfly/dialogs/export/svg.dart:165)
#8      _InkResponseState.handleTap 
(package:flutter/src/material/ink_well.dart:1183)
#9      GestureRecognizer.invokeCallback (package:flutter/src


export img:
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 
UnimplementedError: getSavePath() has not been implemented.
#0      FileSelectorPlatform.getSavePath 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:76)
#1      FileSelectorPlatform.getSaveLocation 
(package:file_selector_platform_interface/src/platform_interface/file_selector_interface.dart:87)
#2      getSaveLocation (package:file_selector/file_selector.dart:101)
#3      exportFile (package:butterfly/api/save_io.dart:26)
#4      exportFile (package:butterfly/api/save.dart:15)
#5      exportImage (package:butterfly/api/save.dart:22)
#6      _ImageExportDialogState.build.<anonymous closure>.<anonymous 
closure> (package:butterfly/dialogs/export/image.dart:155)
<asynchronous suspension>


export pdf:
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 
Null check operator used on a null value
#0      AppLocalizations.of 
(package:flutter_gen/gen_l10n/app_localizations.dart:97)
#1      exportFile (package:butterfly/api/save_io.dart:29)
#2      exportFile (package:butterfly/api/save.dart:15)
#3      exportPdf (package:butterfly/api/save.dart:25)
#4      _PdfExportDialogState.build.<anonymous closure>.<anonymous 
closure> (package:butterfly/dialogs/export/pdf.dart:172)
<asynchronous suspension>


increasing print quality still crashes app