conditional os in UI xml, add system dialog file open on osx, check api format or error message when opening a document, per-char text wrap on NodeText, additional info on create doc dialog like working path

PanoPainter-OSX/main.cpp

@@ -38,15 +38,15 @@ std::mutex task_mutex;
 {
     [[NSApplication sharedApplication] terminate:nil];
 }
-- (std::string)pick_file
+- (std::string)pick_file:(NSArray<NSString*>*)types
 {
     NSOpenPanel *panel = [NSOpenPanel openPanel];
     [panel setCanChooseFiles:YES];
     [panel setCanChooseDirectories:NO];
     [panel setAllowsMultipleSelection:NO]; // yes if more than one dir is allowed
     
-    NSArray* fileTypes = [NSArray arrayWithObjects:@"png", @"PNG", @"jpg", @"JPG", @"jpeg", nil];
-    [panel setAllowedFileTypes:fileTypes];
+    //NSArray* fileTypes = [NSArray arrayWithObjects:@"png", @"PNG", @"jpg", @"JPG", @"jpeg", nil];
+    [panel setAllowedFileTypes:types];
 
     NSInteger clicked = [panel runModal];
 

PanoPainter-OSX/main.h

@@ -22,5 +22,5 @@
 - (void)async_lock;
 - (void)async_unlock;
 - (void)async_swap;
-- (std::string)pick_file;
+- (std::string)pick_file:(NSArray<NSString*>*)types;
 @end