feat(v2.3.0): add JSON flattening, fix file handle leaks, update README

README.md

@@ -1,16 +1,34 @@
-# PNG Metadata Editor v1.0.0
+# PNG Metadata Editor v2.3.0
 
-A graphical tool for viewing and editing metadata in PNG files.
+A graphical tool for viewing and editing metadata in PNG files with an intuitive image browser interface.
 
 ![PNG Metadata Editor Screenshot](screenshot.png)
 
 ## Features
 
+### Core Features
 - View all metadata fields (tEXt, zTXt, iTXt chunks) in PNG files
 - Add, edit, and delete metadata fields
-- Pretty-print JSON-formatted values
 - Copy metadata values to clipboard
 - Visual indication of unsaved changes
+- Pretty-print JSON values in editor (auto-flattens on save)
+
+### Image Browser
+- Browse directories with thumbnail previews
+- Auto-scroll to selected images
+- Trackpad and mousewheel scrolling support
+- Smooth navigation between multiple files
+
+### User Interface
+- Automatic dark mode detection (macOS, Windows, Linux)
+- Adaptive canvas background based on system theme
+- Unicode support throughout UI
+- Resizable panes for optimal workflow
+
+### Technical Improvements
+- Smart JSON handling: displays formatted, saves flattened
+- Proper file handle management for reliable multi-file loading
+- Enhanced scroll region updates for smooth browsing
 
 ## Installation
 
@@ -24,21 +42,37 @@ A graphical tool for viewing and editing metadata in PNG files.
 Install required packages using pip:
 
 ```bash
-pip install pillow pngmeta
+pip install pillow
 ```
 
 ## Usage
 
+### Basic Workflow
+
 1. Run the application:
    ```bash
    python png-meta-editor.py
    ```
 
-2. Open a PNG file using the "Open PNG File" button
+2. **Browse Directory**: Click "Browse Directory" to load thumbnails from a folder
+3. **Select Image**: Click any thumbnail to load its metadata
+4. **View Metadata**: See all fields in the tree view with preview
+5. **Edit Fields**: 
+   - Double-click or use "Edit Field" to modify values
+   - JSON values display formatted but save flattened
+6. **Save Changes**: Click "Save Changes" to write metadata back to file
 
-3. View metadata in the tree view on the left
-4. Select a field to see its full value in the detail pane
-5. Use the buttons to add, edit, or delete fields
+### Keyboard Shortcuts
+
+- **Double-click** on tree item to edit
+- **Enter/Escape** in dialogs to confirm/cancel
+
+### Dark Mode
+
+The application automatically detects your system theme:
+- **macOS**: Reads `AppleInterfaceStyle` setting
+- **Windows**: Reads personalization registry settings  
+- **Linux**: Checks GTK theme preferences
 
 ## Building for Distribution
 
@@ -68,7 +102,7 @@ pyinstaller --name="PNG Metadata Editor" \
             png-meta-editor.py
 ```
 
-#### Mac OS
+#### macOS
 ```bash
 pyinstaller --name="PNG Metadata Editor" \
             --windowed \
@@ -94,15 +128,53 @@ For building, you'll need:
 - `AppIcon.icns` (Mac icon)
 - `requirements.txt` (for dependencies)
 
+## Technical Details
+
+### JSON Handling
+
+The editor intelligently handles JSON metadata:
+- **Display**: Pretty-printed with indentation for readability
+- **Storage**: Automatically flattened to single line to preserve original format
+- **Example**: 
+  ```json
+  // What you see in editor:
+  {
+    "prompt": "a cat",
+    "steps": 20
+  }
+
+  // What gets saved:
+  {"prompt":"a cat","steps":20}
+  ```
+
+### File Management
+
+- Proper file handle release after reading metadata
+- Supports loading multiple files sequentially without issues
+- Thumbnail caching for smooth browsing experience
+
 ## License
 
 This project is licensed under the MIT License - see [LICENSE](LICENSE) for details.
 
 ## Author
 
-Robert Tusa
+Robert Tusa  
 robert@tusa.at
 
 ## Version History
 
-- **1.0.0 (2026-01-05)**: Initial release
+### v2.3.0 (2026-01-07) - Major UI Update
+- Added image browser with thumbnail previews
+- Implemented dark mode detection for all platforms
+- Added trackpad/mousewheel scrolling support
+- Smart JSON flattening (preserves original format)
+- Fixed file loading issues with proper handle management
+- Enhanced scroll region updates
+- Unicode support in UI elements
+
+### v1.0.0 (2026-01-05) - Initial Release
+- Basic metadata viewing and editing
+- Tree view with detail pane
+- Add, edit, delete operations
+- JSON pretty-printing

png-meta-editor.py

@@ -94,10 +94,10 @@ class PNGMetadataEditor:
         top_frame = ttk.Frame(self.root, padding="10")
         top_frame.pack(fill=tk.X)
 
-        ttk.Button(top_frame, text="📄 Open PNG File", command=self.open_file).pack(side=tk.LEFT, padx=5)
-        ttk.Button(top_frame, text="📥 Browse Directory", command=self.browse_directory).pack(side=tk.LEFT, padx=5)
-        ttk.Button(top_frame, text="✅ Save Changes", command=self.save_changes).pack(side=tk.LEFT, padx=5)
-        ttk.Button(top_frame, text="ℹ️ About", command=self.show_about).pack(side=tk.RIGHT, padx=5)
+        ttk.Button(top_frame, text="🌌 Open PNG File", command=self.open_file).pack(side=tk.LEFT, padx=5)
+        ttk.Button(top_frame, text="🗂️ Browse Directory", command=self.browse_directory).pack(side=tk.LEFT, padx=5)
+        ttk.Button(top_frame, text="💾 Save Changes", command=self.save_changes).pack(side=tk.LEFT, padx=5)
+        ttk.Button(top_frame, text="🍺 About", command=self.show_about).pack(side=tk.RIGHT, padx=5)
 
         self.file_label = ttk.Label(top_frame, text="No file loaded", foreground="gray")
         self.file_label.pack(side=tk.LEFT, padx=20)
@@ -191,10 +191,10 @@ class PNGMetadataEditor:
         button_frame = ttk.Frame(editor_frame, padding="10")
         button_frame.pack(fill=tk.X)
 
-        ttk.Button(button_frame, text="🤌 Add Field", command=self.add_field).pack(side=tk.LEFT, padx=5)
+        ttk.Button(button_frame, text="✍️ Add Field", command=self.add_field).pack(side=tk.LEFT, padx=5)
         ttk.Button(button_frame, text="✏️ Edit Field", command=self.edit_entry).pack(side=tk.LEFT, padx=5)
         ttk.Button(button_frame, text="❌ Delete Field", command=self.delete_field).pack(side=tk.LEFT, padx=5)
-        ttk.Button(button_frame, text="✌️ Copy Value", command=self.copy_value).pack(side=tk.LEFT, padx=5)
+        ttk.Button(button_frame, text="📋 Copy Value", command=self.copy_value).pack(side=tk.LEFT, padx=5)
 
         # Status bar at the bottom
         status_frame = ttk.Frame(self.root, relief=tk.SUNKEN)
@@ -421,6 +421,8 @@ class PNGMetadataEditor:
             if hasattr(img, 'text'):
                 self.metadata_dict = dict(img.text)
 
+            img.close()  # Release file handle
+
             self.file_label.config(text=Path(filepath).name, foreground="")
             self.mark_as_saved()
             self.refresh_tree()
@@ -494,6 +496,15 @@ class PNGMetadataEditor:
         except (json.JSONDecodeError, TypeError):
             return value
 
+    def flatten_json_if_valid(self, value):
+        """If value is valid JSON, return it flattened (no indent), otherwise return as-is"""
+        try:
+            parsed = json.loads(value)
+            return json.dumps(parsed, ensure_ascii=False, separators=(',', ':'))
+        except (json.JSONDecodeError, TypeError):
+            return value
+
+
     def truncate_value(self, value, max_length=80):
         """Truncate long values for tree display"""
         value_str = str(value)
@@ -583,7 +594,9 @@ class PNGMetadataEditor:
                 messagebox.showwarning("Invalid Input", "Key cannot be empty")
                 return
 
-            self.metadata_dict[key] = value
+            # Flatten JSON if valid to keep original format
+            flattened_value = self.flatten_json_if_valid(value)
+            self.metadata_dict[key] = flattened_value
             self.mark_as_modified()
             self.refresh_tree()
             self.set_status(f"Added field '{key}'", color="green")
@@ -637,7 +650,9 @@ class PNGMetadataEditor:
 
         def save_edit():
             new_value = value_text.get(1.0, tk.END).strip()
-            self.metadata_dict[key] = new_value
+            # Flatten JSON if valid to keep original format
+            flattened_value = self.flatten_json_if_valid(new_value)
+            self.metadata_dict[key] = flattened_value
             self.mark_as_modified()
             self.refresh_tree()
             self.set_status(f"Updated field '{key}'", color="green")