Add Feature to Download Canvas Drawing as PNG

**Description:**
Hello Team,

I would like to suggest adding a feature to our application that allows users to download their canvas drawings as PNG files. Here are the details:

## Feature Details:
- **Functionality:** Allow users to save their canvas drawings as PNG images.
- **Button/Option:** Provide a button or menu option labeled "Download as PNG".

## Purpose:
This feature aims to:
- Enable users to easily save and share their artwork or designs.
- Enhance the usability of our drawing tools.
- Provide a convenient way for users to export their work.

## Requirements:
- The downloaded PNG should accurately represent the canvas content.
- The feature should be intuitive and easy to use.
- Ensure compatibility across different browsers and devices.

## Additional Notes:
- Consider adding an option to specify the image resolution or quality.
- Maintain transparency in the PNG if applicable.
- Ensure the feature works seamlessly with different canvas sizes and drawing tools.

## Example/Reference:
If you have any mockups or examples, please attach them here or provide links to reference designs.

## Tasks:
1. Implement the functionality to convert the canvas content to a PNG image.
2. Add a button or menu option for users to trigger the download.
3. Test the feature on various devices and browsers to ensure compatibility.
4. Collect feedback from users and make adjustments if necessary.

Thank you for considering this suggestion. I believe this feature will greatly enhance the utility and appeal of our application.

Best regards