My Google Summer of Code 2025 journey with Catrobat

My Google Summer of Code 2025 journey with Catrobat - Amit Matth

When I got selected for Google Summer of Code 2025 with Catrobat, I knew I was about to work on something special bringing the beloved Paintroid experience into a cross-platform Flutter app.

It wasn’t just about porting features; it was about reimagining them for a wider audience and making them more powerful, creative, and fun.

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🚀 The Mission

Paintroid has been a popular Android drawing app for years, but the world is moving cross-platform — and so is creativity.

My project aimed to:

• Complete and polish unfinished tools.

• Add new creative features.

• Expand file format support.

• Make the experience smoother and more intuitive for users.

In short: keep the charm of Paintroid, but give it a fresh, modern, cross-platform life in Flutter.

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🛠️ What I Worked On

1. Completed & Polished Text Tool

One of my first tasks was to finish the pending Text Tool implementation, ensuring it worked seamlessly in Flutter and felt natural for users.

• Added a smart bounding box with 1:1 precision matching the native app.

• Introduced new handles for rotation and edge stretching.

• Improved rendering clarity.

🔗 Issue: PAINTROID-759 | PR: #120

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2. Enhanced Shape Tool with More Styles

The Shape Tool now supports:

• Heart and Star shapes

• Dashed, filled, and filled-with-dash styles

This gives artists more variety and control over their designs.

🔗 Issue: PAINTROID-765 | PR: #121

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3. Clipboard Tool – Copy, Cut, Paste Magic

I implemented a brand-new Clipboard Tool, allowing users to:

• Copy, Cut, and Paste selected areas.

This was a major workflow efficiency boost for artists.

🔗 Issue: PAINTROID-795 | PR: #128

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4. Upgraded Color Picker to Multi-Mode Hub

The original color picker was functional but limited. I transformed it into a multi-mode color hub:

• 🎨 Color Wheel

• 🌈 Saturation Picker

• 🎚️ HSV Sliders

• 🔴 RGB Slider Group

• 🟦 Improved Square Grid Picker

🔗 Issue: PAINTROID-794 | PR: #123

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5. ORA File Support

Added OpenRaster (.ora) file save support, enabling users to export artwork in a widely supported format.

🔗 Issue: PAINTROID-457 | PR: #119

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6. New Creative Tools

• Watercolor Tool – for soft, realistic paint effects.

🔗 Issue: PAINTROID-793 | PR: #124

• Clip Area Tool – to isolate and work on specific parts of the canvas.

🔗 Issue: PAINTROID-796 | PR: #132

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7. Other Contributions

• 🔗 Issue: PAINTROID-753 | PR: #125

• 🔗 Issue: PAINTROID-752 | PR: #126

• 🔗 Issue: PAINTROID-750 | PR: #127

• 🔗 Issue: PAINTROID-704 | PR: #114

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8. Testing Contributions

Alongside implementation, I also worked on strengthening the testing framework:

• Wrote unit tests and integration tests for new and existing tools.

• Ensured stability, maintainability, and smoother future contributions.

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📚 Lessons Learned

• How to translate Android-native features into Flutter while keeping the same feel.

• The importance of tool scope discipline (sticking to one Jira ticket was harder than it sounds!).

• Writing tests for creative tools taught me how to simulate real user actions.

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Acknowledgments ❤️

Thanks to Abdulbaki Celebi for his continuous guidance and mentorship.

And a big thanks to Catrobat for letting me work on such a creative project under Google Summer of Code 2025.

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💻 Curious to dive in? Check out the project repositories here:

• Paintroid Flutter (My GSoC Work)

• Paintroid Native (Original Android App)