Region of Interest
ROI narrows the search to a specific band of the screen. What the options mean, when each one helps, and the cost / accuracy reasons to set it.
Region of Interest (ROI) is a field on Tap, Scroll, and Drag editors. It tells Mavster which part of the screen to search when looking for your target. Default is All (the whole screen).
Why ROI matters
Narrowing the search has two real payoffs:
- Accuracy. A button labeled Settings might appear in the top nav and in the body of a page. If you set ROI to Top navigation, Mavster won't accidentally tap the body match.
- Cost & speed. Smaller regions are cheaper and faster to search than the whole screen.
Pick the narrowest region that reliably contains your target. All is fine when no narrower region applies, but most app UIs have stable bands (status bar, top nav, content, bottom tab bar) that map well to the ROI presets.
The vertical bands
ROI first picks a horizontal slice of the screen:
| Band | Where on screen |
|---|---|
| All | Full screen |
| Top navigation | Top ~20% — title bars, back buttons, top tab bars |
| Top third | Top 33% — headers, hero sections |
| Content | Middle ~75% (12.5%–87.5%) — main scrollable area |
| Bottom third | Bottom 33% — primary action buttons, summaries |
| Bottom navigation | Bottom ~15% — tab bars, persistent action bars |
The horizontal variants
For every band except All, you can optionally narrow to a horizontal slice as well:
| Variant | Width | When to use |
|---|---|---|
| (default — full width) | 0–100% | The whole band |
| Leading 50 | 0–50% | Left half — back buttons, leading icons |
| Trailing 50 | 50–100% | Right half — trailing actions, share / settings |
| Center 33 | ~33.5–66.5% | Middle third — title-area buttons |
For example, Top navigation → Trailing 50 is the typical region for a trailing action icon (settings, share, profile picture) in a phone app's top nav.
How to pick
A short decision tree:
- Is the target in the chrome (top bar, tab bar)? Pick Top navigation or Bottom navigation.
- Is the target in the main body of the screen? Pick Content.
- Is the target near the top or bottom edge but not in the nav? Pick Top third or Bottom third.
- Can you narrow further by side? Pick the matching Leading 50 / Trailing 50 / Center 33 variant.
- Still ambiguous? Leave it on All — better a slower, broader search than the wrong target.
When to leave it on All
- The target's position on screen genuinely varies between runs.
- The screen has only one obvious candidate matching your description.
- You're just getting a test green and will optimize later.
ROI is one of the cheapest tuning levers — it costs nothing to change and there's no risk in trying a narrower region and falling back to All if it doesn't find your target.