[Feature request] Temporarily change screen resolution before capturing screenshot to protect hardware anonymity

[davidhedlund]

Problem Statement

Currently, ScreenshotTile captures a screenshot using the device's existing native screen resolution. Because modern phones typically default to their highest hardware resolution, this exposes specific hardware specifications (such as unique aspect ratios and pixel counts). This information acts as a contributing factor that can be used to identify the hardware model for anyone analyzing the screenshot, raising privacy concerns.

While 1080 × 2400 is a prominent standard for a 20:9 aspect ratio, the 1080p Android market is heavily fragmented:

• 1080 × 2340: A massive baseline standard for mid-range and upper-mid-range devices across major manufacturers (Samsung, Xiaomi, Oppo, OnePlus) for several generations.
• 2280 × 1080 (19:9): A heavily used precursor from OnePlus, Google (older Pixel models), and Huawei during the transition to elongated screens.

Proposed Solution

Implement a feature to temporarily change the screen resolution immediately before a screenshot is captured, and then revert it back to the native setting. By utilizing a standard target like 1080 × 2280, users can mask their screenshots to blend in with common devices (such as older OnePlus or Google Pixel models) rather than exposing their exact native hardware dimensions.

Example workflow:

1. Default State: Phone operates at native resolution (e.g., 1080 × 2400).
2. Trigger Screenshot (via ScreenshotTile):
   • The user triggers the screenshot action using ScreenshotTile.
   • ScreenshotTile actions:
     • Before taking the screenshot, it changes the screen resolution based on the proposed Temporarily change screen resolution setting (e.g., down to 1080 × 2280).
     • Capture the screenshot.
     • Instantly revert the resolution back to the original state.

Suggested Settings UI

A new configuration section in the app preferences:

Temporarily change screen resolution (requires privileged permission):

• Height: x px [e.g, 1080]
• Width: y px [e.g, 2280]

(Where clicking the link opens the exact same type of pop-up to prompt the user:)

Permission Required
ScreenshotTile needs WRITE_SECURE_SETTINGS permission in order to apply resolution which can be granted using ADB. You may use Shizuku app to grant this permission.

This is a one time procedure.

[Dismiss] [Use Shizuku] [ADB procedures]

Potential addition

Randomize

Add a choice to randomize the resolution to fit (guesstimate) the current normal distribution of phone screen size marketshare.

Benefits

• Convenience: This eliminates the need for external, or proprietary apps (such as Pixels: Resolution+DPI Changer) to temporarily change the screen resolution.
• Performance Preservation: Keeps the phone running at its native, optimized display resolution for daily use while standardizing output files only when needed.
• Privacy & Anonymity: Prevents hardware fingerprinting via exact screenshot dimensions by masking output to standard profiles.
• Unique Value Proposition: Makes ScreenshotTile stand out as a pioneering tool in the Android ecosystem for built-in privacy-focused screenshot handling.

Additional Ideas

• While screenshots can alternatively be post-processed on desktop operating systems or other external environments, doing so introduces significant friction and inconvenience since users frequently want or need to upload and share screenshots directly from their mobile devices.
• If implemented, consider abstracting the core resolution-changing logic into a standalone free software pixel resolution changer and distributing it on F-Droid, filling the gap since no such free app currently exists (current alternatives like Pixels: Resolution+DPI Changer are proprietary), while making the codebase easily reusable for ScreenshotTile.

[GrahamxReed]

Context
Canvas fingerprinting appears to be a javascript-encoded identifying measure (looking at places like https://coveryourtracks.eff.org/, https://amiunique.org/, https://creepjs.org/checker#scan, https://browserleaks.com/canvas).

Potential addition
Add a choice to randomize the resolution to fit (guesstimate) the current normal distribution of phone screen size marketshare.

[davidhedlund]

Potential addition Add a choice to randomize the resolution to fit (guesstimate) the current normal distribution of phone screen size marketshare.

Good catch, I was actually on my way to add this so I quoted your text to the original post.

[cvzi]

I don't think an (unprivileged) app can change the resolution at all.

[davidhedlund]

I don't think an (unprivileged) app can change the resolution at all.

You have a point, but it does not require root permission.

An app can change the resolution programmatically, but because Android protects display settings as a system-level privilege, it cannot do so purely as a standard unprivileged app right out of the box. 

Instead, it requires a secure mechanism to execute the necessary command (such as wm size). This is typically handled via root access, a one-time ADB command, or through privilege-granting overlay tools like Shizuku (using wireless debugging), which allows user-space apps to securely execute system commands without needing full root—a popular method used by many apps distributed on F-Droid.

Once these privileges are granted, the app works seamlessly. For example, Pixels: Resolution+DPI Changer (mentioned in the original post) handles this setup gracefully on startup by prompting the user:

Permission Required
Pixels needs WRITE_SECURE_SETTINGS permission in order to apply resolution which can be granted using ADB. You may use Shizuku app to grant this permission.

This is a one time procedure.
 
[Dismiss] [Use Shizuku] [ADB procedures]

Thus, it is entirely possible to implement this feature request in ScreenshotTile, provided that a clear indicator is stated next to the setting, such as:

Temporarily change screen resolution (requires privileged permission):

• Height: x px [e.g, 1080]
• Width: y px [e.g, 2280]

(Where clicking the link opens the exact same type of pop-up to prompt the user:)

Permission Required
ScreenshotTile needs WRITE_SECURE_SETTINGS permission in order to apply resolution which can be granted using ADB. You may use Shizuku app to grant this permission.

This is a one time procedure.

[Dismiss] [Use Shizuku] [ADB procedures]

I added this to the original post.