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   comp.mobile.android      Discussion about Android-based devices      236,147 messages   

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   Message 236,103 of 236,147   
   Hank Rogers to Maria Sophia   
   Re: PSA: Creating *any* RGB solid color    
   19 Feb 26 16:42:10   
   
   XPost: misc.phone.mobile.iphone, alt.comp.os.windows-10   
   From: Hank@nospam.invalid   
      
   Maria Sophia wrote on 2/19/2026 2:06 PM:   
   > To add value so that this becomes a useful reference for all three common   
   > platforms, Android, iOS and Windows, here's a quick summary of details.   
   >   
   > 1. The universal 1x1 pixel solid-color privacy-aware method:   
   > A mathematically perfect solid-color wallpaper only needs one pixel.   
   > Every OS scales it losslessly because all pixels are identical.   
   >   
   > Minimal PPM format (ASCII only):   
   >     P3 1 1 255 R G B   
   > This produces a 1x1 pixel image with the exact RGB values you want.   
   > It contains:   
   > a. no EXIF   
   > b. no metadata   
   > c. no compression artifacts   
   > d. no camera noise   
   > e. no unique patterns   
   > f. no fingerprintable entropy beyond the RGB value   
   > This works on Windows, Android, and iOS/iPadOS.   
   >   
   > 2. Windows notes:   
   > Windows supports solid colors natively, but the GUI color picker:   
   > a. does not accept HEX directly   
   > b. does not always allow precise RGB entry   
   > c. may apply GPU dithering depending on settings   
   >   
   > Using a generated PNG guarantees:   
   > a. exact RGB   
   > b. no dithering   
   > c. no metadata   
   > d. no artifacts   
   > Windows accepts any PNG as wallpaper without modification.   
   >   
   > 3. Android notes:   
   > Android is the most flexible platform.   
   >   
   > Universally true:   
   > a. Any app can set wallpaper via the public API.   
   > b. Any image viewer can "Set as wallpaper".   
   > c. A 1x1 PNG scales perfectly on all devices.   
   >   
   > Not universal:   
   > a. Native solid-color pickers vary by OEM.   
   > b. Google Wallpapers app has a limited palette.   
   > Yet, the offline PPM -> PNG method in this PSA works on all devices.   
   >   
   > 4. IOS/iPadOS notes:   
   > iOS and iPadOS cannot generate a true solid color using the built-in   
   > "Color" wallpaper option. Even when entering a HEX value, Apple applies   
   > a gradient.   
   >   
   > Limitations:   
   > a. All "Color" wallpapers are gradients.   
   > b. No API exists for apps to set wallpaper.   
   > c. No toggle to disable shading.   
   > d. No way to force a flat color through Accessibility.   
   >   
   > Therefore:   
   > a. The best way to get a true solid color is to import an image.   
   >   
   > 5. Privacy benefits of solid colors on the various platforms:   
   >   
   > A. Android (modern versions) exposes only:   
   >    a. 3 main colors   
   >    b. 1 secondary color   
   >    c. 1 tertiary color   
   >    d. luminance metadata   
   >   
   > B. A pure solid color collapses all of these to the same value, producing:   
   >    a. near-zero entropy   
   >    b. no unique fingerprint   
   >    c. no reconstructable image   
   >   
   > iOS:   
   > a. Apps cannot read wallpaper data unless the user gives them the image.   
   >   
   > Windows:   
   > a. Any program can read the wallpaper file, but a 1x1 PNG contains   
   >     nothing but three bytes of color.   
   >   
   > 6. Imagmagic command syntax:   
   > This works on Windows, macOS, Linux, Android (via Termux), etc. but I   
   > could find no native, user-installable version of ImageMagick for iOS   
   > or iPadOS so only iOS can't do what all other operating systems easily do.   
   > I. Create a solid-color PNG from a HEX value:   
   >     magick -size 1x1 xc:"#ABCDEF" solid-abcdef.png   
   >   II. Scale it to device resolution:   
   >     magick solid-abcdef.png -scale 2360x1640! ipad-2360x1640.png   
   >   
   > 7. How does pure solid black help with privacy?   
   > Pure black (#000000) produces the lowest possible entropy on Android.   
   > Every device returns the same WallpaperColors object.   
   >   
   > Benefits:   
   > a. hardest wallpaper to fingerprint   
   > b. reduces OLED power consumption   
   > c. visually clean and uniform   
   >   
   > Note that while the gradient contains more entropy than pure black, on iOS,   
   > apps cannot access it anyway, so the difference is irrelevant in practice.   
   >   
   > Windows exposes the wallpaper file directly, so gradients absolutely   
   > contain more fingerprintable data than pure black would.   
      
   Congrats Mary.  You solved this and added 999999% value with a 1X1 pixel   
   file!   
      
   ELEGANT solution.   
      
   Thanks for helping all us secret agents stay invisible with your super   
   privacy tools.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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