3 ms·

Can you explain letterboxing to a non front-end dev?

neilv 3y ago
Normally, a browser window has a rectangular area of the display that is "visible" and used for the Web page, with browser controls and scrollbars and window decorations around it. To a company that wants to identify who the person is (such as to build a profile of the person and sell that information) one way is to "fingerprint" the browser and how it's used. The dimensions of that visible display rectangle help with this, since individuals will often tend to end up with a window size that's more particular to them than of all possible users. One browser anti-fingerprinting privacy feature targets that telltale rectangle size, with "letterboxing" (different from movie letterboxing). Which means that range of different visible rectangle dimensions of what could be many users get reduced to the same smaller rectangle dimensions. Which (like movie letterboxing) results in large unused margins for all users. So, say that you have a 1920x1080 native window size, including all the decorations and controls. That's a pretty common size, and doesn't fingerprint you very well at all. But your particular preferences for things like window decorations and font sizes and such narrow that down quite a bit. And if you don't have a common display size, nor a maximized window, but you tend to have the window the same size, that can fingerprint you even more. With letterboxing, your 1920x1080 native window might give you, say, a 1600x800 display rectangle for the browser page. And a bunch of other people's native windows, of various sizes in the vicinity, and of various desktop settings, will also get the same 1600x800 display rectangle. With letterboxing, everyone is wasting precious screen space, but they're supposedly harder for adversaries to identify. I'm not thrilled with the tradeoff here. Though it's easier to stomach when so many Web sites make poor use of the display anyway, I've been desensitized. (Sorry, I'd make this explanation shorter, if I had more time.)
- mancerayder 3y ago
  Thanks much for this!

Normally, a browser window has a rectangular area of the display that is "visible" and used for the Web page, with browser controls and scrollbars and window decorations around it. To a company that wants to identify who the person is (such as to build a profile of the person and sell that information) one way is to "fingerprint" the browser and how it's used. The dimensions of that visible display rectangle help with this, since individuals will often tend to end up with a window size that's more particular to them than of all possible users. One browser anti-fingerprinting privacy feature targets that telltale rectangle size, with "letterboxing" (different from movie letterboxing). Which means that range of different visible rectangle dimensions of what could be many users get reduced to the same smaller rectangle dimensions. Which (like movie letterboxing) results in large unused margins for all users. So, say that you have a 1920x1080 native window size, including all the decorations and controls. That's a pretty common size, and doesn't fingerprint you very well at all. But your particular preferences for things like window decorations and font sizes and such narrow that down quite a bit. And if you don't have a common display size, nor a maximized window, but you tend to have the window the same size, that can fingerprint you even more. With letterboxing, your 1920x1080 native window might give you, say, a 1600x800 display rectangle for the browser page. And a bunch of other people's native windows, of various sizes in the vicinity, and of various desktop settings, will also get the same 1600x800 display rectangle. With letterboxing, everyone is wasting precious screen space, but they're supposedly harder for adversaries to identify. I'm not thrilled with the tradeoff here. Though it's easier to stomach when so many Web sites make poor use of the display anyway, I've been desensitized. (Sorry, I'd make this explanation shorter, if I had more time.)

mancerayder 3y ago
Thanks much for this!