0
Not a bug

Viewport and window sizes in the tooltip are not accurate when viewing a site at increased magnification

Tooth McJaw 4 years ago • updated 4 years ago 2
Steps to reproduce
  1. Increase the magnification of a page (Command + +) to 150%.
  2. Drag the window to resize it. Notice that the Viewport values are completely off and the Window height value is also inaccurate while dragging the window.

Answer

Answer
Not a bug
They look ok to me. Here's what I did:
1) I re-sized the viewport to 1366 x 768, which gave me a window size of 1382 x 857.
2) I zoomed in at 150%
3) The tooltip reported a viewport size of 911 x 512 and the same window size as before, which is correct. Window's size doesn't change when zooming while the viewport does, as it should. When zooming in, the page's pixels count doesn't change, just their size; a CSS pixel will be rendered at 150% of it's original size, meaning that  in the original area of 1366 physical pixels will fit less virtual zoomed in pixels. The formula for this is
"physical size" / "zoom"
which gives
1366 / 150% = 1366 * 100 / 150 = 910,(6)
768 / 150% = 768 * 100 / 150 = 512

Everything is much clearer when you increase the zoom to 200% and you'll notice that the viewport size is half than the original; you double the content size and only half remains visible.

Anyway, if you still think this is wrong, then you should send a bug report to the Chrome developers because the tooltip displays the window.innerWidth and window.innerHeight values, exactly as they are reported by Chrome. :)

If you don't get the same values as I did, please reply to this message with the exact values that are displayed when you follow the steps I listed above.


Best Regards,

Ionuț
Answer
Not a bug
They look ok to me. Here's what I did:
1) I re-sized the viewport to 1366 x 768, which gave me a window size of 1382 x 857.
2) I zoomed in at 150%
3) The tooltip reported a viewport size of 911 x 512 and the same window size as before, which is correct. Window's size doesn't change when zooming while the viewport does, as it should. When zooming in, the page's pixels count doesn't change, just their size; a CSS pixel will be rendered at 150% of it's original size, meaning that  in the original area of 1366 physical pixels will fit less virtual zoomed in pixels. The formula for this is
"physical size" / "zoom"
which gives
1366 / 150% = 1366 * 100 / 150 = 910,(6)
768 / 150% = 768 * 100 / 150 = 512

Everything is much clearer when you increase the zoom to 200% and you'll notice that the viewport size is half than the original; you double the content size and only half remains visible.

Anyway, if you still think this is wrong, then you should send a bug report to the Chrome developers because the tooltip displays the window.innerWidth and window.innerHeight values, exactly as they are reported by Chrome. :)

If you don't get the same values as I did, please reply to this message with the exact values that are displayed when you follow the steps I listed above.


Best Regards,

Ionuț
Sorry, after further testing here are a few points that I noticed:
  • Is not actually limited to the increased magnification. 
  • Happens more consistently when I resize the window slowly or very quickly.
  • Probably is actually related to a chrome bug. I've noticed with window.innerWidth and window.innerHeight not being accurate in the past.