933171 - Inline image is displayed 25% bigger then original, if DPI=125% on MS Win

Status: UNCONFIRMED

(Thunderbird :: Message Compose Window, defect)

Description

[Dmitry]

Attachment: screenshot.png

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:21.0) Gecko/20100101 Firefox/21.0 (Beta/Release)
Build ID: 20130511120803

Steps to reproduce:

When I paste the image from clipboard or insert from file, the image is displayed larger then original one. For example, image size 674×430 is displayed as 845×542 (see screenshot). Looking at ratio, it looks that problem is connected with my display DPI setting, which is now 120 DPI (125%).

674*1.25 = 842.5
430*1.25 = 537.5

The problem also applies to Message Reader UI, which incorrectly displays images in e.g. Drafts folder.

Comment 1

[:aceman]

Please see if you do not have the zoom feature enabled (try Ctrl-+ and Ctrl-- and Ctrl-0).

Comment 2

[Dmitry]

I have reset zoom (View → Zoom → Reset) and it had no impact. Honestly I have never used zoom for message preview (I prefer "Minimum font size" setting in "Options → Display"). Also I have "Zoom text only" option enabled.

I suspect that problem appeared after I have upgraded Thunderbird from 21 to 24.

Comment 3

[WADA:World Anti-bad-Duping Agency]

(In reply to Dmitry from comment #0)
> it looks that problem is connected with my display DPI setting, which is now 120 DPI
> (125%).
> 674*1.25 = 842.5
> 430*1.25 = 537.5

It may be by porting of following change in Gecko/Firefox(22?) to Tb 24.
  layout.css.devPixelsPerPx = -1.0
Do you see your problem with "layout.css.devPixelsPerPx = 1.0"?
How about with "layout.css.devPixelsPerPx = 1.1"?

Comment 4

[Dmitry]

Now when you have mentioned I remembered I had experienced the similar problem with FF 22:

https://support.mozilla.org/en-US/questions/959762

When I set "layout.css.devPixelsPerPx = 1.0", then inline images are displayed OK, however the font in main menu is too small. I can increase the font for the message preview pane (then reading is comfortable), but not for folder tree and message list.

I have set system DPI setting to 125% to make interface lager, and the only software products I have difficulties with is FF 22 and TB 24...

Comment 5

[Dmitry]

The problem is described in FAQ (http://forums.mozillazine.org/viewtopic.php?p=13126019#p13126019). Also I agree with Greg Edwards's bug 844604 comment 51, saying:

> A usability issue strikes me: when Windows is set to 150%, it's impossible to zoom the page out to
> device pixels, since that would be 66.6667% but the zoom goes in increments of 10%.

If I set "layout.css.devPixelsPerPx = 1.2" to make UI (menu, tree, etc) comfortable for reading, I cannot set message zoom level precisely to make images be displayed 1-to-1.

Comment 6

[WADA:World Anti-bad-Duping Agency]

(In reply to Dmitry from comment #5)
> I cannot set message zoom level precisely to make images be displayed 1-to-1.
Read bug 934389, and try first zoom size = .25 (change from .3 to .25), as your case is DPI=125%.
   layout.css.devPixelsPerPx = 1.25
      toolkit.zoomManager.zoomValues = .3,.5,.67,.8,.9,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3
   => toolkit.zoomManager.zoomValues = .25,.5,.67,.8,.9,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3
   And zoom with "Zoom Text Only" mode.

Comment 7

[WADA:World Anti-bad-Duping Agency]

Dmitry, do you see problem of Bug 911409(icon in menu is larger than text in menu) on Fx 24 or Fx 25 in your environment with keeping OS DPI=125%?
Is there any difference among layout.css.devPixelsPerPx = -1(default in Tb 24/Fx 22 or later), 1.25, and 1.00?

Comment 8

[Dmitry]

@WADA: The image is displayed "correctly" (that is: pixel-to-pixel) if I set devPixelsPerPx = 1. Then images are displayed as I expect, but UI font everywhere is too small & unreadable.

If I set devPixelsPerPx to -1, this has the same effect as devPixelsPerPx = 1.25: images are upscaled, but UI font is fine.

I have set zoomValues to the list you have, but I can't find the right basis to play with, as with devPixelsPerPx = 1.25 images are 25% larger and font is big enough (no reason to zoom further).

I don't have problems with menu arrow icons on FF 25 on my Windows XP x32. However with devPixelsPerPx = -1 FF increases fonts for pages for 25% thus everything is now larger. To view page as it was in FF 21, I need to set devPixelsPerPx = 1, but this kills font in UI (menu, etc).

Comment 9

[GDPR]

This is still happening as of version 102.3.0 on Windows 11.

Pasting screenshots into OneNote or in GitHub Issues, for example, they're pasted in the correct size (100% or their size).

Pasting inline in Thunderbird Compose window always makes the images larger than they should (at 100% Zoom), and the image seems to be actually sent with the increased size, to the recipient.

Related:
https://bugzilla.mozilla.org/show_bug.cgi?id=934389

Comment 10

[Anje]

Maybe related: Recently, there has been many reports in Support Forum with text size issues when people are using OS screen resolution scale greater than 100%. Typically used by computer using 4k. I'm mentioning it because it may be a related issue regarding pixel size which is being determined by computer. See bug 1872490.

Please try the following if user is using 4k and scale is greater than 100%.
In 'Config Editor':

• Set: 'layout.css.devPixelsPerPx' to default, a negative -1.0
• Set: 'mail.uifontsize' = 12

Then if required to increase font size use: 'Menu app icon' > 'Font Size' and click on + icon to increase the font size to a desireable size.

Does this improve both the font Size and Image size ?

Comment 11

[GDPR]

The bug I submitted (bug 934389) is still happening. I got a comment there saying that it might be a duplicate of bug 933171 .

Seeing your suggestion of the changes in Config Editor, I confirm those values are what I already have.

Changing the Font Size of the composer, or Zooming In/Out doesn't really fix the image issue. If I zoom out, what happens is that the font also decreases, together with the image.

Thank you.