Rendered at a too large size when DPI greater than 96
Reported by
timok...@gmail.com,
Sep 11 2017
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Issue descriptionUserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.78 Safari/537.36 Steps to reproduce the problem: 1. Have X.org running with a DPI higher than 96 (e.g. xdpyinfo |grep dots – resolution: 144x144 dots per inch) 2. Start Chromium without explicitly setting device scale factor What is the expected behavior? Chromium is rendered at a size corresponding to the DPI; that is, it is rendered as if run with the option --force-device-display-scale=(DPI / 96). For instance, for DPI 144, it is expected that the commands chromium and chromium --force-device-scale-factor=1.5 launch the application rendered at the same size. (The expectation is met when the DPI is 96: in that case, chromium and chromium --force-device-scale-factor=1.0 produce exactly the same results) What went wrong? Chromium is rendered at a size which is too large. Trying different options for forcing the device scale factor, running the display at the DPI 144, the following options were made regarding the size that the application was rendered at: chromium --force-device-scale-factor=2.2 < chromium --force-device-scale-factor=2.25 < chromium --force-device-scale-factor=2.3 ≈ chromium When the display DPI is 96, the commands chromium and chromium --force-device-scale-factor=1 Running the display at the DPI 120, the sequence is: chromium --force-device-scale-factor=1.5 < chromium --force-device-scale-factor=1.5625 < chromium --force-device-scale-factor=1.6 ≈ chromium (Hypothesis: somehow the multiplier is applied two times, and then rounded, e.g. 1.5*1.5 = 2.25 ≈ 2.3) Did this work before? N/A Chrome version: 60.0.3112.78 Channel: n/a OS Version: Flash Version:
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Sep 12 2017
Adding proper component for further triaging.
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Sep 15 2017
Tested the issue on 63.0.3217.0 chromium build using Ubuntu 14.04 and is not reproducible with below mentioned steps. 1.DPI of my system is 95.9990234375 [Used xrdb -query | grep dpi in terminal] 2.Launched chromium from terminal using chromium and chromium --force-device-scale-factor=1 3.Navigated to X.org and page rendered same with scale factor and without. @Reporter: Could you please let me know whether we are missing anything in the steps.
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Sep 15 2017
You missed step 1: have X running at dpi *larger* than 96. Please configure X so that xdpyinfo reports e.g. 120 and then compare chromium --force-device-scale-factor=1.25 and chromium. Those should be the same, but aren't for me. Just to be very clear: by X.org I mean the X display server, not the web page. The bug affects the browser as a whole, both web pages and menus.
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Sep 15 2017
Thank you for providing more feedback. Adding requester "sc00335628@techmahindra.com" to the cc list and removing "Needs-Feedback" label. For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
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Sep 15 2017
Chrome doesn't use x DPI because it's not reliable source of the scale. You can control the scale using * Open unity-control-center, click on Displays, then change "scale for menu and title bar"
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Sep 15 2017
That answer would make sense had the browser been rendered at the too small 96 DPI regardless of the display choice. The fact that changing the X DPI makes Chromium too huge clearly means that Chromium _somehow_ uses it, directly or indirectly and that behavior is wrong. If the goal is to not “use x DPI”, then the wording of this bug becomes slightly different: “Chromium reacts to X DPI”.
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Sep 25 2017
You shouldn't alter x's DPI. We're using gtk to compute & retrieve scale info to be consistent with other apps. (Whether or not they work correctly totally depends on apps). The behavior when you change the DPI is undefined. It may do something, or it may be ignored (xrandr --dpi 144 does not change the size/scale in my environment). |
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Comment 1 by ligim...@chromium.org
, Sep 11 2017