Bug 140359

Summary: Text reflows when selected on particular page
Product: WebKit Reporter: Myles C. Maxfield <mmaxfield>
Component: Layout and RenderingAssignee: zalan <zalan>
Status: RESOLVED CONFIGURATION CHANGED    
Severity: Normal CC: zalan
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Webarchive
none
Test reduction.
none
Test reduction. none

Description Myles C. Maxfield 2015-01-12 08:28:39 PST
Created attachment 244446 [details]
Webarchive

http://9to5mac.com/2015/01/12/iphone-separation-study/
Webarchive attached.

Select "The results showed an increase in blood pressure, indicative of stress or anxiety;"

Version 8.0.2 (10600.2.5, r178109)

Window is fullscreen on a 15" rMBP
Comment 1 zalan 2015-01-12 10:01:19 PST
Created attachment 244450 [details]
Test reduction.

This has something to do with computing the available space when float is present.
Comment 2 zalan 2015-01-12 20:31:50 PST
Created attachment 244492 [details]
Test reduction.

New test reduction without float.
Comment 3 zalan 2015-01-12 20:46:50 PST
(In reply to comment #2)
> Created attachment 244492 [details]
> Test reduction.
> 
> New test reduction without float.

It seems to be a float precision issue. 
1. Complex line layout measures text fragments with leading whitespace, while simple line layout measures them without. (while this could result in mismatching line width due to kerning, this is not the case here.)
2. While adding up the text fragments (without the leading whitespace) + the constant whitespace width, we measure the text as 358.0000025px.
3. Complex line layout measures the fragments as 358px.  
Individually each character measures the same width both cases.
Comment 4 zalan 2021-09-13 18:00:38 PDT
Works on ToT (r282369).