[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182 Heiko Tietze changed: What|Removed |Added CC||noelgran...@gmail.com Assignee|libreoffice-b...@lists.free |heiko.tietze@documentfounda |desktop.org |tion.org See Also||https://bugs.documentfounda ||tion.org/show_bug.cgi?id=61 ||993 Status|UNCONFIRMED |ASSIGNED Ever confirmed|0 |1 --- Comment #5 from Heiko Tietze --- Color was changed for bug 61993 (the ticket mentions the suggested calculation of relative luma) and the threshold modified later with https://gerrit.libreoffice.org/c/core/+/117383 "to match Ubuntu" (and some unrelated changes in https://gerrit.libreoffice.org/c/core/+/105526). Going to submit a tentative patch. -- You are receiving this mail because: You are the assignee for the bug.
[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182
--- Comment #4 from Heiko Tietze ---
Created attachment 188297
--> https://bugs.documentfoundation.org/attachment.cgi?id=188297=edit
Playground
Here is a macro to play with the various approaches. Not only the calculation
makes a difference but also the threshold. My personal favorite is the quick
and dirty #5.
We have two functions implemented, isDark() and isBright(), both taking the
luminance into account with thresholds <=62 and >=245 resp. In between is
neither dark nor bright and I cannot assess the implications (beside the
positive effect on all the isDark() cases).
Sub Main
Doc = ThisComponent
Sheets=Doc.Sheets
Sheet=Sheets.getByName("sheet1")
Dim aColor
Dim aLum as Double
Formula = 5
for i = 0 to 11
for j = 0 to 9
Cell=sheet.getcellByposition(i,j)
aColor = Cell.CellBackColor
Select Case Formula
Case 0 REM current implementation in color.hxx
aLum = (Red(aColor) * 76 + Green(aColor) * 151 +
Blue(aColor) * 29) / 256
Threshold = 62
Case 1 REM Photometric/digital ITU BT.709:
https://stackoverflow.com/questions/596216/formula-to-determine-perceived-brightness-of-rgb-color
aLum = Red(aColor) * 0.2126 + Green(aColor) * 0.7152 +
Blue(aColor) * 0.0722
Threshold = 150
Case 2 REM Digital ITU BT.601
aLum = Red(aColor) * 0.299 + Green(aColor) * 0.587 +
Blue(aColor) * 0.114
Threshold = 150
Case 3 REM http://alienryderflex.com/hsp.html
aLum = sqr( (Red(aColor)/255)^2 * 0.299 +
(Green(aColor)/255)^2 * 0.587 + (Blue(aColor)/255)^2 * 0.114 )
Threshold = 0.6
Case 4 REM Andy's Down and Dirty Version;
https://stackoverflow.com/questions/71410478/what-is-the-constant-k-in-calculating-the-luminance
aLum = sqr( (Red(aColor)/255)^2.2 * 0.2126 +
(Green(aColor)/255)^2.2 * 0.7152 + (Blue(aColor)/255)^2.2 * 0.0722 )
Threshold = 0.6
Case 5 REM https://www.w3.org/TR/AERT/#color-contrast
aLum = (Red(aColor) * 299 + Green(aColor) * 587 +
Blue(aColor) * 114) / 1000
Threshold = 150
end select
if (aLum > Threshold) then
Cell.CharColor = RGB(0,0,0)
else
Cell.CharColor = RGB(255,255,255)
end if
next j
next i
End Sub
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[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182 Michael Weghorn changed: What|Removed |Added CC||m.wegh...@posteo.de Keywords||accessibility -- You are receiving this mail because: You are the assignee for the bug.
[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182 V Stuart Foote changed: What|Removed |Added CC||vsfo...@libreoffice.org Blocks||142074 See Also||https://bugs.documentfounda ||tion.org/show_bug.cgi?id=15 ||5745 --- Comment #3 from V Stuart Foote --- Similar is handling (or lack of it) of fg/bg contrast of the Edit cursor, as in see also bug 155745 Referenced Bugs: https://bugs.documentfoundation.org/show_bug.cgi?id=142074 [Bug 142074] [META] Application Colours settings bugs and enhancements -- You are receiving this mail because: You are the assignee for the bug.
[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182
Heiko Tietze changed:
What|Removed |Added
CC||libreoffice-ux-advise@lists
||.freedesktop.org
--- Comment #2 from Heiko Tietze ---
Most if not all automatic colors are set by checking whether the background is
dark. It is implemented in include/tools/color.hxx as
bool IsDark() const
{
// 62 is the number that means it also triggers on Ubuntu in dark mode
return GetLuminance() <= 62;
}
bool IsBright() const
{
return GetLuminance() >= 245;
}
And luminance is sal_uInt8((B * 29UL + G * 151UL + R * 76UL) >> 8);
I wonder how this luminance value relates to your calculation, that apparently
is much better dealing with the contrast.
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[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182 ady changed: What|Removed |Added Keywords||needsUXEval -- You are receiving this mail because: You are the assignee for the bug.
[Libreoffice-bugs] [Bug 156182] FORMATTING Automatic text color can be unreadable with darker cell colors
https://bugs.documentfoundation.org/show_bug.cgi?id=156182 --- Comment #1 from Myndex --- Created attachment 188235 --> https://bugs.documentfoundation.org/attachment.cgi?id=188235=edit An image showing examples of how automatic text color issues and solution See first post for description. -- You are receiving this mail because: You are the assignee for the bug.
