Bug 123260 - FILEOPEN: PPTX imported gradient fill wrong due to different fill algorithm
Summary: FILEOPEN: PPTX imported gradient fill wrong due to different fill algorithm
Status: RESOLVED NOTABUG
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
Version:
(earliest affected)
Inherited From OOo
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords: filter:pptx
Depends on:
Blocks: Impress-Gradient
  Show dependency treegraph
 
Reported: 2019-02-08 10:00 UTC by Tobias Burnus
Modified: 2023-04-17 11:15 UTC (History)
1 user (show)

See Also:
Crash report or crash signature:


Attachments
Screen short - left PowerPoint 2003 (with setting for the second/right color), right LO Impress 6.1.3.2 (21.91 KB, image/png)
2019-02-08 10:00 UTC, Tobias Burnus
Details
The example file opened in PP 2013 and Impress 7.2 (44.36 KB, image/png)
2021-01-19 08:19 UTC, NISZ LibreOffice Team
Details
The example file in MSO 2010 and 2013 (138.54 KB, image/png)
2023-04-17 10:40 UTC, Gabor Kelemen (allotropia)
Details

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Description Tobias Burnus 2019-02-08 10:00:43 UTC
Created attachment 149018 [details]
Screen short - left PowerPoint 2003 (with setting for the second/right color), right LO Impress 6.1.3.2

Test case: attachment 130940 [details] [of bug 105792]
PPTX file (PowerPoint 2007) with gradient-filled rectangle

In PowerPoint the rectangle shows up as horizontal gradient BLUE to TRANSPARENT.
In Impress as BLUE to REDISHGRAY to TRANSPARENT

In the file, the settings are:
  Left: BLUE, 0% transparency
  Right: ORANGE, 100% transparency

PowerPoint seemingly does:
  - calculate the first color (BLUE)
  - calculate the second color (TRANSPARENT/no color)
  - interpolate between them

Impress seemingly does:
  - interpolate between the colors (BLUE->ORANGE)
  - apply to it the interpolation of the transparency
Comment 1 Durgapriyanka 2019-02-08 17:40:19 UTC
Thank you for reporting the bug. I can reproduce the bug 

Version: 6.3.0.0.alpha0+
Build ID: b6b28931435e44aca92b8c0e1659f701e3ed1a87
CPU threads: 2; OS: Windows 6.1; UI render: default; VCL: win; 
TinderBox: Win-x86@42, Branch:master, Time: 2019-01-30_06:57:04
Locale: en-US (en_US); UI-Language: en-US
Calc: threaded
Comment 2 Buovjaga 2019-02-12 19:47:53 UTC
Tested with multiple versions down to 3.3.0. Always been wrong.
Comment 3 NISZ LibreOffice Team 2021-01-19 08:19:33 UTC
Created attachment 169004 [details]
The example file opened in PP 2013 and Impress 7.2

Looks quite similar to how more modern PP renders it (which is quite different from 2003), with the "redishgray" middle part in:

Version: 7.2.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: 2081eac430ac69619149e44b453a2d7dda41fc83
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: Skia/Raster; VCL: win
Locale: en-US (hu_HU); UI: en-US
Calc: CL
Comment 4 QA Administrators 2023-01-20 03:24:53 UTC Comment hidden (obsolete)
Comment 5 Gabor Kelemen (allotropia) 2023-04-17 10:40:23 UTC
Created attachment 186716 [details]
The example file in MSO 2010 and 2013

Looks like the rendering of this example has changed with MSO 2013.
Before only the transparency was considered, since 2013 the color and the transparency are both considered. LO is compatible with the latter.

I think it's a NAB at this point, considering even newer MSO renders it differently.
Comment 6 Buovjaga 2023-04-17 11:15:49 UTC
(In reply to Gabor Kelemen (allotropia) from comment #5)
> Created attachment 186716 [details]
> The example file in MSO 2010 and 2013
> 
> Looks like the rendering of this example has changed with MSO 2013.
> Before only the transparency was considered, since 2013 the color and the
> transparency are both considered. LO is compatible with the latter.
> 
> I think it's a NAB at this point, considering even newer MSO renders it
> differently.

I confirm office.com renders it like MSO 2013.