Opened 7 years ago

Closed 5 years ago

Last modified 5 years ago

#8782 closed bug (fixed)

ShowImage (or BMP translator) convert from PNG to BMP result in a drawing issue

Reported by: Giova84 Owned by: nobody
Priority: normal Milestone: R1
Component: Add-Ons/Translators/BMP Version: R1/Development
Keywords: Cc:
Blocked By: Blocking:
Has a Patch: no Platform: x86

Description

When i open an PNG image containing alpha channel and i convert this image to BMP, the resulting file contain drawing issues showed in the screenshot. hrev44384

Attachments (1)

ShowImage_DrawingIssueBITMAP.png (313.6 KB ) - added by Giova84 7 years ago.

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Change History (6)

by Giova84, 7 years ago

comment:1 by Giova84, 7 years ago

As in this ticket: https://dev.haiku-os.org/ticket/8781 i guess that ShowImage doesn't handle correctly alpha channel.

comment:2 by X512, 7 years ago

Component: Applications/ShowImageAdd-Ons/Translators/BMP
Owner: changed from leavengood to nobody

I see that alpha channel is dropped. It happens because origional BMP format don't support alpha channel so Haiku translator can't use it. But newer versions of format and some programs (including internal windows programs line logonui.exe) using bitmaps with alpha channel.

comment:3 by hometue, 7 years ago

(GCI-2012 Participant) Haiku revision: hrev44702. Not valid, but the transparent portion will be filled with a solid color, while the semi-transparent portion will become a solid version of the same color. System: Haiku R1-alpha4 on Virtualbox 4.1.20 on windows 7 64 bit

comment:4 by pulkomandy, 5 years ago

Resolution: fixed
Status: newclosed

Currently the background is properly cleared to white in that case, which sounds like a reasonable solution. We could extend the BMP translator to fully support alpha now, as it is available in version 3, 4 and 5 of the header: http://msdn.microsoft.com/en-us/library/dd183380(VS.85).aspx http://msdn.microsoft.com/en-us/library/dd183381(v=vs.85).aspx

But it seems not all applications can handle this... Closing the ticket as there is no bug here, only missing functionalities in the BMP translator.

comment:5 by phoudoin, 5 years ago

Or turn this ticket into a low priority enhancement ticket untitled "Add BMPv3+ alpha channel support to BMPTranslator", to keep it on the backlog.

Version 0, edited 5 years ago by phoudoin (next)
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