[Gimp-developer] Feature Request: Premultiplied Alpha for 32-bit Windows BMP

2012-12-23 Thread Matthew Turner 

Hi all,

I write to request a feature addition to the "Windows BMP image (*.BMP)" 
exporter in GIMP.


The exporter currently (GIMP 2.8.2) allows the user to select from a 
variety of sub-formats. One such sub-format is "A8 R8 G8 B8", which 
stores an alpha channel in the unused/reserved byte of each pixel's 
RGBQUAD structure.


This may be suitable and convienient when using BMP as an interchange 
format. However, Windows application developers like myself need to 
create 32-bit BMP images with premultiplied alpha. This is necessary 
because the Windows GDI functions that perform alpha blending of bitmaps 
expect the RGB channels to be premultiplied by the alpha value.


I therefore request the addition of a "premultiplied" variant of "A8 R8 
G8 B8".


I believe this feature should be easy enough to add. The "Export Image 
as BMP" dialog window can be expanded to include an additional radio 
button called, say, "A8 R8 G8 B8 (Premultiplied)". When the user selects 
this option, the pixels should be written using an algorithm along the 
following lines:



if (premultiply)
{
   // These calculations assume integers in the range 0..255

   pixel.rgbBlue = blue * alpha / 255;
   pixel.rgbGreen = green * alpha / 255;
   pixel.rgbRed = red * alpha / 255;
   pixel.rgbReserved = alpha;
}
else
{
   pixel.rgbBlue = blue;
   pixel.rgbGreen = green;
   pixel.rgbRed = red;
   pixel.rgbReserved = alpha;
}


Thanks in advance!

Matthew Turner

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Re: [Gimp-developer] RAW files

2012-12-23 Thread Simone Karin Lehmann 

Am 23.12.2012 um 20:54 schrieb scl :

> the UFRAW plugin [1][2] is your friend here.
> Please keep in mind that the current UFRAW plugin doesn't work with GIMP 
> 2.8.2. Please use GIMP 2.6 or GIMP 2.8.0 then or use UFRAW as


... take a look at http://gimp.lisanet.de/Website/Download.html. The UFRaw 
plying works in these 2.8.2 builds.

Simone



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Re: [Gimp-developer] RAW files

2012-12-23 Thread Paka 
* Henk Kruger  [12-23-12 14:34]:
> Please is it possible for RAW and RF2 (for canon camera users) files on
> the file open menu options?

have a look at photivo which has a plugin for gimp.

-- 
(paka)Patrick Shanahan   Plainfield, Indiana, USA  HOG # US1244711
http://wahoo.no-ip.orgPhoto Album: http://wahoo.no-ip.org/gallery2
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Re: [Gimp-developer] RAW files

2012-12-23 Thread scl 

Please is it possible for RAW and RF2 (for canon camera users) files on
the file open menu options?


Hi,

the UFRAW plugin [1][2] is your friend here.
Please keep in mind that the current UFRAW plugin doesn't work with GIMP 
2.8.2. Please use GIMP 2.6 or GIMP 2.8.0 then or use UFRAW as standalone 
RAW processor. Another way would be processing the RAW files in Canons 
own RAW processor Digital Photo Professional, export them as JPEG or 
TIFF and reopen them in GIMP. This seems to be more inconvenient on the 
first look, but lets you better use Canon camera features than a generic 
RAW processor and have GIMPs image editing features as well.


You find more information on UFRAW in the GIMP-User mailing list [3]. 
There were some postings to this topic this November and December.


BTW AFAIK Canons RAW format is CR2. Is RF2 a typo or is something new 
approaching us?


Kind regards,

Sven


[1] http://registry.gimp.org/node/31
[2] http://ufraw.sourceforge.net/Install.html
[3] https://mail.gnome.org/archives/gimp-user-list/
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Re: [Gimp-developer] RAW files

2012-12-23 Thread Partha Bagchi 
It is possible now with a RAW convertor such as UFRaw. However, UFRaw sends
8-bit data to Gimp and hence would not take advantage of 16-bit editing
that is possible with Gimp 2.9 and beyond.



On Sun, Dec 23, 2012 at 2:22 PM, Henk Kruger  wrote:

>  Dear GIMP developers,
>
> ** **
>
> Please is it possible for RAW and RF2 (for canon camera users) files on
> the file open menu options?
>
> Thank you
>
> ** **
>
> Henk Kruger.
>
> zs4...@gmail.com
>
> ** **
>
> ___
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>
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[Gimp-developer] RAW files

2012-12-23 Thread Henk Kruger 
Dear GIMP developers,

 

Please is it possible for RAW and RF2 (for canon camera users) files on the
file open menu options?

Thank you

 

Henk Kruger.

zs4...@gmail.com

 

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