PNG, BMP & ICO conversions

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FarmerJo
Posts: 3
Joined: Tue Mar 21, 2006 8:37 am

PNG, BMP & ICO conversions

Post by FarmerJo » Tue Mar 21, 2006 8:49 am

Hi,

I have recently started to use icons in my applications and have downloaded a huge collection of them so far. Not all collections are in the format that I need for my application and hence my need for XnView.

Is there any loss in image quality when one format is converted to another?

If I were to convert a BMP image to an ICO image and then convert it back again and repeat this many times, would there be a loss in image quality?

Could I do the same say for a BMP image and a PNG image?

Regards FarmerJo

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Clo
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Location: Bordeaux, France
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All lossless--

Post by Clo » Tue Mar 21, 2006 8:58 am

:) Hello !

- AFAIK, *.BMP - *.ICO and *.PNG are lossless formats. On principle, you could convert (and inverse) into these formats ones others without any problem…
- However, JPEG IS a lossy format, so avoid several conversions into¦from that format.

:mrgreen: Kind regards,
Claude
Clo
Old user ON SELECTIVE STRIKE till further notice

FarmerJo
Posts: 3
Joined: Tue Mar 21, 2006 8:37 am

Post by FarmerJo » Tue Mar 21, 2006 9:35 am

Hi,

Thanks for the reply.

I have another question if I may.

I am using Borland C++ Builder to develop an application and have now added the appropriate toolbar icons. I can use either BMP or ICO bitmaps in the application but my collection is in PNG format. I used XnView to create a set of BMP's and ICO's. Initially some of the bitmap images were displayed with a white background.

After a while I found out that Borland C++ Builder uses the lower left pixel in an image as the transparency colour.

Is it an accepted convention to use the lower left pixel in a BMP as the transparency colour? Does the same apply to the ICO format?

Do you have a recommendation for a good icon editor, preferably freeware or shareware?

Regards FarmerJo

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Clo
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Location: Bordeaux, France
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Rather BMP

Post by Clo » Tue Mar 21, 2006 2:39 pm

:D Hello !

- First : Welcome aboard ! I forgot Image, shame on me !

- There is no special option to follow the Borland's feature for the B¦L pixel as transparency-colour.

• However, you can set it for BMP's and PNG's by choosing it in the colour-map : Image menu >> Edit colour-map.
- Let notice that is available only for pics up to 8 BPP (256 colours).
- Moreover, the transparency is not supported for *.ICO, you would get always a black background instead, making the icon unusable the most times. :(

- So, please use just BMP 8 BPP in your programme.

- A good icon-editor can be found HERE. Just a trivial annoyance : it opens a new empty file always @ each start-up, and is on your back then when closing to save it ! :P

:mrgreen: Kind regards,
Claude
Clo
Last edited by Clo on Tue Mar 21, 2006 6:07 pm, edited 1 time in total.
Old user ON SELECTIVE STRIKE till further notice

FarmerJo
Posts: 3
Joined: Tue Mar 21, 2006 8:37 am

Post by FarmerJo » Tue Mar 21, 2006 3:39 pm

Hi,

Many thanks for the useful information.

I will try your suggestions and download your recommended icon editor.

Regards FarmerJo

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