[ Show ]
Support VoyForums
[ Shrink ]
VoyForums Announcement: Programming and providing support for this service has been a labor of love since 1997. We are one of the few services online who values our users' privacy, and have never sold your information. We have even fought hard to defend your privacy in legal cases; however, we've done it with almost no financial support -- paying out of pocket to continue providing the service. Due to the issues imposed on us by advertisers, we also stopped hosting most ads on the forums many years ago. We hope you appreciate our efforts.

Show your support by donating any amount. (Note: We are still technically a for-profit company, so your contribution is not tax-deductible.) PayPal Acct: Feedback:

Donate to VoyForums (PayPal):

Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time | Archives: 1234567[8]910 ]

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Date Posted: 19:32:21 03/01/01 Thu
Author: Michel
Subject: Re: Grayscale JPEG and Palette
In reply to: Bob Villiers 's message, "Re: Grayscale JPEG and Palette" on 12:22:44 03/01/01 Thu

Hi Bob,

If the image was loaded by Envision, the ImageFormat property of TDibGraphic will be ifGray256 or ifColor256.

There is one situation though, when scanning a gray scale image from a scanner, the format returned if ifColor256. The only way to then tell the difference is to examine the entries in the palette and of all RGB values are the same in every entry.

Best regards,

>Thanks for the reply. I am quite happy with a Jpeg
>automatically producing a colour table and have been
>using PaletteIndex on my current project like a good
>Boy Scout. I am just trying to correct my
>understanding. Incidentally, TJpegImage only produces
>a palette if the line
>DIBNeeded:= True;
>is added. It then produces a palette of index 0 to 235
>grays and 236 to 255 indeterminate, which is curious.
>TDibGraphic produces a colour table with 256 greys
>very satisfactorily.
>The nagging question is how does it differentiate
>between a "Gray" image and a very desaturated colour
>image. Anyway, I can live without an answer <g>.
>Best wishes,

[ Next Thread | Previous Thread | Next Message | Previous Message ]

[ Contact Forum Admin ]

Forum timezone: GMT-5
VF Version: 3.00b, ConfDB:
Before posting please read our privacy policy.
VoyForums(tm) is a Free Service from Voyager Info-Systems.
Copyright © 1998-2019 Voyager Info-Systems. All Rights Reserved.