Short: Env-test if pic-dt supports alpha channel Author: Andreas R. Kleinert Uploader: info ar-kleinert de Type: gfx/misc Version: 1.2 (27.1.2008) Architecture: m68k-amigaos >= 3.1.0; ppc-morphos >= 1.4.5 TestDTAlpha - Freeware. This tool is freely redistributable and usable upon the conditions that this notice remains intact and that modified versions of this archive are not distributed in any way. The author makes no warranty of any kind with respect to this product and explicitly disclaims any implied warranties of merchantability or fitness for any particular purpose. If you are going to this tool within one of your programs and include it into your program's distribution, feel free to do so. In this case you have to add the following statement into your program's documentation: "This program makes use of TestDTAlpha @ 2008 by Andreas R. Kleinert". Note: This tool requires dtimage.library - Freeware. (included is V3.1 for testing purposes) ************************************************************************************ There is at least one V44/45 version of picture.datatype in some OS version which does NOT support alpha channel export (always returns fixed value for alpha byte, no matter what is set by the corresponding image Datatype). This makes it hard for image datatypes to decide whether to support alpha channel or not. This tool does the following: It checks if the first RGBA pixel of a given image - after loading via datatypes - equals 21190385 ($15130355). Actually only the last byte is of interest, which contains an alpha value different from $00 or $FF. If the check is successful, the following ENV variable is created: ENV:Datatypes/PICDTALPHA ALPHA=OK [linefeed] otherwise ENV:Datatypes/PICDTALPHA ALPHA=BAD [linefeed] The ENV variable must have this entry in the first line. Any further content is optional. Syntax: TestDTAlpha 1pixelimage-withalpha.ext Three 1 pixel test files for PNG, TIFF and SVG are included. How to interpret the ENV variable: If it does not exist, assume that pic-dt does support alpha channel and allow the end-user manual control over any kind of settings. If it exists and contains "BAD" then pic-dt does not support alpha channel. If it exists and contains "OK" then pic-dt does support alpha channel. ************************************************************************************ Main changes since previous versions: V1.2 (27.1.2007): - now using dtimage v3.3, which fixes an issue with PDTA_Remap (-> Bernd Roesch) - fixed V1.1 history V1.1 (26.1.2007): - now using dtimage v3.2, which always sets PDTA_DitherQuality to 0, (-> Thomas Klein) - some pic-dts (e.g. with alpha.tif) crashed on 1x1 pixel images on some systems (could not reproduce) (-> Thomas Klein) - added 8x8 pixel image versions ************************************************************************************ © 2008 by Dipl.-Ing. Andreas Kleinert. All rights reserved.