@database loaders.guide @node Main "PPT I/O Modules" This documentation is a short description of the different file types PPT recognizes. Click on the name below to get to the point. [ (*) = Documention not yet complete ] @{" C-code " link C-code} @{" IFF ILBM " link ILBM} @{" Targa " link Targa} @{" JFIF/JPEG " link JPEG} @{" Compuserve GIF " link GIF} @{" PNG " link PNG} @{" PNM/PGM/PPM/PBM " link PNM} @{" Datatypes " link Datatypes} @{" YUVN " link YUVN} PPT saves the I/O modules in the PROGDIR:modules subdirectory. Any modules ending with ".iomod" taken to be an I/O module. NB: V2 used a completely another style of I/O module that ended in ".loader". If you happen to have these around, delete them. They're no use to anyone anymore and PPT wouldn't even load them even if you tried. @endnode @node Datatypes "datatypes.iomod" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: N/A @{b}LOAD FORMATS SUPPORTED@{ub} All picture datatypes you've cobbled your hard drive with. @{b}SAVE FORMATS SUPPORTED@{ub} None. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} None. @{b}DESCRIPTION@{ub} This IO module will use the new OS3.0 datatypes.library in order to load images. You can find new datatypes in Aminet, in directory util/dtype. Note that the current version of picture datatype is not equipped to handle more than 256 color images and thus all images you get have a maximum of 256 colors, even if the original image had more colors. This shortcoming has been corrected with CyberGfx picture.datatype, but so far PPT does not understand it. @{b}NOTES@{ub} The priority of this IO module is -100, so that it won't be tried until all other image loaders have failed to recognize the image. That way your own JPEG datatypes, for example, won't come into play before PPT's internal JPEG IO module. @{b}BUGS@{ub} Does not support the DTM_WRITE method. Is there really a need? @{b}SEE ALSO{@ub} Any good PD archive for a plethora of useful and useless datatypes. @endnode @node GIF "Compuserve GIF" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: INTERLACED/S,TRANSPARENT/N INTERLACED - saves an interlaced file. TRANSPARENT - set the given color to be transparent. Color 0 is always the background color. @{b}LOAD FORMATS SUPPORTED@{ub} GIF87, GIF89a. Interlaced images are supported. Transparent GIFs are supported from v1.1 onwards. @{b}SAVE FORMATS SUPPORTED@{ub} GIF87, GIF89a. Interlaced images are supported. Transparent GIFs are supported. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} None. @{b}DESCRIPTION@{ub} GIF is a very popular format in the PC environment and since it has been adopted as the standard for WWW, it has become extremely widely known. Unfortunately, UNISYS owns the patent for the LZW algorithm used in packing the image in the GIF file and decided that they wish their piece of the action and now you must pay money if you use GIF in a commercial or shareware program. GIF will hopefully be superseded by @{"PNG" link PNG} in the near future. @{b}NOTES@{ub} This module can be spread freely in any case. GIF animations will produce a warning, but you can load the first image in, though. This will have to do until I finish the animation support... ;-> @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @{"PNG" link PNG}, @{"PNG" link PNG}, @{"PNG" link PNG}, ... @endnode @node ILBM "Amiga IFF ILBM" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} Color: 1-8 bitplanes, 24 bitplanes. HAM6, HAM8, Extra Half-Brite. Both compressed and uncompressed images. @{b}SAVE FORMATS SUPPORTED@{ub} Color: 1-8 bitplanes, 24 bitplanes. HAM6, HAM8, Extra Half-Brite. Only compressed images are supported. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} Save: Annotation,Author. Load: Annotation,Author. @{b}DESCRIPTION@{ub} The IFF ILBM format has been the most popular format in the Amiga community. Every graphics package supports it and it is the only format that can save Amiga-specific images like Extra-Halfbrite, HAM and HAM8 (short for Hold And Modify). Also, the OS gives a good support for reading and writing IFF file formats, since the iffparse.library has been standard from version 2.0 onwards. However, the compression used by the ILBM algorithm is not very efficient and thus it looses in any competition for image size. For a much better compression algorithm, use @{"PNG" link PNG}. Of course, if you must save a HAM/HAM8 or ExtraHalfBrite image, only ILBM gives you the possibility to save Amiga viewmodes. @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @endnode @node JPEG "Joint Photographic Experts Group" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: COMPRESSIONLEVEL/N,PROGRESSIVE/S COMPRESSIONLEVEL - JPEG compression level. Must be between 0 and 100, the default is 75. PROGRESSIVE - When this switch is on, a progressive JPEG file will be saved. @{b}LOAD FORMATS SUPPORTED@{ub} 8 bit and 24 bit JFIF files. Progressive files are supported. @{b}SAVE FORMATS SUPPORTED@{ub} 8 bit and 24 bit JFIF files. Progressive files are supported. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} None. @{b}DESCRIPTION@{ub} JPEG is a @{"lossy" link lossy} image format, which is intended for real-world images. It is a very popular format since it produces very small files with no visible degradation. However, I do not recommend that you use JPEG for computer-generated files, because the result may be quite bad. @{b}NOTES@{ub} This loader needs to have a JPEGTMP: assign set up before using. If the JPEG file proves to be too large (for example, progressive JPEGs) to be written or read in one go, a temporary file may be created. @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @{"PNG" link PNG} @endnode @node PNG "Portable Network Graphics" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} 8, 24 and 32 bit images. Interlacing is not supported at the moment. @{b}SAVE FORMATS SUPPORTED@{ub} 8 and 24 bit images. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} None. @{b}DESCRIPTION@{ub} PNG is the new standard, designed to replace @{"GIF" link GIF} by the folks on the 'Net. It offers a very good compression using the patent-free GZIP algorithm and it supports a variety of data formats. Also, the compression is NOT @{"lossy" link lossy}, so no information is lost in this format. I heartily recommend using this format unless you have real-world images and wish to use @{"JPEG" link JPEG} for them. @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @{"JPEG" link JPEG} @endnode @node PPM "Portable Bitmap Format" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} P2,P3,P5 and P6 @{b}SAVE FORMATS SUPPORTED@{ub} P5 and P6 @{b}DESCRIPTION@{ub} PPM is a format used by the NetPBM package. It features a simple, non-compressed format that can handle bitmaps, grayscale and truecolor images alike, both in ASCII and binary formats. @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @endnode @node Targa "TrueVision Targa" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: COMPRESS/S COMPRESS - if this option is specified, the Targa file is compressed using a simple run-length encoding. @{b}LOAD FORMATS SUPPORTED@{ub} 8, 15, 16, 24 and 32 bit, colormapped and non-colormapped formats. Interleaved images are supported when loading. @{b}SAVE FORMATS SUPPORTED@{ub} 8 and 24 bit non-colormapped. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} None. @{b}DESCRIPTION@{ub} Targa is an old image format which is usually quite portable across machines. It is quite popular among PC-folks and is used by programs that do not wish to support very many image formats, as Targa is an extremely simple format. @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @endnode @node C-code "C-code" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} None. @{b}SAVE FORMATS SUPPORTED@{ub} 8 and 24 bit, with optional alpha channel. @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} ANNO. @{b}DESCRIPTION@{ub} This simple saver module writes out the image in a simple format that can be compiled and included in a C-program. The image file consists of several variables: UWORD XX_height : height of the image UWORD XX_width : width of the image UWORD XX_components : # of components in the image UBYTE XX_data[] : an array containing the image data. If the image is a colormapped image, the following variables also exist: UWORD XX_colors : # of colors in the image UBYTE XX_alpha : 0, if there is no alpha channel information UBYTE XX_cmap[] : An array containing the color map. If XX_alpha!=0, then each array element contains 4 values, in the ARGB order, otherwise just simple RGB values. In the above descriptions, XX is replaced by the image name (with any punctuation marks removed). @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @endnode @node YUVN "Vlab YUVN" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} Vlab YUVN. Alpha channel extensions are not currently supported. @{b}SAVE FORMATS SUPPORTED@{ub} @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} ANNO, AUTH. (loading only) @{b}DESCRIPTION@{ub} The YUVN image format is a rare format used (as far as I know) only by the VLab digitizing software by MacroSystem GmbH. Since the format is uncompressed, this is an inefficient method of storing information, and this is why I chose not to support saving YUV. However, if you need it, drop me some mail and I'll try to support saving YUVN images in the next release. @{b}NOTES@{ub} @{b}BUGS@{ub} Since I don't have very many YUV pictures, so I wasn't able to test this loader module thoroughly. If you have a spare VLab scanner, try to test the module as much as you can. Even better, send me some YUV images that have been saved with a variety of options. @{b}SEE ALSO{@ub} @endnode @node lossy "Lossy image compression" Lossy image compression means that in order to achieve greater compression level, some of the information in the original image is discarded. This degradation of the image is usually not visible to the eye, since the eye can be fooled into thinking no degradation has happened. However, if the image is compressed too much, then you're gonna see some so-called artifacts in the resulting image. @endnode @node Dummy "" @{b}REXX TEMPLATE@{ub} LOAD: SAVE: @{b}LOAD FORMATS SUPPORTED@{ub} @{b}SAVE FORMATS SUPPORTED@{ub} @{b}@{"EXTENSIONS" link PPT.guide/Extensions} SUPPORTED@{ub} @{b}DESCRIPTION@{ub} @{b}NOTES@{ub} @{b}BUGS@{ub} @{b}SEE ALSO{@ub} @endnode