ppmtoilbm

Section: User Commands (1)
Updated: 23 October 1994
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NAME

ppmtoilbm - convert a portable pixmap into an IFF-ILBM, IFF-RGBN or IFF-RGB8 file

SYNOPSIS

DESCRIPTION

Reads a portable pixmap as input. Produces an IFF-ILBM, IFF-RGB8 or IFF-RGBN file as output. Supported ILBM types are:

Normal ILBMs: 1-16 planes, with colormap. Amiga display mode Hold-any-modify (HAM) is supported, with 3-10 planes (including the 2 control planes).
Deep ILBMs: 3-48 planes, direct RGB encoding. Usually 24 planes are used (for 8-bit RGB values).
Direct color ILBMs: 3-48 planes, direct RGB encoding. This is an experimental format that supports a different number of planes for each color component.
Colormap files: BMHD + CMAP chunk only, 0 planes.

OPTIONS

Options marked with (*) can be prefixed with a "no", e.g. '-nohamif'. Most options can only be used for IFF-ILBM files, if an option is usable with IFF-RGBN and IFF-RGB8 it is noted in the description. All options can be abbreviated to their shortest unique prefix.

-ilbm | -rgb8 | -rgbn: Write an IFF-ILBM, IFF-RGB8 or IFF-RGBN file. The default is IFF-ILBM.
-maxplanes N: Maximum planes to write in a normal ILBM. If the pixmap does not fit into N planes, ppmtoilbm writes a HAM file (if -hamif is used), a deep file (if -deepif is used), or a direct color file (if -dcif is used), or aborts with an error. The default value is 5 planes (for backwards compatibility), minimum value is 1 and maximum 8. This option can be abbreviated to -mp.
-fixplanes N: If a normal ILBM is written, it will have exactly N planes, even if the number of colors would fit into fewer planes. This option can be abbreviated to -fp.
-hamplanes N: Set the number of planes (including the two control planes) for a HAM picture. The current Amiga hardware supports 6 and 8 planes, so for now you should use only these values. The default value is 6 (for backwards compatibility), minimum value is 3, maximum 10.
-hambits N: Set the number of bits for a color component or index value in a HAM picture. This is the same as -hamplanes N+2
-hammap mode: Select HAM colormap. The default mode is gray for a grayscale colormap. This mode is fastest and all images of the same depth (number of planes) use the same colormap, which is useful for building animations. The mode fixed uses a fixed RGB colormap, evenly distributed pixels on the seven primary color rays (red, green, blue, yellow, magenta, cyan and gray). This mode can also be used for animations, but it is much slower than gray. The modes rgb4 and rgb5 compute an individial colormap for the image, using a simple algorithm for clustering colors in RGB space. These modes give the best results, but are very slow. rgb4 uses a 12-bit lookup table (4 bits per color component), rgb5 a 15-bit table (5 bits per color component).
-deepplanes N: Set the number of planes for a deep ILBM. N must be divisible by 3.
-deepbits N: Set the number of bits for a color component in a deep ILBM. This is the same as -deepplanes 3*N
-dcbits r g b | -dcplanes r g b: Set the number of bits for a color component in a direct color ILBM.
-normal: Turns off -hamif, -24if, -hamforce, -24force, -deepif, -deepforce and -cmaponly and sets compression type to byterun1. This is the default mode for IFF-ILBM files.
-hamif (*) | -deepif (*) | -dcif (*): Write a HAM/deep/direct color file if the pixmap does not fit into the maximum number of planes as given by the -maxplanes option.
-hamforce (*) | -deepforce (*) | -dcforce (*): Write a HAM/deep/direct color file, even if the number of colors would fit in a normal ILBM. Enforcing deep or direct color format allows stream-reading of the image file, as does HAM with gray colormap mode.
-24force (*): Shortcut for -deepplanes 8 -deepforce
-24if (*) (default): Shortcut for -deepplanes 8 -deepforce
-cmaponly: Write a colormap file: only BMHD and CMAP chunks, no BODY chunk, nPlanes = 0.
-ecs | -aga: Set the appropriate -hamplanes and -maxplanes values for the Amiga ECS or AGA chipset. ECS values are used by default for backwards compatibility.
-ham6: Write a HAM picture with 6 planes. This is a shortcut for -hamforce -hamplanes 6
-ham8: Write a HAM picture with 8 planes. This is a shortcut for -hamforce -hamplanes 8
-annotation string
-author string
-copyright string
-name string
-text string: Write an IFF annotation, author, copyright, name and/or text chunk (IDs "ANNO", "AUTH", "(c) ", "NAME", and "TEXT") into the output file. These are generic IFF text chunks and can be used for all file formats.
-hires (*), -lace (*): Sets the HIRES and LACE bits in the CAMG chunk and adjusts BMHD.xAspect/BMHD.yAspect accordingly. Other bits might be set in the CAMG chunk depending on other options. These options can be used with IFF-RGBN and IFF-RGB8 files.
-camg hexval: Write a specific value into the CAMG chunk. The hexadecimal value can be given with or without a 0x prefix. Other bits might be set in the CAMG chunk depending on other options. This option can be used with IFF-RGBN and IFF-RGB8 files.
-nocompress: Do not compress the BODY chunk. Compression requires building the ILBM image in memory; turning compression off allows stream-writing of the image, but the resulting file will usually be 30% to 50% larger. This options affect only IFF-ILBM files, IFF-RGBN and IFF-RGB8 files are always compressed using a pixel repeat count.
-cmethod method: Select compression method. Default is byterun1. Setting method to none is equivalent to using a -nocompress option. method can be abbreviated to the shortest unique prefix. Numeric values (0, 1) are also accepted.
-mapfile ppmfile: Use the colors in ppmfile as the colormap when writing an a normal or HAM ILBM file. The mapfile is a normal PPM image, it can be any shape, all that matters are the colors in it, and the order they appear in. If the colors in the input file do not match those in ppmfile, they are matched to a "best match", the "if"-options have no effect. Using a mapfile allows stream-reading of the image.
-sortcmap: Sort the colormap.
-mmethod method: Select masking method for ILBM files. method can be none
(no masking, default), maskplane and transparentcolor (only for normal ILBMs) lasso masks are are not supported yet. method can be abbreviated to the shortest unique prefix. Numeric values (0, 1, 2, 3) are also accepted.
-maskfile pbmfile: Use a mask file to mark transparent pixels in an IFF-ILBM. If the -mmethod option is not used, masking method is set to maskplane. pbmfile is a normal PBM image, the same size (or larger) as the input file. A pixel value of PBM_WHITE in the mask file means the corresponding in the input file is considered to be transparent, PBM_BLACK indicates an opaque pixel (think of the input file casting a shadow on a white screen). In an IFF-RGBN or IFF-RGB8 file, the mask file is used to set the genlock bits.
-transparent color: Mark the given color as transparent. The color is specified as in ppmmake(1). If the -mmethod options is not used, masking method is set to transparentcolor.
-floyd (*) | -fs (*): Use Floyd-Steinberg error diffusion for mapping the input colors to HAM or to the colors in a mapfile. The results are usually much better than without it, but it takes substantially more CPU time, so the default is off.

BUGS

Not all image types that are supported by ilbmtoppm can be generated with ppmtoilbm.

REFERENCES

Amiga ROM Kernel Reference Manual - Devices (3rd Ed.), Addison Wesley, ISBN 0-201-56775-X, Appendix A: Interchange File Format

AUTHORS

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Time: 21:30:29 GMT, March 01, 2023