How to use the command ppmtoilbm (with examples)

PPMtoILBM is a command-line tool that converts a PPM (Portable Pixmap) image file to an ILBM (Interleaved Bitmap) file format. The ILBM format is widely used in the Amiga computer system and is used to store images, animations, and other graphic data.

Use case 1: Convert a PPM image to an ILBM file

Code:

ppmtoilbm path/to/file.ppm > path/to/file.ilbm

Motivation: You may want to convert a PPM image to an ILBM file to use it in Amiga software or projects that require the ILBM format.

Explanation:

• ppmtoilbm is the command to convert the PPM image to an ILBM file.
• path/to/file.ppm specifies the location of the input PPM image file.
• > is a shell redirect operator that saves the output of the command to a file.
• path/to/file.ilbm is the path and name of the output ILBM file.

Example output: The PPM image will be converted to an ILBM file and saved at the specified location.

Use case 2: Write a maximum of n planes to the ILBM file and produce a HAM/24bit/direct color file if this number is exceeded

Code:

ppmtoilbm -maxplanes n -hamif|24if|dcif path/to/file.ppm > path/to/file.ilbm

Motivation: In some cases, you may want to limit the number of color planes used in the ILBM file or produce a different ILBM file format if the number of planes exceeds a certain threshold.

Explanation:

• -maxplanes n specifies the maximum number of color planes allowed in the ILBM file (n is the number of planes).
• -hamif|24if|dcif specifies the file format to be used if the maximum number of planes is exceeded. You can choose between HAM (Hold-And-Modify), 24-bit/direct color, or direct color formats.
• path/to/file.ppm specifies the input PPM image file.
• > is a shell redirect operator that saves the output of the command to a file.
• path/to/file.ilbm is the path and name of the output ILBM file.

Example output: The PPM image will be converted to an ILBM file with a maximum of n planes. If the number of planes exceeds the specified maximum, the output file will be in the format specified (HAM/24bit/direct color).

Use case 3: Produce an ILBM file with exactly n planes

Code:

ppmtoilbm -fixplanes n path/to/file.ppm > path/to/file.ilbm

Motivation: Sometimes you may want to ensure that the ILBM file has a specific number of color planes, regardless of the input image.

Explanation:

• -fixplanes n specifies the exact number of color planes to be used in the ILBM file (n is the number of planes).
• path/to/file.ppm specifies the input PPM image file.
• > is a shell redirect operator that saves the output of the command to a file.
• path/to/file.ilbm is the path and name of the output ILBM file.

Example output: The PPM image will be converted to an ILBM file with exactly n planes, regardless of the number of planes in the input image.

Use case 4: Select the compression method to be used

Code:

ppmtoilbm -compress|nocompress|savemem path/to/file.ppm > path/to/file.ilbm

Motivation: You may want to choose the compression method used in the ILBM file, depending on the specific requirements of your project or software.

Explanation:

• -compress|nocompress|savemem specifies the compression method to be used in the ILBM file. You can choose between compressing the image data, not compressing it, or using a memory-saving compression method.
• path/to/file.ppm specifies the input PPM image file.
• > is a shell redirect operator that saves the output of the command to a file.
• path/to/file.ilbm is the path and name of the output ILBM file.

Example output: The PPM image will be converted to an ILBM file using the specified compression method.

Conclusion:

The ppmtoilbm command is a versatile tool for converting PPM image files to the ILBM format used in the Amiga computer system. It provides options to control the number of planes, choose different file formats, and select compression methods, allowing you to customize the output ILBM file to suit your specific needs.