How to use the command ppmshadow (with examples)

The ppmshadow command is used to add simulated shadows to a PPM image. PPM is a file format used to store images in a portable manner. Shadows can enhance the visual appeal of an image and add depth to it. The ppmshadow command provides various options to control the appearance of the shadows, such as blur, light source displacement, and more.

Use case 1: Add simulated shadows to a PPM image

Code:

ppmshadow path/to/input_file.ppm > path/to/output_file.ppm

Motivation: Adding shadows to an image can make it look more realistic and visually appealing. This use case allows users to add simulated shadows to a PPM image using the ppmshadow command.

Explanation:

• ppmshadow: The command to add simulated shadows to a PPM image.
• path/to/input_file.ppm: The path to the input PPM image file.
• >: Redirects the output of the command to a file.
• path/to/output_file.ppm: The path to the output PPM image file.

Example output: The input PPM image with simulated shadows will be saved as the output file specified.

Use case 2: Blur the image by the specified number of pixels

Code:

ppmshadow -b n path/to/input_file.ppm > path/to/output_file.ppm

Motivation: Blurring an image can help to reduce noise or create a subtle effect. This use case allows users to blur the image while adding simulated shadows, giving a soft and appealing look to the final output.

Explanation:

• -b n: The -b flag is used to specify blurring the image. n represents the number of pixels to blur the image by.
• path/to/input_file.ppm: The path to the input PPM image file.
• >: Redirects the output of the command to a file.
• path/to/output_file.png: The path to the output PPM image file.

Example output: The input PPM image will be blurred by the specified number of pixels and then simulated shadows will be added. The final output will be saved as the output file specified.

Use case 3: Specify the displacement of the simulated light source

Code:

ppmshadow -x left_offset -y top_offset path/to/input_file.ppm > path/to/output_file.ppm

Motivation: Adjusting the displacement of the simulated light source allows users to control the direction and position of the shadows. This use case provides the flexibility to place the shadows exactly where desired, enhancing the image composition.

Explanation:

• -x left_offset: The -x flag is used to specify the displacement of the simulated light source to the left of the image. left_offset represents the number of pixels to move the light source to the left.
• -y top_offset: The -y flag is used to specify the displacement of the simulated light source to the top of the image. top_offset represents the number of pixels to move the light source to the top.
• path/to/input_file.ppm: The path to the input PPM image file.
• >: Redirects the output of the command to a file.
• path/to/output_file.ppm: The path to the output PPM image file.

Example output: The input PPM image will have simulated shadows added with the specified displacement of the light source. The final output will be saved as the output file specified.

Conclusion:

The ppmshadow command is a versatile tool for adding simulated shadows to PPM images. The various options provided allow users to customize the appearance of the shadows according to their preferences. Whether it’s adding shadows to enhance realism or to create a specific artistic effect, the ppmshadow command is an essential tool for image manipulation.