How to use the command ppmlabel (with examples)

The ppmlabel command is used to add text to a PPM (Portable Pixmap) image. It allows you to specify the position, color, background, angle, and size of the added text. This command is especially useful when you want to annotate or label an image with custom text.

Use case 1: Add text to a PPM image at the specified location

Code:

ppmlabel -x pos_x -y pos_y -text text path/to/input_file.ppm > path/to/output_file.ppm

Motivation: This use case is perfect when you want to add a single text label to the PPM image at a specific location. For example, you may want to label an object in the image with its name or provide additional contextual information.

Explanation:

• -x pos_x: Specifies the x-coordinate of the position where the text will be added.
• -y pos_y: Specifies the y-coordinate of the position where the text will be added.
• -text text: Specifies the text that will be added to the image.
• path/to/input_file.ppm: The path to the input PPM image file.
• > path/to/output_file.ppm: Redirects the output to the specified file path.

Example output: The command ppmlabel -x 100 -y 200 -text "Object 1" input.ppm > output.ppm will add the text “Object 1” to the input.ppm image at position (100, 200) and save the resulting image to output.ppm.

Use case 2: Add multiple texts at different locations

Code:

ppmlabel -x pos_x1 -y pos_y1 -text text1 -x pos_x2 -y pos_y2 -text text2 path/to/input_file.ppm > path/to/output_file.ppm

Motivation: This use case is useful when you need to add multiple text labels to the PPM image at different positions. For example, you may want to annotate various objects in the image or provide a detailed description of different regions.

Explanation:

• -x pos_x1 -y pos_y1: Specifies the x and y coordinates of the first position where the first text will be added.
• -text text1: Specifies the first text that will be added to the image.
• -x pos_x2 -y pos_y2: Specifies the x and y coordinates of the second position where the second text will be added.
• -text text2: Specifies the second text that will be added to the image.
• path/to/input_file.ppm: The path to the input PPM image file.
• > path/to/output_file.ppm: Redirects the output to the specified file path.

Example output: The command ppmlabel -x 100 -y 200 -text "Object 1" -x 300 -y 400 -text "Object 2" input.ppm > output.ppm will add the text “Object 1” to the input.ppm image at position (100, 200) and the text “Object 2” at position (300, 400), then save the resulting image to output.ppm.

Use case 3: Specify the line color, background color, tilt, and size of the added text

Code:

ppmlabel -x pos_x -y pos_y -color line_color -background background_color -angle tilt -size size -text text path/to/input_file.ppm > path/to/output_file.ppm

Motivation: This use case is handy when you want to customize the appearance of the added text. You can specify the line color, background color, tilt, and size to make the text stand out or match the aesthetic of the image.

Explanation:

• -x pos_x: Specifies the x-coordinate of the position where the text will be added.
• -y pos_y: Specifies the y-coordinate of the position where the text will be added.
• -color line_color: Specifies the line color of the text. It could be a color name or a color code.
• -background background_color: Specifies the background color behind the text. It could be a color name or a color code.
• -angle tilt: Specifies the angle at which the text will be tilted (in degrees).
• -size size: Specifies the size of the text.
• -text text: Specifies the text that will be added to the image.
• path/to/input_file.ppm: The path to the input PPM image file.
• > path/to/output_file.ppm: Redirects the output to the specified file path.

Example output: The command ppmlabel -x 100 -y 200 -color red -background yellow -angle 45 -size 24 -text "Object" input.ppm > output.ppm will add the text “Object” to the input.ppm image at position (100, 200) with red line color, yellow background color, tilted at 45 degrees, and a size of 24. The resulting image will be saved to output.ppm.

Conclusion:

The ppmlabel command provides a flexible way to add text to PPM images, allowing users to specify the position, color, background, tilt, and size of the text. This command is useful for annotating images, adding labels, or providing additional information in a customizable manner. Whether you need to add a single text label or multiple texts at different positions, ppmlabel has got you covered.