tools/image-scale-cli/openspec/changes/archive/2026-04-11-scale-image-fixer/specs/image-scaling/spec.md

ADDED Requirements

Requirement: Scale image to fixed dimensions

The system SHALL resize images to specified width and height dimensions while supporting configurable aspect ratio handling.

Scenario: Scale with exact dimensions (stretch)

• WHEN user provides width and height with stretch mode
• THEN image is resized to exact dimensions regardless of original aspect ratio

Scenario: Scale with fit mode (preserve aspect ratio)

• WHEN user provides width and height with fit mode
• THEN image is resized to fit within dimensions while preserving aspect ratio

Scenario: Scale with cover mode (preserve aspect ratio)

• WHEN user provides width and height with cover mode
• THEN image is resized to cover dimensions while preserving aspect ratio, cropping excess

Requirement: Support multiple image formats

The system SHALL process PNG, JPEG, WebP, and GIF image formats for both input and output.

Scenario: Process PNG image

• WHEN user provides a PNG file as input
• THEN system successfully scales and outputs the image

Scenario: Process JPEG image

• WHEN user provides a JPEG file as input
• THEN system successfully scales and outputs the image

Scenario: Process WebP image

• WHEN user provides a WebP file as input
• THEN system successfully scales and outputs the image

Scenario: Process GIF image

• WHEN user provides a GIF file as input
• THEN system successfully scales and outputs the image

Requirement: Batch processing

The system SHALL process multiple images in a single operation when provided with a directory or multiple file paths.

Scenario: Process directory of images

• WHEN user provides a directory path
• THEN all supported images in the directory are scaled

Scenario: Process multiple files

• WHEN user provides multiple file paths
• THEN all specified images are scaled

Requirement: CLI interface

The system SHALL provide a command-line interface for specifying input, output, and scaling options.

Scenario: Scale single image

• WHEN user runs command with input file, output path, width, and height
• THEN scaled image is saved to output path

Scenario: Invalid input handling

• WHEN user provides non-existent file or unsupported format
• THEN system displays clear error message and exits with non-zero code