aspect-calc（方面计算）

Aspect Ratio Calculator

Calculate simplified aspect ratios from pixel dimensions, find missing dimensions from a known ratio, and report decimal and percentage equivalents using GCD simplification.

Input

• Two dimensions (width and height in pixels), OR
• A known ratio (e.g., 16:9) and one dimension (width or height), to calculate the missing value

Output

• Simplified ratio (e.g., 16:9)
• Decimal ratio (e.g., 1.7778)
• Percentage (width as % of height, e.g., 177.78%)
• If solving for missing dimension: the calculated value

Instructions

1. Parse the user's input to determine the mode:

- Mode A: two pixel dimensions given → calculate ratio and metadata - Mode B: ratio + one dimension given → calculate the missing dimension

1. Mode A — Ratio from dimensions:

a. Compute divisor = GCD(width, height) using the Euclidean algorithm: GCD(a, b) = b === 0 ? a : GCD(b, a % b) b. Simplified ratio: (width / divisor):(height / divisor) c. Decimal: (width / height).toFixed(4) d. Percentage: (width / height * 100).toFixed(2)%

1. Mode B — Dimension from ratio:

a. Parse the ratio as rW:rH b. If width is given: height = round(width * rH / rW) c. If height is given: width = round(height * rW / rH)

1. Identify if the ratio matches a known standard and name it:

- 16:9 → HD Video / Widescreen - 4:3 → Classic TV / Standard - 1:1 → Square - 21:9 → Ultrawide - 9:16 → Mobile Video / Story - 3:4 → Portrait Classic - 3:2 → 35mm Film - 2:3 → Portrait Photo

1. Output all results clearly.

Options

• width: positive integer
• height: positive integer
• ratio: string in W:H format — for Mode B
• locked: if true, preserve the current ratio when one dimension changes

Examples

Input: "What is the aspect ratio of 1920x1080?" Output:

• Simplified ratio: 16:9 (HD Video / Widescreen)
• Decimal: 1.7778
• Percentage: 177.78% (width is 177.78% of height)

Input: "I have a 16:9 video, width is 1280px — what height do I need?" Output:

• Width: 1280px, Ratio: 16:9
• Height: 720px
• (1280 × 9 / 16 = 720)

Input: "Simplify 2560x1440" Output:

• Simplified ratio: 16:9 (HD Video / Widescreen)
• Decimal: 1.7778
• Percentage: 177.78%

Input: "What is the aspect ratio of 800x600?" Output:

• Simplified ratio: 4:3 (Classic TV / Standard)
• Decimal: 1.3333
• Percentage: 133.33%

Input: "Give me height for a 21:9 ultrawide at 2560px width" Output:

• Width: 2560px, Ratio: 21:9
• Height: 1097px
• (2560 × 9 / 21 ≈ 1097)

Error Handling

• If either dimension is 0 or negative, return an error: "Dimensions must be positive integers greater than 0."
• If a ratio is provided in an invalid format (not W:H), ask the user to use the W:H format (e.g., 16:9).
• If both dimensions result in the same ratio numerator and denominator equal to 1 (e.g., prime dimensions with no common factor), output the ratio as-is and note it cannot be simplified further.