add image scale [not tested]

2026-03-08 14:14:57 +08:00
parent b091ad73d6
commit 27946da3f9
4 changed files with 487 additions and 0 deletions
--- a/image-scale/main.ts
+++ b/image-scale/main.ts
@@ -0,0 +1,117 @@
+import sharp from "sharp";
+import { parseArgs } from "@std/cli/parse-args";
+import { basename, extname, join } from "@std/path";
+
+/**
+ * Resize an image so that its smallest dimension equals the specified minimum pixels.
+ * Output format is always JPG.
+ *
+ * @param inputPath - Path to the input image (PNG or JPG)
+ * @param outputPath - Path to the output JPG image
+ * @param minPixels - The minimum dimension (width or height) in pixels
+ */
+export async function scaleImage(
+  inputPath: string,
+  outputPath: string,
+  minPixels: number,
+): Promise<void> {
+  if (minPixels <= 0) {
+    throw new Error("minPixels must be a positive number");
+  }
+
+  const metadata = await sharp(inputPath).metadata();
+  const originalWidth = metadata.width;
+  const originalHeight = metadata.height;
+
+  if (!originalWidth || !originalHeight) {
+    throw new Error("Could not determine image dimensions");
+  }
+
+  // Calculate the scale factor based on the smaller dimension
+  const minDimension = Math.min(originalWidth, originalHeight);
+  const scaleFactor = minPixels / minDimension;
+
+  const newWidth = Math.round(originalWidth * scaleFactor);
+  const newHeight = Math.round(originalHeight * scaleFactor);
+
+  await sharp(inputPath)
+    .resize(newWidth, newHeight)
+    .jpeg({ quality: 90 })
+    .toFile(outputPath);
+
+  console.log(
+    `Resized: ${originalWidth}x${originalHeight} -> ${newWidth}x${newHeight} (min dimension: ${minPixels}px)`,
+  );
+}
+
+/**
+ * Generate output path for the scaled image.
+ * Changes the extension to .jpg
+ */
+export function getOutputPath(inputPath: string, outputDir?: string): string {
+  const base = basename(inputPath, extname(inputPath));
+  const dir = outputDir || join(inputPath, "..");
+  return join(dir, `${base}.jpg`);
+}
+
+function printUsage() {
+  console.log(`
+Usage: deno run --allow-read --allow-write main.ts <input-image> [options]
+
+Arguments:
+  input-image          Path to the input image (PNG or JPG)
+
+Options:
+  --min-pixels, -m     Minimum dimension in pixels (default: 1200)
+  --output, -o         Output directory or file path
+  --help, -h           Show this help message
+
+Examples:
+  deno run --allow-read --allow-write main.ts input.png -m 1200
+  deno run --allow-read --allow-write main.ts input.jpg -m 800 -o ./output
+  deno run --allow-read --allow-write main.ts input.png -m 1920 -o ./resized.jpg
+`);
+}
+
+if (import.meta.main) {
+  const flags = parseArgs(Deno.args, {
+    string: ["output", "o", "min-pixels", "m"],
+    boolean: ["help", "h"],
+    alias: {
+      "min-pixels": "m",
+      output: "o",
+      help: "h",
+    },
+    default: {
+      "min-pixels": "1200",
+    },
+  });
+
+  if (flags.help) {
+    printUsage();
+    Deno.exit(0);
+  }
+
+  const inputPath = flags._[0] as string | undefined;
+
+  if (!inputPath) {
+    console.error("Error: Input image path is required");
+    printUsage();
+    Deno.exit(1);
+  }
+
+  const minPixels = parseInt(flags["min-pixels"] as string, 10);
+  const outputPath = flags.output
+    ? flags.output.endsWith(".jpg") || flags.output.endsWith(".jpeg")
+      ? flags.output as string
+      : getOutputPath(inputPath, flags.output as string)
+    : getOutputPath(inputPath);
+
+  try {
+    await scaleImage(inputPath, outputPath, minPixels);
+    console.log(`Output saved to: ${outputPath}`);
+  } catch (error) {
+    console.error("Error:", error instanceof Error ? error.message : error);
+    Deno.exit(1);
+  }
+}