template-project/watermark-canvas.cjs
2025-05-30 18:13:30 +08:00

87 lines
2.8 KiB
JavaScript

const { createCanvas, loadImage, registerFont } = require("canvas");
const exiftool = require("exiftool-vendored");
const fs = require("fs");
const path = require("path");
// Optional: Register a custom font if needed (must be a .ttf or .otf file)
registerFont(path.join(__dirname, "fonts", "OpenSans-Regular.ttf"), {
family: "Open Sans",
});
function getDateInFilename(filename) {
const datePattern = /\d{4}-\d{2}-\d{2}/;
const match = filename.match(datePattern);
return match ? match[0] : null;
}
function getTimeInFilename(filename) {
const time = filename.split("_")[2];
return time ? time.split('.')[0] + ":" + time.split('.')[1] : null;
}
async function getImageDate(filename, imageInput) {
try {
const filePath = path.join(imageInput, filename);
const hasDateInName = /\d{4}-\d{2}-\d{2}/.test(filename);
let dateFromFilename = null;
let timeFromFilename = null;
if (hasDateInName) {
dateFromFilename = getDateInFilename(filename);
timeFromFilename = getTimeInFilename(filename);
}
if (dateFromFilename && timeFromFilename) {
return `${dateFromFilename} ${timeFromFilename}`;
}
const tags = await exiftool.exiftool.read(filePath);
if (tags?.DateTimeOriginal?.rawValue) {
const [dateOnly, timeFull] = tags.DateTimeOriginal.rawValue.split(" ");
const timeOnly = timeFull?.slice(0, 5);
const [year, month, day] = dateOnly.split(":");
return `${year}-${month}-${day} ${timeOnly}`;
}
const stats = await fs.promises.stat(filePath);
const mtime = stats.mtime;
return `${mtime.getFullYear()}-${String(mtime.getMonth() + 1).padStart(2, "0")}-${String(mtime.getDate()).padStart(2, "0")} ${String(mtime.getHours()).padStart(2, "0")}:${String(mtime.getMinutes()).padStart(2, "0")}`;
} catch (err) {
console.error("Failed to read EXIF:", err);
}
}
async function addWatermark(filename, buffer, watermarkText) {
const image = await loadImage(buffer);
const canvas = createCanvas(image.width, image.height);
const ctx = canvas.getContext("2d");
// Draw the original image
ctx.drawImage(image, 0, 0);
// Watermark styles
ctx.font = "32px 'Open Sans'";
ctx.fillStyle = "rgba(255, 255, 255, 0.8)";
ctx.textAlign = "right";
ctx.textBaseline = "bottom";
// Draw the watermark
ctx.fillText(watermarkText, image.width - 10, image.height - 10);
return canvas.toBuffer("image/jpeg");
}
async function watermarkAllImages(bufferMap, imageInput) {
const outputMap = {};
for (const [filename, buffer] of Object.entries(bufferMap)) {
const watermarkText = await getImageDate(filename, imageInput);
const watermarkedBuffer = await addWatermark(filename, buffer, watermarkText);
outputMap[filename] = watermarkedBuffer;
}
return outputMap;
}
module.exports = {
watermarkAllImages,
};