Files
bentopdf/src/js/utils/pdf-operations.ts

525 lines
16 KiB
TypeScript

import { PDFDocument, degrees, rgb, StandardFonts, PageSizes } from 'pdf-lib';
export async function mergePdfs(
pdfBytesList: Uint8Array[]
): Promise<Uint8Array> {
const mergedDoc = await PDFDocument.create();
for (const bytes of pdfBytesList) {
const srcDoc = await PDFDocument.load(bytes);
const copiedPages = await mergedDoc.copyPages(
srcDoc,
srcDoc.getPageIndices()
);
copiedPages.forEach((page) => mergedDoc.addPage(page));
}
return new Uint8Array(await mergedDoc.save({ addDefaultPage: false }));
}
export async function splitPdf(
pdfBytes: Uint8Array,
pageIndices: number[]
): Promise<Uint8Array> {
const srcDoc = await PDFDocument.load(pdfBytes);
const newPdf = await PDFDocument.create();
const copiedPages = await newPdf.copyPages(srcDoc, pageIndices);
copiedPages.forEach((page) => newPdf.addPage(page));
return new Uint8Array(await newPdf.save());
}
export async function rotatePdfUniform(
pdfBytes: Uint8Array,
angle: number
): Promise<Uint8Array> {
const srcDoc = await PDFDocument.load(pdfBytes);
const newPdfDoc = await PDFDocument.create();
const pageCount = srcDoc.getPageCount();
for (let i = 0; i < pageCount; i++) {
const originalPage = srcDoc.getPage(i);
const currentRotation = originalPage.getRotation().angle;
const totalRotation = currentRotation + angle;
if (totalRotation % 90 === 0) {
const [copiedPage] = await newPdfDoc.copyPages(srcDoc, [i]);
copiedPage.setRotation(degrees(totalRotation));
newPdfDoc.addPage(copiedPage);
} else {
const embeddedPage = await newPdfDoc.embedPage(originalPage);
const { width, height } = embeddedPage.scale(1);
const angleRad = (totalRotation * Math.PI) / 180;
const absCos = Math.abs(Math.cos(angleRad));
const absSin = Math.abs(Math.sin(angleRad));
const newWidth = width * absCos + height * absSin;
const newHeight = width * absSin + height * absCos;
const newPage = newPdfDoc.addPage([newWidth, newHeight]);
const x =
newWidth / 2 -
((width / 2) * Math.cos(angleRad) - (height / 2) * Math.sin(angleRad));
const y =
newHeight / 2 -
((width / 2) * Math.sin(angleRad) + (height / 2) * Math.cos(angleRad));
newPage.drawPage(embeddedPage, {
x,
y,
width,
height,
rotate: degrees(totalRotation),
});
}
}
return new Uint8Array(await newPdfDoc.save());
}
export async function rotatePdfPages(
pdfBytes: Uint8Array,
rotations: number[]
): Promise<Uint8Array> {
const srcDoc = await PDFDocument.load(pdfBytes);
const newPdfDoc = await PDFDocument.create();
const pageCount = srcDoc.getPageCount();
for (let i = 0; i < pageCount; i++) {
const rotation = rotations[i] || 0;
const originalPage = srcDoc.getPage(i);
const currentRotation = originalPage.getRotation().angle;
const totalRotation = currentRotation + rotation;
if (totalRotation % 90 === 0) {
const [copiedPage] = await newPdfDoc.copyPages(srcDoc, [i]);
copiedPage.setRotation(degrees(totalRotation));
newPdfDoc.addPage(copiedPage);
} else {
const embeddedPage = await newPdfDoc.embedPage(originalPage);
const { width, height } = embeddedPage.scale(1);
const angleRad = (totalRotation * Math.PI) / 180;
const absCos = Math.abs(Math.cos(angleRad));
const absSin = Math.abs(Math.sin(angleRad));
const newWidth = width * absCos + height * absSin;
const newHeight = width * absSin + height * absCos;
const newPage = newPdfDoc.addPage([newWidth, newHeight]);
const x =
newWidth / 2 -
((width / 2) * Math.cos(angleRad) - (height / 2) * Math.sin(angleRad));
const y =
newHeight / 2 -
((width / 2) * Math.sin(angleRad) + (height / 2) * Math.cos(angleRad));
newPage.drawPage(embeddedPage, {
x,
y,
width,
height,
rotate: degrees(totalRotation),
});
}
}
return new Uint8Array(await newPdfDoc.save());
}
export async function deletePdfPages(
pdfBytes: Uint8Array,
pagesToDelete: Set<number>
): Promise<Uint8Array> {
const srcDoc = await PDFDocument.load(pdfBytes);
const totalPages = srcDoc.getPageCount();
const pagesToKeep: number[] = [];
for (let i = 0; i < totalPages; i++) {
if (!pagesToDelete.has(i + 1)) {
pagesToKeep.push(i);
}
}
if (pagesToKeep.length === 0) throw new Error('Cannot delete all pages');
const newPdf = await PDFDocument.create();
const copiedPages = await newPdf.copyPages(srcDoc, pagesToKeep);
copiedPages.forEach((page) => newPdf.addPage(page));
return new Uint8Array(await newPdf.save());
}
export function parsePageRange(rangeStr: string, totalPages: number): number[] {
const indices: Set<number> = new Set();
const parts = rangeStr.split(',').map((s) => s.trim());
for (const part of parts) {
if (part.includes('-')) {
const [startStr, endStr] = part.split('-');
const start = Math.max(1, parseInt(startStr, 10) || 1);
const end = Math.min(totalPages, parseInt(endStr, 10) || totalPages);
for (let i = start; i <= end; i++) {
indices.add(i - 1);
}
} else {
const page = parseInt(part, 10);
if (page >= 1 && page <= totalPages) {
indices.add(page - 1);
}
}
}
return Array.from(indices).sort((a, b) => a - b);
}
export function parseDeletePages(str: string, totalPages: number): Set<number> {
const pages = new Set<number>();
const parts = str.split(',').map((s) => s.trim());
for (const part of parts) {
if (part.includes('-')) {
const [startStr, endStr] = part.split('-');
const start = Math.max(1, parseInt(startStr, 10) || 1);
const end = Math.min(totalPages, parseInt(endStr, 10) || totalPages);
for (let i = start; i <= end; i++) pages.add(i);
} else {
const page = parseInt(part, 10);
if (page >= 1 && page <= totalPages) pages.add(page);
}
}
return pages;
}
export interface TextWatermarkOptions {
text: string;
fontSize: number;
color: { r: number; g: number; b: number };
opacity: number;
angle: number;
x?: number;
y?: number;
pageIndices?: number[];
}
export async function addTextWatermark(
pdfBytes: Uint8Array,
options: TextWatermarkOptions
): Promise<Uint8Array> {
const pdfDoc = await PDFDocument.load(pdfBytes);
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
if (!ctx) throw new Error('Failed to create canvas context');
const dpr = 2;
const colorR = Math.round(options.color.r * 255);
const colorG = Math.round(options.color.g * 255);
const colorB = Math.round(options.color.b * 255);
const fontStr = `bold ${options.fontSize * dpr}px "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", "Noto Sans Arabic", Arial, sans-serif`;
ctx.font = fontStr;
const metrics = ctx.measureText(options.text);
canvas.width = Math.ceil(metrics.width) + 4;
canvas.height = Math.ceil(options.fontSize * dpr * 1.4);
ctx.font = fontStr;
ctx.fillStyle = `rgb(${colorR}, ${colorG}, ${colorB})`;
ctx.textBaseline = 'middle';
ctx.fillText(options.text, 2, canvas.height / 2);
const blob = await new Promise<Blob>((resolve, reject) => {
canvas.toBlob(
(b) => (b ? resolve(b) : reject(new Error('Canvas toBlob failed'))),
'image/png'
);
});
const imageBytes = new Uint8Array(await blob.arrayBuffer());
const image = await pdfDoc.embedPng(imageBytes);
const pages = pdfDoc.getPages();
const posX = options.x ?? 0.5;
const posY = options.y ?? 0.5;
const imgWidth = image.width / dpr;
const imgHeight = image.height / dpr;
const rad = (options.angle * Math.PI) / 180;
const halfW = imgWidth / 2;
const halfH = imgHeight / 2;
const targetIndices = options.pageIndices ?? pages.map((_, i) => i);
for (const idx of targetIndices) {
const page = pages[idx];
if (!page) continue;
const { width, height } = page.getSize();
const cx = posX * width;
const cy = posY * height;
page.drawImage(image, {
x: cx - Math.cos(rad) * halfW + Math.sin(rad) * halfH,
y: cy - Math.sin(rad) * halfW - Math.cos(rad) * halfH,
width: imgWidth,
height: imgHeight,
opacity: options.opacity,
rotate: degrees(options.angle),
});
}
return new Uint8Array(await pdfDoc.save());
}
export interface ImageWatermarkOptions {
imageBytes: Uint8Array;
imageType: 'png' | 'jpg';
opacity: number;
angle: number;
scale: number;
x?: number;
y?: number;
pageIndices?: number[];
}
export async function addImageWatermark(
pdfBytes: Uint8Array,
options: ImageWatermarkOptions
): Promise<Uint8Array> {
const pdfDoc = await PDFDocument.load(pdfBytes);
const image =
options.imageType === 'png'
? await pdfDoc.embedPng(options.imageBytes)
: await pdfDoc.embedJpg(options.imageBytes);
const pages = pdfDoc.getPages();
const posX = options.x ?? 0.5;
const posY = options.y ?? 0.5;
const imgWidth = image.width * options.scale;
const imgHeight = image.height * options.scale;
const rad = (options.angle * Math.PI) / 180;
const halfW = imgWidth / 2;
const halfH = imgHeight / 2;
const targetIndices = options.pageIndices ?? pages.map((_, i) => i);
for (const idx of targetIndices) {
const page = pages[idx];
if (!page) continue;
const { width, height } = page.getSize();
const cx = posX * width;
const cy = posY * height;
page.drawImage(image, {
x: cx - Math.cos(rad) * halfW + Math.sin(rad) * halfH,
y: cy - Math.sin(rad) * halfW - Math.cos(rad) * halfH,
width: imgWidth,
height: imgHeight,
opacity: options.opacity,
rotate: degrees(options.angle),
});
}
return new Uint8Array(await pdfDoc.save());
}
export type PageNumberPosition =
| 'bottom-center'
| 'bottom-left'
| 'bottom-right'
| 'top-center'
| 'top-left'
| 'top-right';
export type PageNumberFormat = 'simple' | 'page_x_of_y';
export interface PageNumberOptions {
position: PageNumberPosition;
fontSize: number;
format: PageNumberFormat;
color: { r: number; g: number; b: number };
}
export async function addPageNumbers(
pdfBytes: Uint8Array,
options: PageNumberOptions
): Promise<Uint8Array> {
const pdfDoc = await PDFDocument.load(pdfBytes);
const helveticaFont = await pdfDoc.embedFont(StandardFonts.Helvetica);
const pages = pdfDoc.getPages();
const totalPages = pages.length;
for (let i = 0; i < totalPages; i++) {
const page = pages[i];
const mediaBox = page.getMediaBox();
const cropBox = page.getCropBox();
const bounds = cropBox || mediaBox;
const width = bounds.width;
const height = bounds.height;
const xOffset = bounds.x || 0;
const yOffset = bounds.y || 0;
const pageNumText =
options.format === 'page_x_of_y'
? `${i + 1} / ${totalPages}`
: `${i + 1}`;
const textWidth = helveticaFont.widthOfTextAtSize(
pageNumText,
options.fontSize
);
const textHeight = options.fontSize;
const minMargin = 8;
const maxMargin = 40;
const marginPercentage = 0.04;
const horizontalMargin = Math.max(
minMargin,
Math.min(maxMargin, width * marginPercentage)
);
const verticalMargin = Math.max(
minMargin,
Math.min(maxMargin, height * marginPercentage)
);
const safeHorizontalMargin = Math.max(horizontalMargin, textWidth / 2 + 3);
const safeVerticalMargin = Math.max(verticalMargin, textHeight + 3);
let x = 0,
y = 0;
switch (options.position) {
case 'bottom-center':
x =
Math.max(
safeHorizontalMargin,
Math.min(
width - safeHorizontalMargin - textWidth,
(width - textWidth) / 2
)
) + xOffset;
y = safeVerticalMargin + yOffset;
break;
case 'bottom-left':
x = safeHorizontalMargin + xOffset;
y = safeVerticalMargin + yOffset;
break;
case 'bottom-right':
x =
Math.max(
safeHorizontalMargin,
width - safeHorizontalMargin - textWidth
) + xOffset;
y = safeVerticalMargin + yOffset;
break;
case 'top-center':
x =
Math.max(
safeHorizontalMargin,
Math.min(
width - safeHorizontalMargin - textWidth,
(width - textWidth) / 2
)
) + xOffset;
y = height - safeVerticalMargin - textHeight + yOffset;
break;
case 'top-left':
x = safeHorizontalMargin + xOffset;
y = height - safeVerticalMargin - textHeight + yOffset;
break;
case 'top-right':
x =
Math.max(
safeHorizontalMargin,
width - safeHorizontalMargin - textWidth
) + xOffset;
y = height - safeVerticalMargin - textHeight + yOffset;
break;
}
x = Math.max(xOffset + 3, Math.min(xOffset + width - textWidth - 3, x));
y = Math.max(yOffset + 3, Math.min(yOffset + height - textHeight - 3, y));
page.drawText(pageNumText, {
x,
y,
font: helveticaFont,
size: options.fontSize,
color: rgb(options.color.r, options.color.g, options.color.b),
});
}
return new Uint8Array(await pdfDoc.save());
}
export interface FixPageSizeOptions {
targetSize: string;
orientation: string;
scalingMode: string;
backgroundColor: { r: number; g: number; b: number };
customWidth?: number;
customHeight?: number;
customUnits?: string;
}
export async function fixPageSize(
pdfBytes: Uint8Array,
options: FixPageSizeOptions
): Promise<Uint8Array> {
let targetWidth: number;
let targetHeight: number;
if (options.targetSize.toLowerCase() === 'custom') {
const w = options.customWidth ?? 210;
const h = options.customHeight ?? 297;
const units = (options.customUnits ?? 'mm').toLowerCase();
if (units === 'in') {
targetWidth = w * 72;
targetHeight = h * 72;
} else {
targetWidth = w * (72 / 25.4);
targetHeight = h * (72 / 25.4);
}
} else {
const selected =
PageSizes[options.targetSize as keyof typeof PageSizes] || PageSizes.A4;
targetWidth = selected[0];
targetHeight = selected[1];
}
const orientation = options.orientation.toLowerCase();
if (orientation === 'landscape' && targetWidth < targetHeight) {
[targetWidth, targetHeight] = [targetHeight, targetWidth];
} else if (orientation === 'portrait' && targetWidth > targetHeight) {
[targetWidth, targetHeight] = [targetHeight, targetWidth];
}
const sourceDoc = await PDFDocument.load(pdfBytes);
const outputDoc = await PDFDocument.create();
for (const sourcePage of sourceDoc.getPages()) {
const { width: sourceWidth, height: sourceHeight } = sourcePage.getSize();
const embeddedPage = await outputDoc.embedPage(sourcePage);
const outputPage = outputDoc.addPage([targetWidth, targetHeight]);
outputPage.drawRectangle({
x: 0,
y: 0,
width: targetWidth,
height: targetHeight,
color: rgb(
options.backgroundColor.r,
options.backgroundColor.g,
options.backgroundColor.b
),
});
const scaleX = targetWidth / sourceWidth;
const scaleY = targetHeight / sourceHeight;
const useFill = options.scalingMode.toLowerCase() === 'fill';
const scale = useFill ? Math.max(scaleX, scaleY) : Math.min(scaleX, scaleY);
const scaledWidth = sourceWidth * scale;
const scaledHeight = sourceHeight * scale;
const x = (targetWidth - scaledWidth) / 2;
const y = (targetHeight - scaledHeight) / 2;
outputPage.drawPage(embeddedPage, {
x,
y,
width: scaledWidth,
height: scaledHeight,
});
}
return new Uint8Array(await outputDoc.save());
}