95 lines
2.0 KiB
TypeScript
95 lines
2.0 KiB
TypeScript
import sharp from "sharp";
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interface GridLayoutResult {
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cols: number;
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rows: number;
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totalCells: number;
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placeholderCount: number;
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}
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/**
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* 计算宫格布局
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* 1张: 1x1
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* 2张: 2x1
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* 3张: 3x1
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* 4张: 2x2
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* 5-9张: 3x3
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* 10-12张: 3x4
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* 13-15张: 3x5
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* ...以此类推（3列，行数递增）
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*/
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function calculateGridLayout(count: number): GridLayoutResult {
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let cols: number;
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let rows: number;
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if (count <= 0) {
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cols = 1;
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rows = 1;
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} else if (count === 1) {
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cols = 1;
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rows = 1;
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} else if (count === 2) {
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cols = 2;
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rows = 1;
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} else if (count === 3) {
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cols = 3;
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rows = 1;
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} else if (count === 4) {
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cols = 2;
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rows = 2;
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} else if (count <= 9) {
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// 5-9格统一用3x3
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cols = 3;
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rows = 3;
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} else {
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cols = 3;
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rows = Math.ceil(count / 3);
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}
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const totalCells = cols * rows;
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const placeholderCount = totalCells - count;
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return { cols, rows, totalCells, placeholderCount };
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}
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/**
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* 分割宫格图片
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* @param image - 输入的宫格图片 Buffer
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* @param length - 实际需要的图片数量（不包含占位图）
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* @returns 分割后的单张图片 Buffer 数组
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*/
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export default async (image: Buffer, length: number): Promise<Buffer[]> => {
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const metadata = await sharp(image).metadata();
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const { width: totalWidth, height: totalHeight } = metadata;
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if (!totalWidth || !totalHeight) {
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throw new Error("无法获取图片尺寸");
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}
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const { cols, rows } = calculateGridLayout(length);
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const cellWidth = Math.floor(totalWidth / cols);
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const cellHeight = Math.floor(totalHeight / rows);
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const buffers: Buffer[] = [];
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for (let i = 0; i < length; i++) {
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const row = Math.floor(i / cols);
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const col = i % cols;
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const left = col * cellWidth;
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const top = row * cellHeight;
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const cellBuffer = await sharp(image)
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.extract({
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left,
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top,
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width: cellWidth,
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height: cellHeight,
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})
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.png()
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.toBuffer();
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buffers.push(cellBuffer);
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}
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return buffers;
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};
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