node sharp 合并图片

Author: wangdongman

Diff for: sharp/demo.js

@@ -0,0 +1,22 @@
+const f  = require('./merge')
+const ptah = require('path')
+function mergePath (stringPathOrStringPathArray) {
+    return ptah.join(__dirname, stringPathOrStringPathArray)
+}
+const outFilePath = mergePath('merge.png')
+console.log('outFilePath:',outFilePath)
+
+f.mergeImages([
+    'n1.png',
+    'n2.png',
+    'n3.png',
+    'n4.png',
+    'n5.png',
+    'n6.png',
+    'n7.png',
+    'n8.png',
+    'n9.png',
+    'n10.png',
+    'n11.png',
+    'n12.png'
+],outFilePath)

Diff for: sharp/merge.js

@@ -0,0 +1,76 @@
+
+const sharp = require('sharp')
+const path = require('path')
+async function mergeImages(stringArray, outFilePath) {
+
+    if (!Array.isArray(stringArray)) {
+        throw console.error('请传入字符串图片路径数组')
+        return
+    }
+    // 拷贝数组
+    let mergeArray = stringArray.slice()
+
+    // 获取第一张
+    let backgroudImages = mergeArray.shift()
+
+    // 第一张要转换为buffer数据
+    let backgroudBuffer =  getBuffer(backgroudImages)
+    // 获取合并数据
+    let mergeImagesBuffer = await mergeImagesForArray(mergeArray, backgroudBuffer)
+    console.log('mergeImagesBuffer:',mergeImagesBuffer)
+    // mergeImagesBuffer.then((data) => {
+    //    sharp(data.data).toFile(outFilePath);
+    //  }).catch(error => {
+    //    throw new Error('Generate Share Image Failed.');
+    //  });
+    if(mergeImagesBuffer && mergeImagesBuffer.data){
+        outMergeImages(mergeImagesBuffer.data, outFilePath)
+    }else{
+        throw console.error('合成数据出错!')
+    }
+}
+
+function outMergeImages (mergeImagesBuffer, outFilePath) {
+    sharp(mergeImagesBuffer).toFile(outFilePath, function(err, info){})
+}
+
+function getBuffer(stringImagePath) {
+    if (typeof stringImagePath !== 'string') {
+        return new Promise().reject({})
+    }
+    return sharp(stringImagePath).toBuffer({
+        resolveWithObject: true
+    })
+}
+
+// 合并数组里面的全部图片
+function mergeImagesForArray(stringArray, backgroudBuffer) {
+    return stringArray.reduce((input, next_overlay, index) => {
+
+        return input.then(input_result => {
+          return sharp(input_result.data)
+          /*
+          sharp.gravity: { 
+          centre: 0, // 默认
+          north: 1,
+          east: 2,
+          south: 3,
+          west: 4,
+          northeast: 5,
+          southeast: 6,
+          southwest: 7,
+          northwest: 8 }
+          */
+            // options.gravity(centre) 默认居中 { gravity: sharp.gravity.southeast }
+            .overlayWith(next_overlay /* { gravity: sharp.gravity.southeast } */) // 全尺寸图片不支持top/left
+            .toBuffer({ resolveWithObject: true });
+        })
+  
+      }, backgroudBuffer)
+}
+
+
+module.exports = {
+    mergeImages,
+    outMergeImages
+}