Question

我在本地目录中安装了node-canvas和imagediff，并编写了一个比较两个已存在的图像文件的测试示例。它运行得很好，代码如下：

var Canvas = require('canvas')
    , imagediff = require('../lib/imagediff.js')
    , fs = require('fs')
    , path = require('path');

var goodFilePath = path.join(__dirname + '/../diffs/single/test_1_good.png')
    , newFilePath = path.join(__dirname + '/../diffs/single/test_1_new.png')
    , diffFilePath = path.join(__dirname + '/../diffs/single/test_1_diff.png');

var test = function () {
    var img_good = new Canvas.Image()
            , img_new = new Canvas.Image()
            , img_good_data = null
            , img_new_data = null
            , tolerance = 10
            , equal = false
            , diff_result = null;

          fs.readFile(goodFilePath, function (err, squid_good) {
              if (err) throw err;  
              img_good.src = squid_good; 
          }); 
          fs.readFile(newFilePath, function (err, squid_new) {
            if (err) throw err;
            img_new.src = squid_new;
          });

          img_new.onload = function () {
            // convert to image data 
              img_good_data = imagediff.toImageData(img_good);
              img_new_data = imagediff.toImageData(img_new);

              //compare and save diffences in new image file
              equal = imagediff.equal(img_good, img_new, tolerance);
              console.log('Image Good === Image New: ' + equal);
              diff_result = imagediff.diff(img_good_data, img_new_data, tolerance);
              imagediff.imageDataToPNG(diff_result, diffFilePath);
          }          
}


test();

但如果您注意到顶部的require语句，我会将实际的imagediff.js文件拉入我创建的lib文件夹中。我的问题是，当我尝试使用常规require（＆＃39; imagediff＆＃39;）语句时，程序会给出以下Image或Canvas预期错误：

/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/imagediff/imagediff.js:120
    context.drawImage(image, 0, 0);
            ^
TypeError: Image or Canvas expected
    at toImageDataFromImage (/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/imagediff/imagediff.js:120:13)
    at toImageData (/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/imagediff/imagediff.js:108:35)
    at Object.imagediff.toImageData (/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/imagediff/imagediff.js:365:14)
    at img_new.onload (/Users/willko/Desktop/DEBUGGING_IMGDIFF/specs/simple.js:30:45)
    at Image.inspect [as src] (/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/canvas/lib/image.js:29:17)
    at /Users/willko/Desktop/DEBUGGING_IMGDIFF/specs/simple.js:25:29
    at fs.js:266:14
    at Object.oncomplete (fs.js:107:15)

我甚至尝试安装与imagediff使用相同版本的画布，导致以下seg错误错误：

/Users/willko/Desktop/DEBUGGING_IMGDIFF/node_modules/imagediff/imagediff.js:120
    context.drawImage(image, 0, 0);
            ^
[1]    34636 segmentation fault  node simple.js

我的问题：

为什么我不能按正常要求使用此模块？或者为什么它使用文件路径require语句但是否则失败？

require（'image diff'）但不需要问题（'/ path To / image diff.js'）

我的问题：

0 个答案: