InDesign CS5脚本:为什么`#targetengine`不能正常工作？

Question

据我所知，声明#targetengine "myEngineName"将用于InDesign来记住全局变量(在这里找到的信息是:herehttp://incom.org/post/89818)。

然而，这仍然不足以让它记住全局变量，因为它仍然抛出一个关于全局变量imgs的错误：

​

错误号:由于对象不再存在，因此无法完成另一项错误字符串：“if(imgsi.itemLink != null)”。

无论如何，...or是这样的。它不喜欢我的代码中的特定行，似乎忘记了全局变量imgs被实例化为什么。

所以我实现了一个try-catch语句，并恢复了变量imgs并减少了catch中的迭代器.虽然这个解决了问题，但是为什么#targetengine "myEngineName"不像它应该解决的那样解决问题呢？

​

这是我的代码：

​

#target "InDesign" // this solves the "Error Number: 29446" problem
#targetengine "session" // this solves the "Error Number: 30476" problem

var imgs; // global variable for the #targetengine "session" to keep track of
var document = app.activeDocument;
var newFolder = createFolder(document); // if subdirectory images DNE, create this folder with the function below

saveAllImages(document, newFolder); // with the function below

alert("The file conversion is complete!\n\nAll black & white images have been copied to:\n" + newFolder +
        "\.\n\nAll color images have been replaced with the new black & white images in the current InDesign document.");

//---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

function createFolder(doc)
{
    try
    {
      /*
         * type-casting the filePath property (of type object) into a String type;
         * must be a String type to concatenate with the subdirectory variable (also of type String)
         */
        var docPath = String(doc.filePath);
        var subdirectory = "/BLACK AND WHITE IMAGES";
    }
    catch(e)
    {
        alert(e.message + "\n - reload the script, and it should work.");
        exit();
    }

    var imagesFolder = docPath + subdirectory; // concatenating the two variables
    if(!Folder(imagesFolder).exists)
    {
        Folder(imagesFolder).create();
    }

    return imagesFolder; // for instantiation outside of this function

} // end of function createFolder

//---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

function saveAllImages(doc, folder)
{
    imgs = document.allGraphics; // this is a global variable, for the #targetengine "session" to keep track of
    var fileName = "";
    var img = "";
    var imgType = "";

    for(var i = 0; i < imgs.length; i++)
    {
        try
        {
            if(imgs[i].itemLink != null)
            {
                fileName = imgs[i].itemLink.name;

                img = new File(folder + "/" + fileName); // each image instantiated here
                imgType = imgs[i].imageTypeName; // image type is determined here (.tif, .jpg, .png, etc..)

                //alert("The file \"" + fileName + "\"\n\tis a " + imgType + " file."); // Note: escape characters

               /*
                     * array for image options, instantiated from the function below;
                     * options[0] is the "MAXIMUM" image quality property, &
                     * options[1] is the "GRAY" image conversion property;
                     */
                var options = convertToBlackAndWhite(imgType);

                // each image exported to the new folder here, by file type
                switch(imgType)
                {
                    case "GIF":
                        alert("This script cannot convert and export the GIF file:\n\t" + fileName + " !"); // Note: escape characters
                        break;

                    case "Adobe PDF":
                        break;                            
                    case "EPS":
                        break;
                    case "Windows Bitmap":
                        break;
                    case "JPEG":
                        break;
                    case "PNG":
                        break;
                    case "TIFF":
                        options[0]; // maximum image quality
                        options[1]; // black & white conversion

                        imgs[i].exportFile(ExportFormat.JPG, img, false);
                        replaceWithNewImage(doc, fileName, img); // with the function below
                        break;

                    default:
                        alert("\tUnlisted image type: " + imgType + "!\nAdd this type to the switch statement.");
                        break;
                } // end of switch statement

            } // end of if statement
        } // end of try statement
        catch(e)
        {
            /*
                * in case the #targetengine is overloaded, this solves the "Error Number: 30476" problem:
                *           - "The requested action could not be completed because the object no longer exists."
                *               (the second statement #targetengine "session" is also in place to solve this error)
                */
            imgs = document.allGraphics; // global variable reinstantiated in case of error
            i--; // retry the same iteration again, in case of error (the variable " i " is the iterator in the for loop)
        }
    } // end of for loop

} // end of function saveAllImages

//---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

        function convertToBlackAndWhite(fileType)
        {
            // array for image-quality and color-conversion values
            var settings = [];

            // each image exported to the new folder here, by file type
            switch(fileType)
            {                    
                    case "Windows Bitmap":
                        break;
                    case "JPEG":
                        break;
                    case "PNG":
                        break;
                    case "TIFF":
                    settings[0] = "app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.MAXIMUM"; // maximum image quality
                    settings[1] = "app.jpegExportPreferences.jpegColorSpace = JpegColorSpaceEnum.GRAY"; // black & white conversion
                    break;

                default:
                    break;
            } // end of switch statement

            return settings; // for instantiation outside of this function

        } // end of function convertToBlackAndWhite

//---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

function replaceWithNewImage(doc, imageName, newImage)
{
    var links = doc.links;
    var link = "";
    for(var i = 0; i < links.length; i++)
    {
        link = links[i];
        if ( (link.status == LinkStatus.NORMAL) && (link.name == imageName) )
        {
            try
            {
                link.relink(newImage);
                link.update();
            }
            catch(e)
            {
            }
        } // end of if statement
    } // end of for loop

} // end of function replaceWithNewImage

这是我能找到的关于这个错误的唯一信息:高级http://forums.adobe.com/thread/748419

编辑 --

我很确定这个问题与函数replaceWithNewImage有关，因为这个错误不是在没有这个函数的情况下发生的，所以没有必要使用try-catch语句.

Answer 1

阅读您的代码，我看到一些可能是真正有问题的东西。将对文档的引用设置为活动文档。但这一提法仍然贯穿整个会议。事实上，如果切换到另一个文档或关闭文档，则引用将丢失。这可能解释了为什么imgs在某个时候可能没有定义，尽管我认为它应该引起一个错误。在函数范围内包装变量，我保证你一切都会好的;)

Answer 2

首先，尽量避免全局变量，特别是在使用会话引擎时。

如果您的脚本的目标是一个简单的导出链接/修改链接/替换链接，为什么要有持久变量？

在我看来，我将摆脱引擎，只需做一个定期的功能调用。

//myscript.jsx
mySuperFunction();
function mySuperFunction()
{
    var doc;
    if ( app.documents.length == 0 ){ return; }
    doc = app.activeDocument;
    //Do all your stuff
}

(这应该是你所需要的;)

洛奇