将文本在多行表单字段中的顶部对齐以动态生成PDF

Question

I have a PDF form with text aligned in the middle for multiline fields, I am looking for a script that will execute when the file is opened to align those text to the top instead.

It has been created using this converter ( https://www.idrsolutions.com/online-pdf-to-html5-converter ) to generate an HTML version of a PDF form. Then there is a function to convert it back to PDF.

For example with this: https://files.idrsolutions.com/Examples/FDFForms/CVData/form.html

You can enter some text and then click the save icon to generate the PDF.

Here is the generated file too: https://devcn.000webhostapp.com/temp/sampleAlign.pdf

In the PDF generated the text that appears in the multiline form fields is aligned to the middle. If you edit the text with changes it then aligns it to the top. Also if you select the field properties and change the multiline checkbox deselecting and selecting it again the text then too aligns to the top. Would like to automate this somehow so that when the user opens the PDF the texts are aligned to the top.

Answer 1

First, multiline text fields in Acrobat always align to the top unless the field is set to allow rich text and the user defines the field to vertically align the text to the middle; there is no way to define vertically align center in a typical PDF field programmatically and have it stick through a user edit.

What you are seeing when you first open the file is the field appearance which was generated by the converter. You can add a script at the document level that toggles the "delay" property which will cause the appearance to be regenerated by the viewer. You'd add this to a document level script so it runs when the file is first opened. See code and warning below.

nFields = this.numFields;
for (var i = 0; i < nFields; i++) {
    var f = this.getField(this.getNthFieldName(i));
    f.delay = true;
    f.delay = false
}

However, this will only run in a JavaScript capable viewer the can edit PDF like Acrobat and Reader and a few others. When I selected your link, it opened in Chrome first, which doesn't execute JavaScript. Unfortunately, non-javascript capable viewers are built into most browsers now so the likelihood of the file first being opened by the user and having your script run is low. You need to fix the appearance in the conversion process, not in the viewer.

To do that, either preprocess the HTML so that the appearance generated by the converter matches the properties of the PDF field that will be generated or convince IDR to update their software to create appearances that reflect the properties of the field generated rather than the properties of the HTML field source.