Ref

1. Introduction to PDF
2. Fillable PDF

Intro

• Portable Format Document
• A format meant to be displayed identicaly in all platforms and media

Simple Example

• Download

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%PDF-1.7

1 0 obj  % entry point
<<
  /Type /Catalog
  /Pages 2 0 R
>>
endobj

2 0 obj
<<
  /Type /Pages
  /MediaBox [ 0 0 200 200 ]
  /Count 1
  /Kids [ 3 0 R ]
>>
endobj

3 0 obj
<<
  /Type /Page
  /Parent 2 0 R
  /Resources <<
    /Font <<
      /F1 4 0 R 
    >>
  >>
  /Contents 5 0 R
>>
endobj

4 0 obj
<<
  /Type /Font
  /Subtype /Type1
  /BaseFont /Times-Roman
>>
endobj

5 0 obj  % page content
<<
  /Length 44
>>
stream
BT
70 50 TD
/F1 12 Tf
(Hello, world!) Tj
ET
endstream
endobj

xref
0 6
0000000000 65535 f 
0000000010 00000 n 
0000000079 00000 n 
0000000173 00000 n 
0000000301 00000 n 
0000000380 00000 n 
trailer
<<
  /Size 6
  /Root 1 0 R
>>
startxref
492
%%EOF

Structure

Typically, a PDF contains 4 parts:

1. The header, with PDF version(and an option line to specify if the PDF contains binary data)

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%PDF-1.7

2. The body, containing a series of objects

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1 0 obj
...
endobj
2 0 obj
...
endobj
...

3. A cross-reference table that specifies the position of the bojects

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xref
0 6
0000000000 65535 f 
0000000010 00000 n 
0000000079 00000 n 
0000000173 00000 n 
0000000301 00000 n 
0000000380 00000 n

4. A trailer, with information about where the document starts

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trailer
<<
  /Size 6
  /Root 1 0 R
>>
startxref
492
%%EOF

Sign a PDF

• Signing can ensure a PDF has not been modified and to verify that the author is who we expect.
• For example, an important contract.

Fill a PDF form

引用

1. 2019.3.5 国家卫生健康委办公厅关于印发医院智慧服务分级评估标准体系（试行）的通知
2. 医院智慧服务分级评估标准体系(试行)

Tips

• By default, log4js level for default category is set to OFF, thus not outputting any logs. To turn on logging, level must be set other than OFF.
• Levels: TRACE -> DEBUG -> INFO -> WARN -> ERROR -> FATAL

Basic

Install

yarn add oracledb

Example

Simple

Ref

Add proxy to heroku login

Comparison

Ref

1. CORS tutorial
2. 关于CORS和withCredentials

Ref

1. Javascript this

What is this

• this in Javascript refers to the context of the statement in which it is being executed.