In a PDF (Portable Document Format) file, tables are typically encoded using a combination of text positioning and drawing operations. PDF is a file format developed by Adobe that is used to present documents in a manner independent of application software, hardware, and operating systems. It supports the inclusion of various elements, including text, images, and tables.
Here's a simplified explanation of how tables are encoded in PDFs:
Text Content
The textual content of the table, such as numbers or text within cells, is represented as text strings in the PDF file. Each text string is associated with specific coordinates on the page, indicating its position within the table.
Graphics Operations
PDF uses graphics operations to draw lines and shapes, which are employed to create the visual structure of the table. Lines are drawn to form the borders of the table and the individual cells.
Coordinate System
PDF has a coordinate system that allows precise positioning of text and graphics on the page. Tables are positioned based on specific coordinates, and the rows and columns are created by drawing lines between these coordinates.
Attributes and Styles
The PDF format supports the specification of attributes and styles for text and graphics, such as font size, color, and line thickness. These attributes are used to define the appearance of the table, including the font style within cells and the thickness of the borders.
Tabular Structure
Tables are essentially created by defining the coordinates of the table's boundaries, the positions of its rows and columns, and the content within each cell.
Table Elements
Each cell in the table is represented as a combination of text strings and graphic elements. The text represents the content of the cell, while lines and shapes create the visual structure.