[PDFBOX-3421] Optimize float to string conversion in PDAbstractContentStream

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 2.0.2, 2.0.3, 3.0.0 PDFBox
• Fix Version/s: 2.0.3, 3.0.0 PDFBox
• Component/s: PDModel
• Labels: optimization performance
• Environment: Ubuntu 14.04
• Assignee: Tilman Hausherr
• Reporter: Michael Doswald
• Created: 13/Jul/16 14:41
• Updated: 25/Mar/17 18:12
• Resolved: 19/Jul/16 16:05

Description

Drawing lines in a PDF (and also other operations) writes the coordinates to the content stream. Currently, the PDAbstractContentStream#writeOperand(float) method uses the NumberFormat class to convert the float values. This is inefficient for multiple reasons:

• NumberFormat is designed to format numbers locale dependent. That is not needed in this case
• NumberFormat uses a pattern to format the value which is also not needed in this case
• The formatting first creates a String object, converts it to a byte array with ASCII encoding and then writes it to the stream. This generates a lot of garbage.

A different approach to formatting real operands should be used.