[PDFBOX-3858] Optimize 1 component DeviceN colorspace

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.6
• Fix Version/s: 2.0.7, 3.0.0 PDFBox
• Component/s: PDModel, Rendering
• Labels: devicen optimization
• Assignee: Tilman Hausherr
• Reporter: Tilman Hausherr
• Created: 07/Jul/17 16:04
• Updated: 21/Jul/17 04:40
• Resolved: 07/Jul/17 16:20

Description

I received a file (confidential) that has an image with a 1 component DeviceN colorspace that maps (through a long type 4 function) to a CMYK colorspace. Rendering takes over 20 minutes. The reason is that for each pixel, first the type 4 (PostScript) function must be calculated, then the CMYK value must be converted to RGB.

Solution: cache the inputs and the results when the DeviceN colorspace has only 1 component. Rendering time goes down to a few seconds.