[PDFBOX-5376] Image interpolation when there shouldn't be

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.25
• Fix Version/s: 2.0.26, 3.0.0 PDFBox
• Component/s: Rendering
• Assignee: Tilman Hausherr
• Reporter: Tilman Hausherr
• Created: 14/Feb/22 18:07
• Updated: 21/Apr/22 15:38
• Resolved: 14/Feb/22 18:08

Description

Two elements in the rendering of this file (by Kurt Pfeifle)
https://github.com/angea/PDF101/blob/master/handcoded/111_current-transformation-matrix-ctm.pdf
look like shadings but they are not, it's a tiny image. The cause is a miscalculation of isScaledUp which didn't take into account that getScalingFactorX() / getScalingFactorY() may return negative values.

Rendering after the change has mostly invisible differences except for PATTYP2.pdf where they are easier to see.