[PDFBOX-5450] Create Opaque PDFRenderer example

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.26
• Fix Version/s: 2.0.27, 3.0.0 PDFBox
• Component/s: Rendering
• Assignee: Tilman Hausherr
• Reporter: Tilman Hausherr
• Created: 31/May/22 12:39
• Updated: 29/Sep/22 17:57
• Resolved: 31/May/22 14:22

Description

To solve the troubles from PDFBOX-4123 (low print quality of PDFs with unneeded transparency groups)
As mentioned in the mailing list in this thread

Both options are related to transparency groups. These are an extension of XObject forms. I thought about ignoring them, i.e. treat them like ordinary forms.
So I looked at PDXobject.createXObject(); this one is called by PDResources.getXObject(), which is called by DrawObject.process(). That one class can officially be replaced if you extend PageDrawer and call "addOperator(new DrawObject());" in the constructor; that class should have a slightly modified code that does NOT call showTransparencyGroup(), but only showForm() (there are 3 DrawObject classes, copy the one in org.apache.pdfbox.contentstream.operator.graphics). You can extend PageDrawer, but you'll have to extend PDFRenderer as well, see class comment of PageDrawer.

and implemented by tresf in this commit.