Bug report #15728: line pattern fill symbology throws qpainter warnings when line space in map unit and canvas scaled out - QGIS Application - QGIS Issue Tracking

Bug report #15728

line pattern fill symbology throws qpainter warnings when line space in map unit and canvas scaled out

Added by Mathieu Pellerin - nIRV about 8 years ago. Updated about 8 years ago.

Status:	Closed
Priority:	Normal
Assignee:	Mathieu Pellerin - nIRV
Category:	Symbology
Affected QGIS version:	master	Regression?:	No
Operating System:		Easy fix?:	No
Pull Request or Patch supplied:	Yes	Resolution:
Crashes QGIS or corrupts data:	No	Copied to github as #:	23650

Description

When the line pattern fill symbology uses map unit line spacing value and the scale forces the line spacing to effectively disappear, the symbology fails to render, and the following QPainter warnings are printed in the terminal:

Warning: QPainter::begin: Paint device returned engine == 0, type: 3
Warning: QPainter::setRenderHint: Painter must be active to set rendering hints
Warning: QPainter::setPen: Painter not active
Warning: QPainter::setBrush: Painter not active
Warning: QPainter::drawPath: Painter not active
Warning: QPainter::setPen: Painter not active
Warning: QPainter::setBrush: Painter not active
Warning: QPainter::drawPath: Painter not active
Warning: QPainter::end: Painter not active, aborted

Steps to reproduce

Launch QGIS within a terminal to be able to see messages output there
Open the attached test project (qpainter_warnings.qgs)
Gradually zoom out the canvas, until you see the line pattern fill fail to render
Go to the terminal window, you'll see the QPainter warning

qpainter_warnings.zip (6.22 KB) Mathieu Pellerin - nIRV, 2016-10-19 10:15 PM