79 projection errors and quality

.gitignore

@@ -12,3 +12,4 @@ docs
 ~$paper.docx
 revdep
 dev/tmp.R
+Rplots.pdf

DESCRIPTION

@@ -16,8 +16,8 @@ Description: Analyze repertory grids, a qualitative-quantitative
     to quantitatively analyze and visualize repertory grid data (e.g. 'Fransella', 'Bell', & 'Bannister', 
     2004, ISBN: 978-0-470-09080-0). The package is part of the The package is part of the 
     <https://openrepgrid.org/> project.
-Version: 0.1.18
-Date: 2025-08-24
+Version: 0.1.19
+Date: 2026-03-26
 Encoding: UTF-8
 URL: https://github.com/markheckmann/OpenRepGrid
 Imports:

NAMESPACE

@@ -8,6 +8,7 @@ S3method(drawDetails,gmSplitTextGrob)
 S3method(names,repgrid)
 S3method(plot,indexDilemma)
 S3method(print,alignByLoadings)
+S3method(print,biplot2d)
 S3method(print,constructCor)
 S3method(print,constructD)
 S3method(print,constructPca)
@@ -44,6 +45,7 @@ export(addConstruct)
 export(addElement)
 export(addIndexColumnToMatrix)
 export(addProjectionsToBiplot2d)
+export(addQualityToBiplot2d)
 export(addVarianceExplainedToBiplot2d)
 export(alignByIdeal)
 export(alignByLoadings)

NEWS.md

@@ -5,9 +5,15 @@
 * `biplot2d`: New arg `projections` draws perpendicular projection lines from elements onto construct
   axes. Supports `TRUE` (all) or numeric indices. `projections.e` selects which elements to project (#77)
   `projections.col`, `projections.lty`, and `projections.lwd` accept per-element vectors for distinct styling.
+  New arg `projections.error` draws error segments showing the difference between projected and actual
+  rating values on construct axes. (#79)
 * `biplot2d`: Construct pole labels are automatically colorized by preference status (green = preferred,
   red = non-preferred, dark gray = neutral/undefined) when preferred poles are set in the repgrid object.
   New arg `c.color.preferred` controls the behavior (`NULL` = auto-detect, `TRUE` = always, `FALSE` = never) (#71).
+* `biplot2d`: New arg `quality` shows representation quality (cos²) for elements and constructs.
+  When enabled, cos² values are annotated below labels and colors are faded proportionally to quality
+  (well-represented items are opaque, poorly represented ones are transparent). `biplot2d` now
+  invisibly returns a rich list with coordinates, quality values, variance explained, and scaling factors.
 * drop `{styler}` dependency (#72)
 
 # OpenRepGrid 0.1.18