Display additional markup taken from SGF data

[herzbube]

With the intregration of SgfcKit the app has now access to markup properties that are stored inside an SGF file. The app should be able to display this markup.

[herzbube]

SGF defines the following markup properties:

• CR/SQ/TR/MA/SL
  • Data type for all of these is List of Point.
  • A point can only appear in one of these properties.
  • Draw a circle, square, triangle or an "X" on the point(s) or, in the case of SL, markup the point(s) as "selected".
  • Ideas how to render SL
    • Idea 1: Draw a ring around the point. If there is a stone on the point, draw the stone smaller.
    • Idea 2: Use yet another symbol, e.g. a checkmark or star.
• AR/LN
  • Data type for all of these is List of composed Point : Point.
  • The same pair of points can appear only once per property (SGFC does not prevent multiple occurrences, though). Reversed order of points is legal, though.
  • Single-point pairs are illegal (e.g. cc:cc).
  • SGF allows the same pair of points in both AR and LN, although it doesn't make much sense.
  • Draw an arror or a line from the first to the second point.
• LB
  • Data type is List of composed Point : SimpleText
  • Draw a label on the point(s).
• DD
  • Data type is Elist of Point
  • Dim/grey out the point(s)

Notes:

• Markup is only drawn if the board position with those properties is shown.
• Exception is DD, because that is an inheritable property.

[herzbube]

When adding the new markup, also consider whether the rectangle symbol can be improved. I received this user feedback via email:

A shade of white quadrilateral on a black stone is light and difficult to recognize.

[herzbube]

Implementation notes to be added to the in-game manual

• Markup is displayed only in play mode (UIAreaPlayModePlay), i.e. not in scoring mode and not in setup mode
• Order of precedence in which markup is drawn
  • A move number takes precedence
  • If a move number is displayed for the last move it is displayed in red color, compensating for the last move symbol not being displayed
  • Next comes a symbol or label
  • A user preference lets the user decide whether symbols or labels should take precedence
  • The default is symbols
  • Next move marker and last move symbol have lowest priority
  • Reason for low priority: Next move marker and last move symbol are merely a convenience, whereas symbols or labels may be quite important for the understanding of the information in a game node.
• Labels
  • Labels are not displayed if the intersections are too small (same mechanism as with move numbers)
  • A user preference lets the user decide whether labels that are too long should be truncated (not yet implemented)

When markup editing mode is implemented later on

• In markup editing mode the user can place only either a symbol or a label on the same intersection, so there can be no conflict in game data manufactured by Little Go. But external SGF files might contain both a symbol and a label on the same intersection.
• In markup editing mode no move numbers are displayed, so that symbols and labels cannot be hidden by move numbers.
• In markup editing mode the next move marker and last move symbol are also not displayed, so as not to disturb markup editing.

EDIT: A lot of what is written in this comment is no longer true. Strikethrough was applied to the most glaring errors.

[herzbube]

In-game manual updated in commit 22e04d7c04cafa81acbeb882e59bfb367e3cbadf.

[herzbube]

Ready for next release, closing this issue.