Wumpus.Basic.Kernel.Base.DrawingContext

Drawing attributes

** WARNING ** - The drawing context modules need systematic naming schemes both for update functions (primaryColour, ...) and for synthesized selectors (e.g. lowerxHeight). The current names in QueryDC and UpdateDC are expected to change.

Drawing context

data DrawingContext

DrawingContext - the "graphics state" of Wumpus-Basic. DrawingContext is operated on within a Reader monad rather than a State monad so "updates" are delineated within a local operation (called localize in Wumpus), rather than permanent until overridden as per set of a State monad.

Note - round_corner_factor is only accounted for by some graphic objects (certain Path objects and Shapes in Wumpus-Drawing for instance). There many be many objects that ignore it and are drawn only with angular corners.

Also note - in contrast to most other drawing objects in Wumpus, none of the measurement values are parameteric - usually notated with the type variable u in Wumpus. This is so Wumpus can (potentially) support different units e.g. centimeters rather than just Doubles (represening printers points), though adding support for other units has a very low priority.

Constructors

DrawingContext

Fields

glyph_tables :: GlyphMetrics

fallback_metrics :: MetricsOps

stroke_props :: StrokeAttr

font_props :: FontAttr

stroke_colour :: RGBi

fill_colour :: RGBi

line_spacing_factor :: Double

round_corner_factor :: Double

text_margin :: TextMargin

type DrawingContextF = DrawingContext -> DrawingContext

Type synonym for DrawingContext update functions.

data TextMargin

The unit of Margin is always Double representing Points, e.g. 1.0 is 1 Point. Margins are not scaled relative to the current font size.

The default value is 2 point.

Constructors

TextMargin

Fields

text_margin_x :: !Double

text_margin_y :: !Double

standardContext :: FontSize -> DrawingContext

metricsContext :: FontSize -> GlyphMetrics -> DrawingContext

default_drawing_context :: DrawingContext

DrawingCtxM (reader) monad

class (Applicative m, Monad m) => DrawingCtxM m where

Methods

askDC :: m DrawingContext

localize :: (DrawingContext -> DrawingContext) -> m a -> m a

Instances

DrawingCtxM CF

DrawingCtxM (CF1 r1)

DrawingCtxM (TraceDrawing u)

DrawingCtxM (CF2 r1 r2)

Monad m => DrawingCtxM (TraceDrawingT u m)

asksDC :: DrawingCtxM m => (DrawingContext -> a) -> m a

Project a value out of a context.

Glyph metrics

withFontMetrics :: (MetricsOps -> PtSize -> u) -> DrawingContext -> u