wumpus-core-0.41.0: src/Wumpus/Core/PictureInternal.hs
{-# LANGUAGE TypeFamilies #-}
{-# OPTIONS -Wall #-}
--------------------------------------------------------------------------------
-- |
-- Module : Wumpus.Core.PictureInternal
-- Copyright : (c) Stephen Tetley 2009-2010
-- License : BSD3
--
-- Maintainer : Stephen Tetley <stephen.tetley@gmail.com>
-- Stability : highly unstable
-- Portability : GHC
--
-- Internal representation of Pictures.
--
--------------------------------------------------------------------------------
module Wumpus.Core.PictureInternal
(
Picture(..)
, DPicture
, Locale
, FontCtx(..)
, Primitive(..)
, DPrimitive
, SvgAnno(..)
, XLink(..)
, SvgAttr(..)
, PrimPath(..)
, DPrimPath
, PrimPathSegment(..)
, DPrimPathSegment
, AbsPathSegment(..)
, DAbsPathSegment
, PrimLabel(..)
, DPrimLabel
, LabelBody(..)
, DLabelBody
, KerningChar
, DKerningChar
, PrimEllipse(..)
, GraphicsState(..)
, pathBoundary
, mapLocale
-- * Additional operations
, concatTrafos
, deconsMatrix
, repositionDeltas
, zeroGS
, isEmptyPath
, isEmptyLabel
) where
import Wumpus.Core.AffineTrans
import Wumpus.Core.BoundingBox
import Wumpus.Core.Colour
import Wumpus.Core.FontSize
import Wumpus.Core.Geometry
import Wumpus.Core.GraphicProps
import Wumpus.Core.PtSize
import Wumpus.Core.Text.Base
import Wumpus.Core.TrafoInternal
import Wumpus.Core.Utils.Common
import Wumpus.Core.Utils.FormatCombinators
import Wumpus.Core.Utils.JoinList
import Data.AffineSpace -- package: vector-space
import qualified Data.Foldable as F
import qualified Data.IntMap as IntMap
-- | Picture is a leaf attributed tree - where attributes are
-- colour, line-width etc. It is parametric on the unit type
-- of points (typically Double).
--
-- Wumpus\'s leaf attributed tree, is not directly matched to
-- PostScript\'s picture representation, which might be
-- considered a node attributed tree (if you consider graphics
-- state changes less imperatively - setting attributes rather
-- than global state change).
--
-- Considered as a node-attributed tree PostScript precolates
-- graphics state updates downwards in the tree (vis-a-vis
-- inherited attributes in an attibute grammar), where a
-- graphics state change deeper in the tree overrides a higher
-- one.
--
-- Wumpus on the other hand, simply labels each leaf with its
-- drawing attributes - there is no attribute inheritance.
-- When it draws the PostScript picture it does some
-- optimization to avoid generating excessive graphics state
-- changes in the PostScript code.
--
-- Omitting some details, Picture is a simple non-empty
-- leaf-labelled rose tree via:
--
-- > tree = Leaf [primitive] | Picture [tree]
--
-- The additional constructors are convenience:
--
-- @Clip@ nests a picture (tree) inside a clipping path.
--
-- The @Group@ constructor allows local shared graphics state
-- updates for the SVG renderer - in some instances this can
-- improve the code size of the generated SVG.
--
data Picture u = Leaf (Locale u) (JoinList (Primitive u))
| Picture (Locale u) (JoinList (Picture u))
| Clip (Locale u) (PrimPath u) (Picture u)
deriving (Show)
type DPicture = Picture Double
-- | Locale = (bounding box * current translation matrix)
--
-- Pictures (and sub-pictures) are located frame consisting of a
-- bounding box and a translation matrix (represented as a list
-- of affine transformations). So that pictures can be arranged
-- via vertical and horizontal composition their bounding box is
-- cached.
--
-- In Wumpus, affine transformations (scalings, rotations...)
-- transform the CTM rather than the constituent points of
-- the primitives. Changes of CTM are transmitted to PostScript
-- as @concat@ commands (and matrix transforms in SVG).
--
-- So that picture composition is remains stable under affine
-- transformation, the corners of bounding boxes are transformed
-- pointwise when the picture is scaled, rotated etc.
--
type Locale u = (BoundingBox u, [AffineTrafo u])
-- | Wumpus\'s drawings are built from two fundamental
-- primitives: paths (straight line segments and Bezier curves)
-- and labels (single lines of text).
--
-- Ellipses are a included as a primitive only for optimization
-- - drawing a reasonable circle with Bezier curves needs at
-- least eight curves. This is inconvenient for drawing dots
-- which can otherwise be drawn with a single @arc@ command.
--
-- Wumpus does not follow PostScript employing arc as a general
-- path primitive - arcs are used only to draw ellipses. This
-- is because arcs do not enjoy the nice properties of Bezier
-- curves, whereby the affine transformation of a Bezier curve
-- can simply be achieved by the affine transformation of it\'s
-- control points.
--
-- Ellipses are represented by their center, half-width and
-- half-height. Half-width and half-height are used so the
-- bounding box can be calculated using only multiplication, and
-- thus initially only obliging a Num constraint on the unit.
-- Though typically for affine transformations a Fractional
-- constraint is also obliged.
--
-- To represent XLink hyperlinks, Primitives can be annotated
-- with some a hyperlink (likewise a /passive/ font change for
-- better SVG code generation) and grouped - a hyperlinked arrow
-- would want the tip and the arrow body both to be incorporated
-- in thelink even though they are two drawing primitives.
--
-- This means that Primitives aren\'t strictly /primitive/ as
-- the actual implementation is a tree.
--
data Primitive u = PPath PathProps (PrimPath u)
| PLabel LabelProps (PrimLabel u)
| PEllipse EllipseProps (PrimEllipse u)
| PContext FontCtx (Primitive u)
| PSVG SvgAnno (Primitive u)
| PGroup (JoinList (Primitive u))
deriving (Eq,Show)
type DPrimitive = Primitive Double
-- | Set the font /delta/ for SVG rendering.
--
-- Note - this does not change the default colour or font style.
-- It is solely a backdoor into the SVG renderer to potential
-- allow some code size reductions.
--
newtype FontCtx = FontCtx { getFontCtx :: FontAttr }
deriving (Eq,Show)
-- | SVG annotations - annotations can be:
--
-- A hyperlink inside @<a ...> ... </a>@ .
--
-- A group - @<g ...> ... </g>@
--
-- A group inside a hyperlink.
--
data SvgAnno = ALink XLink
| GAnno [SvgAttr]
| SvgAG XLink [SvgAttr]
deriving (Eq,Show)
-- | Primitives can be grouped with hyperlinks in SVG output.
--
-- Note - this is always printed as @xlink:href="..."@. Other
-- types of xlink can be modelled with the unrestrained
-- SvgAnno type.
--
newtype XLink = XLink { getXLink :: String }
deriving (Eq,Show)
-- | Primitives can be labelled with arbitrary SVG properties
-- (e.g @onmouseover@) within a group element.
--
-- Note - annotations should be used only for non-graphical
-- properties. Graphical properties (fill_colour, font_size, etc.)
-- should be set through the appropriate Wumpus functions.
--
data SvgAttr = SvgAttr
{ svg_attr_name :: String
, svg_attr_value :: String
}
deriving (Eq,Show)
-- | PrimPath - start point and a list of path segments.
--
data PrimPath u = PrimPath (Point2 u) [PrimPathSegment u]
deriving (Eq,Show)
type DPrimPath = PrimPath Double
-- | PrimPathSegment - either a relative cubic Bezier /curve-to/
-- or a relative /line-to/.
--
data PrimPathSegment u = RelCurveTo (Vec2 u) (Vec2 u) (Vec2 u)
| RelLineTo (Vec2 u)
deriving (Eq,Show)
type DPrimPathSegment = PrimPathSegment Double
-- Design note - if paths were represented as:
-- start-point plus [relative-path-segment]
-- They would be cheaper to move...
--
-- | AbsPathSegment - either a cubic Bezier curve or a line.
--
-- Note this data type is transitory - it is only used as a
-- convenience to build relative paths.
--
data AbsPathSegment u = AbsCurveTo (Point2 u) (Point2 u) (Point2 u)
| AbsLineTo (Point2 u)
deriving (Eq,Show)
type DAbsPathSegment = AbsPathSegment Double
-- | Label - represented by baseline-left point and text.
--
-- Baseline-left is the dx * dy of the PrimCTM.
--
data PrimLabel u = PrimLabel
{ label_body :: LabelBody u
, label_ctm :: PrimCTM u
}
deriving (Eq,Show)
type DPrimLabel = PrimLabel Double
-- | Label can be draw with 3 layouts.
--
-- The standard layout uses @show@ for PostScript and a single
-- initial point for SVG.
--
-- Kerned horizontal layout - each character is encoded with the
-- rightwards horizontal distance from the last charcaters left
-- base-line.
--
-- Kerned vertical layout - each character is encoded with the
-- upwards distance from the last charcaters left base-line.
--
data LabelBody u = StdLayout EscapedText
| KernTextH [KerningChar u]
| KernTextV [KerningChar u]
deriving (Eq,Show)
type DLabelBody = LabelBody Double
-- | A Char (possibly escaped) paired with is displacement from
-- the previous KerningChar.
--
type KerningChar u = (u,EscapedChar)
type DKerningChar = KerningChar Double
-- | Ellipse represented by center and half_width * half_height.
--
-- Center is the dx * dy of the PrimCTM.
--
data PrimEllipse u = PrimEllipse
{ ellipse_half_width :: u
, ellipse_half_height :: u
, ellipse_ctm :: PrimCTM u
}
deriving (Eq,Show)
--------------------------------------------------------------------------------
-- Graphics state datatypes
-- | Graphics state used by the rendering monads.
--
-- This type is hidden by the top-level module @Wumpus.Core@.
--
data GraphicsState = GraphicsState
{ gs_draw_colour :: RGBi
, gs_font_size :: Int
, gs_font_face :: FontFace
, gs_stroke_attr :: StrokeAttr
}
deriving (Eq,Show)
--------------------------------------------------------------------------------
-- family instances
type instance DUnit (Picture u) = u
type instance DUnit (Primitive u) = u
type instance DUnit (PrimEllipse u) = u
type instance DUnit (PrimLabel u) = u
type instance DUnit (PrimPath u) = u
--------------------------------------------------------------------------------
-- instances
instance (Num u, PSUnit u) => Format (Picture u) where
format (Leaf m prims) = indent 2 $ vcat [ text "** Leaf-pic **"
, fmtLocale m
, fmtPrimlist prims ]
format (Picture m pics) = indent 2 $ vcat [ text "** Tree-pic **"
, fmtLocale m
, fmtPics pics ]
format (Clip m path pic) = indent 2 $ vcat [ text "** Clip-path **"
, fmtLocale m
, format path
, format pic ]
fmtPics :: PSUnit u => JoinList (Picture u) -> Doc
fmtPics ones = snd $ F.foldl' fn (0,empty) ones
where
fn (n,acc) e = (n+1, vcat [ acc, text "-- " <+> int n, format e, line])
fmtLocale :: (Num u, PSUnit u) => Locale u -> Doc
fmtLocale (bb,_) = format bb
instance PSUnit u => Format (Primitive u) where
format (PPath props p) =
indent 2 $ vcat [ text "path:" <+> format props, format p ]
format (PLabel props l) =
indent 2 $ vcat [ text "label:" <+> format props, format l ]
format (PEllipse props e) =
indent 2 $ vcat [ text "ellipse:" <+> format props, format e ]
format (PContext _ a) =
vcat [ text "-- svg ctx change " , format a ]
format (PSVG _ a) =
vcat [ text "-- svg:", format a ]
format (PGroup ones) =
vcat [ text "-- group ", fmtPrimlist ones ]
fmtPrimlist :: PSUnit u => JoinList (Primitive u) -> Doc
fmtPrimlist ones = snd $ F.foldl' fn (0,empty) ones
where
fn (n,acc) e = (n+1, vcat [ acc, text "-- leaf" <+> int n, format e, line])
instance PSUnit u => Format (PrimPath u) where
format (PrimPath pt ps) = vcat (start : map format ps)
where
start = text "start_point " <> format pt
instance PSUnit u => Format (PrimPathSegment u) where
format (RelCurveTo p1 p2 p3) =
text "rel_curve_to " <> format p1 <+> format p2 <+> format p3
format (RelLineTo pt) = text "rel_line_to " <> format pt
instance PSUnit u => Format (PrimLabel u) where
format (PrimLabel s ctm) =
vcat [ dquotes (format s)
, text "ctm=" <> format ctm
]
instance PSUnit u => Format (LabelBody u) where
format (StdLayout enctext) = format enctext
format (KernTextH xs) = text "(KernH)" <+> hcat (map (format .snd) xs)
format (KernTextV xs) = text "(KernV)" <+> hcat (map (format .snd) xs)
instance PSUnit u => Format (PrimEllipse u) where
format (PrimEllipse hw hh ctm) = text "hw=" <> dtruncFmt hw
<+> text "hh=" <> dtruncFmt hh
<+> text "ctm=" <> format ctm
instance Format XLink where
format (XLink ss) = text "xlink:href" <+> text ss
--------------------------------------------------------------------------------
instance Boundary (Picture u) where
boundary (Leaf (bb,_) _) = bb
boundary (Picture (bb,_) _) = bb
boundary (Clip (bb,_) _ _) = bb
instance (Real u, Floating u, FromPtSize u) => Boundary (Primitive u) where
boundary (PPath _ p) = pathBoundary p
boundary (PLabel a l) = labelBoundary (label_font a) l
boundary (PEllipse _ e) = ellipseBoundary e
boundary (PContext _ a) = boundary a
boundary (PSVG _ a) = boundary a
boundary (PGroup ones) = outer $ viewl ones
where
outer (OneL a) = boundary a
outer (a :< as) = inner (boundary a) (viewl as)
inner bb (OneL a) = bb `boundaryUnion` boundary a
inner bb (a :< as) = inner (bb `boundaryUnion` boundary a) (viewl as)
pathBoundary :: (Num u, Ord u) => PrimPath u -> BoundingBox u
pathBoundary (PrimPath st xs) = step st (st,st) xs
where
step _ (lo,hi) [] = BBox lo hi
step pt (lo,hi) (RelLineTo v1:rest) =
let p1 = pt .+^ v1
in step p1 (lo2 lo p1, hi2 hi p1) rest
step pt (lo,hi) (RelCurveTo v1 v2 v3:rest) =
let p1 = pt .+^ v1
p2 = p1 .+^ v2
p3 = p2 .+^ v3
lo' = lo4 lo p1 p2 p3
hi' = hi4 hi p1 p2 p3
in step p3 (lo',hi') rest
lo2 (P2 x1 y1) (P2 x2 y2) = P2 (min x1 x2) (min y1 y2)
hi2 (P2 x1 y1) (P2 x2 y2) = P2 (max x1 x2) (max y1 y2)
lo4 (P2 x1 y1) (P2 x2 y2) (P2 x3 y3) (P2 x4 y4) =
P2 (min x1 $ min x2 $ min x3 x4) (min y1 $ min y2 $ min y3 y4)
hi4 (P2 x1 y1) (P2 x2 y2) (P2 x3 y3) (P2 x4 y4) =
P2 (max x1 $ max x2 $ max x3 x4) (max y1 $ max y2 $ max y3 y4)
labelBoundary :: (Floating u, Real u, FromPtSize u)
=> FontAttr -> PrimLabel u -> BoundingBox u
labelBoundary attr (PrimLabel body ctm) =
retraceBoundary (m33 *#) untraf_bbox
where
m33 = matrixRepCTM ctm
untraf_bbox = labelBodyBoundary (font_size attr) body
labelBodyBoundary :: (Num u, Ord u, FromPtSize u)
=> FontSize -> LabelBody u -> BoundingBox u
labelBodyBoundary sz (StdLayout etxt) = stdLayoutBB sz etxt
labelBodyBoundary sz (KernTextH xs) = hKerningBB sz xs
labelBodyBoundary sz (KernTextV xs) = vKerningBB sz xs
stdLayoutBB :: (Num u, Ord u, FromPtSize u)
=> FontSize -> EscapedText -> BoundingBox u
stdLayoutBB sz etxt = textBoundsEsc sz zeroPt etxt
-- Note - this assumes positive deltas (and a nonempty list)...
--
-- Kern deltas are relative to the left basepoint, so they are
-- irrespective of the actual charater width. Thus to calculate
-- the bounding box Wumpus calculates the bounds of one character
-- then expands the right edge with the sum of the (rightwards)
-- displacements.
--
hKerningBB :: (Num u, Ord u, FromPtSize u)
=> FontSize -> [(u,EscapedChar)] -> BoundingBox u
hKerningBB sz xs = rightGrow (sumDiffs xs) $ textBounds sz zeroPt "A"
where
sumDiffs = foldr (\(u,_) i -> i+u) 0
rightGrow u (BBox ll (P2 x1 y1)) = BBox ll (P2 (x1+u) y1)
-- Note - likewise same assumptions as horizontal version.
-- (A postive distance represents a move downwards)...
--
-- The kern delta is the distance between baselines of successive
-- characters, so character height is irrespective when summing
-- the deltas.
--
-- Also note, that the Label /grows/ downwards...
--
vKerningBB :: (Num u, Ord u, FromPtSize u)
=> FontSize -> [(u,EscapedChar)] -> BoundingBox u
vKerningBB sz xs = downGrow (sumDiffs xs) $ textBounds sz zeroPt "A"
where
sumDiffs = foldr (\(u,_) i -> i+u) 0
downGrow u (BBox (P2 x0 y0) (P2 x1 y1)) = BBox (P2 x0 (y0-u)) (P2 x1 y1)
-- | Ellipse bbox is the bounding rectangle, rotated as necessary
-- then retraced.
--
ellipseBoundary :: (Real u, Floating u) => PrimEllipse u -> BoundingBox u
ellipseBoundary (PrimEllipse hw hh ctm) =
traceBoundary $ map (m33 *#) [sw,se,ne,nw]
where
sw = P2 (-hw) (-hh)
se = P2 hw (-hh)
ne = P2 hw hh
nw = P2 (-hw) hh
m33 = matrixRepCTM ctm
--------------------------------------------------------------------------------
-- Affine transformations
-- Affine transformation of Pictures only transforms the
-- BoundingBox, the primitives within the picture are untouched.
-- The transformation is transmitted to PostScript as a matrix
-- update (frame change).
--
instance (Num u, Ord u) => Transform (Picture u) where
transform mtrx =
mapLocale $ \(bb,xs) -> (transform mtrx bb, Matrix mtrx:xs)
instance (Real u, Floating u) => Rotate (Picture u) where
rotate theta =
mapLocale $ \(bb,xs) -> (rotate theta bb, Rotate theta:xs)
instance (Real u, Floating u) => RotateAbout (Picture u) where
rotateAbout theta pt =
mapLocale $ \(bb,xs) -> (rotateAbout theta pt bb, RotAbout theta pt:xs)
instance (Num u, Ord u) => Scale (Picture u) where
scale sx sy =
mapLocale $ \(bb,xs) -> (scale sx sy bb, Scale sx sy : xs)
instance (Num u, Ord u) => Translate (Picture u) where
translate dx dy =
mapLocale $ \(bb,xs) -> (translate dx dy bb, Translate dx dy:xs)
mapLocale :: (Locale u -> Locale u) -> Picture u -> Picture u
mapLocale f (Leaf lc ones) = Leaf (f lc) ones
mapLocale f (Picture lc ones) = Picture (f lc) ones
mapLocale f (Clip lc pp pic) = Clip (f lc) pp pic
--------------------------------------------------------------------------------
-- Transform primitives
-- Note - Primitives are not instances of transform
--
-- (ShapeCTM is not a real matrix).
--
instance (Real u, Floating u) => Rotate (Primitive u) where
rotate r (PPath a path) = PPath a $ rotatePath r path
rotate r (PLabel a lbl) = PLabel a $ rotateLabel r lbl
rotate r (PEllipse a ell) = PEllipse a $ rotateEllipse r ell
rotate r (PContext a chi) = PContext a $ rotate r chi
rotate r (PSVG a chi) = PSVG a $ rotate r chi
rotate r (PGroup xs) = PGroup $ fmap (rotate r) xs
instance (Real u, Floating u) => RotateAbout (Primitive u) where
rotateAbout r pt (PPath a path) = PPath a $ rotateAboutPath r pt path
rotateAbout r pt (PLabel a lbl) = PLabel a $ rotateAboutLabel r pt lbl
rotateAbout r pt (PEllipse a ell) = PEllipse a $ rotateAboutEllipse r pt ell
rotateAbout r pt (PContext a chi) = PContext a $ rotateAbout r pt chi
rotateAbout r pt (PSVG a chi) = PSVG a $ rotateAbout r pt chi
rotateAbout r pt (PGroup xs) = PGroup $ fmap (rotateAbout r pt) xs
instance Num u => Scale (Primitive u) where
scale sx sy (PPath a path) = PPath a $ scalePath sx sy path
scale sx sy (PLabel a lbl) = PLabel a $ scaleLabel sx sy lbl
scale sx sy (PEllipse a ell) = PEllipse a $ scaleEllipse sx sy ell
scale sx sy (PContext a chi) = PContext a $ scale sx sy chi
scale sx sy (PSVG a chi) = PSVG a $ scale sx sy chi
scale sx sy (PGroup xs) = PGroup $ fmap (scale sx sy) xs
instance Num u => Translate (Primitive u) where
translate dx dy (PPath a path) = PPath a $ translatePath dx dy path
translate dx dy (PLabel a lbl) = PLabel a $ translateLabel dx dy lbl
translate dx dy (PEllipse a ell) = PEllipse a $ translateEllipse dx dy ell
translate dx dy (PContext a chi) = PContext a $ translate dx dy chi
translate dx dy (PSVG a chi) = PSVG a $ translate dx dy chi
translate dx dy (PGroup xs) = PGroup $ fmap (translate dx dy) xs
--------------------------------------------------------------------------------
-- Paths
rotatePath :: (Real u, Floating u) => Radian -> PrimPath u -> PrimPath u
rotatePath ang = mapPath (rotate ang) (rotate ang)
rotateAboutPath :: (Real u, Floating u)
=> Radian -> Point2 u -> PrimPath u -> PrimPath u
rotateAboutPath ang pt = mapPath (rotateAbout ang pt) (rotateAbout ang pt)
scalePath :: Num u => u -> u -> PrimPath u -> PrimPath u
scalePath sx sy = mapPath (scale sx sy) (scale sx sy)
-- Note - translate only needs change the start point /because/
-- the path represented as a relative path.
--
translatePath :: Num u => u -> u -> PrimPath u -> PrimPath u
translatePath x y (PrimPath st xs) = PrimPath (translate x y st) xs
mapPath :: (Point2 u -> Point2 u) -> (Vec2 u -> Vec2 u)
-> PrimPath u -> PrimPath u
mapPath f g (PrimPath st xs) = PrimPath (f st) (map (mapSeg g) xs)
mapSeg :: (Vec2 u -> Vec2 u) -> PrimPathSegment u -> PrimPathSegment u
mapSeg fn (RelLineTo p) = RelLineTo (fn p)
mapSeg fn (RelCurveTo p1 p2 p3) = RelCurveTo (fn p1) (fn p2) (fn p3)
--------------------------------------------------------------------------------
-- Labels
-- Rotate the baseline-left start point _AND_ the CTM of the
-- label.
--
rotateLabel :: (Real u, Floating u)
=> Radian -> PrimLabel u -> PrimLabel u
rotateLabel ang (PrimLabel txt ctm) = PrimLabel txt (rotateCTM ang ctm)
-- /rotateAbout/ the start-point, /rotate/ the the CTM.
--
rotateAboutLabel :: (Real u, Floating u)
=> Radian -> Point2 u -> PrimLabel u -> PrimLabel u
rotateAboutLabel ang pt (PrimLabel txt ctm) =
PrimLabel txt (rotateAboutCTM ang pt ctm)
scaleLabel :: Num u => u -> u -> PrimLabel u -> PrimLabel u
scaleLabel sx sy (PrimLabel txt ctm) = PrimLabel txt (scaleCTM sx sy ctm)
-- Change the bottom-left corner.
--
translateLabel :: Num u => u -> u -> PrimLabel u -> PrimLabel u
translateLabel dx dy (PrimLabel txt ctm) =
PrimLabel txt (translateCTM dx dy ctm)
--------------------------------------------------------------------------------
-- Ellipse
rotateEllipse :: (Real u, Floating u)
=> Radian -> PrimEllipse u -> PrimEllipse u
rotateEllipse ang (PrimEllipse hw hh ctm) =
PrimEllipse hw hh (rotateCTM ang ctm)
rotateAboutEllipse :: (Real u, Floating u)
=> Radian -> Point2 u -> PrimEllipse u -> PrimEllipse u
rotateAboutEllipse ang pt (PrimEllipse hw hh ctm) =
PrimEllipse hw hh (rotateAboutCTM ang pt ctm)
scaleEllipse :: Num u => u -> u -> PrimEllipse u -> PrimEllipse u
scaleEllipse sx sy (PrimEllipse hw hh ctm) =
PrimEllipse hw hh (scaleCTM sx sy ctm)
-- Change the point
--
translateEllipse :: Num u => u -> u -> PrimEllipse u -> PrimEllipse u
translateEllipse dx dy (PrimEllipse hw hh ctm) =
PrimEllipse hw hh (translateCTM dx dy ctm)
--------------------------------------------------------------------------------
-- Additional operations
-- | Destructor for Matrix3'3.
--
-- Pattern matching on 6-tuple may be more convenient than using
-- the Matrix3'3 directly.
--
-- > (M3'3 e0x e1x ox
-- > e0y e1y oy
-- > _ _ _ ) = (e0x,e0y, e1x,e1y, ox,oy)
--
deconsMatrix :: Matrix3'3 u -> (u,u,u,u,u,u)
deconsMatrix (M3'3 e0x e1x ox
e0y e1y oy
_ _ _ ) = (e0x,e0y, e1x,e1y, ox,oy)
-- If a picture has coordinates smaller than (P2 4 4) then it
-- needs repositioning before it is drawn to PostScript or SVG.
--
-- (P2 4 4) gives a 4 pt margin - maybe it sould be (0,0) or
-- user defined.
--
repositionDeltas :: (Num u, Ord u)
=> Picture u -> (BoundingBox u, Maybe (Vec2 u))
repositionDeltas = step . boundary
where
step bb@(BBox (P2 llx lly) (P2 urx ury))
| llx < 4 || lly < 4 = (BBox ll ur, Just $ V2 x y)
| otherwise = (bb, Nothing)
where
x = 4 - llx
y = 4 - lly
ll = P2 (llx+x) (lly+y)
ur = P2 (urx+x) (ury+y)
--------------------------------------------------------------------------------
-- | The initial graphics state.
--
-- PostScript has no default font so we always want the first
-- /delta/ operation not to find a match and cause a @findfint@
-- command to be generated (PostScript @findfont@ commands are
-- only written in the output on /deltas/ to reduce the
-- output size).
--
zeroGS :: GraphicsState
zeroGS = GraphicsState { gs_draw_colour = black
, gs_font_size = (-1)
, gs_font_face = unmatchable_face
, gs_stroke_attr = default_stroke_attr
}
where
unmatchable_face = FontFace "DONT_MATCH" ""
SVG_BOLD_OBLIQUE no_encoding
no_encoding = IntMap.empty
-- | Is the path empty - if so we might want to avoid printing it.
--
isEmptyPath :: PrimPath u -> Bool
isEmptyPath (PrimPath _ xs) = null xs
-- | Is the label empty - if so we might want to avoid printing it.
--
isEmptyLabel :: PrimLabel u -> Bool
isEmptyLabel (PrimLabel txt _) = body txt
where
body (StdLayout esc) = destrEscapedText null esc
body (KernTextH xs) = null xs
body (KernTextV xs) = null xs