Gtk2HsContentsIndex
Graphics.UI.Gtk.Gdk.Region
Portabilityportable (depends on GHC)
Stabilityprovisional
Maintainergtk2hs-users@lists.sourceforge.net
Description

A set of rectangles describing areas to be redrawn.

  • Regions consist of a set of non-overlapping rectangles. They are used to specify the area of a window which needs updating.
Synopsis
makeNewRegion :: Ptr Region -> IO Region
newtype Region = Region (ForeignPtr Region)
regionNew :: IO Region
data FillRule
= EvenOddRule
| WindingRule
regionPolygon :: [Point] -> FillRule -> IO Region
regionCopy :: Region -> IO Region
regionRectangle :: Rectangle -> IO Region
regionGetClipbox :: Region -> IO Rectangle
regionGetRectangles :: Region -> IO [Rectangle]
regionEmpty :: Region -> IO Bool
regionEqual :: Region -> Region -> IO Bool
regionPointIn :: Region -> Point -> IO Bool
data OverlapType
= OverlapRectangleIn
| OverlapRectangleOut
| OverlapRectanglePart
regionRectIn :: Region -> Rectangle -> IO OverlapType
regionOffset :: Region -> Int -> Int -> IO ()
regionShrink :: Region -> Int -> Int -> IO ()
regionUnionWithRect :: Region -> Rectangle -> IO ()
regionIntersect :: Region -> Region -> IO ()
regionUnion :: Region -> Region -> IO ()
regionSubtract :: Region -> Region -> IO ()
regionXor :: Region -> Region -> IO ()
Documentation
makeNewRegion :: Ptr Region -> IO Region
newtype Region
Constructors
Region (ForeignPtr Region)
regionNew :: IO Region
Create an empty region.
data FillRule

Specify how to interpret a polygon.

  • The flag determines what happens if a polygon has overlapping areas.
Constructors
EvenOddRule
WindingRule
show/hide Instances
regionPolygon :: [Point] -> FillRule -> IO Region
Convert a polygon into a Region.
regionCopy :: Region -> IO Region
Copy a Region.
regionRectangle :: Rectangle -> IO Region
Convert a rectangle to a Region.
regionGetClipbox :: Region -> IO Rectangle
Smallest rectangle including the Region.
regionGetRectangles :: Region -> IO [Rectangle]

Turn the Region into its rectangles.

A Region is a set of horizontal bands. Each band consists of one or more rectangles of the same height. No rectangles in a band touch.

regionEmpty :: Region -> IO Bool
Test if a Region is empty.
regionEqual :: Region -> Region -> IO Bool
Compares two Regions for equality.
regionPointIn :: Region -> Point -> IO Bool
Checks if a point it is within a region.
data OverlapType
How a rectangle is contained in a Region.
Constructors
OverlapRectangleIn
OverlapRectangleOut
OverlapRectanglePart
show/hide Instances
regionRectIn :: Region -> Rectangle -> IO OverlapType
Check if a rectangle is within a region.
regionOffset :: Region -> Int -> Int -> IO ()
Move a region.
regionShrink :: Region -> Int -> Int -> IO ()

Move a region.

  • Positive values shrink the region, negative values expand it.
regionUnionWithRect :: Region -> Rectangle -> IO ()
Updates the region to include the rectangle.
regionIntersect :: Region -> Region -> IO ()

Intersects one region with another.

  • Changes reg1 to include the common areas of reg1 and reg2.
regionUnion :: Region -> Region -> IO ()

Unions one region with another.

  • Changes reg1 to include reg1 and reg2.
regionSubtract :: Region -> Region -> IO ()

Removes pars of a Region.

  • Reduces the region reg1 so that is does not include any areas of reg2.
regionXor :: Region -> Region -> IO ()

XORs two Regions.

  • The exclusive or of two regions contains all areas which were not overlapping. In other words, it is the union of the regions minus their intersections.
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