| Portability | portable (depends on GHC) |
|---|---|
| Stability | provisional |
| Maintainer | gtk2hs-users@lists.sourceforge.net |
| Safe Haskell | None |
Graphics.UI.Gtk.Gdk.GC
Contents
Description
Graphics contexts - objects to encapsulate drawing properties
- data GC
- class GObjectClass o => GCClass o
- castToGC :: GObjectClass obj => obj -> GC
- gTypeGC :: GType
- gcNew :: DrawableClass d => d -> IO GC
- data GCValues = GCValues {
- foreground :: Color
- background :: Color
- function :: Function
- fill :: Fill
- tile :: Maybe Pixmap
- stipple :: Maybe Pixmap
- clipMask :: Maybe Pixmap
- subwindowMode :: SubwindowMode
- tsXOrigin :: Int
- tsYOrigin :: Int
- clipXOrigin :: Int
- clipYOrigin :: Int
- graphicsExposure :: Bool
- lineWidth :: Int
- lineStyle :: LineStyle
- capStyle :: CapStyle
- joinStyle :: JoinStyle
- newGCValues :: GCValues
- data Color = Color Word16 Word16 Word16
- data Function
- data Fill
- = Solid
- | Tiled
- | Stippled
- | OpaqueStippled
- data SubwindowMode
- data LineStyle
- data CapStyle
- = CapNotLast
- | CapButt
- | CapRound
- | CapProjecting
- data JoinStyle
- gcNewWithValues :: DrawableClass d => d -> GCValues -> IO GC
- gcSetValues :: GC -> GCValues -> IO ()
- gcGetValues :: GC -> IO GCValues
- gcSetClipRectangle :: GC -> Rectangle -> IO ()
- gcSetClipRegion :: GC -> Region -> IO ()
- gcSetDashes :: GC -> Int -> [(Int, Int)] -> IO ()
Detail
All drawing operations in Gdk take a graphics context (GC) argument. A graphics context encapsulates information about the way things are drawn, such as the foreground color or line width. By using graphics contexts, the number of arguments to each drawing call is greatly reduced, and communication overhead is minimized, since identical arguments do not need to be passed repeatedly.
Most values of a graphics context can be set at creation time by using
gcNewWithValues. A few of the values in the GC, such as the dash
pattern, can only be set by the latter method.
class GObjectClass o => GCClass o Source
castToGC :: GObjectClass obj => obj -> GCSource
gcNew :: DrawableClass d => d -> IO GCSource
Create an empty graphics context.
Intermediate data structure for GCs.
- If
graphicsExposureis set then copying portions into a drawable will generate an"exposure"event, even if the destination area is not currently visible.
Constructors
| GCValues | |
Fields
| |
data Color
Color
- Specifies a color with three integer values for red, green and blue. All values range from 0 (least intense) to 65535 (highest intensity).
Determine how bitmap operations are carried out.
How objects are filled.
Constructors
| Solid | |
| Tiled | |
| Stippled | |
| OpaqueStippled |
data SubwindowMode Source
Constructors
| ClipByChildren | |
| IncludeInferiors |
Instances
| Enum SubwindowMode | visibility of a window |
| Eq SubwindowMode | |
| Show SubwindowMode |
Determines if a line is solid or dashed.
Constructors
| LineSolid | |
| LineOnOffDash | |
| LineDoubleDash |
Specify the how the ends of a line is drawn.
Constructors
| CapNotLast | |
| CapButt | |
| CapRound | |
| CapProjecting |
gcNewWithValues :: DrawableClass d => d -> GCValues -> IO GCSource
Creates a graphics context with specific values.
gcSetValues :: GC -> GCValues -> IO ()Source
Change some of the values of a graphics context.
gcGetValues :: GC -> IO GCValuesSource
Retrieve the values in a graphics context.
gcSetClipRectangle :: GC -> Rectangle -> IO ()Source
Set a clipping rectangle.
- All drawing operations are restricted to this rectangle. This rectangle is interpreted relative to the clip origin.
gcSetClipRegion :: GC -> Region -> IO ()Source
Set a clipping region.
- All drawing operations are restricted to this region. This region is interpreted relative to the clip origin.
gcSetDashes :: GC -> Int -> [(Int, Int)] -> IO ()Source
Specify the pattern with which lines are drawn.
- Every tuple in the list contains an even and an odd segment. Even
segments are drawn normally, whereby the
lineStylemember of the graphics context defines if odd segements are drawn or not. Aphaseargument greater than 0 will dropphasepixels before starting to draw.