gtk-0.12.0: Binding to the Gtk+ graphical user interface library.

Portabilityportable (depends on GHC)
Stabilityprovisional
Maintainergtk2hs-users@lists.sourceforge.net

Graphics.UI.Gtk.Gdk.GC

Contents

Description

Graphics contexts - objects to encapsulate drawing properties

Synopsis

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.

data GC

Instances

Eq GC 
Ord GC 
GObjectClass GC 
GCClass GC 

class GObjectClass o => GCClass o

Instances

castToGC :: GObjectClass obj => obj -> GC

gcNew :: DrawableClass d => d -> IO GC

Create an empty graphics context.

data GCValues

Intermediate data structure for GCs.

  • If graphicsExposure is set then copying portions into a drawable will generate an "exposure" event, even if the destination area is not currently visible.

Instances

Storable GCValues 

data Color

Constructors

Color Word16 Word16 Word16 

Instances

Eq Color 
Show Color 
Storable Color 

data Function

Determine how bitmap operations are carried out.

Instances

Enum Function 
Eq Function 
Show Function 

data Fill

How objects are filled.

Instances

Enum Fill 
Eq Fill 
Show Fill 

data SubwindowMode

Instances

Enum SubwindowMode

visibility of a window

Eq SubwindowMode 
Show SubwindowMode 

data LineStyle

Determines if a line is solid or dashed.

Instances

Enum LineStyle 
Eq LineStyle 
Show LineStyle 

data CapStyle

Specify the how the ends of a line is drawn.

Instances

Enum CapStyle 
Eq CapStyle 
Show CapStyle 

data JoinStyle

Constructors

JoinMiter 
JoinRound 
JoinBevel 

Instances

Enum JoinStyle 
Eq JoinStyle 
Show JoinStyle 

gcNewWithValues :: DrawableClass d => d -> GCValues -> IO GC

Creates a graphics context with specific values.

gcSetValues :: GC -> GCValues -> IO ()

Change some of the values of a graphics context.

gcGetValues :: GC -> IO GCValues

Retrieve the values in a graphics context.

gcSetClipRectangle :: GC -> Rectangle -> IO ()

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 ()

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 ()

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 lineStyle member of the graphics context defines if odd segements are drawn or not. A phase argument greater than 0 will drop phase pixels before starting to draw.