Graphics.UI.GIO.Attributes

Portability	portable
Stability	provisional
Maintainer	ka2_mail@yahoo.com

Contents

Attributes and properties

Generic attribute creators

Common widget classes

Dimensions
HasFont
Drawn
Titled
Able
ToolTip
Accelerated
Positioned
Selection
Icon

Description

Widgets w can have attributes of type a represented by the type Attr w a. An attribute set or read. An example of an attribute is title with type:

 title :: Attr Window String

When an attribute is associated with a value, we call it a property of type Prop w. Properties are constructed with the ('=:') function:

 title =: "hello world"  :: Prop Window

Properties can be set with the set function:

 set win [title =: "hello world"]  :: IO ()

and attributes can be read with the get function:

 get win title  :: IO String

The function get, set and '(=:)' are polymorphic and work for all widgets, but the title attribute just works for windows. Many attributes are defined for multiple widgets and are organised in type classes, for example Deadly and Dimensions.

The ('~:') operator is used to transform an attribute with an update function. For example, the interval on a timer can be doubled with:

 set timer [interval ~: (*2)]

Synopsis

data Attr w a

data Prop w

set1 :: w -> Prop w -> IO ()

set :: w -> [Prop w] -> IO ()

get :: w -> Attr w a -> IO a

with :: w -> [Prop w] -> IO a -> IO a

(=:) :: Attr w a -> a -> Prop w

(~:) :: Attr w a -> (a -> a) -> Prop w

(=::) :: Attr w a -> (w -> a) -> Prop w

(~::) :: Attr w a -> (w -> a -> a) -> Prop w

mapAttr :: (a -> b) -> (a -> b -> a) -> Attr w a -> Attr w b

newAttr :: (w -> IO a) -> (w -> a -> IO ()) -> Attr w a

newStdAttr :: (w -> h) -> (h -> IO a) -> (h -> a -> IO ()) -> Attr w a

newProp :: (w -> IO ()) -> (w -> IO a) -> (w -> a -> IO ()) -> Prop w

varAttr :: (w -> Var a) -> Attr w a

readAttr :: String -> (w -> IO a) -> Attr w a

writeAttr :: String -> (w -> a -> IO ()) -> Attr w a

class Dimensions w

frame :: Dimensions w => Attr w Rect

position :: Dimensions w => Attr w Point

size :: Dimensions w => Attr w Size

width :: Dimensions w => Attr w Int

height :: Dimensions w => Attr w Int

class HasFont w

font :: HasFont w => Attr w Font

class HasFont w => Drawn w

bufferMode :: Drawn w => Attr w BufferMode

pen :: Drawn w => Attr w Pen

color :: Drawn w => Attr w Color

bgcolor :: Drawn w => Attr w Color

hatch :: Drawn w => Attr w HatchStyle

thickness :: Drawn w => Attr w Int

capstyle :: Drawn w => Attr w CapStyle

linestyle :: Drawn w => Attr w LineStyle

joinstyle :: Drawn w => Attr w JoinStyle

drawMode :: Drawn w => Attr w DrawMode

bkDrawMode :: Drawn w => Attr w Bool

class Titled w

title :: Titled w => Attr w String

class Able w

enabled :: Able w => Attr w Bool

class ToolTip w

tooltip :: ToolTip w => Attr w String

class Accelerated w

accel :: Accelerated w => Attr w Key

class Positioned w

pos :: Positioned w => Attr w Int

class Checked w

checked :: Checked w => Attr w Bool

class Countable w

count :: Countable w => Attr w Int

class Countable w => CommandItems w

items :: CommandItems w => Attr w [(String, IO ())]

appendItem :: CommandItems w => w -> (String, IO ()) -> IO ()

insertItem :: CommandItems w => w -> Int -> (String, IO ()) -> IO ()

removeItem :: CommandItems w => w -> Int -> IO ()

removeAllItems :: CommandItems w => w -> IO ()

class Countable w => SingleSelect w

selected :: SingleSelect w => Attr w Int

class Countable w => MultiSelect w

selection :: MultiSelect w => Attr w [Int]

class RangedSelect w

range :: RangedSelect w => Attr w (Int, Int)

selectedPos :: RangedSelect w => Attr w Int

class HasIcon w

icon :: HasIcon w => Attr w (Maybe Bitmap)

Attributes and properties

data Attr w a

Widgets w can have attributes of type a.

data Prop w

A property of a widget w is an attribute that is already associated with a value. Properties are constructed with the '(=:)' operator.

set1 :: w -> Prop w -> IO ()

set :: w -> [Prop w] -> IO ()

Set properties

get :: w -> Attr w a -> IO a

Get an attribute

with :: w -> [Prop w] -> IO a -> IO a

Set properties just for a certain computation. The previous values are automatically restored on return.

(=:) :: Attr w a -> a -> Prop w

Associate an attribute with a new value into a property.

(~:) :: Attr w a -> (a -> a) -> Prop w

Apply an update function to an attribute.

(=::) :: Attr w a -> (w -> a) -> Prop w

Set the value of an attribute with a function that takes the widget itself as an argument.

(~::) :: Attr w a -> (w -> a -> a) -> Prop w

Set the value of an attribute with a function that takes the widget itself and the current value of the attribute as arguments.

Generic attribute creators

mapAttr :: (a -> b) -> (a -> b -> a) -> Attr w a -> Attr w b

(mapAttr get set attr) maps an attribute of Attr w a to Attr w b where (get :: a -> b) is used when the attribute is requested and (set :: a -> b -> a) is applied to current value when the attribute is set.

newAttr :: (w -> IO a) -> (w -> a -> IO ()) -> Attr w a

Create a new attribute with a specified getter and setter function.

newStdAttr :: (w -> h) -> (h -> IO a) -> (h -> a -> IO ()) -> Attr w a

The newStdAttr function is useful for creation of many standard attributes

newProp :: (w -> IO ()) -> (w -> IO a) -> (w -> a -> IO ()) -> Prop w

varAttr :: (w -> Var a) -> Attr w a

Helper function to implement an attribute that just gets or sets a Var member.

readAttr :: String -> (w -> IO a) -> Attr w a

Define a read-only attribute. Takes the name of the attribute as its first argument.

writeAttr :: String -> (w -> a -> IO ()) -> Attr w a

Define a write-only attribute. Takes the name of the attribute as its first argument.

Common widget classes

Dimensions

class Dimensions w

Widgets with dimensions have a width, height and position. Only the frame method is not defaulted.

Instances

Dimensions CompoundControl

Dimensions Window

frame :: Dimensions w => Attr w Rect

The outer frame of a widget.

position :: Dimensions w => Attr w Point

The upper-left corner.

size :: Dimensions w => Attr w Size

The size.

width :: Dimensions w => Attr w Int

The width.

height :: Dimensions w => Attr w Int

The height.

HasFont

class HasFont w

Widgets with a font.

Instances

HasFont CompoundControl

HasFont Window

font :: HasFont w => Attr w Font

The font.

Drawn

class HasFont w => Drawn w

Instances

Drawn CanvasPen

Drawn CompoundControl

Drawn Window

bufferMode :: Drawn w => Attr w BufferMode

The buffering mode. If the window is buffered then all drawing operations are first performed to memory buffer and after that the buffer is copied to the output device.

pen :: Drawn w => Attr w Pen

The pen

color :: Drawn w => Attr w Color

The (fore ground) color of the widget.

bgcolor :: Drawn w => Attr w Color

The back ground color.

hatch :: Drawn w => Attr w HatchStyle

The hatch style.

thickness :: Drawn w => Attr w Int

The thickness of the drawing pencil.

capstyle :: Drawn w => Attr w CapStyle

The cap style.