HTk.Widgets.Canvas

HTk's strongcanvas widget/strong.br A canvas is a drawing pad, that can also contain widgets in embedded windows.br A canvas widget contains strongcanvas items/strong.

Documentation

data Canvas

The Canvas datatype.

Instances

Eq Canvas

Methods

(==) :: Canvas -> Canvas -> Bool

(/=) :: Canvas -> Canvas -> Bool

Destroyable Canvas

A canvas widget can be destroyed.

Methods

destroy :: Canvas -> IO ()

Synchronized Canvas

You can synchronize on a canvas object (in JAVA style).

Methods

synchronize :: Canvas -> IO b -> IO b

GUIObject Canvas

Internal.

Methods

toGUIObject :: Canvas -> GUIOBJECT

cname :: Canvas -> String

cset :: GUIValue a => Canvas -> ConfigID -> a -> IO Canvas

cget :: GUIValue a => Canvas -> ConfigID -> IO a

HasEnable Canvas

A canvas widget is a stateful widget, it can be enabled or disabled.

Methods

state :: State -> Config Canvas

getState :: Canvas -> IO State

disable :: Config Canvas

enable :: Config Canvas

isEnabled :: Canvas -> IO Bool

HasBorder Canvas

A canvas widget has a configureable border.

Methods

borderwidth :: Distance -> Config Canvas

getBorderwidth :: Canvas -> IO Distance

relief :: Relief -> Config Canvas

getRelief :: Canvas -> IO Relief

HasSize Canvas

You can specify the size of a canvas.

Methods

width :: Distance -> Config Canvas

getWidth :: Canvas -> IO Distance

height :: Distance -> Config Canvas

getHeight :: Canvas -> IO Distance

size :: Size -> Config Canvas

getSize :: Canvas -> IO Size

HasColour Canvas

A canvas widget has a foreground and background colour.

Methods

legalColourID :: Canvas -> ConfigID -> Bool

setColour :: Canvas -> ConfigID -> Colour -> IO Canvas

getColour :: Canvas -> ConfigID -> IO Colour

HasTooltip Canvas

A canvas can have a tooltip (only displayed if you are using tixwish).

Methods

tooltip :: String -> Canvas -> IO Canvas

destroyTooltip :: Canvas -> IO ()

Widget Canvas

A canvas widget has standard widget properties (concerning focus, cursor).

Methods

cursor :: CursorDesignator ch => ch -> Config Canvas

getCursor :: Canvas -> IO Cursor

takeFocus :: Bool -> Config Canvas

getTakeFocus :: Canvas -> IO Bool

Container Canvas

A canvas is also a container for widgets, because it can contain widgets in embedded windows.

HasPostscript Canvas

The contents of a canvas is printable.

Methods

postscript :: Canvas -> [CreationConfig PostScript] -> IO ()

HasScroller Canvas

A canvas is a scrollable widget.

Methods

isWfOrientation :: Canvas -> Orientation -> Bool

scrollbar :: Orientation -> ScrollBar -> Config Canvas

moveto :: Orientation -> Canvas -> Fraction -> IO ()

scroll :: Orientation -> Canvas -> Int -> ScrollUnit -> IO ()

view :: Orientation -> Canvas -> IO (Fraction, Fraction)

GUIObject c => HasBBox Canvas c

You can request the bounding box size of a canvas item (use a canvas tag for the bounding box of a set of items).

Methods

bbox :: Canvas -> c -> IO (Maybe (Distance, Distance, Distance, Distance))

newCanvas

Arguments

:: Container par

=> par

the parent widget, which has to be a container widget (an instance of class Container).

-> [Config Canvas]

the list of configuration options for this canvas.

-> IO Canvas

A canvas widget.

Constructs a new canvas widget and returns a handler.

closeEnough

Arguments

:: Double

the distance to be set.

-> Canvas

the canvas to apply this configuration.

-> IO Canvas

The concerned canvas.

Sets the maximum distance from the mouse to an overlapped object.

getCloseEnough

Arguments

:: Canvas

the canvas to get this configuration from.

-> IO Double

The requested distance.

Selector for the maximum distance from the mouse to an overlapped object.

confine

Arguments

:: Bool

Bool, see above.

-> Canvas

the canvas to apply this configuration.

-> IO Canvas

The concerned canvas.

True constraints view to the scroll region.

getConfine

Arguments

:: Canvas

the canvas to get this configuration from.

-> IO Bool

The confine configuration as a Bool value (see confine).

Selector for the confine configuration, constraints view to the scroll region if True.

screenToCanvasCoord

Arguments

:: Canvas

the concerned canvas widget.

-> Orientation

the orientation (Vertical or Horizontal).

-> Distance

the input coordinate.

-> Maybe Distance

an optional grid (the output can be rounded to multiples of this grid if specified).

-> IO Distance

The requested distance in the specified orientation.

Maps from screen X or Y coordinates (orientation parameter) to the corresponding coordinates in canvas space.

type ScrollRegion = (Position, Position)

The ScrollRegion datatype (scrollable region of the canvas widget).

scrollRegion

Arguments

:: ScrollRegion

the scroll region to set.

-> Canvas

the canvas widget to apply this scrollregion.

-> IO Canvas

The concerned canvas.

Sets the scrollable region for a canvas widget.

getScrollRegion

Arguments

:: Canvas

the canvas widget to get the applied scroll region from.

-> IO ScrollRegion

The requested scroll region.

Gets the applied scroll region from a canvas widget.

scrollIncrement

Arguments

:: Orientation

the orientation (Vertical or Horizontal).

-> Distance

the distance to set.

-> Canvas

the canvas widget to apply this scrolling distance.

-> IO Canvas

The concerned canvas.

Sets the distance for one scrolling unit.