https://github.com/oswald2/chart-fltkhs

FLTKHS backend for the Chart Haskell library.
https://github.com/oswald2/chart-fltkhs

chart fltk fltkhs haskell

Last synced: 29 days ago
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FLTKHS backend for the Chart Haskell library.

• Host: GitHub
• URL: https://github.com/oswald2/chart-fltkhs
• Owner: oswald2
• License: bsd-3-clause
• Created: 2019-06-12T20:42:29.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2020-06-13T16:14:09.000Z (over 4 years ago)
• Last Synced: 2025-01-08T20:22:10.246Z (29 days ago)
• Topics: chart, fltk, fltkhs, haskell
• Language: Haskell
• Size: 73.2 KB
• Stars: 2
• Watchers: 1
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Chart-fltkhs

FLTKHS backend for the Chart Haskell library.

Builds the library and (if specified) the examples, which resemble the examples from https://github.com/timbod7/haskell-chart/wiki.

**Note:** *Transparency is not supported by FLTK, so e.g. Examples 8, 9 and 10 from the Chart library will not look correctly. This is a limitation of FLTK itself.*

To render a Chart to a widget, it is best to create a custom widget and override it's draw method.

## Building ##

### Stack ###

Just use stack build. If you specify the flag 'examples', also the examples will be built:

> stack build

To build with examples: 

> stack build --flag Chart-fltkhs:examples

### Cabal ###

It is recommended to use cabal new-build:

> cabal new-build

To build with examples:

> cabal new-build -f examples

### A usage example: ###

```haskell

widget' <- widgetCustom

    (FL.Rectangle (Position (X 0) (Y 0)) (Size (Width width) (Height height)))

    Nothing

    drawChart

    defaultCustomWidgetFuncs

```

Here, `drawChart` is the provided draw method for the widget. A possible implementation

could be this:

```haskell

-- The char itself, to be used here with 'Graphics.Rendering.Chart.Easy'

signal :: [Double] -> [(Double,Double)]

signal xs = [ (x,(sin (x*3.14159/45) + 1) / 2 * sin (x*3.14159/5)) | x <- xs ]

-- the overloaded drawing function

drawChart :: Ref Widget -> IO ()

drawChart widget = do

    -- determine a clipping area for the whole widget first

    rectangle' <- getRectangle widget

    -- with this clipping area, we draw the graph. This graph is taken from Example1

    -- from the Chart library

    withFlClip rectangle' $

        renderToWidgetEC widget $ do

            layout_title .= "Amplitude Modulation"

            setColors [opaque blue, opaque red]

            plot (line "am" [signal [0,(0.5)..400]])

            plot (points "am points" (signal [0,7..400]))

```

For more detailed examples, look into the [examples](https://github.com/oswald2/Chart-fltkhs/tree/master/examples) directory.