1
我在Haskell
和使用Chart
模块。 在活动的GTK
窗口中没有渲染文档。所以我tryed我自己:图Gtk渲染失败
import Graphics.Rendering.Chart.Easy
import Graphics.Rendering.Chart.Gtk
signal :: [Double] -> [(Double,Double)]
signal xs = [ (x,(sin (x*3.14159/45) + 1)/2 * (sin (x*3.14159/5))) | x <- xs ]
main = renderableToWindow def 300 300 $ 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]))
但是,这是不正确的,造成ghc -o main main.hs
回报:
[1 of 1] Compiling Main (main.hs, main.o)
main.hs:7:8:
Couldn't match expected type ‘Control.Monad.Trans.State.Lazy.StateT
(Layout Double Double)
(Control.Monad.Trans.State.Lazy.State CState)
()
-> t’
with actual type ‘IO()’
Relevant bindings include main :: t (bound at main.hs:7:1)
The first argument of ($) takes one argument,
but its type ‘IO()’ has none
In the expression:
renderableToWindow def 300 300
$ 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])) }
In an equation for ‘main’:
main
= renderableToWindow def 300 300
$ do { layout_title .= "Amplitude Modulation";
setColors [opaque blue, ....];
plot (line "am" [signal ...]);
.... }
所以现在我的问题:如何做出正确的GTK渲染?
谢谢!完美解决方案 –