haskell - 使用 wxHaskell 显示完整图像

Question

我正在使用 wxHaskell 在窗口中显示完整图像。我的代码是：

import Graphics.UI.WX
import Graphics.UI.WXCore

main :: IO ()
main = start testimg

testimg :: IO ()
testimg = do
  f <- frame [text := "Test Image"]
  p <- panel f []

  image <- bitmapCreateFromFile "landscape.png"
  imagep <- panel p [ on paint := onPaint image ]

  set f [ layout:= fill $ container p $ widget imagep ]

  where
    onPaint image dc rect = drawBitmap dc image pointZero True []

无论如何，当应用程序运行时，什么都不会显示（甚至窗口的边框也不显示）。我怎样才能让它工作？

Answer 1

fill您之前错过了一个widget imagep效果，即您在图片中绘制的面板没有任何表面。我也建议设置一个 outerSize。您可能还想查看https://github.com/wxHaskell/wxHaskell/blob/master/samples/wx/ImageViewer.hs以获得灵感。祝你好运！

import Graphics.UI.WX
import Graphics.UI.WXCore

main :: IO ()
main = start testimg

testimg :: IO ()
testimg = do
  f <- frame [text := "Test Image"]
  p <- panel f []

  image <- bitmapCreateFromFile "landscape.png"
  imagep <- panel p [ on paint := onPaint image ]

  set f [ layout:= fill $ container p $ fill $ widget imagep 
        , outerSize := sz 500 500
        ]

  where
    onPaint image dc rect = drawBitmap dc image pointZero True []