nimforum mirror - NiGui - thread issue - what am I doing wrong ?

IvanS (orginal) [2021-06-14T14:27:08+02:00] view original

I'm trying out some stuff to see if NiGui is suited for my needs. Played a bit with editing samples, but got into an issue with threads. And I need those, or Windows will complain with a 'not responding' warning.

I started with the thread example adding a text area and a button to play/pause. When [Play/Pause] is clicked the first time (toggled to false), updates halt, as expected, but when toggled again (to true) nothing happens. The clicks are registered, but the thread does not respond anymore. Obviously I am doing it the wrong way.

# Based on "This example shows how to change a control from another thread" from the nigui examples
# Trying to start/stop var update in thread

import nigui
import strutils, strformat

var
  window: Window
  container: LayoutContainer
  button_start: Button
  button_play: Button
  pbar: ProgressBar
  thread: Thread[void]

var
  p: int
  s: string
  play: bool = true

app.init()

window = newWindow("NiGui Example")

container = newLayoutContainer(Layout_Vertical)
container.padding = 10
window.add(container)

button_start = newButton("Start thread")
button_play = newButton("Play/Pause")
container.add(button_start)


var textArea = newTextArea()
# Create a multiline text box.
# By default, a text area is empty and editable.

proc update() =
  {.gcsafe.}:
    echo "In update pass ", p, ", [play] is ", play
    if play:
      pbar.value = pbar.value + 0.01
      app.sleep(100)
      p += 1
      s = fmt("Pass {p:5d}")
      textArea.addLine(s)
      app.queueMain(update)

proc start() =
  {.gcsafe.}:
    app.queueMain(update)

button_start.onClick = proc(event: ClickEvent) =
  container.remove(button_start)
  
  container.add(button_play)
  pbar = newProgressBar()
  container.add(pbar)
  container.add(textArea)   # Add the text area to the container.
  
  createThread(thread, start)

button_play.onClick = proc(event: ClickEvent) =
  echo "Play/Pause clicked"
  # play = !play (compiler error, can't do that in Nim)
  if play == false:
    play = true
  else:
    play = false
  echo "toggled play to ", play

window.show()
app.run()

Mirror of forum.nim-lang.org

8113 :: NiGui - thread issue - what am I doing wrong ?