osu-framework/osu.Framework/Input/SDLWindowTextInput.cs

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using osu.Framework.Graphics.Primitives;
using osu.Framework.Platform;

namespace osu.Framework.Input
{
    internal class SDLWindowTextInput : TextInputSource
    {
        private readonly ISDLWindow window;

        public SDLWindowTextInput(ISDLWindow window)
        {
            this.window = window;
        }

        private void handleTextInput(string text)
        {
            // SDL sends IME results as `SDL_TextInputEvent` which we can't differentiate from regular text input
            // so we have to manually keep track and invoke the correct event.

            if (ImeActive)
            {
                TriggerImeResult(text);
            }
            else
            {
                TriggerTextInput(text);
            }
        }

        private void handleTextEditing(string? text, int selectionStart, int selectionLength)
        {
            if (text == null) return;

            TriggerImeComposition(text, selectionStart, selectionLength);
        }

        protected override void ActivateTextInput(TextInputProperties properties)
        {
            window.TextInput += handleTextInput;
            window.TextEditing += handleTextEditing;
            window.StartTextInput(properties);
        }

        protected override void EnsureTextInputActivated(TextInputProperties properties)
        {
            window.StartTextInput(properties);
        }

        protected override void DeactivateTextInput()
        {
            window.TextInput -= handleTextInput;
            window.TextEditing -= handleTextEditing;
            window.StopTextInput();
        }

        public override void SetImeRectangle(RectangleF rectangle)
        {
            window.SetTextInputRect(rectangle);
        }

        public override void ResetIme()
        {
            base.ResetIme();
            window.ResetIme();
        }
    }
}