ebiten/exp/textinput/textinput.go

94 lines
2.4 KiB
Go

// Copyright 2023 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package textinput provides a text-inputting controller.
// This package is experimental and the API might be changed in the future.
//
// This package is supported by macOS and Web browsers so far.
package textinput
import (
"unicode/utf16"
"github.com/hajimehoshi/ebiten/v2/internal/ui"
)
// State represents the current state of text inputting.
type State struct {
// Text represents the current inputting text.
Text string
// CompositionSelectionStartInBytes represents the start position of the selection in bytes.
CompositionSelectionStartInBytes int
// CompositionSelectionStartInBytes represents the end position of the selection in bytes.
CompositionSelectionEndInBytes int
// Committed reports whether the current Text is the settled text.
Committed bool
// Error is an error that happens during text inputting.
Error error
}
// Start starts text inputting.
// Start returns a channel to send the state repeatedly, and a function to end the text inputting.
//
// Start returns nil and nil if the current environment doesn't support this package.
func Start(x, y int) (states chan State, close func()) {
cx, cy := ui.Get().LogicalPositionToClientPositionInNativePixels(float64(x), float64(y))
return theTextInput.Start(int(cx), int(cy))
}
func convertUTF16CountToByteCount(text string, c int) int {
return len(string(utf16.Decode(utf16.Encode([]rune(text))[:c])))
}
type session struct {
ch chan State
done chan struct{}
}
func newSession() *session {
return &session{
ch: make(chan State, 1),
done: make(chan struct{}),
}
}
func (s *session) end() {
if s.ch == nil {
return
}
close(s.ch)
s.ch = nil
close(s.done)
}
func (s *session) trySend(state State) {
for {
select {
case s.ch <- state:
return
default:
// Only the last value matters.
select {
case <-s.ch:
case <-s.done:
return
}
}
}
}