@thi.ng/imgui/behaviors/text.js

Immediate mode GUI with flexible state handling & data only shape output

import { clamp0 } from "@thi.ng/math/interval";
import { Key } from "../api.js";
const WS = /\s/;
const __nextNonAlpha = (src, i) => {
  const n = src.length;
  while (i < n && WS.test(src[i])) i++;
  for (; i < n && !WS.test(src[i]); i++) {
  }
  return i;
};
const __prevNonAlpha = (src, i) => {
  while (i > 0 && WS.test(src[i])) i--;
  for (; i > 0 && !WS.test(src[i]); i--) {
  }
  return i;
};
const __getNext = (gui, txt, cursor, dir) => {
  cursor += dir;
  return gui.isAltDown() ? (dir < 0 ? __prevNonAlpha : __nextNonAlpha)(txt, cursor) : cursor;
};
const handleTextfieldKeys = (gui, state, filter, txt, cursor, drawCursor, maxLen) => {
  const txtLen = txt.length;
  const move = (next, delta) => {
    state.cursor = next;
    if (drawCursor + delta < 0) {
      state.offset = Math.max(state.offset + delta, 0);
    } else if (drawCursor + delta > maxLen) {
      state.offset = Math.min(
        state.offset + delta,
        clamp0(txtLen - maxLen)
      );
    }
  };
  const k = gui.key;
  switch (k) {
    case "":
      break;
    case Key.TAB:
      gui.switchFocus();
      break;
    case Key.ENTER:
      return txt;
    case Key.BACKSPACE:
      if (cursor > 0) {
        const next = __getNext(gui, txt, cursor, -1);
        move(next, next - cursor);
        return txt.substring(0, next) + txt.substring(cursor);
      }
      break;
    case Key.DELETE:
      if (cursor < txtLen) {
        const next = __getNext(gui, txt, cursor, 1);
        return txt.substring(0, cursor) + txt.substring(next + 1);
      }
      break;
    case Key.LEFT:
      if (cursor > 0) {
        const next = __getNext(gui, txt, cursor, -1);
        move(next, next - cursor);
      }
      break;
    case Key.RIGHT:
      if (cursor < txtLen) {
        const next = __getNext(gui, txt, cursor, 1);
        move(next, next - cursor);
      }
      break;
    case Key.HOME:
      move(0, -cursor);
      break;
    case Key.END:
      move(txtLen, txtLen - cursor);
      break;
    default: {
      if (k.length === 1 && filter(k)) {
        move(cursor + 1, 1);
        return txt.substring(0, cursor) + k + txt.substring(cursor);
      }
    }
  }
};
export {
  handleTextfieldKeys
};