BangleApps/apps/iconlaunch/app.js

{
  const s = require("Storage");
  const settings = s.readJSON("launch.json", true) || { showClocks: true, fullscreen: false,direct:false,oneClickExit:false };

  function returnToClock() {
    Bangle.setUI();
    setTimeout(eval,0,s.read(".bootcde"));
  }

  if( settings.oneClickExit)
    setWatch(returnToClock, BTN1);

  if (!settings.fullscreen) {
    Bangle.loadWidgets();
    Bangle.drawWidgets();
  }

  var apps = s
    .list(/\.info$/)
    .map((app) => {
      var a = s.readJSON(app, 1);
      return (
        a && {
          name: a.name,
          type: a.type,
          icon: a.icon,
          sortorder: a.sortorder,
          src: a.src,
        }
      );
    })
    .filter(
      (app) =>
      app &&
      (app.type == "app" ||
        (app.type == "clock" && settings.showClocks) ||
        !app.type)
    );
  apps.sort((a, b) => {
    var n = (0 | a.sortorder) - (0 | b.sortorder);
    if (n) return n; // do sortorder first
    if (a.name < b.name) return -1;
    if (a.name > b.name) return 1;
    return 0;
  });
  apps.forEach((app) => {
    if (app.icon) app.icon = s.read(app.icon); // should just be a link to a memory area
  });

  let scroll = 0;
  let selectedItem = -1;
  const R = Bangle.appRect;

  const iconSize = 48;

  const appsN = Math.floor(R.w / iconSize);
  const whitespace = (R.w - appsN * iconSize) / (appsN + 1);

  const itemSize = iconSize + whitespace;

  function drawItem(itemI, r) {
    g.clearRect(r.x, r.y, r.x + r.w - 1, r.y + r.h - 1);
    let x = 0;
    for (let i = itemI * appsN; i < appsN * (itemI + 1); i++) {
      if (!apps[i]) break;
      x += whitespace;
      if (!apps[i].icon) {
        g.setFontAlign(0,0,0).setFont("12x20:2").drawString("?", x + r.x+iconSize/2, r.y + iconSize/2);
      } else {
        g.drawImage(apps[i].icon, x + r.x, r.y);
      }
      if (selectedItem == i) {
        g.drawRect(
          x + r.x - 1,
          r.y - 1,
          x + r.x + iconSize + 1,
          r.y + iconSize + 1
        );
      }
      x += iconSize;
    }
    drawText(itemI);
  }

  function drawItemAuto(i) {
    var y = idxToY(i);
    g.reset().setClipRect(R.x, y, R.x2, y + itemSize);
    drawItem(i, {
      x: R.x,
      y: y,
      w: R.w,
      h: itemSize
    });
    g.setClipRect(0, 0, g.getWidth() - 1, g.getHeight() - 1);
  }

  let lastIsDown = false;

  function drawText(i) {
    const selectedApp = apps[selectedItem];
    const idy = (selectedItem - (selectedItem % 3)) / 3;
    if (!selectedApp || i != idy) return;
    const appY = idxToY(idy) + iconSize / 2;
    g.setFontAlign(0, 0, 0);
    g.setFont("12x20");
    const rect = g.stringMetrics(selectedApp.name);
    g.clearRect(
      R.w / 2 - rect.width / 2,
      appY - rect.height / 2,
      R.w / 2 + rect.width / 2,
      appY + rect.height / 2
    );
    g.drawString(selectedApp.name, R.w / 2, appY);
  }

  function selectItem(id, e) {
    const iconN = E.clip(Math.floor((e.x - R.x) / itemSize), 0, appsN - 1);
    const appId = id * appsN + iconN;
    if( settings.direct && apps[appId])
    {
      load(apps[appId].src);
      return;
    }
    if (appId == selectedItem && apps[appId]) {
      const app = apps[appId];
      if (!app.src || s.read(app.src) === undefined) {
        E.showMessage( /*LANG*/ "App Source\nNot found");
      } else {
        load(app.src);
      }
    }
    selectedItem = appId;
    drawItems();
  }

  function idxToY(i) {
    return i * itemSize + R.y - (scroll & ~1);
  }

  function YtoIdx(y) {
    return Math.floor((y + (scroll & ~1) - R.y) / itemSize);
  }

  function drawItems() {
    g.reset().clearRect(R.x, R.y, R.x2, R.y2);
    g.setClipRect(R.x, R.y, R.x2, R.y2);
    var a = YtoIdx(R.y);
    var b = Math.min(YtoIdx(R.y2), 99);
    for (var i = a; i <= b; i++)
      drawItem(i, {
        x: R.x,
        y: idxToY(i),
        w: R.w,
        h: itemSize,
      });
    g.setClipRect(0, 0, g.getWidth() - 1, g.getHeight() - 1);
  }

  drawItems();
  g.flip();

  const itemsN = Math.ceil(apps.length / appsN);

  function onDrag(e){
    g.setColor(g.theme.fg);
    g.setBgColor(g.theme.bg);
    let dy = e.dy;
    if (scroll + R.h - dy > itemsN * itemSize) {
      dy = scroll + R.h - itemsN * itemSize;
    }
    if (scroll - dy < 0) {
      dy = scroll;
    }
    scroll -= dy;
    scroll = E.clip(scroll, 0, itemSize * (itemsN - 1));
    g.setClipRect(R.x, R.y, R.x2, R.y2);
    g.scroll(0, dy);
    if (dy < 0) {
      g.setClipRect(R.x, R.y2 - (1 - dy), R.x2, R.y2);
      let i = YtoIdx(R.y2 - (1 - dy));
      let y = idxToY(i);
      while (y < R.y2) {
        drawItem(i, {
          x: R.x,
          y: y,
          w: R.w,
          h: itemSize,
        });
        i++;
        y += itemSize;
      }
    } else {
      // d>0
      g.setClipRect(R.x, R.y, R.x2, R.y + dy);
      let i = YtoIdx(R.y + dy);
      let y = idxToY(i);
      while (y > R.y - itemSize) {
        drawItem(i, {
          x: R.x,
          y: y,
          w: R.w,
          h: itemSize,
        });
        y -= itemSize;
        i--;
      }
    }
    g.setClipRect(0, 0, g.getWidth() - 1, g.getHeight() - 1);
  }

  Bangle.setUI({
    mode: "custom",
    drag: onDrag,
    touch: (_, e) => {
      if (e.y < R.y - 4) return;
      var i = YtoIdx(e.y);
      selectItem(i, e);
    },
  });
}