Add widget_utils swipeOn method to hide widgets and allow them to be …

…swiped back onto the screen

modules/widget_utils.js

@@ -1,7 +1,6 @@
-/* Utilities for handling widgets - mainly showing/hiding */
-
 /// hide any visible widgets
 exports.hide = function() {
+  exports.cleanup();
   if (!global.WIDGETS) return;
   g.reset(); // reset colors
   for (var w of global.WIDGETS) {
@@ -16,7 +15,8 @@ exports.hide = function() {
 
 /// Show any hidden widgets
 exports.show = function() {
-  if (!global.WIDGETS) return;
+  exports.cleanup();
+  if (!global.WIDGETS) return;  
   for (var w of global.WIDGETS) {
     if (!w._draw) return; // not hidden
     w.draw = w._draw;
@@ -26,3 +26,101 @@ exports.show = function() {
     w.draw(w);
   }
 };
+
+/// Remove any intervals/handlers/etc that we might have added. Does NOT re-show widgets that were hidden
+exports.cleanup = function() {
+  delete Bangle.appRect;
+  if (exports.swipeHandler) {
+    Bangle.removeListener("swipe", exports.swipeHandler);
+    delete exports.swipeHandler;
+  }
+  if (exports.animInterval) {
+    clearInterval(exports.animInterval);
+    delete exports.animInterval;
+  }
+  if (exports.hideTimeout) {
+    clearTimeout(exports.hideTimeout);
+    delete exports.hideTimeout;
+  }
+}
+
+/** Put widgets offscreen, and allow them to be swiped
+back onscreen with a downwards swipe. Use .show to undo. 
+Bangle.js 2 only at the moment. */
+exports.swipeOn = function() {
+  exports.cleanup();
+  if (!global.WIDGETS) return;
+
+  /* TODO: maybe when widgets are offscreen we don't even
+  store them in an offscreen buffer? */
+
+  // force app rect to be fullscreen
+  Bangle.appRect = { x: 0, y: 0, w: g.getWidth(), h: g.getHeight(), x2: g.getWidth()-1, y2: g.getHeight()-1 };
+  // setup offscreen graphics for widgets
+  let og = Graphics.createArrayBuffer(g.getWidth(),24,16,{msb:true});
+  og.theme = g.theme;
+  og._reset = og.reset;
+  og.reset = function() {
+    return this._reset().setColor(g.theme.fg).setBgColor(g.theme.bg);    
+  };
+  og.reset().clearRect(0,0,og.getWidth(),og.getHeight());
+  let _g = g;
+  let offset = -24; // where on the screen are we? -24=hidden, 0=full visible
+
+  function queueDraw() {
+    if (offset>-24) Bangle.setLCDOverlay(og, 0, offset);
+    else Bangle.setLCDOverlay();
+  }
+
+  for (var w of global.WIDGETS) {
+    if (w._draw) return; // already hidden
+    w._draw = w.draw;
+    w.draw = function() {
+      g=og;
+      this._draw(this);
+      g=_g;
+      if (offset>-24) queueDraw();
+    };
+    w._area = w.area;
+    if (w.area.startsWith("b"))
+      w.area = "t"+w.area.substr(1);
+  }
+  Bangle.drawWidgets();
+
+  function anim(dir, callback) {
+    if (exports.animInterval) clearInterval(exports.interval);
+    exports.animInterval = setInterval(function() {
+      offset += dir;
+      let stop = false;
+      if (dir>0 && offset>=0) { // fully down
+        stop = true;
+        offset = 0;
+      } else if (dir<0 && offset<-23) { // fully up
+        stop = true;
+        offset = -24;
+      }
+      if (stop) {
+        clearInterval(exports.animInterval);
+        delete exports.animInterval;
+        if (callback) callback();
+      }
+      queueDraw();
+    }, 50);
+  }
+  // On swipe down, animate to show widgets
+  exports.swipeHandler = function(lr,ud) {
+    if (exports.hideTimeout) {
+      clearTimeout(exports.hideTimeout);
+      delete exports.hideTimeout;
+    }
+    if (ud>0 && offset<0) anim(4, function() {
+      exports.hideTimeout = setTimeout(function() {
+        anim(-4);
+      }, 2000);
+    });
+    if (ud<0 && offset>-24) anim(-4);
+
+  };  
+  Bangle.on("swipe", exports.swipeHandler);
+};
+