Use proper soft keyboard events

...or as close as it gets because the way input events work on mobile is awful.

html_orig/jssrc/soft_keyboard.js

@@ -23,16 +23,63 @@ $.ready(() => {
     else input.blur()
   }
 
+  let lastCompositionString = '';
+  let compositing = false;
+
+  let sendInputDelta = function (newValue) {
+    let resend = false;
+    if (newValue.length > lastCompositionString.length) {
+      if (newValue.startsWith(lastCompositionString)) {
+        // characters have been added at the end
+        Input.sendString(newValue.substr(lastCompositionString.length))
+      } else resend = true;
+    } else if (newValue.length < lastCompositionString.length) {
+      if (lastCompositionString.startsWith(newValue)) {
+        // characters have been removed at the end
+        Input.sendString('\b'.repeat(lastCompositionString.length -
+          newValue.length))
+      } else resend = true;
+    } else if (newValue !== lastCompositionString) resend = true;
+
+    if (resend) {
+      // the entire string changed; resend everything
+      Input.sendString('\b'.repeat(lastCompositionString.length) +
+        newValue)
+    }
+    lastCompositionString = newValue;
+  }
+
   input.addEventListener('keydown', e => {
-    if (e.key === 'Backspace') {
-      e.preventDefault()
-      e.stopPropagation()
-      Input.sendString('\b')
+    if (e.key === 'Unidentified') return;
+
+    e.preventDefault();
+    input.value = '';
+
+    if (e.key === 'Backspace') Input.sendString('\b')
+    else if (e.key === 'Enter') Input.sendString('\x0d')
+  })
+  input.addEventListener('input', e => {
+    e.stopPropagation();
+
+    if (e.isComposing) {
+      sendInputDelta(e.data);
+    } else {
+      if (e.data) Input.sendString(e.data);
+      else if (e.inputType === 'deleteContentBackward') {
+        lastCompositionString
+        sendInputDelta('');
+      }
     }
   })
-  input.addEventListener('keypress', e => {
-    e.stopPropagation()
-  })
+  input.addEventListener('compositionstart', e => {
+    lastCompositionString = '';
+    compositing = true;
+  });
+  input.addEventListener('compositionend', e => {
+    lastCompositionString = '';
+    compositing = false;
+    input.value = '';
+  });
 
   Screen.on('open-soft-keyboard', () => input.focus())
 })

html_orig/jssrc/term_screen.js

@@ -333,9 +333,9 @@ class TermScreen {
   }
 
   // schedule a draw in the next tick
-  scheduleDraw () {
+  scheduleDraw (aggregateTime = 1) {
     clearTimeout(this._scheduledDraw);
-    this._scheduledDraw = setTimeout(() => this.draw(), 1)
+    this._scheduledDraw = setTimeout(() => this.draw(), aggregateTime)
   }
 
   getFont (modifiers = {}) {
@@ -788,7 +788,7 @@ class TermScreen {
       }
     }
 
-    this.scheduleDraw();
+    this.scheduleDraw(16);
     this.emit('load');
   }