From d838777e04099971d21ee443ab771363a4ef2939 Mon Sep 17 00:00:00 2001
From: Lasse Lauwerys <65569591+Iemand005@users.noreply.github.com>
Date: Wed, 13 Nov 2024 16:14:11 +0100
Subject: [PATCH] Touch support bug fixes (#1527)

* Improved touch support

* Fix touch support scaling error

* Fix touch scaling precision on all zoom levels

* Improved touch experiene, fixed zooming on textarea elements and fixed context menu.

* Minor bug fix
---
 src/extensions/core/simpleTouchSupport.ts | 73 ++++++++++-------------
 1 file changed, 32 insertions(+), 41 deletions(-)

diff --git a/src/extensions/core/simpleTouchSupport.ts b/src/extensions/core/simpleTouchSupport.ts
index 43f5ff894..8f88cefdb 100644
--- a/src/extensions/core/simpleTouchSupport.ts
+++ b/src/extensions/core/simpleTouchSupport.ts
@@ -8,7 +8,7 @@ let touchCount = 0
 app.registerExtension({
   name: 'Comfy.SimpleTouchSupport',
   setup() {
-    let zoomPos
+    let touchDist
     let touchTime
     let lastTouch
     let lastScale
@@ -26,7 +26,7 @@ app.registerExtension({
       }
     }
 
-    app.canvasEl.addEventListener(
+    app.canvasEl.parentElement.addEventListener(
       'touchstart',
       (e: TouchEvent) => {
         touchCount++
@@ -43,7 +43,7 @@ app.registerExtension({
             lastScale = app.canvas.ds.scale
             lastTouch = getMultiTouchCenter(e)
 
-            zoomPos = getMultiTouchPos(e)
+            touchDist = getMultiTouchPos(e)
             app.canvas.pointer_is_down = false
           }
         }
@@ -51,56 +51,47 @@ app.registerExtension({
       true
     )
 
-    app.canvasEl.addEventListener('touchend', (e: TouchEvent) => {
-      touchCount = e.touches?.length ?? touchCount - 1
+    app.canvasEl.parentElement.addEventListener('touchend', (e: TouchEvent) => {
+      touchCount--
 
       if (e.touches?.length !== 1) touchZooming = false
       if (touchTime && !e.touches?.length) {
         if (new Date().getTime() - touchTime > 600) {
-          try {
-            // hack to get litegraph to use this event
-            e.constructor = CustomEvent
-          } catch (error) {}
-          // @ts-expect-error
-          e.clientX = lastTouch.clientX
-          // @ts-expect-error
-          e.clientY = lastTouch.clientY
-
-          app.canvas.pointer_is_down = true
-          // @ts-expect-error
-          app.canvas._mousedown_callback(e)
+          if (e.target === app.canvasEl) {
+            app.canvasEl.dispatchEvent(
+              new PointerEvent('pointerdown', {
+                button: 2,
+                clientX: e.changedTouches[0].clientX,
+                clientY: e.changedTouches[0].clientY
+              })
+            )
+            e.preventDefault()
+          }
         }
         touchTime = null
       }
     })
 
-    app.canvasEl.addEventListener(
+    app.canvasEl.parentElement.addEventListener(
       'touchmove',
       (e) => {
         touchTime = null
-        if (e.touches?.length === 2) {
+        if (e.touches?.length === 2 && lastTouch && !e.ctrlKey && !e.shiftKey) {
+          e.preventDefault() // Prevent browser from zooming when two textareas are touched
           app.canvas.pointer_is_down = false
           touchZooming = true
-          // @ts-expect-error
-          LiteGraph.closeAllContextMenus()
+
+          LiteGraph.closeAllContextMenus(window)
           // @ts-expect-error
           app.canvas.search_box?.close()
-          const newZoomPos = getMultiTouchPos(e)
+          const newTouchDist = getMultiTouchPos(e)
 
           const center = getMultiTouchCenter(e)
 
-          let scale = app.canvas.ds.scale
-          const diff = zoomPos - newZoomPos
+          let scale = (lastScale * newTouchDist) / touchDist
 
-          scale = lastScale - diff / 100
-
-          const newX = ((center.clientX - lastTouch.clientX) * 1) / scale
-          const newY = ((center.clientY - lastTouch.clientY) * 1) / scale
-
-          const convertCanvasToOffset = (pos, scale) => [
-            pos[0] / scale - app.canvas.ds.offset[0],
-            pos[1] / scale - app.canvas.ds.offset[1]
-          ]
+          const newX = (center.clientX - lastTouch.clientX) / scale
+          const newY = (center.clientY - lastTouch.clientY) / scale
 
           // Code from LiteGraph
           if (scale < app.canvas.ds.min_scale) {
@@ -113,20 +104,19 @@ app.registerExtension({
 
           app.canvas.ds.scale = scale
 
+          // Code from LiteGraph
           if (Math.abs(app.canvas.ds.scale - 1) < 0.01) {
             app.canvas.ds.scale = 1
           }
 
           const newScale = app.canvas.ds.scale
 
-          var oldCenter = convertCanvasToOffset(
-            [center.clientX, center.clientY],
-            oldScale
-          )
-          var newCenter = convertCanvasToOffset(
-            [center.clientX, center.clientY],
-            newScale
-          )
+          const convertScaleToOffset = (scale) => [
+            center.clientX / scale - app.canvas.ds.offset[0],
+            center.clientY / scale - app.canvas.ds.offset[1]
+          ]
+          var oldCenter = convertScaleToOffset(oldScale)
+          var newCenter = convertScaleToOffset(newScale)
 
           app.canvas.ds.offset[0] += newX + newCenter[0] - oldCenter[0]
           app.canvas.ds.offset[1] += newY + newCenter[1] - oldCenter[1]
@@ -147,6 +137,7 @@ LGraphCanvas.prototype.processMouseDown = function (e) {
   if (touchZooming || touchCount) {
     return
   }
+  app.canvas.pointer_is_down = false // Prevent context menu from opening on second tap
   return processMouseDown.apply(this, arguments)
 }