From 5dbd13040f1c0b78dd62f7142d204a31da393cb6 Mon Sep 17 00:00:00 2001
From: ARCHI86 <svferdinand@mail.ru>
Date: Mon, 11 Nov 2024 17:59:20 +0300
Subject: [PATCH] =?UTF-8?q?=D1=85?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 GraphPage.xaml          | 32 ++++++++++++-----------
 GraphPage.xaml.cs       | 58 +++++++++++++++++++++++++++++++++++------
 PinchToZoomContainer.cs | 12 +++++++++
 3 files changed, 79 insertions(+), 23 deletions(-)
 create mode 100644 PinchToZoomContainer.cs

diff --git a/GraphPage.xaml b/GraphPage.xaml
index 8885936..d5791a2 100644
--- a/GraphPage.xaml
+++ b/GraphPage.xaml
@@ -3,20 +3,22 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="NotesDataAnalyst.GraphPage"
              Title="GraphPage">
-
     <ContentPage.Content>
-        <Grid RowDefinitions="*,Auto" Padding="10">
-            <!-- Канва для рисования занимает верхнюю часть экрана -->
-            
-                <AbsoluteLayout Grid.Row="0">
-                <GraphicsView x:Name="canvasView" 
-                              HeightRequest="8000"
-                              WidthRequest="8000"
-                              />
-                    
-            </AbsoluteLayout>
-            
-            <!-- Панель с кнопками внизу -->
+        <Grid Padding="10" RowDefinitions="*,Auto">
+            <!-- Канва для рисования в отдельном ContentView -->
+            <ContentView Grid.Row="0">
+                <ContentView.GestureRecognizers>
+                    <PanGestureRecognizer PanUpdated="OnPanUpdated"/>
+                    <PinchGestureRecognizer PinchUpdated="OnPinchUpdated"/>
+                </ContentView.GestureRecognizers>
+                <AbsoluteLayout>
+                    <GraphicsView x:Name="canvasView" 
+                                  HeightRequest="8000"
+                                  WidthRequest="8000"/>
+                </AbsoluteLayout>
+            </ContentView>
+            <ContentView Grid.Row="1">
+                <!-- Панель с кнопками внизу -->
             <ScrollView Grid.Row="1" Orientation="Horizontal" HorizontalScrollBarVisibility="Always" VerticalScrollBarVisibility="Never">
                 <StackLayout Orientation="Horizontal" Spacing="1" Padding="20">
                     <Button Text="Добавить" Clicked="OnAddNodeClicked" WidthRequest="100"/>
@@ -25,14 +27,14 @@
                     <Button Text="Редактировать текст" Clicked="OnEditTextClicked" />
                 </StackLayout>
             </ScrollView>
-
+            </ContentView>
             <!-- Поле для редактирования текста -->
             <Entry x:Name="textEditor"
                    IsVisible="False"
                    BackgroundColor="White"
                    TextColor="Black"
                    FontSize="18"
-                   Completed="OnTextEditorCompleted" />
+                   Grid.Row="1" />
         </Grid>
     </ContentPage.Content>
 </ContentPage>
diff --git a/GraphPage.xaml.cs b/GraphPage.xaml.cs
index fc545af..0686d55 100644
--- a/GraphPage.xaml.cs
+++ b/GraphPage.xaml.cs
@@ -19,6 +19,15 @@ namespace NotesDataAnalyst
         private bool _isNodeBeingMoved = false;
         private const double SmoothFactor = 0.85; // Коэффициент сглаживания
         private Point _lastTranslation;
+        // Переменная для хранения центральной точки жеста (между двумя пальцами при старте масштабирования)
+        private Point _gestureCenter;
+        
+        private Point _canvasTranslation = new Point(0, 0);
+
+        double currentScale = 1;
+        double startScale = 1;
+        double xOffset = 0;
+        double yOffset = 0;
 
         public GraphPage()
         {
@@ -110,24 +119,57 @@ namespace NotesDataAnalyst
 
             }
         }
-        private void OnPinchUpdated(object sender, PinchGestureUpdatedEventArgs e)
+        void OnPinchUpdated(object sender, PinchGestureUpdatedEventArgs e)
         {
             if (e.Status == GestureStatus.Started)
             {
-                // Сохраняем начальный масштаб
-                _initialScale = _scale;
+                // Store the current scale factor applied to the wrapped user interface element,
+                // and zero the components for the center point of the translate transform.
+                startScale = Content.Scale;
+                Content.AnchorX = 0;
+                Content.AnchorY = 0;
             }
-            else if (e.Status == GestureStatus.Running)
+            if (e.Status == GestureStatus.Running)
             {
-                // Вычисляем новый масштаб
-                _scale = Math.Max(0.5, Math.Min(_initialScale * e.Scale, 3.0));
+                // Calculate the scale factor to be applied.
+                currentScale += (e.Scale - 1) * startScale;
+                currentScale = Math.Max(1, currentScale);
 
-                // Применяем масштаб к канве
-                canvasView.Scale = _scale;
+                // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
+                // so get the X pixel coordinate.
+                double renderedX = Content.X + xOffset;
+                double deltaX = renderedX / Width;
+                double deltaWidth = Width / (Content.Width * startScale);
+                double originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;
+
+                // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
+                // so get the Y pixel coordinate.
+                double renderedY = Content.Y + yOffset;
+                double deltaY = renderedY / Height;
+                double deltaHeight = Height / (Content.Height * startScale);
+                double originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;
+
+                // Calculate the transformed element pixel coordinates.
+                double targetX = xOffset - (originX * Content.Width) * (currentScale - startScale);
+                double targetY = yOffset - (originY * Content.Height) * (currentScale - startScale);
+
+                // Apply translation based on the change in origin.
+                Content.TranslationX = Math.Clamp(targetX, -Content.Width * (currentScale - 1), 0);
+                Content.TranslationY = Math.Clamp(targetY, -Content.Height * (currentScale - 1), 0);
+
+                // Apply scale factor
+                Content.Scale = currentScale;
+            }
+            if (e.Status == GestureStatus.Completed)
+            {
+                // Store the translation delta's of the wrapped user interface element.
+                xOffset = Content.TranslationX;
+                yOffset = Content.TranslationY;
             }
         }
 
 
+
         private async void OnEditTextClicked(object sender, EventArgs e)
         {
             // Проверяем, выбрана ли нода
diff --git a/PinchToZoomContainer.cs b/PinchToZoomContainer.cs
new file mode 100644
index 0000000..c663006
--- /dev/null
+++ b/PinchToZoomContainer.cs
@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NotesDataAnalyst
+{
+    internal class PinchToZoomContainer
+    {
+    }
+}