Question by DrCubeMan · Jun 19, 2020 at 10:29 AM · editor mouse editorwindow vector2 editor window

Correct behavior of the mouse wheel when zooming in a 2D area (Unity Editor)

Hi, i am programming a graph (like the shader graph) in UnityEditor and wanted to do the zooming with the mouse.

There is a Vector2D offset so you can move around in the graph. There is a float scale that holds the current scale and goes from 10f to 200f.

Nodes for example are displayed like this:

 public void Draw(Vector2 offset, GUIStyle fontSizeNode, float scale)
     {
 
         float x = positionNode.x;  
         float y = positionNode.y; 
 
         //Draw Node
         GUI.DrawTexture(ScaleRect(x, y, width, 32f, scale, offset), nodeTopStyle.normal.background);
         y += 32f ; 
         GUI.DrawTexture(ScaleRect(x, y, width, 110f, scale, offset), nodeMidStyle.normal.background);
         y += 110f; 
         GUI.DrawTexture(ScaleRect(x, y, width, 29f, scale, offset), nodeBottomStyle.normal.background);
 }
 
  Rect ScaleRect(float x, float y, float width, float hight, float scale, Vector2 offset)
     {
         x = x / 100f * scale + offset.x;
         y = y / 100f * scale + offset.y;
 
         width = width / 100f * scale;
         hight = hight / 100f * scale;
  
         return new Rect(x, y, width, hight);
     }

So if I use the mouse wheel, I should zoom to the position where the mouse is. Actually the offset should only be adjusted slightly but it is kind of difficult. Does anyone have an idea?

    if (e.type == EventType.ScrollWheel)
             {        
                 if (e.delta.y < 0)
                 {                   
                    //  offset += e.mousePosition / 100f * (100f - scale) ;
                   
                     scale += 5f;        
                     Repaint();
                 }
                     
                 else
                 {
                     if (scale <= 11f)
                         return;
 
                     scale -= 5f;                                
                     Repaint();
                 }                                
             }

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