UnityEngine.UI.CanvasScaler.HandleScaleWithScreenSize C# (CSharp) Method

        protected virtual void HandleScaleWithScreenSize()
        {
            Vector2 vector = new Vector2((float) Screen.width, (float) Screen.height);
            int targetDisplay = this.m_Canvas.targetDisplay;
            if ((targetDisplay > 0) && (targetDisplay < Display.displays.Length))
            {
                Display display = Display.displays[targetDisplay];
                vector = new Vector2((float) display.renderingWidth, (float) display.renderingHeight);
            }
            float scaleFactor = 0f;
            switch (this.m_ScreenMatchMode)
            {
                case ScreenMatchMode.MatchWidthOrHeight:
                {
                    float a = Mathf.Log(vector.x / this.m_ReferenceResolution.x, 2f);
                    float b = Mathf.Log(vector.y / this.m_ReferenceResolution.y, 2f);
                    float p = Mathf.Lerp(a, b, this.m_MatchWidthOrHeight);
                    scaleFactor = Mathf.Pow(2f, p);
                    break;
                }
                case ScreenMatchMode.Expand:
                    scaleFactor = Mathf.Min((float) (vector.x / this.m_ReferenceResolution.x), (float) (vector.y / this.m_ReferenceResolution.y));
                    break;

                case ScreenMatchMode.Shrink:
                    scaleFactor = Mathf.Max((float) (vector.x / this.m_ReferenceResolution.x), (float) (vector.y / this.m_ReferenceResolution.y));
                    break;
            }
            this.SetScaleFactor(scaleFactor);
            this.SetReferencePixelsPerUnit(this.m_ReferencePixelsPerUnit);
        }