ZedGraph 源码修改 选择X轴放大

ZedGraph 源码修改 选择X轴放大

通过修改源码实现 图谱区域选择区域缩放，X轴可以实现选中区域横向缩放

1.在ZedGraphControl 类中增加 _isXSelectZoom 属性，用来标识是否选择X轴坐标

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2. 在 MasterPane 类中增加 FindXPaneRect 方法用于查找X坐标轴具体区域,此方法也可以直接改为返回bool 仅用于验证

 /// 

        /// 查找X轴空白
        /// 
        /// 
        /// 
        public GraphPane FindXPaneRect(PointF mousePt)
        {
            foreach (GraphPane pane in _paneList)
            {
                double chartX= pane.Chart._rect.X;
                double startChartY = pane.Chart._rect.Y+ pane.Chart._rect.Height;
                if (mousePt.Y > startChartY)
                    return pane;
            }
            return null;
        }

3.在ZedGraphControl.Events 类中 ZedGraphControl_MouseDown事件中修改代码如下

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4. 在ZedGraphControl.Events 类中CalcScreenRect 方法中 修改如下代码，控制选择区域虚线矩形显示问题

private Rectangle CalcScreenRect( Point mousePt1, Point mousePt2 )
        {
            Point screenPt = PointToScreen( mousePt1 );
            Size size = new Size( mousePt2.X - mousePt1.X, mousePt2.Y - mousePt1.Y );
            Rectangle rect = new Rectangle( screenPt, size );

            if ( _isZooming )
            {
                Rectangle chartRect = Rectangle.Round( _dragPane.Chart._rect );

                Point chartPt = PointToScreen( chartRect.Location );

                if ( !_isEnableVZoom || _isXSelectZoom)
                {
                    rect.Y = chartPt.Y;
                    rect.Height = chartRect.Height + 1;
                }
                else if ( !_isEnableHZoom )
                {
                    rect.X = chartPt.X;
                    rect.Width = chartRect.Width + 1;
                }
            }

            return rect;
        }

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5.修改 ZedGraphControl.Events 类中HandleZoomFinish 方法

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