[Nplot-devel] [ nplot-Bugs-2590560 ] PlotSurface2D displays data incorrectly when YAxis1.Reversed

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Bugs item #2590560, was opened at 2009-02-11 16:22
Message generated for change (Settings changed) made by jamcquay
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https://sourceforge.net/tracker/?func=detail&atid=821568&aid=2590560&group_id=161868

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Category: None
Group: 0.9.9.2
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Brent Browning (brent_browning)
>Assigned to: Jamie McQuay (jamcquay)
Summary: PlotSurface2D displays data incorrectly when YAxis1.Reversed

Initial Comment:
I am using NPlot to display contour charts using PlotSurface2D.  When I reverse the Y axis order the chart does not display correctly.

My data goes from 0,0 to 10,10 (11 rows and 11 columns).  I want data point 0,0 to appear in the upper left hand corner of the plot.  The default has Y values increasing so 0,0 is in the lower left.

When I set YAxis1.Reversed I get the desired effect of the numbers on the Y axis (0 is at the top and 10 is at the bottom).  But the data is plotted incorrectly.  Data from row 0 is plotted on row 1, etc.  

Here is a code fragment for how I am plotting the data:

	int row = 10;
	int col = 10;
	double[,] map = new double[row, col];
		for (int i = 0; i < row; i++)
		{
			for (int j = 0; j < col; j++)
			{
				map[i, j] = i;
			}
		}
	this.myPlotSurface.Clear();
	myPlotSurface.Title = "Grid Survey";
	NPlot.ImagePlot ip = new NPlot.ImagePlot(map, 0, 1, 0, 1);
	ip.Gradient = new NPlot.LinearGradient(Color.Blue, Color.Red);
	ip.Center = false;
	myPlotSurface.Add(ip);

	// Reverse Y axis so grid matches physical space
	myPlotSurface.YAxis1.Reversed = true;

	NPlot.Grid grid = new NPlot.Grid();
	grid.HorizontalGridType = NPlot.Grid.GridType.Fine;
	grid.VerticalGridType = NPlot.Grid.GridType.Fine;
	myPlotSurface.Add(grid);
	myPlotSurface.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.Default;
	myPlotSurface.AddInteraction(new NPlot.Windows.PlotSurface2D.Interactions.MouseWheelZoom());
	myPlotSurface.Refresh();




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>Comment By: Jamie McQuay (jamcquay)
Date: 2009-03-24 21:48

Message:
reproduced, looking into.

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Comment By: Brent Browning (brent_browning)
Date: 2009-02-12 15:47

Message:
I made a tentative fix by changing ImagePlot.cs as follows:

public void Draw( Graphics g, PhysicalAxis xAxis, PhysicalAxis yAxis )
{
    ....

    // BRENTB - 2009/02/12
    // Fix for bug when [XY]Axis1.Reversed == true
    // See artifact 2590560 filed against NPlot for details
    //
    //if ( !hPositive )
    //{
    //    wY += yStep_;
    //}
    //if (!wPositive )
    //{
    //    wX += xStep_;
    //}
    ....
}


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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=821568&aid=2590560&group_id=161868