3.3.16 Contour Plot from Matrix

Version Info

Minimum Origin Version Required: Origin 7.5

Example

This example to show how to add contour plotting and then use the following two functions to custom Z levels and fill colors. Please refer to DataPlot::SetColormap for more information.

void plot_contour()
{
	MatrixPage mp;
	mp.Create("origin");
	MatrixLayer ml = mp.Layers(0);
	Matrix mat(ml);
	mat.SetSize(10, 10);
	for(int ii=0; ii<mat.GetNumRows();ii++)
		for(int jj=0; jj<mat.GetNumCols();jj++)
			mat[ii][jj] = sin(ii+jj);
		
	MatrixObject mobj = ml.MatrixObjects();
	
	GraphPage gp;
	gp.Create("contour", CREATE_HIDDEN); // use template, create as hidden to avoid unneeded drawing	
	GraphLayer glay = gp.Layers();	
	int nPlot = glay.AddPlot(mobj, IDM_PLOT_CONTOUR);	
	glay.Rescale();
	
	DataPlot dp = glay.DataPlots(nPlot);
	if(dp)
	{
		set_contour_colormap(dp);
	}
	gp.SetShow();
}

void set_contour_colormap(DataPlot& dp)
{	
	vector vLevels;
	BOOL bLogScale;
	if( !dp.GetColormap(vLevels, bLogScale) )
		return;
	
	// shrink or extend z levels 
	int nLevels = vLevels.GetSize();
	if( nLevels >= 5)
		nLevels -= 2;
	else
		nLevels += 2;
	
	double min = vLevels[0], max = vLevels[nLevels-1];	
	double step = (max - min)/(nLevels-1);
	vLevels.Data(min, max, step);
	
	// set z levels
	if( !dp.SetColormap(vLevels) )
		return;	
	
	vector<uint> vColors(nLevels-1); // the size  of vColors must be nLevels-1
	for(int ii = 0; ii < vColors.GetSize(); ii++)
	{
		int gg = 255* ii / (nLevels-1);
		int bb = 255 * (nLevels-ii-1)/(nLevels-1);
		int nRGB = RGB(0, gg, bb);
		vColors[ii] = RGB2OCOLOR(nRGB);
	}
	
	// call DataPlot::SetColormap(const vector<double>& vz, BOOL bLogScale=FALSE) to set z levels
	if( !dp.SetColormap(vLevels) )
	{
		printf("Fail to set z levels\n");
		return;
	}
	
	// call DataPlot::SetColormap(TreeNode& trColormap) to set colormap
	Tree tr; 
	tr.ColorMap.Details.Colors.nVals = vColors;
	if(!dp.SetColormap(tr))
	{
		printf("Fail to set colormap\n");
		return;	
	}
	
}