Arbitrary Scaling of Gizmo Plot

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The default for a Gizmo surface plot is a cube, the XYZ limits of which correspond to the full range of the data. "Zooming" into part of the range requires the use clip planes, which is nontrivial to set up. The first code snippet lists the Display List commands that enable the clip planes. The procedure "SetGizmoScales()" performs the clipping to the specified xyz range. The function GizmoRescale() enable the default Gizmo cube to have a non-unity aspect ratio. The available options are setting the xy aspect ratio to match that of the displayed data, and an arbitrary scaling of the z-dimension.

// **************************************************************************************
// This section of code is PART of the Gizmo window creation routine.  
// It sets up clip planes to prevent data that extends beyond the xyz range of the Gizmo cube from being displayed.
// The first line sets things up for non-unity scaling, if desired later.
	ModifyGizmo setDisplayList=1, opName=scale0, operation=scale, data={1,1,1}	// enables non-even scaling (default is cubic)
	ModifyGizmo setDisplayList=2, opName=enable0, operation=enable, data=12288	// enables clip plane 0
	ModifyGizmo setDisplayList=3, opName=enable1, operation=enable, data=12289	// enables clip plane 1
	ModifyGizmo setDisplayList=4, opName=enable2, operation=enable, data=12290	// enables clip plane 2
	ModifyGizmo setDisplayList=5, opName=enable3, operation=enable, data=12291	// enables clip plane 3
	ModifyGizmo setDisplayList=6, opName=enable4, operation=enable, data=12292	// enables clip plane 4
	ModifyGizmo setDisplayList=7, opName=enable5, operation=enable, data=12293	// enables clip plane 5
	ModifyGizmo setDisplayList=8, opName=ClipPlane0, operation=ClipPlane, data={0,0,0,1,1}	// clips at bottom
	ModifyGizmo setDisplayList=9, opName=ClipPlane1, operation=ClipPlane, data={1,0,0,-1,1}	// clips at top
	ModifyGizmo setDisplayList=10, opName=ClipPlane2, operation=ClipPlane, data={2,1,0,0,1}	// clips at xmin
	ModifyGizmo setDisplayList=11, opName=ClipPlane3, operation=ClipPlane, data={3,-1,0,0,1}	// clips at xmax
	ModifyGizmo setDisplayList=12, opName=ClipPlane4, operation=ClipPlane, data={4,0,1,0,1}	// clips at ymin
	ModifyGizmo setDisplayList=13, opName=ClipPlane5, operation=ClipPlane, data={5,0,-1,0,1}	// clips at ymax
	ModifyGizmo setDisplayList=14, object=surface0					// actual surface
	ModifyGizmo setDisplayList=15, opName=disable0, operation=disable, data=12288	// disables clip plane 0
	ModifyGizmo setDisplayList=16, opName=disable1, operation=disable, data=12289	// disables clip plane 1
	ModifyGizmo setDisplayList=17, opName=disable2, operation=disable, data=12290	// disables clip plane 2
	ModifyGizmo setDisplayList=18, opName=disable3, operation=disable, data=12291	// disables clip plane 3
	ModifyGizmo setDisplayList=19, opName=disable4, operation=disable, data=12292	// disables clip plane 4
	ModifyGizmo setDisplayList=20, opName=disable5, operation=disable, data=12293	// disables clip plane 5
// **************************************************************************************
// **************************************************************************************
// Procedure manually sets the XYZ range of the Gizmo plot
// NOTE: one can return to autorange (i.e., plotting full range of data) with:
//           ModifyGizmo ScalingMode=2
Proc SetGizmoScales(xMin, xMax, yMin, yMax, zMin, zMax) 		
	Variable	xMin, xMax, yMin, yMax, zMin, zMax
	ModifyGizmo setOuterBox={xMin,xMax,yMin,yMax, zMin, zMax}
	ModifyGizmo update=2		// NOTE: doesn't work with update=1
// **************************************************************************************
// **************************************************************************************
// Function allows Gizmo display cube to be set to something other than cube.  
// XY aspect ratio can be set to match displayed xy data range.
// Z aspect ratio can be set arbitrarily anywhere from 0-1
Function GizmoRescale() 
	Variable zAxisScaling = 1
	Variable xyScalingMode
	Prompt zAxisScaling, "Scaling Factor for z-axis (default=1)"
	Prompt xyScalingMode, "XY axes scaling", popup, "None (default);Scaled to displayed xy data range"
	DoPrompt "Gizmo Scaling Parameters", zAxisScaling, xyScalingMode
		return -1		// user cancelled
	String Cmd
	Variable xAxisScaling = 1
	Variable yAxisScaling = 1
	Variable diag
	// want to scale xy plane to data's aspect ratio
		NVAR /Z aspectRatio = root:gGizmoXYaspectRatio  // displayed aspect ratio already stored as global variable
		if( !NVAR_Exists(aspectRatio) )
			Variable /G root:gGizmoXYaspectRatio = 1
			print "Warning: unknown xy aspect ratio - setting to unity"
			yAxisScaling = aspectRatio
			xAxisScaling = 1/aspectRatio
		diag = sqrt(xAxisScaling^2 + yAxisScaling^2)	// this scaling always shrinks - compensate
		xAxisScaling *= sqrt(2)/diag
		yAxisScaling *= sqrt(2)/diag
	// create actual display list (order is important)
	sprintf Cmd, "ModifyGizmo setDisplayList=1, opName=scale0, operation=scale, data={%f,%f,%f}", xAxisScaling, yAxisScaling, zAxisScaling
	Execute Cmd
// **************************************************************************************

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