3D Plot

Creates a wireframe representation of the currently-selected image. A dialog box allows interactive adjustment of various graph parameters.

1. Img.# - The image to be graphed (should not need to be changed).
2. x${^\circ}$- Angle around x axis to rotate the graph.
3. y${^\circ}$- Angle around y axis to rotate the graph.
4. z${^\circ}$- Angle around z axis to rotate the graph.
5. x scale - Magnification in x dimension (0.01 - 10x).
6. y scale - Magnification in y dimension.
7. z scale - Magnification in z dimension.
8. x ctr - x coordinate of image to use as x axis of rotation. If this value is set appropriately, the graph should remain centered when rotating around x axis.
9. y ctr - y coordinate of image to use as y axis of rotation. If this value is set appropriately, the graph should remain centered when rotating around y axis.
10. z ctr - z coordinate of image to use as z axis of rotation. If this value is set appropriately, the graph should remain centered when the z scale is changed.
11. x trans - x translation for positioning of graph.
12. y trans - y translation for positioning of graph.
13. z trans - z translation for positioning of graph.
14. granularity - the degree of fineness of the graph. Lower values give more detail, but take longer to render.
15. color - Selects method by which graph should be colored.
    1. 0 = all white (not recommended for surface plots)
    2. 1 = grayscale, intensity is proportional to z
    3. 2 = original colors
16. Invert Z - Multiply image pixel values by -1 to swap white and black coordinates.
17. Rotate X - Continuous animated rotation about x axis.
18. Rotate Y - Continuous animated rotation about y axis.
19. Rotate Z - Continuous animated rotation about z axis.
20. Surface - Toggle between wireframe and surface plot.

Notes:

1. If the image on which the graph is based is unloaded, the graph still is visible but becomes unmodifiable. Unloading the image while the graph is being adjusted produces unpredictable results.
2. The x,y, and z scale magnify the graph in the original xyz coordinates, which will usually differ from the screen x-y coordinates.
3. The graph is handled like any other image, and can be saved and printed. Currently there is no provision for saving in a vector format; graphs are saved as bitmap images. Future versions will have vector printing in PostScript format.
4. Small graphs ( $<200 \times 200$) are redrawn continuously as the scale indicator is dragged. Larger graphs are only redrawn when the mouse is unclicked after changing a value. If you have a fast computer, this behavior can be modified by editing the section after the line ``Callbacks for x,y,z rotation sliders'' in xmtnimage41.cc and recompiling.
5. For images larger than the width of the screen, it is recommended to use ``Image..Change Size'' to make a smaller copy of the image before creating a graph.
6. If the original image is still present, the dialog box can be reopened at any time to adjust the graph, by clicking on the desired graph and selecting ``Process..3d graph'' again. If you select the image first, a new graph will be created instead.
7. Not all image operations are functional on graphs.
8. Future versions of tnimage will allow interactive rotating of the graph by dragging on parts of the graph.
9. For color images, better results are obtained if the image is converted to screen bits/pixel first.
10. For color mode 1 (grayscale), the intensity varies with the plotted z value. If the graph is too dark, it can be lightened by translating on the z axis. Similarly, changing the z scale adjusts the grayscale gradient of the plot.
11. Grayscale images can be plotted in color (e.g., a color spectrum with high z values encoded by red and low encoded by blue) by the following procedure:
    1. Click on the graph to select it.
    2. Convert the image to color (``Color...Gray scalecolor'').
    3. Select desired colormap (``Color..Colormap/False color..Select colormap'').
    4. Click on one of the 3d controls to rebuild the graph. If this has no effect, click on the graph again and press Ctrl-R to rebuild the graph image.
    5. Spectrum and multicolor 1 give the best results.
12. If the Z scale is too small, this indicates the contrast in the image is too low. This can occur with 10- and 12-bit images, which are stored in memory as 16 bits/pixel. To correct this, select ``Color..Contrast'' and click ``Maximize Value''.