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5.8 Some tips on achieving ideal drawing quality

Many functions of Multiwfn involve plotting graph, below are some suggestions for getting ideal drawing quality:

  • Do not take screenshot, but use an option like "save picture" or "export graphical file" to generate the image file. This is particularly important for Linux system, because the quality of the graph shown on the screen is often poor. The effect of image file is independent of platform.

  • If the graph to be plotted only consists of texts, straight lines and curves, it is strongly suggested to change "graphformat" in settings.ini to a vector format, such as .pdf and .svg (see Section 2.8 for detail), because in this case the texts and lines look very smooth, the graph can be losslessly scaled, and meantime the file size is very small. Since vector format is not directly supported by many applications programs, you can then manually convert the image file from vector format to pixel format.

  • When the graph contains gradient colors, such as isosurface map, color-filled map and so on, the default .png format is the best choice. In order to make the axes, texts and outlines of objects as smooth as possible, I suggest save the image file with large size (see Section 2.8 on how to change size), then use advanced image editor such as Photoshop, or Irfanview (my favourite image viewer) to shrink the graph to the size you actually need, in this process the resample will be done automatically, anti-aliasing effect can thus be equivalently realized. By the way, before choosing the option used to generate image file, I suggest properly zooming to make the system fill the entire drawing area as much as possible.

  • Please always pay attention to all options in the menu, Multiwfn has many options to control plotting parameters, graph quality under default settings may be significantly improved by properly using corresponding options. In addition, in settings.ini file there are many parameters controlling plotting effect, I suggest you briefly check comment of each parameter in this file to find the ones you often need to change.

  • For plotting isosurface map, use relatively high quality of grid (i.e. relatively small grid spacing, or equivalently, relatively high number of grid points) to generate grid data. If lighting effect is not satisfactory, in the menu bar of the GUI for showing isosurface, use "Set lighting" in "Other settings" to adjust lightings. In addition, using VMD to plot this kind of map can get much better rendering effect, see Section 4.A.14 for related introduction and example.

  • Use VMD plotting script whenever possible. For example, as illustrated in Section 4.2.5, using VMD to plot paths and critical points can yield much better effect than directly plotting them in the GUI window of topology module of Multiwfn; as also introduced in Section 4.A.14, via VMD plotting script very ideal isosurface map of grid data can be obtained via merely a few steps