In color display or output, lines may be drawn with different colors, and atoms, stick bonds and polyhedra may be filled with different colors (except in pen plots, in which atoms, stick bonds and polyhedra are always blank or white). In black-and-white display or output, various dot-patterns, simulating shades of gray, are normally used for fills, and for lines if they are wide enough.
This section discusses the common aspects of color/shade input for lines and fills, as occurs in many input dialogs in ATOMS. Depending on the type of display and output involved, any of three different sets of colors or patterns/shades may be used.
(a) For color screen displays, printer, Raster, Metafile or PICT output, actual colors are used. The RGB components, which are numbers ranging from zero to 255 can be directly entered in the edit boxes, but the color is most easily and reliably selected with the Select...Color buttons. These bring up the Select Color dialog, presenting the colors of the current main palette. If the color is being selected for a fill, and if shading for the object in question (atom, stick bond or polyhedron) is selected in the Shading dialog in the Input2 menu, the color chosen here is that at maximum (perpendicular) illumination. If front-to-back fading has been selected in the Shading dialog in the Input2 menu, the chosen color is that for the foremost atom.
For 16-, 24- or 32-bit color screen displays you have complete freedom to choose colors. For 8- or 4-bit color the fill colors of shaded atoms, bonds and polyhedra may be forced at plot time to one of a limited number of allowed colors. For 8-bit color the number of colors allowed depends on the number of atom shading zones selected in the Shading dialog in the Input2 menu. See the general section Colors, Palettes and DotPatterns for further information on palettes for the 8-bit color mode.
For best results on a wide range of display and output devices, chose the simplest colors, which are firstly colors 0-7 in the default main palette, and secondly colors 8-15
(b) For black-and-white screen displays and printer, raster or metafile output, either true grays or dot patterns of various densities are used. The codes for these shades or patterns range from 0 for white to 15 for solid black.
The selected pattern is used for fills if shading is not in effect. If shading is in effect, selected in the Shading dialog in the Input2 menu, the actual fill patterns shown may either start at white for maximum illumination, or at the pattern number selected here depending on the setting of the Use initial patterns checkbox in the Shading dialog.
The selected pattern is used for lines only if the width of the line is greater than one dot. The width of various types of lines is set in the Line Widths dialog in the Input2 menu. Note that rendering of gray-scale for lines in black-and-white printed output is determined by the printer driver, not ATOMS. Many printer drivers do not support gray lines and pattern numbers other than 15 may give either white or black lines.
(c) For pen-plotters the number requested refers to the pen number used in drawing the lines. For atoms, stick bonds and polyhedra, this refers to the outlines; there are no fills in pen plots (the interiors of atoms, stick bonds and polyhedra are always blank). These numbers are not used if the single-pen mode is selected in the Pen Plotter Settings dialog in the Settings menu.
When changing the red, green and blue values directly in the edit boxes which appear in many dialogs in ATOMS, the rectangle showing the actual color does not change until the focus shifts from the current edit field, that is until the mouse is clicked in another place in the dialog.