TEX's halign primitive

To shade cells in an alignment, use

  \coloralign

instead of "". Then, to color the columns in one or more rows, type

  \CC
    <row of colors>\cr
    <rows to be colored>\cr
  \ECC

For example: =height11.5pt depth6.5pt width0pt # & #

& Tamarind&Chiplote

& Lulu&Serrano

Guanabana&Larga

"" and "" stand for ``ColorCells'' and ``EndColorCells'', respectively. You cannot change the name of "" with "" or "". There is no "to" or "spread" because the space inserted by "" won't be shaded.

These macros are not very robust. You can make best use of them by knowing how they work. "" just saves the preamble, and otherwise is identical to "". "" finds the height of the rows that have to be colored, and then "" draws a rectangle using TEX's line-drawing primitives in each cell, colored by the color commands included in the first line that follows "". E.g.,

  \yellow &&\red \cr

draws a yellow rectangle in column 1, nothing in column 2, and a red rectangle in column 3. Then "" goes back up the height of the rectangle, so that TEX's current point is back where it was when "" started. At this point, "" has finished its work. When the next rows of the alignment environment are processed by "", they are put down on top of the rectangles, and hence have colored backgrounds.

"" finds the height of the rows to be colored by putting the rows into an "" environment, using the preamble that was saved by "", and then measuring the height of the resulting box.