Floating maps: how BMS places maps using ACCUM

In our example map on page Defining the map: DFHMDI, we described placing maps on a screen or page absolutely, by specifying the number of the line and column for the upper left corner. However, maps can float. That is, they can be positioned relative to maps already written to the same page and to any edge of the page. Floating maps save program logic when you need to support multiple screen sizes or build pages piecemeal out of headers, detail lines and trailers, where the number of detail lines depends on the data.

The BMS options that allow you to do this are:

When you are building a composite screen with the ACCUM option, the position on the screen of any particular map is determined by:

The space remaining on the page, in turn, depends on:

The placement rules we are about to list apply even if you do not specify ACCUM, although JUSTIFY values of FIRST and LAST are ignored. However, without ACCUM, each SEND MAP corresponds to a separate page, and thus the space remaining on the page is always the whole page.

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