Bravo (software)

From Wikipedia, the free encyclopedia

Bravo was the first WYSIWYG document preparation program. It provided multi-font capability using the bitmap displays on the Xerox Alto personal computer. It was produced at Xerox PARC by Butler Lampson, Charles Simonyi and colleagues in 1974.

Bravo was a so-called "moded" editor - characters typed on the keyboard were usually commands to Bravo, except when in "insert" or "append" mode, in which case they were entered into the buffer. Bravo did make extensive use of the mouse for marking locations in the text, as well as selecting areas of the text, but it was not used for commands in any way. (The decision to use an old-fashioned user interface was actually a deliberate choice on the part of the designers, to limit the size of the problem they were tackling.)

In addition to a long list of commands for controlling the formatting of the text (e.g. the ability to adjust left and right margins for sections of text, select fonts, etc) Bravo also supported use of multiple buffers (i.e. files), and also multiple windows.

Although Bravo usually displayed the text with formatting (e.g. with justification, fonts, and proportional spacing of characters), it did not normally attempt to reproduce the way a page would look in hardcopy. This was because the Alto monitor provided a resolution of 72 pixels per inch, but the laser printers used at PARC provided a resolution of 300 PPI. This meant that the screen could at best only provide an approximation of the way the page would look when printed. Instead, the normal display mode showed the text using character sizes, etc, more suited to the capability of the display.

There was a special display mode which did attempt to show the text exactly as it would appear when printed, and the normal command set worked in that mode as well. However, because the screen image was necessarily an approximation, one would occasionally find characters and words slightly off (a problem that continues to this day with word processing systems).

72 PPI was an approximation of the 72.27 points per inch used in the commercial printing industry; Bravo also used the 72 point standard, so that distances, etc would normally be specific in terms of "points" in Bravo.

Bravo was the base for Gypsy, a later document system on the Alto, the first with a modern graphical user interface.