Display apparatus for simultaneous display of lines of characters having different line pitches

摘要

An information processing apparatus includes a RAM for storing character information and line pitch information corresponding thereto; a CRT for simultaneously displaying character information having different line pitches; a font ROM supplied with the character information from the RAM and which supplies a corresponding video signal to the CRT; and a line pitch switching circuit for supplying a signal to the font ROM in response to the line pitch information stored in the RAM so that the display means displays the character information with a correct line pitch. A method of vertically scrolling the character information display by the CRT includes the steps of storing a first portion of the character information with corresponding line pitch information in the RAM; computing a variable termed the sum of the constant from the line pitch information for a second portion of the character information to be displayed on the CRT; adjusting the line pitch of the last line of the second portion of the character information, if necessary, so that the sum of the constant is equal to a fixed value; shifting the character information in the RAM to store the second portion of the character information therein; and then substituting the adjusted line pitch information for the second portion of the character information during a vertical blanking period after a start signal from the apparatus is detected.