Matrix Orbital GLK24064-25 Legacy - Manual (Page 17)

3 Displaying Text
This chapter describes the various text display commands in detail.
3.1 General
Text is displayed on the display using fonts saved in its internal flash memory. The display is supplied
with a 5x7 font installed. If this is suitable, there is no need to install any other fonts.
3.2 Writing Text to the Display
When the display receives a character, it displays that character at the position currently defined. The next
character sent to the module then advances to the following position on the display. Characters are drawn
using the currently selected font, and only characters defined in the current font are actually processed.
Characters which are not defined by the current font are ignored, and the positioning is not advanced for the
next character.
The position where text is to be displayed is a single pixel location stored in the display’s volatile memory
and maintained internally by the display’s firmware. This position is manipulated by the commands shown
in the following section.
3.3 Text Commands
In this section commands are identified by their names and decimal values.
3.3.1 Auto scroll on (254 81)
When auto scrolling is on, it causes the display to shift the entire display’s contents up to make room for
a new line of text when the text reaches the scroll position defined by the "Set font metrics" command in the
display memory (normally the bottom right character position - default value for the GLK24064-25 is 64).
3.3.2 Auto scroll off (254 82)
When auto scrolling is disabled, text will wrap to the top left corner of the display area. Existing graphics
or text in the display area are not erased before text is placed. When using proportional fonts without auto
scrolling, care should be taken to clear areas where text is being written, particularly when wrapping occurs.
This may be done using the “Draw solid rectangle” command with the colour set to white.
Matrix Orbital GLK24064-25 13