Matrix Orbital GLC24064 - Manual (Page 20)

3.3.6 Set Current Font (254 49 [font ID])
This command instructs the display to use the font specified by [font identifier] as the default font. The
value specified should refer to a font already present in the display’s memory.
NOTE The font ID is established when the font is saved to the display, normally using
the mogd.exe program. The installed 5x7 font ID is 0x01, unless changed by user.
3.3.7 Set Font Metrics (254 50 [metrics])
Where [metrics] = [left margin][top margin][x space][y space][scroll row]
This command defines the metrics of a font already present in the display’s memory.
[left margin] specifies the first pixel column to use for the first character in a row. In some instances,
a font may not evenly fit on the screen, and dividing the extra space between the margins will improve the
overall appearance of the font. [top margin] specifies the top pixel row to begin drawing the first row of
text on the display area. [x space] specifies the number of pixels to place between characters (i.e. character
spacing). [y space] specifies the number of pixels to place between rows of text (i.e. line spacing). [scroll
row] specifies the pixel row where scrolling should start (or, if auto scrolling is off, where wrapping should
occur). Typically, this value should be set to the first pixel row immediately below the last row of text that
will fit the display.
4 Displaying Graphics
This chapter describes the various graphics-display commands in detail. Uploading a graphic to position
1 will result in that bitmap being displayed when the unit is powered on.
4.1 General
Since the display is a bit-mapped device, it may be used to display graphics. Graphic images may be
created by means of a pixel oriented graphics program, saved as bitmaps, and loaded into the display using
the mogd.exe program. Images may be saved in the display’s memory and displayed upon command, or they
may be downloaded ’on the fly’ (in-line) during display operation.
NOTE ’saved’ and ’on the fly’ graphics images are processed differently. These differ-
ences must be taken into account when processing graphics.
Saved bitmaps use each byte (8 bits) to represent a vertical column of 8 pixels. The next byte represents the
next column to the right. If the graphic is ’taller’ than 8 pixels, the LSB of the next data byte will be the next
pixel. Orientation is top to bottom - LSB to MSB. Pixels / bits are ’packed’, meaning; if the height of the
graphic is not an even multiple of 8, the leftover bits go on the next X column to the right, etc.
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