Drawing On The Graph Screen - Texas Instruments TI-89 Manual Book

Drawing on the Graph Screen

Pixel vs. Point
Coordinates
Tip: For information about
pixel coordinates in split
screens, refer to
Chapter 14.
Note: Pixel commands start
with Pxl , such as PxlChg .
Erasing Drawn
Objects
Drawing a Point or
Pixel
To create a drawing object on the Graph screen, use the
commands listed in this section.
When drawing an object, you can use either of two coordinate
systems to specify a location on the screen.
¦
Pixel coordinates — Refer to the pixels that physically make up
the screen. These are independent of the viewing window
because the screen is always:
159 (0 to 158) pixels wide and 77 (0 to 76) pixels tall.
TI.89:
239 (0 to 238) pixels wide and 103 (0 to 102) pixels tall.
TI.92 Plus:
¦
Point coordinates — Refer to the coordinates in effect for the
current viewing window (as defined in the Window Editor).
0,0 TI-89: 158,0
TI-92 Plus: 238,0
TI-89: 158,76
TI-89: 0,76
TI-92 Plus: 238,102
TI-92 Plus: 0,102
Pixel coordinates
(independent of viewing window)
Many drawing commands have two forms: one for pixel coordinates
and one for point coordinates.
Command Description
Erases all drawn objects from the Graph screen.
ClrDraw
Command Description
PtChg or Toggles (inverts) a pixel at the specified coordinates.
PxlChg PtChg
pixel closest to the specified point. If the pixel is off,
it is turned on. If the pixel is on, it is turned off.
PtOff or Turns off (erases) a pixel at the specified
coordinates.
PxlOff
affects the pixel closest to the specified point.
Turns on (displays) a pixel at the specified
PtOn or
PxlOn coordinates.
affects the pixel closest to the specified point.
PtTest or Returns true or false to indicate if the specified
coordinate is on or off, respectively.
PxlTest
Displays a character string at the specified
PtText or
coordinates.
PxlText
-10,10
-10,-10
Point coordinates
(for standard viewing window)
, which uses point coordinates, affects the
, which uses point coordinates,
PtOff
PtOn , which uses point coordinates,
Chapter 17: Programming
10,10
10,-10
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