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This topic discusses the use of annotations and events to create a custom
scale.
Using Line Annotations to create a scale
Disable the default scale and replace it with your own tick marks and/or
grid lines defined with line annotations.
Also refer to demo project example 005 on creating custom scales.
For custom y axes:
For custom x axes:
Custom scales generally use special line
annotation types of...
PELAT_GRIDTICK 7 PELAT_GRIDLINE 8
These annotation types will create tick marks and grid lines as needed.
They will function as normal grid lines and can be controlled by the user
via the GridLineControl user customization, or by the developer with the
GridLineControl property.
For more information on adding annotations to a chart, look at Question
10.
The following example shows how to create a simple textual y axis.
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'** Disable default scale **'
Pego1.ShowYAxis = PESA_EMPTY
'** Generally, a custom y axis will need manual range control **'
Pego1.ManualScaleControlY
= PEMSC_MINMAX
Pego1.ManualMinY = 0
Pego1.ManualMaxY = 1000
'** Create custom grid lines with HorzLineAnnotations **'
'** Note that GridLineControl will control these annotations **'
Pego1.HorzLineAnnotation(0) = 200
Pego1.HorzLineAnnotationType(0) = PELAT_GRIDLINE
Pego1.HorzLineAnnotationText(0) = "|LLow Value"
Pego1.HorzLineAnnotation(1)
= 500
Pego1.HorzLineAnnotationType(1)
= PELAT_GRIDLINE
Pego1.HorzLineAnnotationText(1)
= "|LMedium Value"
Pego1.HorzLineAnnotation(2)
= 800
Pego1.HorzLineAnnotationType(2)
= PELAT_GRIDLINE
Pego1.HorzLineAnnotationText(2)
= "|LHigh Value"
Pego1.HorzLineAnnotation(3)
= 350
Pego1.HorzLineAnnotationType(3)
= PELAT_GRIDTICK
Pego1.HorzLineAnnotationText(3)
= ""
Pego1.HorzLineAnnotation(4)
= 650
Pego1.HorzLineAnnotationType(4)
= PELAT_GRIDTICK
Pego1.HorzLineAnnotationText(4)
= ""
'** Set LeftMargin to allocate space for line annotation text **'
'** Use the longest string used in annotations.
Pego1.LeftMargin = "Medium Value
"
'** Set this to see annotations **'
Pego1.ShowAnnotations = True
'** Increase line annotation text size **'
Pego1.LineAnnotationTextSize
= 100
'** Put Grid In Front **'
Pego1.GridInFront = True
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The following image is produced by the above code.
Note the three labels on left y axis.
This example first disables the default y axis with ShowYAxis.
Next, it manually chooses a range for the new y axis. This new range
will be from 0 to 1000.
Next, three grid-line annotations are added at coordinates of 200, 500,
and 800 within the 0 to 1000 axis range. Note that the HorzLineAnnotationText
items are using justification codes "|L" to place text on the
outside left edge. Refer to HorzLineAnnotationText
for more info on justifying line annotation text.
Next, two grid-tick annotations are added at coordinates 350 and 650.
Note that the text for these annotations is a null string.
Next, the LeftMargin property
is set. This is a textual property which should be set to the largest
string used for any annotation text. ProEssentials will use this example
text to determine the amount of space to reserve for line annotations
placed on the outside left edge of the chart. It's usually a good idea
to make this text string slightly larger by a few characters.
Finally, ShowAnnotations
is set to true, LineAnnotationTextSize
will generally be set to 100, and the grid is placed in front with GridInFront.
Using the CustomGridNumber Event
This method of creating a custom scale uses an event to allow the developer
opportunity to change the textual representation of a data value.
You set one or more of the following properties to true to enable event
processing:
Please refer to demo project example 132 on
seeing the specifics of handling the CustomGridNumber
event within the development language of your choice.
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