Charts > Using the Charts Library > Scales Display > Using Single Scale Displayers > Setting General Properties
 
Setting General Properties
The following properties are defined for all the single scale displayers. The methods followed by an asterisk (*) are defined as pure virtual at the level of the IlvAbstractScaleDisplayer class and are redefined at the level of the IlvSingleScaleDisplayer class.
 
Property
Methods
Default Value
Step and Label Definition Properties
Scale Steps Updater
getStepsUpdater
IlvAutoScaleStepsUpdater
Step and Substep Numbers
getStepsCount
getSubStepsCount
getTotalSubStepsCount
0
0
0
Step and Substep Units
getStepUnit
getSubStepUnit
0
0
Definition of Text Labels by Hand
getStepLabelsCount
getStepLabel
getStepLabels
setStepLabel *
setStepLabels *
0
Step Labels Computation:
    By Applying a Format
   
   
    By Applying a Callback
    Converting Data Values
    into Step Labels
   
getStepLabelFormat
setStepLabelFormat *
   
getValueToLabelCB
getValueToLabelCBData
setValueToLabelCB *
   
IlvDefaultStepLabelFormat
   
   
0
0
   
Ticks and Labels Display Properties
Layout Properties:
    Position of Ticks
    
    
    Position of Labels
    
    
    Offset Between Ticks
    and Step Labels
    
getTickLayout
setTickLayout *
    
getLabelLayout
setLabelLayout *
    
getOffset
setOffset *
    
TickOutside
    
    
LabelOutside
    
    
IlvDefaultScaleOffset
    
Size Properties:
    Major Ticks
    
    
    Minor Ticks
    
    
    Step Labels
    
getMajorTickSize
setMajorTickSize *
    
getMinorTickSize
setMinorTickSize *
    
getStepLabelSizes
    
IlvDefaultScaleMajorTickSize
    
    
IlvDefaultScaleMinorTickSize
Step Label Properties:
    Angle
    
    
    Palette
    
    
    Drawn at Axes Crossings
    
    
    Drawn When Overlapping
    
getStepLabelAngle
setStepLabelAngle *
    
getStepLabelsPalette
setStepLabelsPalette *
    
isDrawingLabelOnCrossings
drawLabelOnCrossings *
    
isDrawingOverlappingLabels
drawOverlappingLabels *
    
0
    
    
0
    
    
IlvFalse
    
    
IlvTrue
Visibility:
    Major Ticks
    
    
    Minor Ticks
    
    
    Step Labels
    
areMajorTicksVisible
setMajorTicksVisible
    
areMinorTicksVisible
setMinorTicksVisible
    
areStepLabelsVisible
setStepLabelsVisible
    
IlvTrue
    
    
IlvTrue
    
    
IlvTrue
Axis Display Properties
Arrow at the End:
    Arrow Drawn
    
    
    Arrow Width
    
    
    Arrow Length
    
    
isAxisOriented
setAxisOriented *
    
getArrowWidth
setArrowWidth *
    
getArrowLength
setArrowLength *
    
IlvFalse
    
    
IlvDefaultScaleArrowWidth
    
    
IlvDefaultScaleArrowLength
    
Axis Label:
    Label
    
    
    Offset Between
    Axis and Label
    
    Size
    
getAxisLabel
setAxisLabel
     
getAxisLabelOffset
setAxisLabelOffset *
     
getAxisLabelSizes
    
0
    
    
2*IlvDefaultScaleOffset
      
    
    
Palettes:
    Axis
    
    
    Axis Label
    
    
getAxisPalette
setAxisPalette *
    
getAxisLabelPalette
setAxisLabelPalette *
    
0
    
    
0
    
Visibility
isAxisVisible
setAxisVisible
IlvTrue
Defining the Steps and Substeps
The computation of the steps and substeps for a given scale is performed by a dedicated object called scale steps updater that is set on the scale. This object is returned by the IlvSingleScaleDisplayer::getStepsUpdater method.
For more details on the scale steps updaters, see the section Using Scale Steps Updaters to Compute Scales Graduations.
Defining the Step Labels to be Displayed
By default, the step labels that are displayed are simply numerical labels corresponding to the data values represented by the scale. These labels are formatted by applying the format returned by the IlvSingleScaleDisplayer::getStepLabelFormat method.
However, you can change the step labels to be displayed by default by doing one of the following:
*By specifying text labels by hand
This can be done by means of the setStepLabels method. The labels that will be displayed are then the text labels set by hand..
Note: In this case, the number of steps will be equal to the number of text labels that are set by hand.
*By defining a callback indicating how to convert a given data value into a step label
This callback must be of the IlvValueToLabelCB type:
typedef char* (* IlvValueToLabelCB )(IlDouble, IlAny);
This kind of callback can be set by means of the setValueToLabelCB method. The labels that will be displayed are those returned by the callback that is set.
Example: Callback Converting Data Values into Step Labels
The following example shows how to define a callback that displays data values expressed in seconds in the form “hours-minutes-seconds.”
1. To define the callback, use the following code:
char*
hours_minutes_seconds(IlDouble value, IlAny cbData)
{
char buffer[126];
IlvUInt modulo;
IlvUInt hours;
IlvUInt minutes;
IlvUInt seconds;
if (value >= 3600) {
hours = (IlvUInt)value / 3600;
modulo = (IlvUInt)value % 3600;
}
else {
modulo = value;
hours = 0;
}
if (modulo >= 60) {
minutes = modulo / 60;
seconds = modulo % 60;
}
else {
minutes = 0;
seconds = modulo;
}
sprintf(buffer, "%d-%d-%d", hours, minutes, seconds);
return IlvCopyString(buffer);
}
2. To set the callback on the scale displayer, use the following code:
scaleDisplayer->setValueToLabelCB(hours_minutes_seconds);
Defining the Position of the Ticks Relative to the Axis
The position of the ticks relative to the axis is defined by the enumeration type TickLayout. The following positions are possible:
*TickInside
The ticks extend inside of the data display area.
*TickOutside
The ticks extend outside of the data display area.
*TickCross
The ticks cross the axis and extend both inside and outside of the data display area.
By default, the position of the ticks of a scale is set to TickOutside. This setting can be changed by means of the setTickLayout method.
Defining the Position of the Labels Relative to the Axis
The position of the labels relative to the axis is defined by the enumeration type LabelLayout. The following positions are possible:
*LabelInside
The labels extend inside of the data display area.
*LabelOutside
The labels extend outside of the data display area.
By default, the position of the labels of a scale are set to LabelOutside. This position applies both to the step labels and to the axis label. The setting can be changed by means of the setLabelLayout method.
Defining Whether the Step Labels are Drawn at Axes Crossings
By default, step labels are not drawn at the axes crossings. However, you can specify that the step labels should be drawn at the axes crossings for a given scale by calling the drawLabelOnCrossings method with IlvTrue as a parameter.
Defining Whether Overlapping Step Labels are Drawn
By default, step labels are drawn even if they overlap. However, you can specify that overlapping step labels should not be drawn for a given scale by calling the drawOverlappingLabels method with IlvFalse as a parameter.
Version 6.1
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