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PegChart
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Overview |
Derived from class
PegThing
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The PegChart class, although itself a derived class,
is the base class for all of the charts in the KwikPeg Library.
The PegChart is a virtual base class. Hence, it is not
possible to instantiate a PegChart object directly.
The purpose of the PegChart class is to provide a framework
for its derived children. It provides extended styles which ease the construction
of charts. It also provides the services needed to draw charts with
optional tick marks, value labels and grid lines along the X axis
and/or Y axis.
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To use the PegChart class or its derivatives,
your KwikPeg configuration must have the following option enabled: |
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Drawing: Charts |
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PegLineChart
PegMultiLineChart
PegStripChart
The PegChart class supports
the following extended style flags:
CS_AUTOSIZE |
If this flag is set, the chart will always take up the
entire mClient region of its parent.
When the parent is resized or moved, the PegChart
object also resizes itself appropriately. |
CS_DRAWXGRID |
Draw grid lines along the X axis in the chart region. |
CS_DRAWYGRID |
Draw grid lines along the Y axis in the chart region. |
CS_DRAWXTICS |
Draw tick marks along the X axis at the specified intervals. |
CS_DRAWYTICS |
Draw tick marks along the Y axis at the specified intervals. |
CS_DRAWXLABELS |
Draw incremental value labels along the X axis below the chart.
The label values are based on the minimum and maximum possible
values of X. |
CS_DRAWYLABELS |
Draw incremental value labels along the Y axis to the left of the chart.
The label values are based on the minimum and maximum possible
values of Y. |
CS_DUALYLABELS |
Draw Y axis value labels along both the left and right
edges of the chart.
This style flag is ignored if the CS_DRAWYLABELS style flag
is not also set. |
CS_DUALYTICS |
Draw Y axis tick marks along both the left and right
edges of the chart.
This style flag is ignored if the CS_DRAWYTICS style flag
is not also set. |
CS_DRAWLINEFILL |
Fill the area between the trace lines and the (x,y=0) axis
with the currently specified fill color. |
CS_XAXISONZEROY |
Draw the X axis along the Y=0 axis instead of below the chart.
This style flag is ignored if the CS_DRAWXTICS style flag
is not also set. |
Constructors:
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PegChart(const PegRect &Rect,
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LONG lMinX, LONG lMaxX,
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LONG lMinY, LONG lMaxY,
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WORD wMajorXScale = 0,
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WORD wMajorYScale = 0)
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This constructor creates a derived chart
in the rectangle specified by parameter Rect.
If style flag CS_AUTOSIZE is to be used
(see function SetExStyle()), you may want to draw the chart
in the parent's mClient rectangle.
Parameters lMinX and lMaxX specify the
minimum and maximum X (horizontal) values. Parameters lMinY and
lMaxY specify the minimum and maximum Y (vertical) values.
Data points which lie outside these ranges, although not rejected, will not
be viewable in the chart rectangle.
Parameters wMajorXScale and wMajorYScale define
the intervals along the X and Y axes respectively at which major tick marks
will be drawn. Of course, tick marks are only drawn if the object's
CS_DRAWXTICS or CS_DRAWYTICS extended style
flag is set.
For example, if the minimum Y value
is -100, the maximum Y value is 900, the Y scale is 100 and
the CS_DRAWYTICS extended style flag is set, then tick marks
will be drawn on the Y axis at intervals of 100 starting at -100 and ending
at 900. Consequently, there will be 11 tick marks drawn on the Y axis.
If the CS_DRAWYGRID extended style flag is also set,
horizontal grid lines will also be drawn at the same tick mark intervals.
The interval at which axis label values are drawn is independent of
the tick mark/grid line scaling interval. Hence, tick marks might appear
at intervals of 100 with the axis values labeled at intervals of 200.
Public Functions:
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virtual void Draw(void)
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The PegChart class overrides the Draw()
function to draw the background color of the chart area and
the optional tick marks, value labels and grid lines.
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PegRect GetChartRegion() const
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This function returns the rectangle which indicates the location
on the screen at which the chart is being drawn.
If the CS_AUTOSIZE extended style flag is set, the rectangle
will be based on the position and size of the chart's parent.
The chart and its tick marks and labels, if needed, will be drawn
within this rectangle.
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WORD GetExStyle(void) const
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This function returns the current
extended style flags value
from variable mwExStyle.
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PegFont *GetFont(void) const
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This function returns a pointer
to the current font being used to draw X and Y axis labels.
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WORD GetMajorTicSize(void) const
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WORD GetMinorTicSize(void) const
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These functions return the number of pixels used for the length
of a major and minor tick mark.
Hence, this value represents the height of an X axis tick
mark and the width of a Y axis tick mark.
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WORD GetMajorXScale(void) const
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WORD GetMajorYScale(void) const
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These functions return the interval at which tick marks and
grid lines are drawn along the X and Y axis.
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LONG GetMaxX(void) const
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LONG GetMaxY(void) const
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These functions return the maximum allowable value for X and Y.
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WORD GetMinorXScale(void) const
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WORD GetMinorYScale(void) const
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These functions return the interval at which minor tick marks
are drawn along the X and Y axis.
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LONG GetMinX(void) const
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LONG GetMinY(void) const
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These functions return the minimum allowable value for X and Y.
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WORD GetXLabelHeight(void) const
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This function returns the height of the labels
drawn along the X axis.
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WORD GetXLabelScale(void) const
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WORD GetYLabelScale(void) const
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These functions return the interval at which value labels
are drawn along the X and Y axis.
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WORD GetYLabelWidth(void) const
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This function returns the width of the labels
drawn along the Y axis.
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virtual void MapDataToPoint(PegChartPoint *pPoint)
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This function converts the data point held in the private
PegChartPoint structure referenced by pPoint
to screen coordinates. The conversion accounts for the size of the
chart region and the ranges allowed for X and Y values.
The screen coordinates are stored in the PegChartPoint structure.
This function is used only by the KwikPeg derived chart classes.
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virtual void MapPointToData(PegChartPoint *pPoint)
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This function converts the screen coordinates held in the private
PegChartPoint structure referenced by pPoint
to a data point value. The conversion uses the size of the
chart region and the ranges allowed for X and Y values.
The data point value is stored in the PegChartPoint structure.
This function is used only by the KwikPeg derived chart classes.
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virtual SIGNED Message(const PegMessage &Mesg)
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The PegChart class overrides
the Message() function to recalculate the chart location
or layout when its parent is moved or resized.
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virtual void RecalcLayout(BOOL bRedraw = TRUE)
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This function calculates the layout of the chart in preparation for
rendering the chart on the screen. If parameter bRedraw is
TRUE, the visible display is updated.
This function is used only by the KwikPeg derived chart classes.
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virtual void RecalcSize(
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const PegRect &NewRect,
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BOOL bRedraw = TRUE)
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This function resets the chart's location and size as specified by the
the rectangle NewRect. The function then calls the
RecalcLayout() function passing it the bRedraw flag.
This function is used only by the KwikPeg derived chart classes.
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void SetExStyle(WORD wStyle)
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This function sets the current
extended style flags maintained
in variable mwExStyle to the value specified
by wStyle. The style flag value is generated by ORing
the style flag masks to identify the features which the chart must support.
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void SetFont(PegFont *pFont)
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This function sets the font to be used for drawing axis labels
to the font referenced by pFont.
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void SetMajorTicSize(WORD wSize)
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void SetMinorTicSize(WORD wSize)
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These functions set the number of pixels used for the length
of a major and minor tick mark.
Parameter wSize represents the height of an X axis tick
mark and the width of a Y axis tick mark.
The default value for a major tick is 12 pixels.
The default value for a minor tick is 8 pixels.
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void SetMajorXScale(WORD wScale)
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void SetMajorYScale(WORD wScale)
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These functions set the interval at which tick marks and
grid lines will be drawn along the X and Y axis.
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void SetMaxX(LONG lData)
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void SetMaxY(LONG lData)
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These functions set the maximum value for X and Y.
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void SetMinorXScale(WORD wScale)
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void SetMinorYScale(WORD wScale)
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These functions set the interval at which minor tick marks
will be drawn along the X and Y axis.
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void SetMinX(LONG lData)
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void SetMinY(LONG lData)
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These functions set the minimum value for X and Y.
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void SetXLabelHeight(WORD wHeight)
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This function sets the height of the labels
drawn along the X axis.
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void SetXLabelScale(WORD wScale)
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void SetYLabelScale(WORD wScale)
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These functions set the interval at which value labels
will be drawn along the X and Y axis.
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void SetYLabelWidth(WORD wWidth)
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This function sets the width of the labels
drawn along the Y axis.
Objects of the PegChart class are not
directly instantiable. See the single line chart
(PegLineChart),
the multiline chart
(PegMultiLineChart)
and the strip chart
(PegStripChart)
for examples of classes derived from the PegChart
class.
