CChart Example

The CChart example that is included in the Objective Chart kit shows how SRGCompoundDisplay is used and how a customized chart can be built from sub-components.

The relevant portions of the OnNewDocument() function are shown below. Some additional style settings have been added for illustrative purposes. Additional comments have been inserted to clarify various portions of the code.

// We build a simple two axis chart with fixed ratio

// axes that convert millimeters to inches

//This display wraps and manages all the other items.

SRGCompoundDisplay *pCD=new SRGCompoundDisplay;

// First, let’s set up the axis scales

SRGDecimalScale *pDS=new SRGDecimalScale;

pDS->SetResolution(100.0); // 100 mm

pDS->SetFormatString(“%g mm”);

pDS->SetLabelSide(FALSE);

pCD->SetYLabelA(pDS); // set labels for left axis

pDS=new SRGDecimalScale;

pDS->SetResolution(1.0); // one inch

pDS->SetLabelSide(TRUE);

pCD->SetYLabelB(pDS); // set labels for right axis

pDS=new SRGIndexScale;

pDS->SetLabelSide(FALSE);

pDS->SetResolution(0); // auto scale the indices

pDS->GetStyle()->SetAutoOrientation(FALSE);

pDS->SetOrientation(45);

pDS->SetLocationPoint(SRGraphLabel::TopCenter);

pCD->SetXLabelA(pDS); // X axis scale

// set tick marks on the three axes

SRGTickMarks *pT=new SRGTickMarks; // add tic marks

pT->SetMajorTickColor(CXCLR_BLUE); // blue

pT->SetMinorTickRatio(0); // no minor ticks

pT->SetMajorTickWidth(3); // fat

pT->SetTickSide(FALSE);

pCD->SetXTickMarksA(pT);

pT=new SRGTickMarks;

pT->SetMajorTickColor(CXCLR_RED); // red

pT->SetMinorTickRatio(0); // no minor ticks

pT->SetMajorTickWidth(1); // normal

pT->SetTickSide(FALSE);

pCD->SetYTickMarksA(pT);

pT=new SRGTickMarks;

pT->SetMajorTickColor(CXCLR_GREEN); // green

pT->SetMinorTickRatio(1); // minor ticks

pT->SetMajorTickWidth(1); // normal

pT->SetTickSide(TRUE);

pCD->SetYTickMarksB(pT);

// Each axis will have an individual grid line style

SRGGridLines *pG=new SRGGridLines;

pG->SetMajorGridColor(CXCLR_BLUE); // blue

pG->SetMajorGridStyle(PS_SOLID); // solid

pG->SetMinorGridRatio(0); // no minor grids

pG->SetMajorGridWidth(2); // fat

pCD->SetXGridLinesA(pG);

pG=new SRGGridLines;

pG->SetMajorGridColor(CXCLR_RED); // red

pG->SetMajorGridStyle(PS_DOT); // dots

pG->SetMinorGridRatio(0); // no minor grids

pG->SetMajorGridWidth(1); // normal

pCD->SetYGridLinesB(pG);

pG=new SRGGridLines;

pG->SetMajorGridColor(CXCLR_GREEN); // green

pG->SetMajorGridStyle(PS_DASH); // dashes

pG->SetMinorGridRatio(1); // at the half mark

pG->SetMajorGridWidth(1); // normal

pCD->SetYGridLinesA(pG);

Here the relationship between the two y-axes is established. First, the display is told that there is a correlation.

pCD->SetYRelationship(TRUE);

Then the conversion ratio between the right and left axes is specified. Note that setting this ratio to zero will invoke a special function that can be overridden to do more complex conversion. (For example, temperature conversion between degrees Celsius and degrees Fahrenheit.)

pCD->SetYRatio(1.0/25.4);// inches to millimeters

This code sets ups the display. Note that the display has a deferred draw setting. This ensures that its final graphic output is generated after all the other items (grids, etc.) are drawn. It is also possible do tell this item not to defer drawing and defer all the grid lines. That way the grids will be shown on top of the data.

SRGraphDisplay *pD=new SRGraphDisplay;

pD->GetStyle()->SetGraphStyle(CX_GRAPH_VBAR);

pD->GetStyle()->SetAxisStyle(CX_AXIS_CLASSIC);

pD->GetStyle()->SetDeferDraw(TRUE);

// fixed axis limits

pD->GetStyle()->SetUseMaxScale(TRUE);

pD->SetMinRangeY(.0);

pD->SetMaxRangeY(4000.);

pCD->SetYGraphDisplayA(pD);// set chart display

The next four sections create and register labels that are used to annotate the four axes. Note how the font size of last label is adjusted to create a title for the chart. Labels that are displayed on the sides of the chart are oriented to read vertically so that they take up far less space. SetParent() is called because GetAnnotation() requires the parent SRGraph object’s country code.

SRGraphLabel * pL=new SRGraphLabel;

pL->SetParent(&m_Graph);

pL->SetAnnotation("Millimeters");

pCD->GetYAxisA()->RegisterTitle(pL);

pL=new SRGraphLabel;

pL->SetParent(&m_Graph);

pL->SetAnnotation("Inches");

pCD->GetYAxisB()->RegisterTitle(pL);

pL=new SRGraphLabel;

pL->SetParent(&m_Graph);

pL->SetAnnotation("Items");

pCD->GetXAxisA()->RegisterTitle(pL);

pL=new SRGraphLabel;

pL->SetParent(&m_Graph);

pL->SetAnnotation("The Compound Chart");

pL->SetFontSize(24);

pCD->GetXAxisB()->RegisterTitle(pL);

// Now add a data watcher to highlight things

// more than 10 ft long!

SRGDataWatcher *pDW=new SRGDataWatcher;

// trigger type is already set but...

pDW->SetScanType(CX_SCAN_ABOVELIMIT);

pDW->SetHighLimit(25.4*120);//(Ten feet in mm)

// Data watcher is based on SRGGridLines

// so the same styles can be used

pDW->SetMajorGridColor(CXCLR_RED);

pDW->SetMajorGridWidth(3);

pCD->SetYDataWatcherA(pDW);

The single compound component with all its sub-components is placed onto the SRGraph m_ComponentList.

m_Graph.AddComponent(pCD);

Thi s code creates the chart in Compound Chart.

Compound Chart