ChartDirector 5.1 (C++ Edition)
Using ChartDirector with MFC
This section describes how to use ChartDirector with MFC on Windows.
MFC Sample Programs
ChartDirector comes with a number of MFC sample programs in the "ChartDirector/mfcdemo" subdirectory. If you are using Visual Studio, you may open the solution file "mfcdemo.sln", and it will open the Visual Studio solution with the sample projects.
Note: The Visual Studio project files for the sample programs are based on Visual Studio 2005. If you are using later versions of Visual Studio, it may prompt you to convert them to match the Visual Studio version. Please proceed to convert them. If you are using earlier versions of Visual Studio, you may need to recreate the project files in order to compile the sample code. ChartDirector has been tested to be compatible with Visual Studio 6 or later.
Project Name | Description
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helloworld | The "Hello World" example of using ChartDirector with MFC. This is a basic MFC project displaying a simple bar chart.
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mfcdemo | The main MFC sample program, containing a chart browser for browsing over 100 sample charts.
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financedemo | An interactive financial chart will comprehensive technical indicators support.
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tracklegend | Demonstrates a sweep line track cursor with dynamic legend entries for the data points at the cursor position.
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tracklabel | Demonstrates a sweep line track cursor with dynamic labels for the data points at the cursor position.
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trackaxis | Demonstrates a sweep line track cursor with dynamic axis labels for the data points at the cursor position.
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trackbox | Demonstrates a track rectangle and a floating legend box for the data points in the rectangle.
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trackfinance | A finance chart with a sweep line track cursor and dynamic legend entries for the price and technical indicator values at the cursor position.
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crosshair | Demonstrates a crosshair cursor with dynamic axis labels showing the position of the cursor.
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realtimedemo | A simple realtime chart with configurable update rate from 250ms to 2 sec.
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realtimetrack | A realtime chart with configurable update rate and a sweep line track cursor that displays dynamic legend entries.
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simplezoomscroll | A simple zoomable and scrollable chart that uses mouse click and drag to control zooming and scrolling.
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zoomscrolltrack | Demonstrates using mouse click and drag, mouse wheel, and a scrollbar to control zooming and scrolling. There is also a sweep line track cursor that displays dynamic legend entries.
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zoomscrolltrack2 | Demonstrates using mouse click and drag, mouse wheel, and a scrollbar to control zooming and scrolling. The axis range can also be set using date picker controls, and there is also a sweep line track cursor that displays dynamic data labels.
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xyzoomscroll | Demonstrates using mouse click and drag, mouse wheel, a slider, and a navigation pad to control zooming and scrolling.
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To try a sample program, simply set the corresponding project as the "StartUp Project", then compile and run the program.
It is recommended you start with the helloworld project and then the mfcdemo project. The mfcdemo project contains over 100 sample charts illustrating various chart types and how to use ChartDirector in general. The charts are from simple to sophisticated, and are designed for use as tutorials.
The CChartViewer MFC Control
All ChartDirector MFC sample programs uses the
CChartViewer control to display charts and handle mouse interactions. The CChartViewer is a derived class of the MFC CStatic control. It is released in source code format.
To use CChartViewer in your own project:
- Include "ChartViewer.h" and "ChartViewer.cpp" in your project.
- Use the VC++ Dialog Editor to put a "Picture Control" in your Form or Dialog. Set the "Type" to "Bitmap". Set a valid resource ID for the control.
- Add a member variable for the control (eg. right click on the control and select "Add variable"), and set the variable type to CChartViewer.
- Visual Studio should automatically add the following line in the header file of your Form or Dialog. You may open the header file to verify if this is the case.
#include "chartviewer.h"
Displaying Charts On Screen
To display a chart using CChartViewer, only one line of code is needed:
// m_ChartViewer is a CChartViewer control; myChart is a BaseChart pointer
m_ChartViewer.setChart(myChart);
Handling Hot Spots Mouse Interactions
Hot spots are special regions in on the chart that are usually used to represent chart objects, such as data representation objects (sectors for pie chart, bars for bar charts, etc). One can display tool tips when the mouse is over the hot spots, and/or to make the hot spots clickable with mouse cursor feedback.
In ChartDirector, hot spots for the charts are defined using standard HTML image maps (text strings containing HTML
tags). The
BaseChart.getHTMLImageMap method can be used to generate image maps automatically for a chart. To set the image map to the CChartViewer control, one may use:
After setting the image map, the CChartViewer control will display the tool tips defined in the image map when the mouse is over the hot spots. For clickable hot spots, it will also change the mouse cursor into a "hand" shape.
When the mouse clicks on the CChartViewer control, a
BN_CLICKED notification code will be sent to the parent container. The parent container can handle this message and use
ImageMapHandler to determine which hot spot has been clicked.
Microsoft MFC documentation contains the details on how to handle BN_CLICKED notification code. In brief, the steps are:
Adding Track Cursor to the Chart
In ChartDirector, track cursors can be created by drawing them on a "dynamic layer" when the mouse moves on the chart. For example, drawing a horizontal line and a vertical line will create a crosshair cursor that tracks the mouse. Other things, such as legend entries, data labels and axis labels, can also be drawn, allowing them to update as the mouse moves over the chart.
CChartViewer will send
CVN_MouseMovePlotArea notification codes to the parent container when the mouse moves over the extended plot area. The track cursor drawing code can be implemented in the handler of this message.
Handling View Port Interactions
A view port can be imagined as a window to an underlying surface. For example, a data series with 10 years of data can be imagined as a long surface. If only 1 year of data is displayed, we may consider this as the view port showing 10% of the underlying surface.
Scrolling can be handled as moving the view port, while zooming in and out can be handled as changing the view port size.
CChartViewer supports using mouse click and drag to control the view port (see
CChartViewer.setMouseUsage). When the view port is changed by mouse actions, CChartViewer will send a
CVN_ViewPortChanged notification code to its parent container. The parent can handle this message and redraw the chart to reflect the updated view port.
CChartViewer also includes methods for changing the view port programmatically. This allows external controls (such as scroll bars, mouse wheel, sliders, date picker, etc) to manipulate the view port.
Microsoft MFC documentation contains the details on how to handle the control notification messages. In brief, the steps are:
- Add an ON_CONTROL entry to the message map section of the Window. An example is as follows, in which IDC_ChartViewer is the resource ID of the CChartViewer control, and OnViewPortChanged is the event handling method.
ON_CONTROL(CVN_ViewPortChanged, IDC_ChartViewer, OnViewPortChanged)
- Declare the event handling method in the message map function section of the header file.
afx_msg void OnViewPortChanged();
- Add the implementation of the event handling method. For example:
void CMyDialog::OnViewPortChanged()
{
// View Port may have changed
// - update other controls if necessary
// - redraw chart
}
Printing Charts On Paper
ChartDirector can output charts in BMP or DIB (Device Independent Bitmap) format. The easiest method to print the chart is to blit the DIB directly to the printer device context. For example:
// Output the chart as BMP
MemBlock bmp = c->makeChart(Chart::BMP);
// The BITMAPINFOHEADER is 14 bytes offset from the beginning
LPBITMAPINFO header = (LPBITMAPINFO)(bmp.data + 14);
// The bitmap data
LPBYTE bitData = (LPBYTE)(bmp.data) +
((LPBITMAPFILEHEADER)(bmp.data))->bfOffBits;
// The scaling factor to adjust for printer resolution
// (pDC = CDC pointer representing the printer device context)
double xScaleFactor = pDC->GetDeviceCaps(LOGPIXELSX) / 96.0;
double yScaleFactor = pDC->GetDeviceCaps(LOGPIXELSY) / 96.0;
// Output to device context
StretchDIBits(pDC->m_hDC, (int)(40 * xScaleFactor), (int)(40 * yScaleFactor),
(int)(header->bmiHeader.biWidth * xScaleFactor),
(int)(header->bmiHeader.biHeight * yScaleFactor),
0, 0, header->bmiHeader.biWidth, header->bmiHeader.biHeight,
bitData, header, DIB_RGB_COLORS, SRCCOPY);
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