CBarChart is a simple MFC control derived from
CWnd. It helps you develop your own charts quickly and print them easily.
A few days ago, I needed to add a chart to a project. When completed, I thought to myself that it's not too bad, so I decided to share it with my workmates in Code Project, and here it is.
I did not have a lot of time to work on this control, so I had to keep it as simple as possible. My goals for creating this chart were as follows:
- Development should not take more than two or three days.
- The chart must be more attractive rather than accurate. Since users are not familiar with the application and even computers, I had to do my best to attract their attention.
- It has to be easy to understand, not filled with a lot of data that mostly confuse new users.
- It should be printable.
- It should be reusable.
With all the above assumptions, I started what you see here. Enjoy and please help me with the invaluable notes, bugs reports, ideas, etc. that you think might improve the quality of this code.
First we have to create a chart:
- Add BarChart.cpp and BarChart.h to your project.
#include "BarChart.h" to the top of header file of class in which you want to add this chart.
- Add a
membrt variable of type
- In your cpp file, use the
Create method of the member variable to create a chart control.
Create suceeds, it returns
Title text and background color
You can use
SetBKColor to add a title or change color of the background of control.
m_chart.SetTitle("A test chart, displaying some dummy data...");
m_chart.SetBKColor(RGB(255, 255, 240));
Finally, to add bars to the chart, use
AddBar method as follows:
Note that the control uses this color (last parameter of
AddBar) to create a gradient for the bar, which in my humble opinion is more polished.
You can also decide whether to see grid lines, labels or values:
m_chart.ShowBarText(1, m_bShowText, TRUE);
Also note that the first parameter of
ShowBarText is used to toggle between two states: 0 indicates show value of the bar at the top of it and 1 indicates show percentage regarding other values.
You can also change default behaviour of the grid. By default, the grid fills the chart background by crossed vertical and horizontal lines resulting in rectangles with 10 (device) unit width and height. To change this behavior, use
SetGridLines member function.
The bar is able to scale itself if had been asked to, but quality drops suddenly since it uses
StretchBlt. This decreases quality drastically. I hope you don't mind since I did not have enough time to redraw the whole chart to fit in to the screen.
m_chart.SetWindowPos( 0, 0, 0,
rcClient.Height() , SWP_NOMOVE);
You can use
RemoveAll to remove bars from the control for a specific zero based index or totally respectively.
SaveToFile to save the chart as a bitmap file. Function accepts a
CString member function that is set to empty by default. If this string is empty, function prompts for file path by displaying a
FileSaveAs dialog box. This function returns
False in case of failure. Use
GetLastErrorMessage() member function to get a string describing reason for failure.
It would be appreciated if someone checks out saving to bitmap code, to make sure there are no bugs.
Print function to print the chart.
Use this function with care: According to the article by Roger Allen: PrintingTricksAndTips if we are going to print a bitmap, it is better to use DIB's instead of DDB's. So this function takes a parameter of type
bCompatible (default is
If you set the parameter to
true, it means you asked the chart to use DIB's which is recommended. I just copy-pasted the code snippet that Mr. Roger Allen provided and created two copies of the
Print one that uses
StretchBlt directly, and one that uses the code mentioned to convert it to DIB.
To me both types of functions work fine. But unfortunately, I did not have enough time to check the printing process correctly. So it would be very kind of you to report any bugs you might find or any corrections. I'm not familiar enough with printing.
CBarChart uses ODBC Version 3 to connect to the database.
To connect the chart to an ODBC data source, use one of the forms of
// Use this form to call a stored procedure or a query and use
// result set as chart input
ReadFromDatabase("DS Name", "Stored proc/Query Name", "List of all parameters",
"Bars Color", "UserName", "Password"));
// Note that the query or stored procedure MUST have at least 2 columns,
// First column MUST be of type char with maximum length of 50 and
// Second a double. These columns will be used as input data for the chart.
Second form can be used to conect to a table
m_chart.ReadFromDatabase("DS Name", "Table name", "Filter",
"Laabel column name", "dValue column name",
Bars color , "username", "password");
Below is an example of a call to these functions
if (!m_chart.ReadFromDatabase("CHTst", "SpChartGetSale", "1, 12",
RGB(0, 0, 0), "hamed", "hamed"))
m_chart.ReadFromDatabase("CHTst", "Sales", "",
RGB(0, 0, 0) , "hamed", "hamed");
I added a sample access database file to the download list. You can add this to your 'system' or 'user' data sources in ODBC Administration tool in the control panel. Name it
CHTst and press the 'FromDatabase' button on the sample application. What you see is a result set of a call to a stored procedure that is done with one line of code. Enjoy.
- Version (Or perhaps first beta version).
- Some scaling bugs fixed
- Tooltips added.
- Unsigned long double converted to double
- Some functions changed.
- Tooltip updated.
- Some comments added.
- Tooltips now behave much like real tooltips.
- Database connections added.
- Tooltip bug fixed.(it disappears as control loses capture.)
- Save to bitmap added
- Grid updated
- Mr. Nishant S. for his article about creating gradients.
- Mr. Chris Maunder for his nice article called MFC Grid, that helped me for printing.
- Mr. Roger Allen for 'Printing tips and tricks from the trenches' article.
- Mr. David Bennett and Mr. Chuck Wood in Visual C Unleashed book, for code snippets and help for ODBC database programming.