Visual C++ .NET GDI+ Examples: Column Chart

	GDI+ Examples: Column Chart

Introduction

A chart is a technique of representing numeric values using colored shapes. The shape(s) can be geometric or not. To draw such a chart, you can use your knowledge of GDI+ techniques. In this exercise, we use the Graphics::DrawRectangle() method to draw a series of rectangles that represent a column chart.

Practical Learning: Creating the Chart

Start a new Windows Forms Application named WeeklySales
Set the form's Icon to Drive:\Program Files\Microsoft Visual Studio .NET 2003\Common7\Graphics\icons\Office\GRAPH07.ICO

Design the form as follows:

Control	Name	Text	Other Properties
Label		Monday
Label		Tuesday
Label		Wednesday
Label		Thursday
Label		Friday
TextBox	txtMonday	12000	TextAlign: Right
TextBox	txtTuesday	11000	TextAlign: Right
TextBox	txtWednesday	8500	TextAlign: Right
TextBox	txtThursday	16800	TextAlign: Right
TextBox	txtFriday	17500	TextAlign: Right
Button	Generate	btnGenerate

Double-click an unoccupied area on the form and implement its Load event as follows:

#pragma once


namespace WeeklySales1
{
	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;

	/// <summary> 
	/// Summary for Form1
	///
	/// WARNING: If you change the name of this class, you will need to change the 
	///          'Resource File Name' property for the managed resource compiler tool 
	///          associated with all .resx files this class depends on.  Otherwise,
	///          the designers will not be able to interact properly with localized
	///          resources associated with this form.
	/// </summary>
	public __gc class Form1 : public System::Windows::Forms::Form
	{	
	public:
		Form1(void)
		{
			InitializeComponent();
		}
  
	protected:
		void Dispose(Boolean disposing)
		{
			if (disposing && components)
			{
				components->Dispose();
			}
			__super::Dispose(disposing);
		}
	private: System::Windows::Forms::Button *  btnGenerate;
	private: System::Windows::Forms::TextBox *  txtFriday;
	private: System::Windows::Forms::Label *  label5;
	private: System::Windows::Forms::TextBox *  txtThursday;
	private: System::Windows::Forms::Label *  label4;
	private: System::Windows::Forms::TextBox *  txtWednesday;
	private: System::Windows::Forms::Label *  label3;
	private: System::Windows::Forms::TextBox *  txtTuesday;
	private: System::Windows::Forms::Label *  label2;
	private: System::Windows::Forms::TextBox *  txtMonday;
	private: System::Windows::Forms::Label *  label1;

	private:
		/// <summary>
		/// Required designer variable.
		/// </summary>
		System::ComponentModel::Container * components;
		Graphics *graphDrawingArea;
		Bitmap   *bmpDrawingArea;

		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		void InitializeComponent(void)
		{
			
			. . . No Change

		}	
	private: System::Void Form1_Load(System::Object *  sender, System::EventArgs *  e)
		{
			 bmpDrawingArea   = new Bitmap(Width, Height);
			 graphDrawingArea = Graphics::FromImage(bmpDrawingArea);
		}

};
}

Return to the form and click an empty area on it. In the Properties window, click the Events button

Double-click the Paint field and implement its event as follows:

private: System::Void Form1_Paint(System::Object *  sender, System::Windows::Forms::PaintEventArgs *  e)
		 {
			 e->Graphics->DrawImage(bmpDrawingArea, 0, 0);
		 }

Double-click the Generate button and implement its Click event as follows:

private: System::Void btnGenerate_Click(System::Object *  sender, System::EventArgs *  e)
 {
	 int monday = this->txtMonday->Text->ToInt32(0) / 100;
	 int tuesday = this->txtTuesday->Text->ToInt32(0) / 100;
	 int wednesday = this->txtWednesday->Text->ToInt32(0) / 100;
	 int thursday = this->txtThursday->Text->ToInt32(0) / 100;
	 int friday = this->txtFriday->Text->ToInt32(0) / 100;

	 graphDrawingArea->Clear(this->BackColor);

	 graphDrawingArea->FillRectangle(new SolidBrush(Color::Red),       this->txtMonday->Left+5,    280-monday,    40, monday);
	 graphDrawingArea->DrawRectangle(new Pen(Color::Black),            this->txtMonday->Left+5,    280-monday,    40, monday);
	 graphDrawingArea->FillRectangle(new SolidBrush(Color::Blue),      this->txtTuesday->Left+5,   280-tuesday,   40, tuesday);
	 graphDrawingArea->DrawRectangle(new Pen(Color::Black),            this->txtTuesday->Left+5,   280-tuesday,   40, tuesday);
	 graphDrawingArea->FillRectangle(new SolidBrush(Color::Fuchsia),   this->txtWednesday->Left+5, 280-wednesday, 40, wednesday);
	 graphDrawingArea->DrawRectangle(new Pen(Color::Black),            this->txtWednesday->Left+5, 280-wednesday, 40, wednesday);
	 graphDrawingArea->FillRectangle(new SolidBrush(Color::Brown),     this->txtThursday->Left+5,  280-thursday,  40, thursday);
	 graphDrawingArea->DrawRectangle(new Pen(Color::Black),            this->txtThursday->Left+5,  280-thursday,  40, thursday);
	 graphDrawingArea->FillRectangle(new SolidBrush(Color::Turquoise), this->txtFriday->Left+5,    280-friday,    40, friday);
	 graphDrawingArea->DrawRectangle(new Pen(Color::Black),            this->txtFriday->Left+5,    280-friday,    40, friday);

	 graphDrawingArea->DrawRectangle(new Pen(Color::Black), 10, 280, Width - 30, 1);
	 Invalidate();
}

Execute the application and test the form
After using it, close the form


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