bargraph.cs

ASP.NET 建立和发布可自定义 Web 报表的指南

				if (lblFormat != null) lblFormat.Dispose();
				if (pen != null) pen.Dispose();
				if (sfVLabel != null) sfVLabel.Dispose();
			}
		}

		//*********************************************************************
		//
		// This method draws x axis and all x labels
		//
		//*********************************************************************

		private void DrawXLabelArea(Graphics graph)
		{
			Font lblFont = null;
			SolidBrush brs = null;
			StringFormat lblFormat = null;
			Pen pen = null;

			try
			{
				lblFont = new Font(_fontFamily, _labelFontSize);
				brs = new SolidBrush(_fontColor);
				lblFormat = new StringFormat();
				pen = new Pen(_fontColor);

				lblFormat.Alignment = StringAlignment.Center;

				// Draw x axis
				graph.DrawLine(pen, _xOrigin, _yOrigin + _graphHeight, _xOrigin + _graphWidth, _yOrigin + _graphHeight);

				float currentX;
				float currentY = _yOrigin + _graphHeight + 2.0f;	// All x labels are drawn 2 pixels below x-axis
				float labelWidth = _barWidth + _spaceBtwBars;		// Fits exactly below the bar
				int i = 0;

				// Draw x labels
				foreach(ChartItem item in DataPoints)
				{
					currentX = _xOrigin + (i * labelWidth);
					RectangleF recLbl = new RectangleF(currentX, currentY, labelWidth, lblFont.Height);
					string lblString = _displayLegend ? item.Label : item.Description;	// Decide what to show: short or long

					graph.DrawString(lblString, lblFont, brs, recLbl, lblFormat);
					i++;
				}
			}
			finally
			{
				if (lblFont != null) lblFont.Dispose();
				if (brs != null) brs.Dispose();
				if (lblFormat != null) lblFormat.Dispose();
				if (pen != null) pen.Dispose();
			}
		}

		//*********************************************************************
		//
		// This method determines where to place the legend box.
		// It draws the legend border, legend description, and legend color code.
		//
		//*********************************************************************

		private void DrawLegend(Graphics graph)
		{
			Font lblFont = null;
			SolidBrush brs = null;
			StringFormat lblFormat = null;
			Pen pen = null;

			try
			{
				lblFont = new Font(_fontFamily, _legendFontSize);
				brs = new SolidBrush(_fontColor);
				lblFormat = new StringFormat();
				pen = new Pen(_fontColor);
				lblFormat.Alignment = StringAlignment.Near;

				// Calculate Legend drawing start point
				float startX = _xOrigin + _graphWidth + _graphLegendSpacer;
				float startY = _yOrigin;

				float xColorCode = startX + _spacer;
				float xLegendText = xColorCode + _legendRectangleSize + _spacer;
				float legendHeight = 0.0f;
				for(int i=0; i<DataPoints.Count; i++)
				{
					ChartItem point = DataPoints[i];
					string text = point.Description + " (" + point.Label + ")";
					float currentY = startY + _spacer + (i * (lblFont.Height + _spacer));
					legendHeight += lblFont.Height + _spacer;

					// Draw legend description
					graph.DrawString(text, lblFont, brs, xLegendText, currentY, lblFormat);

					// Draw color code
					graph.FillRectangle(new SolidBrush(DataPoints[i].ItemColor), xColorCode, currentY + 3f, _legendRectangleSize, _legendRectangleSize);
				}

				// Draw legend border
				graph.DrawRectangle(pen, startX, startY, _legendWidth, legendHeight + _spacer);
			}
			finally
			{
				if (lblFont != null) lblFont.Dispose();
				if (brs != null) brs.Dispose();
				if (lblFormat != null) lblFormat.Dispose();
				if (pen != null) pen.Dispose();
			}
		}

		//*********************************************************************
		//
		// This method calculates all measurement aspects of the bar graph from the given data points
		//
		//*********************************************************************

		private void CalculateGraphDimension() 
		{
			FindLongestTickValue();
			
			// Need to add another character for spacing; this is not used for drawing, just for calculation
			_longestTickValue += "0";		
			_maxTickValueWidth = CalculateImgFontWidth(_longestTickValue, _labelFontSize, FontFamily);
			float leftOffset = _spacer + _maxTickValueWidth;
			float rtOffset = 0.0f;

			if (_displayLegend) 
			{
				_legendWidth = _spacer + _legendRectangleSize + _spacer + _maxLabelWidth + _spacer;
				rtOffset = _graphLegendSpacer + _legendWidth + _spacer;
			}
			else
				rtOffset = _spacer;		// Make graph in the middle

			_graphHeight = _totalHeight - _topBuffer - _bottomBuffer;	// Buffer spaces are used to print labels
			_graphWidth = _totalWidth - leftOffset - rtOffset;
			_xOrigin = leftOffset;
			_yOrigin = _topBuffer;

			// Once the correct _maxValue is determined, then calculate _scaleFactor
			_scaleFactor = _maxValue / _graphHeight;
		}

		//*********************************************************************
		//
		// This method determines the longest tick value from the given data points.
		// The result is needed to calculate the correct graph dimension.
		//
		//*********************************************************************

		private void FindLongestTickValue()
		{
			float currentTick;
			string tickString;
			for (int i=0; i<_yTickCount; i++)
			{
				currentTick = _maxValue - i*_yTickValue;	
				tickString = currentTick.ToString("#,###.##");
				if (_longestTickValue.Length < tickString.Length)
					_longestTickValue = tickString;
			}
		}

		//*********************************************************************
		//
		// This method calculates the image width in pixel for a given text
		//
		//*********************************************************************

		private float CalculateImgFontWidth(string text, int size, string family)
		{
			Bitmap bmp = null;
			Graphics graph = null;
			Font font = null;

			try
			{
				font = new Font(family, size);

				// Calculate the size of the string.
				bmp = new Bitmap(1,1,PixelFormat.Format32bppArgb);
				graph = Graphics.FromImage(bmp);
				SizeF oSize = graph.MeasureString(text, font);
			
				return oSize.Width;
			}
			finally
			{
				if (graph != null) graph.Dispose();
				if (bmp != null) bmp.Dispose();
				if (font != null) font.Dispose();
			}
		}
		
		//*********************************************************************
		//
		// This method creates abbreviation from long description; used for making legend
		//
		//*********************************************************************

		private string MakeShortLabel(string text)
		{
			string label = text;
			if (text.Length > 2) 
			{
				int midPostition = Convert.ToInt32(Math.Floor(text.Length/2));
				label = text.Substring(0,1) + text.Substring(midPostition, 1) + text.Substring(text.Length-1,1);
			}
			return label;
		}

		//*********************************************************************
		//
		// This method calculates the max value and each tick mark value for the bar graph.
		//
		//*********************************************************************

		private void CalculateTickAndMax()
		{
			float tempMax = 0.0f;

			// Give graph some head room first about 10% of current max
			_maxValue *= 1.1f;

			if (_maxValue != 0.0f)
			{
				// Find a rounded value nearest to the current max value
				// Calculate this max first to give enough space to draw value on each bar
				double exp = Convert.ToDouble(Math.Floor(Math.Log10(_maxValue)));
				tempMax = Convert.ToSingle(Math.Ceiling(_maxValue / Math.Pow(10, exp)) * Math.Pow(10, exp));
			}
			else
				tempMax = 1.0f;

			// Once max value is calculated, tick value can be determined; tick value should be a whole number
			_yTickValue = tempMax / _yTickCount;
			double expTick = Convert.ToDouble(Math.Floor(Math.Log10(_yTickValue)));
			_yTickValue = Convert.ToSingle(Math.Ceiling(_yTickValue / Math.Pow(10, expTick)) * Math.Pow(10, expTick));

			// Re-calculate the max value with the new tick value
			_maxValue = _yTickValue * _yTickCount;
		}

		//*********************************************************************
		//
		// This method calculates the height for each bar in the graph
		//
		//*********************************************************************

		private void CalculateSweepValues()
		{
			// Called when all values and scale factor are known
			// All values calculated here are relative from (_xOrigin, _yOrigin)
			int i = 0;
			foreach(ChartItem item in DataPoints)
			{
				// This implementation does not support negative value
				if (item.Value >= 0) item.SweepSize = item.Value/_scaleFactor;
				
				// (_spaceBtwBars/2) makes half white space for the first bar
				item.StartPos = (_spaceBtwBars/2) + i * (_barWidth+_spaceBtwBars);
				i++;
			}
		}

		//*********************************************************************
		//
		// This method calculates the width for each bar in the graph
		//
		//*********************************************************************

		private void CalculateBarWidth(int dataCount, float barGraphWidth)
		{
			// White space between each bar is the same as bar width itself
			_barWidth = barGraphWidth / (dataCount * 2);  // Each bar has 1 white space 
			_spaceBtwBars = _barWidth;
		}

		//*********************************************************************
		//
		// This method assigns default value to the bar graph properties and is only 
		// called from BarGraph constructors
		//
		//*********************************************************************

		private void AssignDefaultSettings()
		{
			// default values
			_totalWidth = 700f;
			_totalHeight = 450f;
			_fontFamily = "Verdana";
			_backColor = Color.White;
			_fontColor = Color.Black;
			_topBuffer = 30f;
			_bottomBuffer = 30f;
			_yTickCount = 2;
			_displayLegend = false;
			_displayBarData = false;
		}
	}
}