Please note how we take the font size of the label, title, and ticks into consideration when determining the PlotArea size. We measure the font size using the g.MeasureString method:
SizeF labelFontSize = g.MeasureString("A", cs.LabelFont);
SizeF titleFontSize = g.MeasureString("A", cs.TitleFont);
SizeF tickFontSize = g.MeasureString("A", cs.TickFont);
We also find the maximum string size of the tick markers, making sure that there is enough room for the axis labels:
SizeF yTickSize = g.MeasureString(
cs.YLimMin.ToString(), cs.TickFont);
for (float yTick = cs.YLimMin;
yTick <= cs.YLimMax; yTick += cs.YTick) {
SizeF tempSize = g.MeasureString(
yTick.ToString(), cs.TickFont);
if (yTickSize.Width < tempSize.Width) {
yTickSize = tempSize;
} }
Taking all these factors into account, we determine the margins of the PlotArea relative to the ChartArea, and we are finally able to create the Rectangle of PlotArea.
Modifying Chart Style
Compared to the previous project, here we add more features to the ChartStyle class. The following is the code listing of this class:
using System;
using System.Collections;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace Example3_3 {
public class ChartStyle {
private Form1 form1;
private Rectangle chartArea;
private Rectangle plotArea;
private Color chartBackColor;
private Color chartBorderColor;
private Color plotBackColor = Color.White;
private Color plotBorderColor = Color.Black;
private float xLimMin = 0f;
private float xLimMax = 10f;
private float yLimMin = 0f;
private float yLimMax = 10f;
private DashStyle gridPattern = DashStyle.Solid;
private Color gridColor = Color.LightGray;
private float gridLineThickness = 1.0f;
private bool isXGrid = true;
private bool isYGrid = true;
private string xLabel = "X Axis";
private string yLabel = "Y Axis";
private string sTitle = "Title";
private Font labelFont = new Font("Arial", 10, FontStyle.Regular);
private Color labelFontColor = Color.Black;
private Font titleFont = new Font("Arial", 12, FontStyle.Regular);
private Color titleFontColor = Color.Black;
private float xTick = 1f;
private float yTick = 2f;
private Font tickFont;
private Color tickFontColor = Color.Black;
public ChartStyle(Form1 fm1) {
form1 = fm1;
chartArea = form1.ClientRectangle;
chartBackColor = fm1.BackColor;
chartBorderColor = fm1.BackColor;
PlotArea = chartArea;
tickFont = form1.Font;
}
public Font TickFont {
get { return tickFont; } set { tickFont = value; } }
public Color TickFontColor {
get { return tickFontColor; } set { tickFontColor = value; } }
public Color ChartBackColor {
get { return chartBackColor; } set { chartBackColor = value; } }
public Color ChartBorderColor {
get { return chartBorderColor; }
set { chartBorderColor = value; } }
public Color PlotBackColor {
get { return plotBackColor; } set { plotBackColor = value; } }
public Color PlotBorderColor {
get { return plotBorderColor; } set { plotBorderColor = value; } }
public Rectangle ChartArea {
get { return chartArea; } set { chartArea = value; } }
public Rectangle PlotArea {
get { return plotArea; } set { plotArea = value; } }
public bool IsXGrid {
get { return isXGrid; } set { isXGrid = value; } }
public bool IsYGrid {
get { return isYGrid; } set { isYGrid = value; } }
public string Title {
get { return sTitle; } set { sTitle = value; } }
public string Label {
get { return xLabel; } set { xLabel = value; } }
public string YLabel {
get { return yLabel; }
set { yLabel = value; } }
public Font LabelFont {
get { return labelFont; } set { labelFont = value; } }
public Color LabelFontColor {
get { return labelFontColor; } set { labelFontColor = value; } }
public Font TitleFont {
get { return titleFont; } set { titleFont = value; } }
public Color TitleFontColor {
get { return titleFontColor; } set { titleFontColor = value; } }
public float XLimMax {
get { return xLimMax; } set { xLimMax = value; } }
public float XLimMin {
get { return xLimMin; } set { xLimMin = value; } }
public float YLimMax {
get { return yLimMax; } set { yLimMax = value; } }
public float YLimMin {
get { return yLimMin; } set { yLimMin = value; } }
public float XTick {
get { return xTick; }
set { xTick = value; } }
public float YTick {
get { return yTick; } set { yTick = value; } }
virtual public DashStyle GridPattern {
get { return gridPattern; } set { gridPattern = value; } }
public float GridThickness {
get { return gridLineThickness; } set { gridLineThickness = value; } }
virtual public Color GridColor {
get { return gridColor; } set { gridColor = value; } }
public void AddChartStyle(Graphics g) {
// Draw ChartArea and PlotArea:
Pen aPen = new Pen(ChartBorderColor, 1f);
SolidBrush aBrush = new SolidBrush(ChartBackColor);
g.FillRectangle(aBrush, ChartArea);
g.DrawRectangle(aPen, ChartArea);
aPen = new Pen(PlotBorderColor, 1f);
aBrush = new SolidBrush(PlotBackColor);
g.FillRectangle(aBrush, PlotArea);
g.DrawRectangle(aPen, PlotArea);
SizeF tickFontSize = g.MeasureString("A", TickFont);
// Create vertical gridlines:
float fX, fY;
if (IsYGrid == true) {
aPen = new Pen(GridColor, 1f);
aPen.DashStyle = GridPattern;
for (fX = XLimMin + XTick; fX < XLimMax; fX += XTick) {
g.DrawLine(aPen, Point2D(new PointF(fX, YLimMin)), Point2D(new PointF(fX, YLimMax)));
} }
// Create horizontal gridlines:
if (IsXGrid == true) {
aPen = new Pen(GridColor, 1f);
aPen.DashStyle = GridPattern;
for (fY = YLimMin + YTick; fY < YLimMax; fY += YTick) {
g.DrawLine(aPen, Point2D(new PointF(XLimMin, fY)), Point2D(new PointF(XLimMax, fY)));
} }
// Create the x-axis tick marks:
aBrush = new SolidBrush(TickFontColor);
for (fX = XLimMin; fX <= XLimMax; fX += XTick) {
PointF yAxisPoint = Point2D(new PointF(fX, YLimMin));
g.DrawLine(Pens.Black, yAxisPoint,
new PointF(yAxisPoint.X, yAxisPoint.Y - 5f));
StringFormat sFormat = new StringFormat();
sFormat.Alignment = StringAlignment.Far;
SizeF sizeXTick = g.MeasureString(fX.ToString(), TickFont);
g.DrawString(fX.ToString(), TickFont, aBrush, new PointF(yAxisPoint.X + sizeXTick.Width / 2, yAxisPoint.Y + 4f), sFormat);
}
// Create the y-axis tick marks:
for (fY = YLimMin; fY <= YLimMax; fY += YTick) {
PointF xAxisPoint = Point2D(new PointF(XLimMin, fY));
g.DrawLine(Pens.Black, xAxisPoint,
new PointF(xAxisPoint.X + 5f, xAxisPoint.Y));
StringFormat sFormat = new StringFormat();
sFormat.Alignment = StringAlignment.Far;
g.DrawString(fY.ToString(), TickFont, aBrush, new PointF(xAxisPoint.X - 3f,
xAxisPoint.Y - tickFontSize.Height / 2), sFormat);
}
aPen.Dispose();
aBrush.Dispose();
AddLabels(g);
}
private void AddLabels(Graphics g) {
float xOffset = chartArea.Width / 30.0f;
float yOffset = chartArea.Height / 30.0f;
SizeF labelFontSize = g.MeasureString("A", LabelFont);
SizeF titleFontSize = g.MeasureString("A", TitleFont);
// Add horizontal axis label:
SolidBrush aBrush = new SolidBrush(LabelFontColor);
SizeF stringSize = g.MeasureString(XLabel, LabelFont);
g.DrawString(XLabel, LabelFont, aBrush,
new Point(PlotArea.Left + PlotArea.Width / 2 - (int)stringSize.Width / 2, ChartArea.Bottom - (int)yOffset - (int)labelFontSize.Height));
// Add y-axis label:
StringFormat sFormat = new StringFormat();
sFormat.Alignment = StringAlignment.Center;
stringSize = g.MeasureString(YLabel, LabelFont);
// Save the state of the current Graphics object GraphicsState gState = g.Save();
g.TranslateTransform(xOffset,
yOffset + titleFontSize.Height
+ yOffset / 3 + PlotArea.Height / 2);
g.RotateTransform(-90);
g.DrawString(YLabel, LabelFont, aBrush, 0, 0, sFormat);
// Restore it:
g.Restore(gState);
// Add title:
aBrush = new SolidBrush(TitleFontColor);
stringSize = g.MeasureString(Title, TitleFont);
if (Title.ToUpper() != "NO TITLE") {
g.DrawString(Title, TitleFont, aBrush,
new Point(PlotArea.Left + PlotArea.Width / 2 - (int)stringSize.Width / 2,
ChartArea.Top + (int)yOffset));
}
aBrush.Dispose();
}
public PointF Point2D(PointF pt) {
PointF aPoint = new PointF();
if (pt.X < XLimMin || pt.X > XLimMax ||
pt.Y < YLimMin || pt.Y > YLimMax) {
pt.X = Single.NaN;
pt.Y = Single.NaN;
}
aPoint.X = PlotArea.X + (pt.X - XLimMin) * PlotArea.Width / (XLimMax - XLimMin);
aPoint.Y = PlotArea.Bottom - (pt.Y - YLimMin) * PlotArea.Height / (YLimMax - YLimMin);
return aPoint;
} } }
To this class, we add more member fields and corresponding properties, which can be used to manipulate the chart layout and appearance. You can easily understand the meaning of each field and property from its name. We also add the following member fields to define the chart gridlines
private DashStyle gridPattern = DashStyle.Solid;
private Color gridColor = Color.LightGray;
private float gridLineThickness = 1.0f;
private bool isXGrid = true;
private bool isYGrid = true;