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<%--
Pro ASP.NET Web Forms Techniques, Second Edition
By Alex Homer
ISBN: 1-59059-317-0
Published: Dec 2003
Publisher: Apress.com
--%>
<%@Page Language="C#" %>
<%@Import Namespace="System.Drawing" %>
<script runat="server">
void Page_Load() {
// array to hold list of 168 "known" colors
Color[] aKnownCols = new Color[168];
KnownColor eValue;
for (eValue = 0; eValue <= KnownColor.YellowGreen; eValue++) {
aKnownCols[(int) eValue] = Color.FromKnownColor(eValue);
}
// array to hold list of 216 browser-safe colors
Color[] aSafeCols = new Color[216];
int rValue, gValue, bValue;
int iPointer = 0;
for (rValue = 0; rValue <= 255; rValue += 51) {
for (gValue = 0; gValue <= 255; gValue += 51) {
for (bValue = 0; bValue <= 255; bValue += 51) {
aSafeCols[iPointer] = Color.FromArgb(rValue, gValue, bValue);
iPointer += 1;
}
}
}
// create a table containing the browser-safe colors
// and indicate any matching .NET standard color
// declare variables, we'll create 5 rows simultaneously
TableRow oRow1, oRow2, oRow3, oRow4, oRow5;
TableCell oCell;
Color oKnown;
String sDecimalVals, sHexVals, sKnown;
// to create empty cell with colored background
String sColorCell = "<font size=5> </font>";
// create empty Table object and five Row objects
Table oTable = new Table();
oRow1 = new TableRow();
oRow2 = new TableRow();
oRow3 = new TableRow();
oRow4 = new TableRow();
oRow5 = new TableRow();
// set horizontal alignment for three rows
oRow2.HorizontalAlign = HorizontalAlign.Center;
oRow3.HorizontalAlign = HorizontalAlign.Center;
oRow4.HorizontalAlign = HorizontalAlign.Center;
// iterate through array of safe colors
foreach (Color oColor in aSafeCols) {
// create the strings showing decimal and hex RGB values
sDecimalVals = oColor.R.ToString() + "," + oColor.G.ToString()
+ "," + oColor.B.ToString();
sHexVals = "#" + oColor.R.ToString("x2") + oColor.G.ToString("x2")
+ oColor.B.ToString("x2");
// see if this color is same as any standard color by iterating
// through "known" colors array and comparing ARGB values.
// not breaking at first match avoids returning "system" colors
// such as "DialogText" and "WindowTitleBarText" which come first
sKnown = "";
foreach (Color oEKnown in aKnownCols) {
if (oEKnown.ToArgb() == oColor.ToArgb()) {
sKnown = oEKnown.Name;
}
}
// create a new cell, and add LiteralControl containing value
oCell = new TableCell();
oCell.Controls.Add(new LiteralControl(sColorCell));
// set properties for this cell, and add to row 1
oCell.BorderColor = Color.Black;
oCell.BorderStyle = BorderStyle.Solid;
oCell.BorderWidth = Unit.Pixel(1);
oCell.BackColor = oColor;
oRow1.Cells.Add(oCell);
// repeat for cells containing decimal and hex RGB values
oCell = new TableCell();
oCell.Controls.Add(new LiteralControl(sDecimalVals));
oRow2.Cells.Add(oCell);
oCell = new TableCell();
oCell.Controls.Add(new LiteralControl(sHexVals));
oRow3.Cells.Add(oCell);
// create cell for matching "known" color if there is one
oCell = new TableCell();
if (sKnown != "") {
oCell.Controls.Add(new LiteralControl(sKnown));
// create color object using "known" color name
Color oEKnown = Color.FromName(sKnown);
oCell.BackColor = oEKnown;
oCell.BorderColor = Color.Black;
oCell.BorderStyle = BorderStyle.Solid;
oCell.BorderWidth = Unit.Pixel(1);
// see if we need to use white text on this background
// color when displaying color name in cell
if (oEKnown.R < 124 && oEKnown.G < 124) {
oCell.ForeColor = Color.White;
}
}
// add "known color" cell to row 4
oRow4.Cells.Add(oCell);
// create cell in row 5 to provide space between color rows
oCell = new TableCell();
oCell.Controls.Add(new LiteralControl(" "));
oRow5.Cells.Add(oCell);
// if Blue element of color has reached 255 start a new row
// add five existing rows to table, create new ones and set
// horizontal alignment for the three of them holding text
if (oColor.B == 255) {
oTable.Rows.Add(oRow1);
oTable.Rows.Add(oRow2);
oTable.Rows.Add(oRow3);
oTable.Rows.Add(oRow4);
oTable.Rows.Add(oRow5);
oRow1 = new TableRow();
oRow2 = new TableRow();
oRow3 = new TableRow();
oRow4 = new TableRow();
oRow5 = new TableRow();
oRow2.HorizontalAlign = HorizontalAlign.Center;
oRow3.HorizontalAlign = HorizontalAlign.Center;
oRow4.HorizontalAlign = HorizontalAlign.Center;
}
}
// table complete, so insert into page within PlaceHolder control
ctlPlaceholder.Controls.Add(oTable);
}
</script>
<!doctype html public "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<title>Browser-safe and Standard Colors</title>
</head>
<body>
Browser-safe and Standard Colors
<asp:PlaceHolder id="ctlPlaceholder" runat="server" />
</body>
</html>
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