问题
MVC3 VB.NET application using Itextsharp. I have a section of code that generates a pdf file everything looks great but I would like to alternate the line colors in that pdf file between 2 color so that the values are easy to follow for the person looking at it. Is there a way to set the background color of a whole line based on font size to a set color? A function I would be using this in is below:
For Each _reg_ In _reg
Dim _registrant As reg_info = _reg_
If y_line1 <= 30 Then
doc.NewPage()
_Page = _Page + 1
y_line1 = 670
End If
If y_line1 = 670 Then
cb.BeginText()
cb.SetFontAndSize(BF_Times, 6)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, _datePrinted + " " + _timePrinted, 500, 770, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_RIGHT, "Page Number" + " " + _Page, 600, 770, 0)
cb.SetFontAndSize(BF_Times, 8)
cb.ShowTextAligned(PdfContentByte.ALIGN_CENTER, _reportHead + " Overrides ", 304, 720, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "First Name", 20, 700, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "Last Name", 80, 700, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "Last Four", 160, 700, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "Email Address", 300, 700, 0)
cb.EndText()
End If
cb.BeginText()
cb.SetFontAndSize(BF_Times, 8)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, _registrant.first_name, 20, y_line1, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, _registrant.last_name, 80, y_line1, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, _registrant.last_four_social, 160, y_line1, 0)
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, _registrant.email, 300, y_line1, 0)
_total += 1
cb.EndText()
y_line1 = y_line1 - 15
Next
I thought about just setting the background color of the line by using the y_line1 and using a modulus to determine if the color should be grey or white. But I have found no code samples anywhere about how to set a whole line background color.. Any ideas????
回答1:
There is no concept of "background color" in the PDF spec in relation to text. Anything that looks like a background color, even a table, is just text drawn on top of a rectangle (or some other shape).
To draw a rectangle you just call the Rectangle method on your PdfContentByte object. It takes a lower left x,y and a width and a height. The color is determined by a previous call to one of the color fills such as SetColorFill().
When working with the raw canvas its recommended that you also use SaveState() and RestoreState(). Since the fill commands are shared between objects but mean different things these can help avoid confusion. SaveState() sets a flag allowing you to undo all graphics state changes when you call RestoreState().
The code below is a full working VB.Net 2010 WinForms app targeting iTextSharp 5.1.2.0 that shows off the above. It creates a sample file on the desktop with a line of text repeated 7 times. Each line toggles back and forth between two background colors. Additionally it draws a stroke around the line of text to simulate a border.
Option Strict On
Option Explicit On
Imports System.IO
Imports iTextSharp.text
Imports iTextSharp.text.pdf
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
''//Test file that we'll create
Dim TestFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "TestFile.pdf")
''//Test String that we'll repeat
Dim TestString = "It was the best of times..."
''//Create an array of our test string
Dim TestArray = {TestString, TestString, TestString, TestString, TestString, TestString, TestString}
''//Create our generic font
Dim BF_Times = BaseFont.CreateFont(BaseFont.TIMES_BOLD, BaseFont.CP1250, BaseFont.NOT_EMBEDDED)
''//Standard PDF setup, change as needed for your stream type
Using FS As New FileStream(TestFile, FileMode.Create, FileAccess.Write, FileShare.None)
Using Doc As New Document(PageSize.LETTER)
Using writer = PdfWriter.GetInstance(Doc, FS)
Doc.Open()
''//Grab the raw content object
Dim cb = writer.DirectContent
''//Set our starter Y coordinate
Dim y = 670
''//Loop through our string collection
For I = 0 To (TestArray.Count - 1)
''//Store the current graphics state so that we can unwind it later
cb.SaveState()
''//Set the fill color based on eve/odd
cb.SetColorFill(If(I Mod 2 = 0, BaseColor.GREEN, BaseColor.BLUE))
''//Optional, set a border
cb.SetColorStroke(BaseColor.BLACK)
''//Draw a rectangle. NOTE: I'm subtracting 5 from the y to account for padding
cb.Rectangle(0, y - 5, Doc.PageSize.Width, 15)
''//Draw the rectangle with a border. NOTE: Use cb.Fill() to draw without the border
cb.FillStroke()
''//Unwind the graphics state
cb.RestoreState()
''//Flag to begin text
cb.BeginText()
''//Set the font
cb.SetFontAndSize(BF_Times, 6)
''//Write some text
cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT, TestArray(I), 0, y, 0)
''//Done writing text
cb.EndText()
''//Decrease the y accordingly
y -= 15
Next
Doc.Close()
End Using
End Using
End Using
Me.Close()
End Sub
End Class
来源：https://stackoverflow.com/questions/9574160/setting-the-background-color-of-a-contentbyte-itextsharp