Re: Encrypting files - Visual Basic Discussion Boards

Smithers-Jones6-Feb-08 23:36

6-Feb-08 23:36

thanks richard. but i think i can't solve my problem like this.
sure, i could easily find out the height of my complete text ( i alreday did that), bit i thinks that doesn't help.

let me explain, what i want to do:

in my app i need to print data:
name & address & some other information (no problem so far)
some description (which varies in length between nothing at all to some pages (taken from a memo-column in my underlying database)
for drawing this description i use the space (as rectangleF), that is left on the page after printing the other stuff like name/address/and so on.
but if the description is longer than the space still available, i have to find out which part of the description did already fit on the page, and what part of that string is left to print on the following page/pages.
i can't figure out a possibility to come to a result with graphics.measurestring. maybe i need to strip down the text line by line, but i tried this earlier and didn't like it at all.

Re: printing strings [modified]

Richard Blythe7-Feb-08 9:45

Richard Blythe

7-Feb-08 9:45

I see what your getting at now. I did some digging and found that an overload on MeasureString() will output the characters fitted, which should be just what you need!
I've create an example on how to use this feature. Originally I was going to write all of the code in a button handler but it got a little messy. I ended up writing a light wieght class called "StringGenerator" that you can customize. To try this sample, perform the following steps:

1. Create a new class called "StringGenerator" and insert the code below marked: // <<<< StringGenerator Code >>>>>>
1. create a blank form and set it to be the startup form
2. add a button with it's position set to: x=5,y=5
3. double click on the button to generate an event handler.
4. Insert the code snippet below:

'begin code snippet
Dim g As Graphics = Me.CreateGraphics()
Dim sf As StringFormat = New StringFormat()
Dim intY As Integer = 20
Dim originalText As String = "This is very boring text but I don't look at what the text says, I just look at what results the text will bring."

Dim stringG As New MyClasses.StringGenerator( _
originalText, g, Me.Font, New RectangleF(80, intY, 60, 50), sf)
stringG.DrawCurrentString()

While (stringG.HasMoreCharsToDraw)
intY += 60 'in this sample, 60 creates a 10 px padding
stringG.SetNewBounds(New RectangleF(80, intY, 60, 50))
stringG.DrawCurrentString()
End While
'cleanup
g.Dispose()
sf.Dispose()

'End code snippet

Note:This code is still very primitive but it will definitely get you started. If you step through the code, you won't see any output. Remove all the breakpoints to see the dynamically generated graphics. Let me know how it turns out!

' <<<< StringGenerator Code >>>>>>
'insert into -> EMPTY <- class file!

Namespace MyClasses

Public Class StringGenerator
Dim g As Graphics
Dim rectF As RectangleF
Dim sf As StringFormat
Dim fnt As Font
Dim chars() As Char
Dim startIndex As Int32
Dim charsFitted As Int32
Dim linesFilled As Int32
Dim strDisplayText As String
Dim strCurText As String
Dim blnHasMoreChars As Boolean
Public blnClipToNearestWord As Boolean = True

Public Sub New(ByVal text As String, ByRef graphics As Graphics, ByRef font As Font, ByRef rectStartingBounds As RectangleF, ByRef stringFormat As StringFormat)
chars = text.ToCharArray()
rectF = rectStartingBounds
strCurText = text
g = graphics
fnt = font
'set blnHasMoreChars to an initial value of true;
blnHasMoreChars = True
End Sub

Public Sub DrawCurrentString()
MeasureMyCharacters()

'you can write your own custom code here, such as
'allowing a different color input. Don't allow a
'different font because it will mess you measurements up!
g.DrawRectangle(Pens.Red, Rectangle.Round(rectF))
g.DrawString(strDisplayText, fnt, Brushes.Black, rectF, sf)
End Sub

Public Sub SetNewBounds(ByVal rectFBounds As RectangleF)
rectF = rectFBounds
End Sub

Private Sub MeasureMyCharacters()
'This method takes 'strCurText' and measures it with the
'bounds supplied. MeasureString() returns a SizeF object
'but we are only interested in the output generated by the
' 'charsFitted' variable.
g.MeasureString(strCurText, fnt, rectF.Size, sf, charsFitted, linesFilled)

'If amount of chars fitted in rectF is less than
'the number of characters remaining to fit...
If (charsFitted < strCurText.Length - 1) Then
'do we want to clip to the nearest word?
If (blnClipToNearestWord) Then
'we will now loop backwards to find the first
'occurrence of a character separation: " "
For i As Integer = charsFitted + startIndex To 0 Step -1
If chars(i) = " " Then 'is the char a space?
'reduce the amount of characters fitted
'to the first word occurrence
charsFitted = (i - startIndex) + 1
i = -1 'terminate the loop
End If
Next
End If
blnHasMoreChars = True
Else
blnHasMoreChars = False
End If
'create the display contents
strDisplayText = New String(chars, startIndex, (charsFitted))
startIndex = (charsFitted + startIndex)
'assign strCurText the chars remaining to print
strCurText = New String(chars, startIndex, (chars.Length - startIndex))
End Sub

Public Function HasMoreCharsToDraw() As Boolean
HasMoreCharsToDraw = blnHasMoreChars
End Function

End Class
End Namespace

may your code be error free.
(okay, maybe two lines.)

modified on Thursday, February 7, 2008 5:20 PM

Re: printing strings

Smithers-Jones13-Feb-08 9:36

Smithers-Jones

13-Feb-08 9:36

sorry that i come back with an answer that late. have been off for the last days.

thanks for the string generator code (and special thanks for converting it to vb.net - i just wanted to start to do it myself, when i spotted your message modification).
i integrated it to my printing routine, and it worked great. only very little modifications where necessary to make it suit to my needs.
thanks a lot.

"I love deadlines. I like the whooshing sound they make as they fly by." (DNA)

Re: printing strings

Richard Blythe13-Feb-08 12:05

Richard Blythe

13-Feb-08 12:05

Glad to help. Maybe one day you'll pull me out of a fix!

If you could rent a programmer a hour and a half for a dollar and a half, how much would he charge for 10 hours?

Encrypting files

duo!@#6-Feb-08 4:05

duo!@#

6-Feb-08 4:05

I want to know how to get the files byte codes encrypt them and also able to decrypt

I intent to use a simple encryption algo the XOR operation

But i dun even know how to do it where do i store the files values to and how do i make sure the file gets encrypted.