HTML Highlighting

[Tom_H]

I am currently working on a HTML Editor, and use a module to highlight the HTML code. This highlights the tags, attibute values, comments, etc in different colours, and works fine. The only problem is that it is VERY SLOW! With large files it can take up to 10 seconds to highlight, which is way to slow.

As I'm quite new to VB, I'd appreciate it if you could help me with my problem by showing me code (or telling me where I can find it) which I could use. I don't really want to use any OCX files or anything like that. I would also like to make make comments italic, head/body/html tags bold etc.

Please help,

Tom

[Static]

well I discovered this...
at least for the visual effect

I used 2 RichTextBoxes...1 hidden

when Coloring was to occur (like when ENTER was pressed)
It would copy text to the second window...do the color then give it back to the first...then it just flashes

also look into getting the current line that is being typed on.
so all you should try to color is the current line

Download the code to my VBBrowser (link below) the code is a little hard to follow but what you need is in there...

the code window in the browser will color each line after enter is hit. it is about 90-90% accurate
a few bugs to work out still but...hey... no time

[Matthew Gates]

Use this code, seems fast enough. Good for an HTML Editor.

'Author: Megatron
'Origin: http://www.vbforums.com
'Purpose: Highlight Text in RichTextBox Automatically
'Version: VB5+ 




Option Explicit
Const vbDarkBlue = &H800000

Private Sub HighlightText(sKeyword As String, iColour As Long)
    Dim nStart As Integer
    Dim sPrevChar As String
    Dim sNextChar As String
                                            
    nStart = InStr(1, LCase(RichTextBox1.Text), sKeyword)
                                                                             
    Do While nStart <> 0
        If nStart > 1 Then
            sPrevChar = Mid$(RichTextBox1.Text, nStart - 1, 1)
        Else
            sPrevChar = " "
        End If
                                                    
        If Len(RichTextBox1.Text) >= nStart + Len(sKeyword) Then
            sNextChar = Mid$(RichTextBox1.Text, nStart + Len(sKeyword), 1)
        Else
            sNextChar = " "
        End If
                                                           
        If (sPrevChar = Chr(32) Or sPrevChar = Chr(13) Or _
        sPrevChar = Chr(10) Or sPrevChar = Chr(9)) And _
        (sNextChar = Chr(32) Or sNextChar = Chr(13) Or _
        sNextChar = Chr(10) Or sNextChar = Chr(9)) Then
        
        With RichTextBox1
            .SelStart = nStart - 1
            .SelLength = Len(sKeyword)
            .SelColor = iColour
            .SelText = StrConv(sKeyword, vbProperCase)
            .SelStart = Len(RichTextBox1.Text)
            .SelColor = vbBlack
        End With
    
        End If
                                                  
        nStart = InStr(nStart + Len(sKeyword), LCase(RichTextBox1.Text), sKeyword)
    Loop
End Sub



Private Sub Form_Resize()
    RichTextBox1.Move 0, 0, ScaleWidth, ScaleHeight
End Sub

Private Sub RichTextBox1_Change()
    With RichTextBox1
        .SelStart = 0
        .SelLength = Len(.Text)
        .SelColor = vbBlack
        .SelStart = Len(.Text)
    End With
    
                           
    ' Add more custom words here
    HighlightText "if", vbDarkBlue
    HighlightText "then", vbDarkBlue
    HighlightText "else", vbDarkBlue
    HighlightText "for", vbDarkBlue
    HighlightText "next", vbDarkBlue
    HighlightText "do", vbDarkBlue
    HighlightText "while", vbDarkBlue
    HighlightText "until", vbDarkBlue
    HighlightText "loop", vbDarkBlue
End Sub

[Peder]

Maby the code is fast, but you have to write all the tags yourself, it had been much smarter if the code detect the < and > itself. Besides: The code doesn't highlight comment and values. I've never seen a good Highlighter to VB, they are all slow. It's weird that VB doesn't have it, because Delphi have plenty (and they are all VERY good).

---------------
Peder

[Peder]

Maby the code is fast, but you have to write all the tags yourself, it had been much smarter if the code detect the < and > itself. Besides: The code doesn't highlight comment and values. I've never seen a good Highlighter to VB, they are all slow. It's weird that VB doesn't have it, because Delphi have plenty (and they are all VERY good).

---------------
Peder

[Tom_H]

I need it to be:

- fast
- highlight tags, as well as their values
- highlight comments, css etc
- make certain tags/comments italic or bold
- update when the user hits return (or up or down keys)
- no OCX's, DDL's etc

Well the one I am currently using does most of the above, but is way too slow, and can take up to 10 secs to update when the user hits return (if working with large files).

Anyone have a solution?

Tom

[Tygur]

I have writen some comparatively fast code in VB to highlight files. It takes 0.2 seconds to colorize (Is there a better word?) a 9K file (still too slow by my standards). I've attached an EXE that uses the code so you can test out its speed. You can use it to load a file, and it also colorizes as you type.

Because so much trouble went into making the code, I'd rather not post it, but I will tell you what I did. It'll be very obvious why it was so much trouble.

Basically, I looked at the RTF specification and wrote code to change the TextRTF property of the richtextbox so the html code can be colorized. This is much faster, but not nearly as easy.

Is it fast enough for you guys? If so, I may make an OCX..

[Tygur]

Oh, I didn't see your message for no OCX..
If you want to try doing it yourself, I'll happily answer any questions you may have.. (Also, I'm considering changing my mind about the code, but I'm not sure)

[Tom_H]

ok, thanks, I'll take a look at it later.

I may decide to turn to an ocx if i can't get a suitable solution as code, and as i am quite a beginner to vb (i've only been using it for about 1 or 2 months now), I may take you up on your offer for the ocx, as the method you suggested (looking at the RTF text spec) would probably be a bit too complex for me!

Does it support cascading style sheet highlighting as well? And can you, for example, make all comment tags italic using it?

Tom

[Tom_H]

after looking at the exe you sent, i think that the one i am currently using is faster then your one...

how can i write a bit of code to tell me how long my highlighter is taking to highlight in a MsgBox (like yours does in the title)? Then I can compare the two.

if you want to c the code that i am currently using then just email me (it is too long to post here).

Cheers,

Tom

[Tygur]

This is the way I did it in my sample:

Dim sngStart As Single, sngEnd As Single
sngStart = Timer
'Do the stuff you want to time here
sngEnd = Timer
Me.Caption = "Time Taken: " & Round(sngEnd - sngStart, 3) & " Seconds"

[Tom_H]

I don't suppose anybody could tell me how I can highlight (or select) the line above the current line in a rich text box when the user presses return (if that makes sense!).

Tom

[Dim A]

This might help. This code will tell you the current cursor position after a user presses the return key.

Private Sub Text1_KeyPress(KeyAscii As Integer)

If KeyAscii = vbKeyReturn Then
    Debug.Print Text1.SelStart
End If

End Sub

It should then just be a matter of counting back from this position to the last carriage return.

- Dim A

[Dim A]

You might like this code block better. I think there's some issue with vbcr/vblinefeed/vbnewline so you might want to look into that.

Private Sub Text1_KeyPress(KeyAscii As Integer)
Dim x As Long
Dim y As Long
Dim found As Boolean
Dim LastLine As String

If KeyAscii = vbKeyReturn Then
    x = Text1.SelStart
    y = x
    
    While y > 1 And found = False
        y = y - 1
        If Mid$(Text1.Text, y, 1) = vbCr Then
            found = True
        End If
    Wend

    If y = 0 Then y = 1

    LastLine = Mid$(Text1.Text, y, x - y + 1)
    Debug.Print LastLine
End If
End Sub

Anyways... y is the position of the CR just before the last line, x is the position after the last CR, and of course LastLine is the last line of text.

Hope this helps, I didn't get a chance to polish it up.

- Dim A

[Tom_H]

Thanks Dim A.

Tyger, i sent u an email but it came back with "FAILURE NOTICE" !? is your email account working? i will try it again, and i'll send it to you using both of the addresses you gave me.

Tom

[Tom_H]

If anyone want to see the HTML editor, and also a CSS editor (which I only made today!), the EXE's can be downloaded from the links below. These files do not include any runtime files or OCX's (Rich Text Box, Windows Common Controls 6 SP-3, and Common Dialog).

HTML Editor
CSS Editor

Tom

[Tom_H]

If anybody has any suggestions for either of these two editors, please e-mail them to me, or just post them here.

Cheers,

Tom

[Tom_H]

Ok guys, keep the suggestions coming...

I have also updated the two files very slightly.

HTML Editor (144kb)
CSS Editor (18kb)

These files contain no run-time files or OCX's.

If anyone wants to see the code that I am using to highlight the html code, send me an e-mail.

Tom

[weikiat]

I suggest you use 2 different level of coding
As in as the user types, you use seltext to go back and forward the letter the user types in and determine what colour to use. Then another level is using the slower colouring code that is much slower but for colouring a whole bunch of text at a go.
If you don't get what i mean, try my Developer suite with autocomplete and color coding html editor from www.twk.2ya.com

What i need now, is a even faster code to color the text.

[weikiat]

Notice that in my program, when you paste some html codes inside, the code will be automatically coloured before insertion.