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Mario Sernicola · Guest

Hi,

I'd like to show the lines of a TRichEdit continuosly, from the first until
the last line
by code.

I use

SendMessage(TRichEdit1->Handle, WM_VSCROLL, SB_LINEDOWN, 0);

with a TTimer control with Interval = 650,

but the result is not so pretty.

I'd like a continuosly smoothed scrolling (like About windows of Dreamweaver
MX).

There's a way to do this?

TNX

Mario Sernicola

Atlantee · Guest

You can use this technique, based on a RichEdit control
Owned by a ScrollBox Parent. This is the code:

TScrollBox* ScrollBox1;
TRichEdit* RichEdit1;
const int SCROLL_DISTANCE_Y = 1; //Scroll Speed
const int RICHEDIT_HEIGHT = 1000;
const int SCROLLBOX_HEIGHT = 300;
const int NUMBER_OF_SCROLLS = 100;
//--------------------------------------------------------------------------
-
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
Color = clBlue;

ScrollBox1 = new TScrollBox(this);
ScrollBox1->Parent = this;
ScrollBox1->Top = 10;
ScrollBox1->Left = 10;
ScrollBox1->Width = 225;
ScrollBox1->Height = SCROLLBOX_HEIGHT;
ScrollBox1->VertScrollBar->Visible = false;
ScrollBox1->HorzScrollBar->Visible = false;

RichEdit1 = new TRichEdit(ScrollBox1);
RichEdit1->Parent = ScrollBox1;
RichEdit1->Top = 0;
RichEdit1->Left = 0;
RichEdit1->Width = ScrollBox1->Width-2;
RichEdit1->Height = RICHEDIT_HEIGHT;
RichEdit1->Lines->Clear();
RichEdit1->Color = (TColor)0x00efd345;

for (int i = 0; i < 200; i++)
{
RichEdit1->Text = RichEdit1->Text + "This is a story "
+ IntToStr(i) + ". ";
}

RichEdit1->SelStart = 0; // move text cursor to top of edit
RichEdit1->HideScrollBars = true;
RichEdit1->Font->Name = "Times New Roman";
RichEdit1->Font->Size = 10;
}
//--------------------------------------------------------------------------
-

void __fastcall TForm1::Button2Click(TObject *Sender)
{
int count = 0;

while(count++ < NUMBER_OF_SCROLLS)
{
if (abs(RichEdit1->Top) < RICHEDIT_HEIGHT-SCROLLBOX_HEIGHT)
{
ScrollBox1->ScrollBy(0, -SCROLL_DISTANCE_Y);
ScrollBox1->Refresh();
Sleep(20);
}
else
break;
}
}
//--------------------------------------------------------------------------
-

void __fastcall TForm1::Button3Click(TObject *Sender)
{
int count = 0;

while(count++ < NUMBER_OF_SCROLLS)
{
if (RichEdit1->Top < 0)
{
ScrollBox1->ScrollBy(0, SCROLL_DISTANCE_Y);
ScrollBox1->Refresh();
Sleep(20);
}
else
break;
}
}
//--------------------------------------------------------------------------
-

If you like you could use threads to produce an even smoother scrolling,
specially if
you intend to use big while loops.

Rodolfo

"Mario Sernicola" <mariosernicola.nospam (AT) libero (DOT) nospam.it> wrote

Mario Sernicola · Guest

Thank you Rodolfo,

all runs perfectly, and your solution is very elegant (even if I've to spend
some lines of code :)

I think it's better if I calculate the height of TRichEdit depend on numbers
of lines and font height (of course ;)

Another question:

Can I change at runtime the font of a line or a portion of text in a
TRichEdit? I can do the same thing in Property Editor?

I've written every lines in my TRichEdit by Propery Editor, bt I'd like to
see "Credits", "License" and other text in bold font.

Thank you very much

Timothy H. Buchman · Guest

Mario Sernicola <mariosernicola> wrote

Atlantee · Guest

"Mario Sernicola" <mariosernicola.nospam (AT) libero (DOT) nospam.it> wrote

Atlantee · Guest

Mario Sernicola · Guest

Thank you Rodolfo

I'll download your component at soon as possible!

Thank you very much

Mario Sernicola

Rodolfo Frino - Macrosoft · Guest

Now that I looked again to my component I remembered that it cannot
change a portion of text *in the same line* of RichEdit. It only changes the
font in different lines.

However, having said that, the code I posted before, which I copy here

void __fastcall TForm1::Button4Click(TObject *Sender)
{
RichEditEx1->Lines->Clear();
RichEditEx1->Font->Size = 20;
RichEditEx1->Lines->Add("C++ Builder Version 5.0");

RichEditEx1->SelStart = 0;
RichEditEx1->SelLength = 4;
RichEditEx1->SelAttributes->Color = clRed;
RichEditEx1->SelAttributes->Style =
RichEditEx1->SelAttributes->Style << fsUnderline;
RichEditEx1->SelAttributes->Name = "Times New Roman"; //<==== font1

RichEditEx1->SelStart = 4;
RichEditEx1->SelLength = 10;
RichEditEx1->SelAttributes->Height = 72;
RichEditEx1->SelAttributes->Color = clBlack;
RichEditEx1->SelAttributes->Style =
RichEditEx1->SelAttributes->Style << fsUnderline;
RichEditEx1->SelAttributes->Name = "Arial Black"; //<======= font2

RichEditEx1->SelStart = 11;
RichEditEx1->SelLength = 12;
RichEditEx1->SelAttributes->Color = clYellow;
RichEditEx1->SelAttributes->Style =
RichEditEx1->SelAttributes->Style << fsItalic;
RichEditEx1->SelAttributes->Height = 30;
RichEditEx1->SelAttributes->Name = "MS Sans Serif"; //<===== font3

}

does different fonts *on a single RichEdit line*. One thing you could do
then, if you wish,
is to add a new write method to RichEditEx with the above functionality.

Rodolfo

"Mario Sernicola"

Rodolfo Frino - Macrosoft · Guest

This is the link to the threaded version of RichEdit with Smooth Scroll:

http://www.geocities.com/rodolfofrino/RichEditSmoothScrollWithThreads.html

Rodolfo