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Programming => Graphics and Multimedia => Graphics => Topic started by: cov on June 07, 2013, 11:21:18 am

Title: Newline in canvas.Textout
Post by: cov on June 07, 2013, 11:21:18 am

Hi,

I have a string 'A long sentence which is split'+#13+#10+'over multiple lines'.

I'm using Canvas.Textout to write it to the Canvas.

Is there a way of doing this neatly?

Or must I split it into a TStringList and TextOut each entry?

Title: Re: Newline in canvas.Textout
Post by: Zoran on June 07, 2013, 11:42:26 am

Canvas has TextOut and TextRect methods which does the same - write text to canvas, but TextRect seems to be more adjustible.
Instead of Canvas.TextOut, use Canvas.TextRect, but first adjust Canvas.TextStyle as in the following example:

Code: [Select]

procedure TForm1.FormPaint(Sender: TObject);
var
  TextStyle: TTextStyle;
begin
  TextStyle := Canvas.TextStyle;
  TextStyle.SingleLine := False;
  TextStyle.Wordbreak := True;
  TextStyle.Opaque := False;
  Canvas.TextStyle := TextStyle;
  Canvas.TextOut(5, 5, 'trt' + LineEnding + 'mrt'); // line breaking does not work
  Canvas.TextRect(Self.ClientRect, 45, 45, 'trt' + LineEnding + 'mrt'); // line breaking works!
end; 


Title: Re: Newline in canvas.Textout
Post by: exdatis on June 07, 2013, 12:10:43 pm

Thank you very much Zoran.

Title: Re: Newline in canvas.Textout
Post by: cov on June 07, 2013, 12:41:56 pm

Yes, indeed, thanks, Zoran.

A question, though: TextRect requires 4 arguments: a TRect, an X position, a Y position and the string.

How do you define the TRect?

if TextExtent:=Image1.Canvas.TextExtent('A long sentence which is split'+#13+#10+'over multiple lines');

I would have thought that giving Rect(0,0,TextExtent.cx,TextExtent.cy) would have been okay.

But it seems that the following is needed:

Image1.Canvas.TextRect(Rect(x,y,TextExtent.cx+x,TextExtent.cy+y),x,y,'A long sentence which is split'+#13+#10+'over multiple lines');

Is this correct?

Title: Re: Newline in canvas.Textout
Post by: Zoran on June 07, 2013, 02:09:27 pm

Quote from: exdatis on June 07, 2013, 12:10:43 pm

Thank you very much Zoran.

Quote from: cov on June 07, 2013, 12:41:56 pm

Yes, indeed, thanks, Zoran.

You are welcome :)

Quote from: cov on June 07, 2013, 12:41:56 pm

A question, though: TextRect requires 4 arguments: a TRect, an X position, a Y position and the string.

How do you define the TRect?

if TextExtent:=Image1.Canvas.TextExtent('A long sentence which is split'+#13+#10+'over multiple lines');

I would have thought that giving Rect(0,0,TextExtent.cx,TextExtent.cy) would have been okay.

But it seems that the following is needed:

Image1.Canvas.TextRect(Rect(x,y,TextExtent.cx+x,TextExtent.cy+y),x,y,'A long sentence which is split'+#13+#10+'over multiple lines');

Is this correct?

It seems to be correct. I know nothing more about it than what I learned by trying. Try for yourself.
When TextStyle.Opaque is set to True, you can see the rectangle.
I suggest you to play with TextStyle values and see what you get. ;)

See here about TextStyle values: http://lazarus-ccr.sourceforge.net/docs/lcl/graphics/ttextstyle.html

Something about TextRect method: http://lazarus-ccr.sourceforge.net/docs/lcl/graphics/tcanvas.textrect.html. You can see there that you can also use TextStyle directly as a TextRect parameter, in longer version of this method (instead of setting the Canvas.TextStyle property).