Re: paint program using canvas

From:
Andy Cho <dogmeat37@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 16 Aug 2009 05:39:11 -0700 (PDT)
Message-ID:
<f6e6d0a0-20c9-4d45-8d49-9baafa4628f4@v20g2000yqm.googlegroups.com>
On 8=EC=9B=9416=EC=9D=BC, =EC=98=A4=ED=9B=848=EC=8B=9C19=EB=B6=84, "John B.=
 Matthews" <nos...@nospam.invalid> wrote:

In article
<1450ddd2-3e2d-4f64-bde1-6a3105a28...@v36g2000yqv.googlegroups.com>,
  Andy Cho <dogmea...@gmail.com> wrote:

I'm developing small paint program using canvas class. But I don't
know how retain lines which I draw. All lines are disapeared when
another window is on top of my paint window.


Suppose each line has these attributes:

      class Line {

            Point p1; Point p2; float width;

            public Line(Point p1, Point p2, float width) =

{

                  this.p1 = p1;
                  this.p2 = p2;
                  this.width = width;
            }
      }

Create a suitable collection of Lines:

      List<Line> lines = new ArrayList<Line>();

Each time the user creates a line, add it to the list:

      lines.add(new Line(...));

Finally loop through all the lines in your paint() method, drawing each
one:

      for (Line line : lines) { ... }

And how can I control the thickness of lines.


See Knute Johnson's example, nearby.

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>


Thanks John
I've wrote my own LineData class including coordinates, thickness and
color.
Regards

Andy

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