DrawLine in a PictureBox

[Jon Cosby]

I'm using this to draw rectangles in a PictureBox image. Not all of the
rectangles are complete, and after drawing several, some of them start
disapearing. What's the reason for this?
Pen selPen = new Pen(Color.White );
Graphics graphic = this.PicBox.Cre ateGraphics();

............... ...
Point coord1 = new Point(x0, y0);
Point coord2 = new Point(x0, y);
Point coord3 = new Point(x, y0);
Point coord4 = new Point(x, y);

graphic.DrawLin e(selPen, coord1, coord2);
graphic.DrawLin e(selPen, coord1, coord3);
graphic.DrawLin e(selPen, coord2, coord4);
graphic.DrawLin e(selPen, coord3, coord4);

[Paul E Collins]

"Jon Cosby" <jc****@nospam. net> wrote:

I'm using this to draw rectangles in a PictureBox
image. Not all of the rectangles are complete, and
after drawing several, some of them start
disapearing. What's the reason for this?

Unless you draw your graphics in response to a Paint event, they won't be
updated with the rest of the form. You can see this effect by dragging
another window over your window. Try something like this instead:

private void MyPictureBox_Pa int(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;

using Pen selPen = new Pen(Color.White )
{
// do your drawing here
}
}

PictureBox is not necessarily the best control to use, as this page
explains:
http://www.bobpowell.net/picturebox.htm

P.

[Krzemo]

Bitmap bitmap = new Bitmap(100, 100);
Graphics graphic = Graphics.FromIm age(bitmap);

......

Bitmap bitmap = new Bitmap(pb.Size. Width,pb.Size.H eight );

pb.Image=bitmap ;

or :

class MyPictureBox:Pi ctureBox

{

protected override void OnPaint(PaintEv entArgs e)

{

Graphics graphic = e.Graphics;

......

}

}

Regards,

Krzemo.

U¿ytkownik "Jon Cosby" <jc****@nospam. net> napisa³ w wiadomo¶ci
news:Zv******** *********@newsr ead1.news.pas.e arthlink.net...

I'm using this to draw rectangles in a PictureBox image. Not all of the
rectangles are complete, and after drawing several, some of them start
disapearing. What's the reason for this?
Pen selPen = new Pen(Color.White );
Graphics graphic = this.PicBox.Cre ateGraphics();

............... ...
Point coord1 = new Point(x0, y0);
Point coord2 = new Point(x0, y);
Point coord3 = new Point(x, y0);
Point coord4 = new Point(x, y);

graphic.DrawLin e(selPen, coord1, coord2);
graphic.DrawLin e(selPen, coord1, coord3);
graphic.DrawLin e(selPen, coord2, coord4);
graphic.DrawLin e(selPen, coord3, coord4);

[Jon Cosby]

This works for Windows bitmaps and jpeg, but it doesn't like the formatting
of gif files. Is there a way to reset this?
imgFile = this.GetImageDi alog.FileName.T oString();
MyBitmap = new Bitmap(imgFile) ;

graphic = Graphics.FromIm age(MyBitmap); // A Graphics object cannot be
created from
//
an image that has an indexed pixel format.
"Krzemo" <pk****@ka.onet .pl> wrote in message
news:c6******** **@news.onet.pl ...

Bitmap bitmap = new Bitmap(100, 100);
Graphics graphic = Graphics.FromIm age(bitmap);

.....

Bitmap bitmap = new Bitmap(pb.Size. Width,pb.Size.H eight );

pb.Image=bitmap ;

or :

class MyPictureBox:Pi ctureBox

{

protected override void OnPaint(PaintEv entArgs e)

{

Graphics graphic = e.Graphics;

.....

}

}

Regards,

Krzemo.

U¿ytkownik "Jon Cosby" <jc****@nospam. net> napisa³ w wiadomo¶ci
news:Zv******** *********@newsr ead1.news.pas.e arthlink.net...

I'm using this to draw rectangles in a PictureBox image. Not all of the
rectangles are complete, and after drawing several, some of them start
disapearing. What's the reason for this?
Pen selPen = new Pen(Color.White );
Graphics graphic = this.PicBox.Cre ateGraphics();

............... ...
Point coord1 = new Point(x0, y0);
Point coord2 = new Point(x0, y);
Point coord3 = new Point(x, y0);
Point coord4 = new Point(x, y);

graphic.DrawLin e(selPen, coord1, coord2);
graphic.DrawLin e(selPen, coord1, coord3);
graphic.DrawLin e(selPen, coord2, coord4);
graphic.DrawLin e(selPen, coord3, coord4);

[Krzemo]

Maybe something like this:

Bitmap bitmap = new Bitmap(pb.Size. Width,pb.Size.H eight );
MyBitmap = new Bitmap(imgFile) ;
graphic = Graphics.FromIm age(bitmap);
graphic.DrawIma geUnscaled(MyBi tmap ,0,0,pb.Size.Wi dth,pb.Size.Hei ght ) ;
//draw gif image on bitmap
pb.Image=bitmap ;
Regards,
Krzemo.

U¿ytkownik "Jon Cosby" <jc****@nospam. net> napisa³ w wiadomo¶ci
news:bB******** *********@newsr ead1.news.pas.e arthlink.net...

This works for Windows bitmaps and jpeg, but it doesn't like the formatting of gif files. Is there a way to reset this?
imgFile = this.GetImageDi alog.FileName.T oString();
MyBitmap = new Bitmap(imgFile) ;

graphic = Graphics.FromIm age(MyBitmap); // A Graphics object cannot be created from
//
an image that has an indexed pixel format.
"Krzemo" <pk****@ka.onet .pl> wrote in message
news:c6******** **@news.onet.pl ...

Bitmap bitmap = new Bitmap(100, 100);
Graphics graphic = Graphics.FromIm age(bitmap);

.....

Bitmap bitmap = new Bitmap(pb.Size. Width,pb.Size.H eight );

pb.Image=bitmap ;

or :

class MyPictureBox:Pi ctureBox

{

protected override void OnPaint(PaintEv entArgs e)

{

Graphics graphic = e.Graphics;

.....

}

}

Regards,

Krzemo.

U¿ytkownik "Jon Cosby" <jc****@nospam. net> napisa³ w wiadomo¶ci
news:Zv******** *********@newsr ead1.news.pas.e arthlink.net...

I'm using this to draw rectangles in a PictureBox image. Not all of the rectangles are complete, and after drawing several, some of them start
disapearing. What's the reason for this?
Pen selPen = new Pen(Color.White );
Graphics graphic = this.PicBox.Cre ateGraphics();

............... ...
Point coord1 = new Point(x0, y0);
Point coord2 = new Point(x0, y);
Point coord3 = new Point(x, y0);
Point coord4 = new Point(x, y);

graphic.DrawLin e(selPen, coord1, coord2);
graphic.DrawLin e(selPen, coord1, coord3);
graphic.DrawLin e(selPen, coord2, coord4);
graphic.DrawLin e(selPen, coord3, coord4);