drawing a single point

[MC D]

Ok, dumb question, but how do you draw a single point in gdi? I thought you
could use the .DrawLine method and just specify the same start and end
point, but that does nothing. In otherwords, if I have:

g.DrawLine(myPe n,x,y,x,y)

nothing happens. I can have:

g.DrawLine(myPe n,x,y,x+1,y+1)

and I can see what I am wanting, but obviously it's kinda' wierd-ish. So
how do you draw an individual point? (DrawElipse has the same problem).

Thanks,

D
``````````````` ``````````````` ``

[Steve DuMosch [MSFT]]

yes, there is no DrawPoint function. The best way is to use DrawRectangle
like you have it with 1 pixel width. You may find more information here:
http://www.dotnetforums.net/t75324.html

[Fergus Cooney]

Hi D, Hi,

As you've found, DrawLine (oPenSesame, X, Y, X, Y) gives you nothing.

This is by design - and I'd like to know by who, come on own up!! I first
came across it in VB3 when doing owner-drawn controls and it makes a right
mess of the code when you want to be pixel-perfect. A line is always drawn
just short of the specified endpoint so, to get your line, you have to extend
the co-ordinates. Bad news when doing diagonals! I think I read somewhere once
that it's something to do with making it easy to draw sequences of lines? I
wish they'd left it 'harder' for us.

Regards,
Fergus

[Herfried K. Wagner [MVP]]

"MC D" <as***@earthtal k.com> scripsit:

Ok, dumb question, but how do you draw a single point in gdi? I thought you
could use the .DrawLine method and just specify the same start and end
point, but that does nothing. In otherwords, if I have:

g.DrawLine(myPe n,x,y,x,y)

nothing happens. I can have:

g.DrawLine(myPe n,x,y,x+1,y+1)

and I can see what I am wanting, but obviously it's kinda' wierd-ish. So
how do you draw an individual point? (DrawElipse has the same problem).

\\\
Private Sub Form1_Paint( _
ByVal sender As Object, _
ByVal e As System.Windows. Forms.PaintEven tArgs _
) Handles MyBase.Paint
e.Graphics.Fill Rectangle( _
Brushes.Red, _
New Rectangle(100, 100, 1, 1) _
)
End Sub
///

--
Herfried K. Wagner
MVP · VB Classic, VB.NET
<http://www.mvps.org/dotnet>

[José Manuel Agüero]

Hello, Fergus:

You have information about how lines and polygons are drawn in the DirectX documentation: http://msdn.microsoft.com/library/de...asp?frame=true

I hope its instructive.

Regards.
"Fergus Cooney" <fi******@tesco .net> escribió en el mensaje news:uf******** ******@TK2MSFTN GP12.phx.gbl...
| Hi D, Hi,
|
| As you've found, DrawLine (oPenSesame, X, Y, X, Y) gives you nothing.
|
| This is by design - and I'd like to know by who, come on own up!! I first
| came across it in VB3 when doing owner-drawn controls and it makes a right
| mess of the code when you want to be pixel-perfect. A line is always drawn
| just short of the specified endpoint so, to get your line, you have to extend
| the co-ordinates. Bad news when doing diagonals! I think I read somewhere once
| that it's something to do with making it easy to draw sequences of lines? I
| wish they'd left it 'harder' for us.
|
| Regards,
| Fergus
|
|

[José Manuel Agüero]

Hello, Herfried:

I don't know how GDI+ is internally optimized but, don't you think DrawLine consumes less process time than FillRectangle for the same purpose? Ok, I know that for a single dot it's not important, but it could be for a large number of dots.

Does anybody know why doesn't exist a DrawPoint function? Or a DrawMarker?

Regards.
"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> escribió en el mensaje news:ON******** ******@TK2MSFTN GP09.phx.gbl...
| "MC D" <as***@earthtal k.com> scripsit:
| > Ok, dumb question, but how do you draw a single point in gdi? I thought you
| > could use the .DrawLine method and just specify the same start and end
| > point, but that does nothing. In otherwords, if I have:
| >
| > g.DrawLine(myPe n,x,y,x,y)
| >
| > nothing happens. I can have:
| >
| > g.DrawLine(myPe n,x,y,x+1,y+1)
| >
| > and I can see what I am wanting, but obviously it's kinda' wierd-ish. So
| > how do you draw an individual point? (DrawElipse has the same problem).
|
| \\\
| Private Sub Form1_Paint( _
| ByVal sender As Object, _
| ByVal e As System.Windows. Forms.PaintEven tArgs _
| ) Handles MyBase.Paint
| e.Graphics.Fill Rectangle( _
| Brushes.Red, _
| New Rectangle(100, 100, 1, 1) _
| )
| End Sub
| ///
|
| --
| Herfried K. Wagner
| MVP · VB Classic, VB.NET
| <http://www.mvps.org/dotnet>

[Herfried K. Wagner [MVP]]

José Manuel Agüero <jmaguero, cliente de vodafone (es)> scripsit:

I don't know how GDI+ is internally optimized but, don't you think DrawLine consumes less process time than FillRectangle for the same purpose? Ok, I know that for a single dot it's not important, but it could be for a large number of dots.

I remember DrawLine placed the point on the wrong position or it didn't
draw it at all...

--
Herfried K. Wagner
MVP · VB Classic, VB.NET
<http://www.mvps.org/dotnet>

[José Manuel Agüero]

Hello, Herfried:

You are right... partially. In fact the last point of a line is never displayed. I haven't been able to find complete information, only a sample graphic in http://msdn.microsoft.com/library/de...asp?frame=true that doesn't contain an explanation. You can see in the line sample that the last pixel is not displayed.
So, to draw a pixel at (10, 20) you should use, for example, drawline(pen,10 ,20,11,20). That is, ending one pixel to the right (or up or left or down, it's the same)

Regards.
"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> escribió en el mensaje news:%2******** ********@TK2MSF TNGP11.phx.gbl. ..
| José Manuel Agüero <jmaguero, cliente de vodafone (es)> scripsit:
| > I don't know how GDI+ is internally optimized but, don't you think DrawLine consumes less process time than FillRectangle for the same purpose? Ok, I know that for a single dot it's not important, but it could be for a large number of dots.
|
| I remember DrawLine placed the point on the wrong position or it didn't
| draw it at all...
|
| --
| Herfried K. Wagner
| MVP · VB Classic, VB.NET
| <http://www.mvps.org/dotnet>

[Fergus Cooney]

Hi Jose,

Thanks for the link 0 it was interesting. Makes you wonder when even such
small things as a two pixel lines is considered as a triangle!!

Regards,
Fergus