Re: Zero Width Pen Draws through clipped region...

Where you able to reproduce the problem with the code I posted?

"Bob Powell [MVP]" wrote:

Let me take a look and I'll get back to you.


--
--
Bob Powell [MVP]
Visual C#, System.Drawing

Ramuseco Limited .NET consulting
http://www.ramuseco.com

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"Geoff" <Geoff@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:88B65041-E5ED-40A7-91D5-0009F8EEAC7E@xxxxxxxxxxxxxxxx
Program.cs
----------------------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace ClipBug
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main( )
{
Application.EnableVisualStyles( );
Application.SetCompatibleTextRenderingDefault( false );
Application.Run( new Form1( ) );
}
}
}


"Bob Powell [MVP]" wrote:

Geoff.

Please post a complete file that reproduces your problem.

--
--
Bob Powell [MVP]
Visual C#, System.Drawing

Ramuseco Limited .NET consulting
http://www.ramuseco.com

Find great Windows Forms articles in Windows Forms Tips and Tricks
http://www.bobpowell.net/tipstricks.htm

Answer those GDI+ questions with the GDI+ FAQ
http://www.bobpowell.net/faqmain.htm

All new articles provide code in C# and VB.NET.
Subscribe to the RSS feeds provided and never miss a new article.


"Geoff" <Geoff@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:51D68FBA-558C-4453-A9A5-9DF1DFF3C34B@xxxxxxxxxxxxxxxx
Anyone read my post? Anyone able to reproduce the problem?

"Geoff" wrote:

Here is my setup:
Windows Vista Ultimate
Visual Studio 2005
Intel Core 2 CPU 6600 @ 2.40 GHz
RAM: 2045 MB
.NET 2.0

The problem is:
Using a zero width pen I can draw into areas that are not part of the
clip
region.

Place a panel on a Form and attach to the paint event. In the paint
event
create a rectangle whose right edge is outside the client area of the
panel
BUT whose left, top, and bottom edges are inside the client area.

Exclude the rectangle from the graphics clip region.

I fill large rectangle with a color so that I can see that my clip
region
is
correct and it does clip on the fill.

Draw a line down the panel. A line that intersects the top and bottom
edge
of the rectangle that was excluded from the clip region.

The line has to be vertical, like this:
graphics.DrawLine(pen, 10, 0, 10, 100);

I call this drawing a line down the form, from a small Y value to a
larger Y
value.

If you draw the line up then it is clipped properly.

The line draws right through the clipped area.

IF you make the clip rectangle fit completely inside the client area
of
the
panel the clipping works correctly.

IF you use a pen that is more than one pixel the clipping works
correctly.

IF you draw UP the clipping works correctly.

Is there any attribute of the Graphics object, Pen, Brush, or anything
I
can
set to make this work?

Things that make the clipping work that are not options:
- I can't draw up all of the time, and besides that would work for
lines
but
not for a rectangle. (The problem exists drawing rectangles as well)
- I can't clip the area to the client rectangle before hand.
- I can't call GDI directly, even though I wrote a test for Polyline
and
the
clipping works correctly.
(When I say I can't, read, it would be significant to rewrite all of
the
code to make the changes. For instance, I cache graphics paths to
increase
redraw performance and I would loose all of that)

I attached the code. Notice that if you change the width of the panel
the
clipping behavior changes.

Here is the code:

<FORM>

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace ClipBug
{
public partial class Form1 : Form
{
public Form1( )
{
InitializeComponent( );
}

private void panel1_Paint( object sender, PaintEventArgs e )
{

Graphics graphics = e.Graphics;

Rectangle rectA = new Rectangle( 100, 50, 400, 100 );
//this
rectangle's right side is outside the client
Rectangle rectB = new Rectangle( 100, 175, 300, 100 );

Region r = new Region( );
r.MakeInfinite( );
r.Exclude( rectA );
r.Exclude( rectB );


Region oldClip = graphics.Clip;

graphics.SetClip( r,
System.Drawing.Drawing2D.CombineMode.Intersect );

//fill some large rectangle to see the clipping region at
work.
graphics.FillRectangle( Brushes.LightCoral, 0, 0, 10000,
10000 );


Pen blackPen = new Pen( Brushes.Black, 1.0f );
Pen yellowPen = new Pen( Brushes.Yellow, 1.0f );


int x = 0;
for( int i = 0; i < 500; i++ )
{
//draw a line down...
graphics.DrawLine( blackPen, x - 10, 0, x - 10, 225 );

//draw a line up...
graphics.DrawLine( yellowPen, x, 300, x, 25 );

x += 20;
}

//even rectangles don't clip when drawing "down"
//graphics.DrawRectangle( blackPen, 150, 10, 10, 300 );

blackPen.Dispose( );
yellowPen.Dispose( );

graphics.Clip = oldClip;

}

private void panel1_SizeChanged( object sender, EventArgs e )
{
panel1.Invalidate( true );
}
}
}

<DESIGNER>

namespace ClipBug
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should
be
disposed; otherwise, false.</param>
protected override void Dispose( bool disposing )
{
if( disposing && ( components != null ) )
{
components.Dispose( );
}
base.Dispose( disposing );
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent( )
{
this.panel1 = new System.Windows.Forms.Panel( );
this.SuspendLayout( );
//
// panel1
//
this.panel1.Anchor = (
(System.Windows.Forms.AnchorStyles)(
( (
( System.Windows.Forms.AnchorStyles.Top |
System.Windows.Forms.AnchorStyles.Bottom )
| System.Windows.Forms.AnchorStyles.Left )
|
System.Windows.Forms.AnchorStyles.Right ) ) );
this.panel1.BackColor = System.Drawing.Color.White;
this.panel1.BorderStyle =
System.Windows.Forms.BorderStyle.FixedSingle;
this.panel1.Location = new System.Drawing.Point( 52, 44 );
this.panel1.Name = "panel1";
this.panel1.Size = new System.Drawing.Size( 500, 300 );
this.panel1.TabIndex = 0;
this.panel1.Paint += new
System.Windows.Forms.PaintEventHandler(
this.panel1_Paint );
this.panel1.SizeChanged += new System.EventHandler(
this.panel1_SizeChanged );
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF( 6F,
13F );
this.AutoScaleMode =
System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size( 625, 440 );
.

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