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C# PrintPageEventArgs.Graphics.DrawRectangle prints incorrect size

I expected the code below to draw a rectangle 3 inches wide by 1 inch tall. Instead, the actual rectangle on the printed page is 4 inches wide by 2 inches tall.
Every rectangle I attempt to draw is always 1 inch wider and taller than I expect.
What am I doing wrong?
What addition properties in PrintPageEventArgs.Graphics should I be setting to get a correctly sized rectangle on the printed page?
void printDocument_PrintPage(object sender, PrintPageEventArgs e)
{
e.Graphics.PageUnit = GraphicsUnit.Inch;
e.Graphics.DrawRectangle(Pens.LightGray, 1, 1, 3, 1);
}

The code below fixed this issue. I suspect the default pen width is 1, which is interpreted as 1 inch. That made the rectangle extra big. Specifying a pen width of 0 fixed it.
void printDocument_PrintPage(object sender, PrintPageEventArgs e)
{
e.Graphics.PageUnit = GraphicsUnit.Inch;
Pen pen = new Pen(Color.LightGray, 0);
e.Graphics.DrawRectangle(pen, 1, 1, 3, 1);
}

How to zoom picturebox along with graphics

I want to zoom picture box along with graphics.
this will Zoom the only image part not the graphics part.
public Image PictureBoxZoom(Image imgP, Size size)
{
Bitmap bm = new Bitmap(imgP, Convert.ToInt32(imgP.Width * size.Width), Convert.ToInt32(imgP.Height * size.Height));
Graphics grap = Graphics.FromImage(bm);
grap.InterpolationMode = InterpolationMode.HighQualityBicubic;
return bm;
}
private void zoomSlider_Scroll(object sender, EventArgs e)
{
if (zoomSlider.Value > 0 && img != null)
{
pictureBox1.SizeMode = PictureBoxSizeMode.CenterImage;
pictureBox1.Image = null;
pictureBox1.Image = PictureBoxZoom(img, new Size(zoomSlider.Value, zoomSlider.Value));
}
}
the source of image is:
img = Image.FromStream(openFileDialog1.OpenFile());
Picture is zooming but when we draw the rectangle outside image then it's not zooming along with image.
See image:

You can do this (rather) easily by scaling the e.Graphics object in the Paint event.. See here for an example!
So to work with you code you probably should add this to the Paint event:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.ScaleTransform(zoom, zoom);
// now do your drawing..
// here just a demo ellipse and a line..
Rectangle rect = panel1.ClientRectangle;
g.DrawEllipse(Pens.Firebrick, rect);
using (Pen pen = new Pen(Color.DarkBlue, 4f)) g.DrawLine(pen, 22, 22, 88, 88);
}
To calculate the zoom factor you need to do a little calculation.
Usually you would not create a zoomed Image but leave that job to the PictureBox with a SizeMode=Zoom.
Then you could write:
float zoom = 1f * pictureBox1.ClientSize.Width / pictureBox1.Image.Width;
To center the image one usually moves the PictureBox inside a Panel. And to allow scrolling one sets the Panel to Autocroll=true;
But since you are creating a zoomed Image you should keep track of the current zoom by some other means.
Note:
But as you use PictureBoxSizeMode.CenterImage maybe your problem is not with the zooming after all?? If your issue really is the placement, not the size of the drawn graphics you need to do a e.Graphics.TranslateTransform to move it to the right spot..

Winforms C# Gradient Opacity bitmap

I want to make a bitmap that has a linear opacity applied. (i.e. it is more opaque on the left side and get progressively less opaque as it approaches the right.)
Is this possible? I know its possible to have a constant opacity level.

I know its possible to have a constant opacity level
So don't make it constant, LinearGradientBrush has no trouble interpolating the alpha value. A simple demonstration of a form that has the BackgroundImage set:
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
var rc = new Rectangle(20, 20, this.ClientSize.Width - 40, 50);
using (var brush = new System.Drawing.Drawing2D.LinearGradientBrush(
rc,
Color.FromArgb(255, Color.BlueViolet),
Color.FromArgb(0, Color.BlueViolet),
0f)) {
e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
e.Graphics.FillRectangle(brush, rc);
}
}
Produced:

Put the BitMap into a PictureBox control. Then you will have to use the PictureBox's Paint event handler to do the fading. Something like
private void pictureBox_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(pictureBox.Image, 0, 0,
pictureBox.ClientRectangle, GraphicsUnit.Pixel);
Color left = Color.FromArgb(128, Color.Blue);
Color right = Color.FromArgb(128, Color.Red);
LinearGradientMode direction = LinearGradientMode.Horizontal;
LinearGradientBrush brush = new LinearGradientBrush(
pictureBox.ClientRectangle, left, right, direction);
e.Graphics.FillRectangle(brush, pictureBox.ClientRectangle);
}
This example fades the image overlay from blue to red. I am sure you can play with this to get what you want working.
I hope this helps.

C# draw with Alpha channel

I have a panel on which I draw a radius frame with shadow. But I have a simple frame and a single color. How can I make her to be with smooth tints?
I think you need to use RGB and Alpha channel.
Color BorderColor = Color.FromArgb(((int)(((byte)(161)))), ((int)(((byte)(164)))), ((int)(((byte)(169)))));
private void AfyTextBox_Paint(object sender, PaintEventArgs e)
{
DrawShadow(e);
GraphicsPath path = RoundedRectangle.Create(0, 0, this.Width - 5, this.Height - 5, 3);
e.Graphics.DrawPath(new Pen(BorderColor), path);
}

How can I use the Pen tool to draw a simple black line on a PictureBox's Image object?

I'm trying to draw a line that goes from middle top to bottom.
I know I have to use the Pen class to accomplish this.
private void RepaintPreview()
{
Pen blackPen = new Pen(Brushes.Black);
blackPen.Width = 1.0f;
blackPen.LineJoin = System.Drawing.Drawing2D.LineJoin.Bevel;
ptbTablePreview.Image.draw?
}
Basically, how can I draw this line on the image? Thank you.

I tried the following, and it works with me:
1- I set the image of the picturebox in design time
2- I handled the Paint event of the picturebox, and added the following code:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
using (Pen p = new Pen(Color.Black, 2))
{
e.Graphics.DrawLine(p, new Point(pictureBox1.Width / 2, 0), new Point(pictureBox1.Width / 2, pictureBox1.Height));
}
}