We Keep Coding

C# Zoomed image in Picturebox gets cropped in top left

I want to make very simplistic paint/image editor. Mainly, for pixel editing, but that doesn't seem relevant.
To ease up my effort, I decided to keep the image size at 16x16.
I populate the form, add a PixelBox and slap a default image on it.
Of course, I need to make the pixels visible, set the interpolation to NearestNeighbor.
Then, I stretch the pixelbox to 320x320. And there the situation arises.
The image is displayed as thus:
Cropped image
Could someone shed some light on this? This is just a 16x16 image with a checkerboard pattern that I made, but I can't figure out why it is displayed with that offset at the top left.
Also, no code as been yet added. I assume this is default behavior?

If you look at the examples on the page that exact same error happens, so it must be a bug on the PixelBox.
Instead of using a custom control for this type of operation just use the standard PictureBox and scale the image by yourself:
public Bitmap ScaleBitmap(Bitmap src, Size NewSize)
{
Bitmap bmp = new Bitmap(NewSize.Width, NewSize.Height, src.PixelFormat);
Graphics g = Graphics.FromImage(src);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
g.DrawImage(src, new Rectangle(Point.Empty, NewSize), new Rectangle(0, 0, src.Width, src.Height), GraphicsUnit.Pixel);
g.Dispose();
return bmp;
}

Convert PictureBox image to bitmap

I am working with a fingerprint module and am able to capture and display the output in a picture box (C#). Now picture.Image is null even though picturebox displays an image. So I am trying to save the picturebox image as bmp and then assign that bmp to the same picturebox so that Picturebox.image is not null.
Here is the code :
Bitmap bmp = new Bitmap(picFP.width, picFP.height);
picFP.DrawToBitmap(bmp, picFP.ClientRectangle);
bmp.Save("path", Imageformat.bmp);
picFP.image = bmp;
Here bitmap image saved is blank. What can be the problem?

A PictureBox has three layers it can display and PictureBox.DrawToBitmap will put all three things into the Bitmap:
The BackgroundImage
The Image
Any graphics created in or from the Paint event
If your bitmap comes out black then you have none of the three, or the last you have is all black.
From your description it seems as if you can display the image in the PictureBox.
So I assume that you don't display it in the right way, probably you do it like this:
using (Graphics G = picFP.CreateGraphics())
G.DrawImage(yourCapturedImage, ..)
This will not work as it only creates non-persistent graphics. These go away with e.g. each minimize-restore cycle and are not called from the DrawToBitmap call
If you really want to draw it onto the PB's surface use the Paint event! But the more natural choice would be to set the PB's Image directly:
picFP.Image = yourCapturedImage;
Update 1 As you now reveal that you don't display it yourself but simply give the control handle to the external code objNitgen=picFP.Handle; the same applies: It is that Nitgen draws only onto the surface and the result is non-persistent.
In this case the remedy is either
Taking a screenshot of the result and then work from that. Here is a post that shows you how to capture a control via screenshot..
Or you may want to check if Nitgen will draw into a bitmap directly..
For this you should be to pass it not a handle to the PictureBox but to a Bitmap instead:
private void button_Click(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap(picFP.ClientSize.Width, picFP.ClientSize.Height);
Graphics G = Graphics.FromImage(bmp);
IntPtr dc= G.GetHdc();
objNitgen = dc;
objNitgen.capture();
G.ReleaseHdc(dc);
pictureBox1.Image = bmp; // now display..
bmp.Save(yourfilename); // .. and/or save
}
Update 2
You noted in a comment that doing a manual screenshot also does not capture the image; so it seems the control handle is only used to overlay it with the image much like video overlays do; if this is the case I doubt you can get at the image without using other, more fitting Nitgen SDK methods.

Get selected portion of image in picturebox in another picturebox

I have a picturebox with image, in which I have drawn a rectangular selection. I want to get the selected portion of image in another picturebox. How can I get that? Please help.

Suppose the rect is the Rectangle which you passed in the Graphics.DrawRectangle is calculated in your the coordinates of your pictureBox. You can use RectangleToScreen and RectangleToClient to get that portion in another pictureBox like this:
Rectangle portion = pictureBox2.RectagleToClient(pictureBox1.RectangleToScreen(rect));
//portion is the Rectangle calculated in the coordinates of pictureBox2.

Use coordinates of the selection to create Rectangle rectangle then:
Bitmap sourceBitmap = new Bitmap(pictureBoxImage);
Bitmap croppedBitmap = sourceBitmap.Clone(rectangle, sourceBitmap.PixelFormat);
after that you may use croppedBitmap in another picturebox. Don't forget to dispose unused images. That's all.

Paste the contents of a Bitmap into a PictureBox

I'm currently writing a little paint application where the user is able to draw on a Panel. I am working on the select tool and want to be able to select a certain area of the Panel, and then paste this selected area directly into a PictureBox that I have just to the right of the Panel.
My problem is that my code at the moment is not working correctly, when I try to paste the Bitmap that I am creating from the panel I am getting a big red X in the PictureBox instead of the actual image. I know that the image is copying to the Bitmap correctly because I tried putting some code around it to save it to disk as a jpeg and then look at the image, and it is all displaying fine.
Here is my code:
private void tbCopy_Click(object sender, EventArgs e)
{
int width = selectList[0].getEnd().X - selectList[0].getInitial().X;
int height = selectList[0].getEnd().Y - selectList[0].getInitial().Y;
using (Bitmap bmp = new Bitmap(width, height))
{
pnlDraw.DrawToBitmap(bmp, new System.Drawing.Rectangle(
selectList[0].getInitial().X,
selectList[0].getInitial().Y,
width, height));
pbPasteBox.Image = bmp;
}
}
the width and height are just the dimensions of the area that I want to copy, and selectList is a List that contains one object which contains the coordinates of the area I want to copy.
Any help would be greatly appreciated.

Your problem is the using(){} when the code inside the using braces has completed the object inside the () is disposed of as it is deemed no longer needed.
Simply removing the brace to just have Bitmap bmp = new Bitmap(width, height) should solve your problem

C# Remove drawing from PictureBox

I have a PictureBox pic , and an Image img, pic.Image = img
and I draw some rectangles on the Image using
Graphics g = Grpahics.FromImage(pic.Image);
g.DrawRectangle(...);
But at one point, I want to remove the rectangle from the Image,I tried
pic.Image = getOriginalImage();
pic.Refresh();
but the image remains the same(Rectangles are still on top of the Image)
I know there's a method graphics.Clear(Color),but it replace the entire Image with a solid color
How do I remove the drawing only from the PictureBox?
Thanks
Edit:
I already saved the original and when I erase I use the original image

You are overwriting the original image. Save the image locally and clone it into the PictureBox.Image property. Then clone again when you want to erase

Draw the background image again using Graphics.DrawImage() or assign the image again to the Image property. Using a Graphics object in this way is writing directly to the image displayed in the PictureBox and it does not keep separate copies of what is written using a Graphics object and the background Image.