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How to completely cover an image with a transparent using C# Graphics.DrawImage

I'm triying to cover an image with another in order to provide a watermark but it has to cover the entire source image. The problem is that the watermark provided is of 600x600 and the source image can have any size and aspect ratio. So far it does not cover the source image entirely.

I solved it like this (in a very straightforward way).
private void button1_Click(object sender, EventArgs e)
{
var image = new Bitmap( this.pictureBox1.Image.Width, this.pictureBox1.Image.Height);
var rect = new Rectangle(0, 0, this.pictureBox1.Image.Width, this.pictureBox1.Image.Height);
Graphics graphics = Graphics.FromImage(image);
graphics.DrawImage(this.pictureBox1.Image, 0, 0);
var waterMarkImage = new Bitmap(this.pictureBox2.Image.Width, this.pictureBox2.Image.Height);
for (int y = 0; y < waterMarkImage.Height; y++)
{
for (int x = 0; x < waterMarkImage.Width; x++)
{
var color = (this.pictureBox2.Image as Bitmap).GetPixel(x, y);
color = Color.FromArgb(50, color.R, color.G, color.B);
waterMarkImage.SetPixel(x, y, color);
}
}
graphics.DrawImage(waterMarkImage, rect);
this.pictureBox3.Image = image;
}
In pictureBox1 I loaded main image. In pictureBox2 I loaded "water mark". In the event handler I created resulting image (first main image then the second) and loaded it into pictureBox3. To get water mark affect I reduced alpha component of color (I set it to 50).

How to print full content of win form c# [duplicate]

I have a windows forms project written in C#. The main form has a TabControl on it and there is a requirement for one of the users to be able to print one of the TabPages. The form is very long and I use a vertical scroll bar. The whole of the form needs to be able to be printed.
I have tried using the DrawToBitmap method to convert to a bitmap first, but this will only include the portion of the form that the user can see. Some other solutions I have tried involve screen capturing, which has the same issue.
How can I print out, or get an image, of the whole of the tab page, including the parts the user only sees when they scroll down?

This is rather simple for any control including TabControls and TabPages but not Forms.
All you need to do is enlarge the relevant controls enough to show all their content. (They don't have to be actually visible on screen.)
Here is an example:
tabControl1.Height = 10080;
tabPage2.Height = 10050;
dataGridView1.Height = 10000;
dataGridView1.Rows.Add(3000);
for (int i = 0; i < dataGridView1.Rows.Count; i++) dataGridView1[0, i].Value = i;
using (Bitmap bmp = new Bitmap(tabControl1.Width , tabControl1.Height ))
{
tabControl1.DrawToBitmap(bmp, tabControl1.ClientRectangle);
bmp.Save("D:\\xxxx.png", ImageFormat.Png);
}
This saves the full content of the DataGridView, the TabPage and the TabControl..
Note: that this will not work with forms, which can't much exceed the screen dimensions..
Update: Here is code that saves a form with vertical scrolling by patching several bitmaps together. It can, of course be expanded to include horizontal scrolling as well. I have coded a similar solution for larger Panels here.
static void saveLargeForm(Form form, string fileName)
{
// yes it may take a while
form.Cursor = Cursors.WaitCursor;
// allocate target bitmap and a buffer bitmap
Bitmap target = new Bitmap(form.DisplayRectangle.Width, form.DisplayRectangle.Height);
Bitmap buffer = new Bitmap(form.Width, form.Height);
// the vertical pointer
int y = 0;
var vsc = form.VerticalScroll;
vsc.Value = 0;
form.AutoScrollPosition = new Point(0, 0);
// the scroll amount
int l = vsc.LargeChange;
Rectangle srcRect = ClientBounds(form);
Rectangle destRect = Rectangle.Empty;
bool done = false;
// we'll draw onto the large bitmap with G
using (Graphics G = Graphics.FromImage(target))
{
while (!done)
{
destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);
int v = vsc.Value;
vsc.Value = vsc.Value + l;
form.AutoScrollPosition = new Point(form.AutoScrollPosition.X, vsc.Value + l);
int delta = vsc.Value - v;
done = delta < l;
y += delta;
}
destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);
}
// write result to disc and clean up
target.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
target.Dispose();
buffer.Dispose();
GC.Collect(); // not sure why, but it helped
form.Cursor = Cursors.Default;
}
It makes use of a helper function to determine the the net size of the virtual client rectangle, ie excluding borders, title and scrollbar:
static Rectangle ClientBounds(Form f)
{
Rectangle rc = f.ClientRectangle;
Rectangle rb = f.Bounds;
int sw = SystemInformation.VerticalScrollBarWidth;
var vsc = f.VerticalScroll;
int bw = (rb.Width - rc.Width - (vsc.Visible ? sw : 0) ) / 2;
int th = (rb.Height - rc.Height) - bw * 2;
return new Rectangle(bw, th + bw, rc.Width, rc.Height );
}

Winforms - how to print the whole of a form, including unseen parts?

I have a windows forms project written in C#. The main form has a TabControl on it and there is a requirement for one of the users to be able to print one of the TabPages. The form is very long and I use a vertical scroll bar. The whole of the form needs to be able to be printed.
I have tried using the DrawToBitmap method to convert to a bitmap first, but this will only include the portion of the form that the user can see. Some other solutions I have tried involve screen capturing, which has the same issue.
How can I print out, or get an image, of the whole of the tab page, including the parts the user only sees when they scroll down?

This is rather simple for any control including TabControls and TabPages but not Forms.
All you need to do is enlarge the relevant controls enough to show all their content. (They don't have to be actually visible on screen.)
Here is an example:
tabControl1.Height = 10080;
tabPage2.Height = 10050;
dataGridView1.Height = 10000;
dataGridView1.Rows.Add(3000);
for (int i = 0; i < dataGridView1.Rows.Count; i++) dataGridView1[0, i].Value = i;
using (Bitmap bmp = new Bitmap(tabControl1.Width , tabControl1.Height ))
{
tabControl1.DrawToBitmap(bmp, tabControl1.ClientRectangle);
bmp.Save("D:\\xxxx.png", ImageFormat.Png);
}
This saves the full content of the DataGridView, the TabPage and the TabControl..
Note: that this will not work with forms, which can't much exceed the screen dimensions..
Update: Here is code that saves a form with vertical scrolling by patching several bitmaps together. It can, of course be expanded to include horizontal scrolling as well. I have coded a similar solution for larger Panels here.
static void saveLargeForm(Form form, string fileName)
{
// yes it may take a while
form.Cursor = Cursors.WaitCursor;
// allocate target bitmap and a buffer bitmap
Bitmap target = new Bitmap(form.DisplayRectangle.Width, form.DisplayRectangle.Height);
Bitmap buffer = new Bitmap(form.Width, form.Height);
// the vertical pointer
int y = 0;
var vsc = form.VerticalScroll;
vsc.Value = 0;
form.AutoScrollPosition = new Point(0, 0);
// the scroll amount
int l = vsc.LargeChange;
Rectangle srcRect = ClientBounds(form);
Rectangle destRect = Rectangle.Empty;
bool done = false;
// we'll draw onto the large bitmap with G
using (Graphics G = Graphics.FromImage(target))
{
while (!done)
{
destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);
int v = vsc.Value;
vsc.Value = vsc.Value + l;
form.AutoScrollPosition = new Point(form.AutoScrollPosition.X, vsc.Value + l);
int delta = vsc.Value - v;
done = delta < l;
y += delta;
}
destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);
}
// write result to disc and clean up
target.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
target.Dispose();
buffer.Dispose();
GC.Collect(); // not sure why, but it helped
form.Cursor = Cursors.Default;
}
It makes use of a helper function to determine the the net size of the virtual client rectangle, ie excluding borders, title and scrollbar:
static Rectangle ClientBounds(Form f)
{
Rectangle rc = f.ClientRectangle;
Rectangle rb = f.Bounds;
int sw = SystemInformation.VerticalScrollBarWidth;
var vsc = f.VerticalScroll;
int bw = (rb.Width - rc.Width - (vsc.Visible ? sw : 0) ) / 2;
int th = (rb.Height - rc.Height) - bw * 2;
return new Rectangle(bw, th + bw, rc.Width, rc.Height );
}

Render 16 bits image in picturebox

I have an array which consists in PixelData extracted from a Dicom Image.
Here's the code:
byte[] bytes = img.PixelData.GetFrame(0).Data; // img is the Dicom Image
int count = bytes.Length / 2;
ushort[] words = new ushort[count];
for (int i = 0, p = 0; i < count; i++, p += 2)
{
words[i] = BitConverter.ToUInt16(bytes, p);
}
pixels16 = words.ToList(); //pixels16 contains now the PixelData for the Grayscale image
Now, here's my question, how do I render that into a Picturebox??

My code for converting Bitmaps from Format16bppGrayScale to Format8bppIndexed format. PictureBox can easy show this format. (If you want, you can use different palette).
public Bitmap Gray16To8bppIndexed(Bitmap BmpIn)
{
if (BmpIn.PixelFormat != PixelFormat.Format16bppGrayScale)
throw new BadImageFormatException();
byte[] ImageData = new byte[BmpIn.Width * BmpIn.Height * 2];
Rectangle Re = new Rectangle(0, 0, BmpIn.Width, BmpIn.Height);
BitmapData BmpData = BmpIn.LockBits(Re, ImageLockMode.ReadOnly, BmpIn.PixelFormat);
Marshal.Copy(BmpData.Scan0, ImageData, 0, ImageData.Length);
BmpIn.UnlockBits(BmpData);
byte[] ImageData2 = new byte[BmpIn.Width * BmpIn.Height];
for (long i = 0; i < ImageData2.LongLength; i++)
ImageData2[i] = ImageData[i * 2 + 1];
ImageData = null;
Bitmap BmpOut = new Bitmap(BmpIn.Width, BmpIn.Height, PixelFormat.Format8bppIndexed);
BmpData = BmpOut.LockBits(Re, ImageLockMode.WriteOnly, BmpOut.PixelFormat);
Marshal.Copy(ImageData2, 0, BmpData.Scan0, ImageData2.Length);
BmpOut.UnlockBits(BmpData);
ImageData2 = null;
BmpData = null;
ColorPalette GrayPalette = BmpOut.Palette;
Color[] GrayColors = GrayPalette.Entries;
for (int i = 0; i < GrayColors.Length; i++)
GrayColors[GrayColors.Length - 1 - i] = Color.FromArgb(i, i, i);
BmpOut.Palette = GrayPalette;
return BmpOut;
}

Well, I don't know the specifics, because it depends on how you really want to go about it (if performance is important, you need to create your own subclass of Bitmap, but otherwise, Bitmap.SetPixel would work fine).
But essentially, you need to shove those pixels into a Bitmap, then set the picture box's image to that bitmap, like:
Bitmap bitmap = new Bitmap(width, height);
for(int y = 0;y < height;y++)
for(int x = 0;x < width;x++)
bitmap.SetPixel(x,y, Color.fromRGB(/* unpack your R,G,B channel of your pixel here */);
pictureBox.Image = bitmap;

You can utilize the AForge .NET Framework, which is a great .NET library for image processing. The built-in .NET Picturebox could not nativley display images with System.Drawing.Imaging.PixelFormat.Format16bppGrayScale, but the AForge library has its own Picturebox control, check this out. It expects a .NET Image.
You can include AForge to your project easily with NuGet:
Install-Package AForge.Controls
Install-Package AForge.Imaging
Or just
Install-Package AForge
Example code below:
//SOME BYTES
//Load here the DICOM image
int width=640, height=480;
int numberOfPixels = width*height;
byte[] source = new byte[2*numberOfPixels];
//With AFORGE
var image = AForge.Imaging.UnmanagedImage.Create(width, height, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale);
IntPtr ptrToImage = image.ImageData;
//Copies the bytes from source to the image
//System.Runtime.InteropServices
Marshal.Copy(source, 0, ptrToImage,numberOfPixels);
//WITH .NET
System.Drawing.Bitmap bitmapImage = new System.Drawing.Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale);
var imageData = bitmapImage.LockBits(new System.Drawing.Rectangle(0, 0, width, height), System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale);
Marshal.Copy(source, 0, imageData.Scan0, numberOfPixels);
bitmapImage.UnlockBits(imageData);

Got this idea from a friend. The inputImage.ImageSource property is a 2D array with grayscale pixel values.
Bitmap grayscaleImage = new Bitmap(inputImage.ImageSource);
for (int x = 0; x < grayscaleImage.Width; x++)
{
for (int y = 0; y < grayscaleImage.Height; y++)
{
byte[,] tempMatrix = inputImage.ImageGrayscale;
byte temp = tempMatrix[x, y];
Color tempColor = Color.FromArgb(255, temp, temp, temp);
grayscaleImage.SetPixel(x, y, tempColor);
}
}
picboxDisplay.Image = grayscaleImage;

convert bitonal TIFF to bitonal PNG in C#

I need to convert bitonal (black and white) TIFF files into another format for display by a web browser, currently we're using JPGs, but the format isn't crucial. From reading around .NET doesn't seem to easily support writing bitonal images, so we're ending up with ~1MB files instead of ~100K ones. I'm considering using ImageMagick to do this, but ideally i'd like a solution which doesn't require this if possible.
Current code snippet (which also does some resizing on the image):
using (Image img = Image.FromFile(imageName))
{
using (Bitmap resized = new Bitmap(resizedWidth, resizedHeight)
{
using (Graphics g = Graphics.FromImage(resized))
{
g.DrawImage(img, new Rectangle(0, 0, resized.Width, resized.Height), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel);
}
resized.Save(outputFilename, System.Drawing.Imaging.ImageFormat.Jpeg);
}
}
Is there any way to achieve this?
Thanks.

I believe the problem can be solved by checking that resized bitmap is of PixelFormat.Format1bppIndexed. If it's not, you should convert it to 1bpp bitmap and after that you can save it as black and white png without problems.
In other words, you should use following code instead of resized.Save(outputFilename, System.Drawing.Imaging.ImageFormat.Jpeg);
if (resized.PixelFormat != PixelFormat.Format1bppIndexed)
{
using (Bitmap bmp = convertToBitonal(resized))
bmp.Save(outputFilename, System.Drawing.Imaging.ImageFormat.Png);
}
else
{
resized.Save(outputFilename, System.Drawing.Imaging.ImageFormat.Png);
}
I use following code for convertToBitonal :
private static Bitmap convertToBitonal(Bitmap original)
{
int sourceStride;
byte[] sourceBuffer = extractBytes(original, out sourceStride);
// Create destination bitmap
Bitmap destination = new Bitmap(original.Width, original.Height,
PixelFormat.Format1bppIndexed);
destination.SetResolution(original.HorizontalResolution, original.VerticalResolution);
// Lock destination bitmap in memory
BitmapData destinationData = destination.LockBits(
new Rectangle(0, 0, destination.Width, destination.Height),
ImageLockMode.WriteOnly, PixelFormat.Format1bppIndexed);
// Create buffer for destination bitmap bits
int imageSize = destinationData.Stride * destinationData.Height;
byte[] destinationBuffer = new byte[imageSize];
int sourceIndex = 0;
int destinationIndex = 0;
int pixelTotal = 0;
byte destinationValue = 0;
int pixelValue = 128;
int height = destination.Height;
int width = destination.Width;
int threshold = 500;
for (int y = 0; y < height; y++)
{
sourceIndex = y * sourceStride;
destinationIndex = y * destinationData.Stride;
destinationValue = 0;
pixelValue = 128;
for (int x = 0; x < width; x++)
{
// Compute pixel brightness (i.e. total of Red, Green, and Blue values)
pixelTotal = sourceBuffer[sourceIndex + 1] + sourceBuffer[sourceIndex + 2] +
sourceBuffer[sourceIndex + 3];
if (pixelTotal > threshold)
destinationValue += (byte)pixelValue;
if (pixelValue == 1)
{
destinationBuffer[destinationIndex] = destinationValue;
destinationIndex++;
destinationValue = 0;
pixelValue = 128;
}
else
{
pixelValue >>= 1;
}
sourceIndex += 4;
}
if (pixelValue != 128)
destinationBuffer[destinationIndex] = destinationValue;
}
Marshal.Copy(destinationBuffer, 0, destinationData.Scan0, imageSize);
destination.UnlockBits(destinationData);
return destination;
}
private static byte[] extractBytes(Bitmap original, out int stride)
{
Bitmap source = null;
try
{
// If original bitmap is not already in 32 BPP, ARGB format, then convert
if (original.PixelFormat != PixelFormat.Format32bppArgb)
{
source = new Bitmap(original.Width, original.Height, PixelFormat.Format32bppArgb);
source.SetResolution(original.HorizontalResolution, original.VerticalResolution);
using (Graphics g = Graphics.FromImage(source))
{
g.DrawImageUnscaled(original, 0, 0);
}
}
else
{
source = original;
}
// Lock source bitmap in memory
BitmapData sourceData = source.LockBits(
new Rectangle(0, 0, source.Width, source.Height),
ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
// Copy image data to binary array
int imageSize = sourceData.Stride * sourceData.Height;
byte[] sourceBuffer = new byte[imageSize];
Marshal.Copy(sourceData.Scan0, sourceBuffer, 0, imageSize);
// Unlock source bitmap
source.UnlockBits(sourceData);
stride = sourceData.Stride;
return sourceBuffer;
}
finally
{
if (source != original)
source.Dispose();
}
}

Have you tried saving using the Image.Save overload with Encoder parameters?
Like the Encoder.ColorDepth Parameter?

Trying jaroslav's suggestion for color depth doesn't work:
static void Main(string[] args)
{
var list = ImageCodecInfo.GetImageDecoders();
var jpegEncoder = list[1]; // i know this is the jpeg encoder by inspection
Bitmap bitmap = new Bitmap(500, 500);
Graphics g = Graphics.FromImage(bitmap);
g.DrawRectangle(new Pen(Color.Red), 10, 10, 300, 300);
var encoderParams = new EncoderParameters();
encoderParams.Param[0] = new EncoderParameter(Encoder.ColorDepth, 2);
bitmap.Save(#"c:\newbitmap.jpeg", jpegEncoder, encoderParams);
}
The jpeg is still a full color jpeg.
I don't think there is any support for grayscale jpeg in gdi plus. Have you tried looking in windows imaging component?
http://www.microsoft.com/downloads/details.aspx?FamilyID=8e011506-6307-445b-b950-215def45ddd8&displaylang=en
code example: http://www.codeproject.com/KB/GDI-plus/windows_imaging.aspx
wikipedia: http://en.wikipedia.org/wiki/Windows_Imaging_Component

This is an old thread. However, I'll add my 2 cents.
I use AForge.Net libraries (open source)
use these dlls. Aforge.dll, AForge.Imaging.dll
using AForge.Imaging.Filters;
private void ConvertBitmap()
{
markedBitmap = Grayscale.CommonAlgorithms.RMY.Apply(markedBitmap);
ApplyFilter(new FloydSteinbergDithering());
}
private void ApplyFilter(IFilter filter)
{
// apply filter
convertedBitmap = filter.Apply(markedBitmap);
}

Have you tried PNG with 1 bit color depth?
To achieve a size similar to a CCITT4 TIFF, I believe your image needs to use a 1-bit indexed pallette.
However, you can't use the Graphics object in .NET to draw on an indexed image.
You will probably have to use LockBits to manipulate each pixel.
See Bob Powell's excellent article.