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Quote: is a fetter, a snare, a pustulous canker, a travesty, a daily water-boarding for those who use it,
I couldn't possibly improve on that! 
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I got a little confused with the Bitmap.LockBits() function. Though I can see that my code achieves what I want it to do with good performance, I do not fully understand how it works...
public unsafe ushort[,] GetDataFromBitmap(Bitmap source, Rectangle rect)
{
ushort[,] result = new ushort[rect.Width, rect.Height];
BitmapData bmpData = source.LockBits(rect, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
byte* scan0 = (byte*)bmpData.Scan0.ToPointer();
int bytesPerPixel = 3;
int stride = bmpData.Stride;
for (int y = 0; y < rect.Height; y++)
{
for (int x = 0; x < rect.Width; x++)
{
byte* bluePointer = scan0 + y*stride + x*bytesPerPixel;
byte blue = *bluePointer;
source is a bitmap of 2736x3648 pixels of 24bit RGB, and rect has a size of 240x320, positioned somewhere within the source image.
The value of stride is 10944 - that is 4*2736. That is source.Width, not rect.Width. Also ...bluePointer = scan0 + y*stride... somehow indicates that the locked bytes do not represent the "new" image defined by the rectangle, but that scan0 just points to a position in the original image corresponding to the top left corner of the rectangle. Why do I need a Rectangle, when a Point could do so also?
bytesPerPixel is 3 (corresponding to 1 byte RGB each), while stride/source.Width is 4 (i.e. alignment to 32=2^5 bits), but it is ...bluePointer = x*bytesPerPixel + ....
Now I am confused. Can someone explain those strange parameters and values?
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Ok...
LockBits effectively prevents the Garbage Collector from moving the data in memory - so pointers and so forth can be used directly instead of having to de-reference every time you wanted to use it. Because the GC is outside your direct control, if you don't use LockBits then the data you are pointing at can be "moved" in memory at will, rendering your pointers invalid. But it doesn't copy the memory - it just locks it in place.
Your data may be 3 bytes per pixel (i.e. has no Alpha channel) but that's inefficient to access: 32 bit quantities are a lot faster to throw around than 24 bit values, so your image is "padded" to 32bits with a default "solid" alpha channel.
stride is 4*2736 because it's a bytes count, rather than a pixel count - and a pixel is a 32 bit quantity (ARGB, with each "part" occupying a byte). So each row in your image of 2736 pixels takes stride bytes - i.e. to advance from one row in your rectangle to the same relative position in the next row means advancing by the width of your image, not the width of your rectangle:
-------------------
|C ------ |
|D |A |E |
| |B | |
| ------ |
| |
------------------- If C is (0,0) on your image, and D is (0,1); A is (0,0) in your rect, and B is (0,1) in your rect (A is (5,1) in your image, B is (5,2)) then to move from the memory byte starting the rect A to the memory byte starting rect B, means adding the number of bytes in a whole row of the image - adding the bytes in the rect width would move you to E instead.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Thanks for your explanations.
So LockBits pins all the bytes of the original bitmap, not only a selected amount of them, doesn't it?
And I see another point of confusion. Stride=10944=4*source.Height=3*source.Width. And the latter multiplication is the correct way of determining Stride, the former one only happened to coincide (due to the 4x3 format of my camera). Now I understand why it is the coordinate of Height (y) which gets multiplied with stride; with the other interpretation it does not make sense. And looks like there is no padding.
But I still do not understand why I have to pass a Rectangle instead of a Point.
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Bernhard Hiller wrote: But I still do not understand why I have to pass a Rectangle instead of a Point.
 You'd have to ask Microsoft about that!
But it's probably because it's not something you logically want to do: locking a single pixel isn't going to be more efficient than GetPixel / SetPixel. Logically, you want to access a rectangle (which will be the whole bitmap often as not) rather than a single dot.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Not to challenge, but to ask, but isn't LockBits a GDI+ call and nothing to do with .NET and hence garbage collection?
Regards,
Rob Philpott.
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Challenge away!
That's not how it was explained to me, but a quick look through the reference sources says you're right: it's just a wrapper for a call to GDI+
Interesting...
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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string[] s = data.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
what does it mean?
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It means that the Split method is invoked on the data class, with a new string array as parameters (containing only a newline), without any additional options (like removing empty items from the array), and assigning the result to a string-array called s.
There are easier ways to learn a language than by copy/pasting the parts you don't recognize. I'd recommend Head First C#
--edit; forgot a closing tag
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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Take a string and split it based on any new lines in it. Can I suggest that now would be a good time for you to:
a. Invest in a basic C# book - your questions have all been very basic so this leads me to suspect you have no experience in the language
and
b. Learn how to Google - again, your questions could all have been answered with a quick search.
This space for rent
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I already showed you where to look for this sort of information. Please make an effort to do your own studying and research.
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There's a IntelliSense-description for every standard .NET method which Visual Studio will show to you when you type the opening bracket.
There's the MSDN online documentation which you can easily invoke by placing the cursor onto the class or method name in question and pressing F1.
And here's a good, free PDF-book on programming in C#:
Introduction to Programming with C# / Java Books[^]
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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It means that you need to read C# documentation and learn to use Google !
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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Simple. Just input a string and split it with new line with no special split options like 'RemoveEmptyEntries' (The return value does not include array elements that contain an empty string)
Find More .Net development tips at : .NET Tips
The only reason people get lost in thought is because it's unfamiliar territory.
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what is the difference between "string data = sp_gsm.ReadExisting();" and "string data2 = sp_rf.ReadLine();"
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how do I find the execution path of C# code using antlr for AST generation
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Sorry, no idea. This is the C# forum.
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what does "cmd.ExecuteNonQuery();"mean?
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It means your SQL command string doesn't return any SELECT information: it's an INSERT, UPDATE, or similar instead.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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0
down vote
favorite
I was able to serialize a List of objects (List) using this code:
public static string Serialize(object obj)
{
using (MemoryStream memoryStream = new MemoryStream())
using (StreamReader reader = new StreamReader(memoryStream))
{
DataContractSerializer serializer = new DataContractSerializer(obj.GetType());
serializer.WriteObject(memoryStream, obj);
memoryStream.Position = 0;
return reader.ReadToEnd();
}
}
However, I'm not able to deserialize using this code:
public static object Deserialize(string xml, Type toType)
{
using (Stream stream = new MemoryStream())
{
byte[] data = System.Text.Encoding.UTF8.GetBytes(xml);
stream.Write(data, 0, data.Length);
stream.Position = 0;
DataContractSerializer deserializer = new DataContractSerializer(toType);
return deserializer.ReadObject(stream);
}
}
I'm not able to understand the problem. I'm using the last method by calling it with:
Deserialize(SerializedObject, List), but I'm getting an error saying List<FilesToProcess> is a type, which is not valid in the given context
Could anyone help? I'm a bit over my head with this.
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Sooo, I have the doubtful honor of answering my own question.
The problem was that I was trying to assign the output of
`public static object Deserialize(string xml, Type toType)`
to a List<filestoprocess> generic called listOfFiles, when I should have assigned to an object and then cast to a `List<filestoprocess>` using
List
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Hello
I need a project about convert of bonary to decimal and vice versa in C#
Modify the calculator by method project to convector of Binary to Decimal and vice versa.
The user should be only able to enter the 1 and 0 in binary textbox, and decimal numbers in decimal textbox.
modified 4-May-16 1:28am.
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Member 12077780 wrote: I need a project about ...
Then I suggest you start by designing the user interface and working out exactly what you need to do with it.
We aren't here to do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.
Try it yourself, you may find it is not as difficult as you think!
If you meet a specific problem, then please ask about that and we will do our best to help. But we aren't going to do it all for you!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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