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Hi!
I would really appreciate some info about how to compare two image files to see if they are equal, .png files in this case. What techniques are there? Any help appreciated.. 
And merry coding christmas everybody!
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It depends on how you define equal images. You can check if all the pixels are the same but I don't think it has too much sense.
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Yes, check if all pixels are the same is what I want to do, sorry if I wasn't clear enough. They are the same size with the same colours but the pixels are placed differently, so to check if they're all the same would be the best say I guess. Ofcourse I could compare the images exact size (lots of them have different size ofcourse), but since I'll have a few hundreds of images, that wouldn't be the best way to do it I guess. Do you have any knowledge about how to easily compare all the pixels? Is there any existing function for this or so?
/Joplinazz
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You can use GetPixel() method of Image class but it will be slow so I suggest you use unsafe code. Here are several articles that should help you: Articles by Christian Graus[^]
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I would probably try it this way first:
1) Make both images the same size. I would probably shrink the larger of the two. You could probably deduce that if the images don't have the same size ratio, then they aren't the same, thus possibly short-cutting this step.
2) Convert both images to 8 bit color, and change resulting black pixels to some other 8-bit color.
3) Combine both images into a single image by or'ing the colors for each pixel position. If the pixel has the same color value for both images, change it to black.
4) See what percentage of of pixels are not black, and set some sort of percentage threshold for determining equality.
I am NOT a graphics guy, so someone else may be able to suggest a better solution. If nothing else, it would be a fun programming exercise.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001
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Thanks for your answer. That thing about to check some sort of percentage of the pixels that's black doesn't sound too stupid.. I'll look into it. Do you happen to have any knowledge about how to easily check if all the pixels are the same in both images?
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Joplinazz wrote: Do you happen to have any knowledge about how to easily check if all the pixels are the same in both images?
You're gonna have to do that one pixel at a time I think...
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001
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Hi,
you could read the files as binary data and calculate a CRC on them, assuming equal CRC
means equal data (there is an odd chance this is not true, depending on the length of
the CRC).
but then different files might still represent the same image (not sure PNG format allows for that to happen); if this matters, read the image with Image.FromFile, save it in a fixed non-compressing format to a MemoryStream and do the CRC stuff (or a full compare) on the MemoryStreams.
If you rely on CRC, you can fill a Dictionary with filenames and CRCs;
if you rely on full image compare, you may end up trying to hold all images at the same
time, severely loading your system.
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Hi,
How to get the url and webpage name from IE browser and firefox in window with c# ?
Thanks
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You can try finding url textbox by using FindWindowEx api and then retrieving text by getwindowtext api.
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It's okay, I've figured out how to do it. Thanks for the really quick reply though
jt.
j.t.
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Next time reply in the same thread, no need to start a new one.
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You are welcome
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Hi All!
I'm working on a small personal project, hoping that it will eventually automate pretty much everything I do in Windows. But, the only thing I cannot find information regarding is how to launch a WindowsScriptHost (wsh) file from a c# application. For example:
I have a form, and on that form is a button named "Copy File". Now I want to click that button and then have some c# code that will just simple run/launch that file that I specify. I am using JScript for WSH. Does any body have any ideas/pointers? Any help would be much appreciated.
Regards,
jt
j.t.
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You can use Process class to launch files programmatically.
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Incase anybody else needs to know, I have the following code which launches my Jscript file once a buttonn is clicked:
private void button1_Click(object sender, EventArgs e)
{
Process CopyFile = new Process();
CopyFile.StartInfo.FileName = "C:\\Users\\jason\\Development\\Client\\Playground\\CopyFile.js";
CopyFile.StartInfo.Arguments = "ProcessStart.cs";
CopyFile.Start();
}
j.t.
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If you don't need much control how the process runs you can also use static Start() method of Process class to launch application and pass argument.
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Hello everyone,
I am writing a console application which is using http(s) to send a couple of binary files to IIS server (an ASP.Net application). I am wondering in order to improve upload performance and reliability, which C# APIs should I use to upload files and any special points I need to consider in my scenario?
thanks in advance,
George
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friendz,
am doing an application which allows user to write their email address in a text box, while saving this i need to store this in to a .csv file. is it possible to create a .csv file at run time, and everytime i need to update the file....
self confidence+hard work=SUCCESS
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MS Lee wrote: friendz
To form a plural in English the general rule is to add an "s" to the end of the word. Adding a "z" makes you look like a marketing person trying to connect with teenagers.
MS Lee wrote: is it possible to create a .csv file at run time
Yes, a CSV file is simply one where the Values are Separated by Commas. You can use StringBuilder or string.Format to build each line and then write it to the stream like any other file.
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thanks friend,
but here i hv got stuck, i couldnt move further,
each time whwn i add a email address i need to save with the existing file, .. i dont know to move further
self confidence+hard work=SUCCESS
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MS Lee wrote: each time whwn i add a email address i need to save with the existing file,
So, what code have you got so far?
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sorry sorry i just confused...
am having a text box to get email address and a combo box to select its category
for e.g
category might be as IT Dept, Mech Dept and so,
at the first form am inserting these to in to a table.
in another form i have only the combo box which has loaded with the category data.
when i select any category i need all the emails belongs to this category should come with a .csv file..
am stuck in " how to seperate emailid's as per the category and how to bundle it and make a .csv file at run time ... ?
self confidence+hard work=SUCCESS
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Welcome in the CP's Memorable Quotes page [^], Colin.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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CPallini wrote: Memorable Quotes page
It is an honour. You should link back to the original use of the quote for reference too.
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