Error with getting pixels
I have tried to create some code to get the pixels of an uploaded image but the function doesn't seem to work correctly. It gives extremely strange outputs so it isn't that the r,g,b values are looking at the wrong index in the array. It does work for black and white but no colours. Does anyone know why?
This is the part of my code where the error occurs
var pixelData = createBytes(width, height);
string oldr = "0", oldb = "0", oldg = "0";
string[] compressed = new string[height * width];
int godown = 0;
var path = op.FileName;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
int index = y * (width*4) + 4 * x; byte blue = pixelData[index]; byte green = pixelData[index + 1]; byte red = pixelData[index + 2]; int arraySlot = x +(y*width);int StandardArraySlot = arraySlot - godown; string r = red.ToString("D3"); string g = green.ToString("D3"); string b = blue.ToString("D3"); MessageBox.Show(r+" "+g+" "+b); public byte[] createBytes(int width,int height) { int stride = width * 4; byte[] pixelData = new byte[height * stride]; image.CopyPixels(new Int32Rect(0, 0, width, height), pixelData, stride, 0); return pixelData;
}
int index = y * (width*4) + 4 * x; byte blue = pixelData[index]; byte green = pixelData[index + 1]; byte red = pixelData[index + 2]; int arraySlot = x +(y*width);int StandardArraySlot = arraySlot - godown; string r = red.ToString("D3"); string g = green.ToString("D3"); string b = blue.ToString("D3"); MessageBox.Show(r+" "+g+" "+b); public byte[] createBytes(int width,int height) { int stride = width * 4; byte[] pixelData = new byte[height * stride]; image.CopyPixels(new Int32Rect(0, 0, width, height), pixelData, stride, 0); return pixelData;
}
8 Replies
format the code with $code
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Get an example by typing
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For longer snippets, use: https://paste.mod.gg/also stuff like this
int index = y * (width4) + 4 x;
is y * (width * 4) + 4 * x)?
`yes it is that in my code but I think that just pasting it into dicord has deleted it
the method gets the wrong pixels but i cant see why.
like for a pixel of 85,160,34 it gave a value of 0,18,0 and for some pixels it says that they are 0,0,0 (black when they clearly arent)
symbols like ~ * ` _ are used for formatting in discord and many other services
have you tried to check pixel by pixel where's the first difference? it could give you a hint
also, making sure the format is rgba or argb or what else
all pixels are wrong, none of them share any value woith the supposed result
if it was argb or rgba I would at least see a value in common so it cant be that
exactly a pixel of 53,255,107 gives a value of 0,18,0
and afterwards the same pixel of 53,255,107 givesd a value of 0,0,0
is there a conversion happening, maybe? how did you create
image? is Format what you expect it to be?
you could also try drawing it to look if you can understand some common artifacts/issuesthank you so much for your help but I have fixed the problem by changing the function to another one and this works fine. I don't know why the other function didn't work though