When I try to understand SFML, I tried to set an icon with RenderWindowInstanse.SetIcon()
the method, that takes 3 parameters, fist two is size, 3 - byte[], then I try to use File.ReadAllBytes()
and same tools in c#, but that don't work, I search and find on-site ImageInstanse.Pixels property that returns byte[] like a parameter, that's works but I don't understand why they are returning different byte arrays
In SFML.NET, Image.Pixels returns an array of bytes that are nicely organized RGBA pixel values that represent the image in memory.
.NET's own File.ReadAllBytes() function returns the bytes that come from the file itself in the system's storage device.
Every file has a format that defines the layout and meaning of the bytes that make up that file. Image files are an extension of that concept as there any many different file formats for images. The pixel data for an image has to be encoded (and/or compressed) according to the format it is being saved as. This means that the bytes in the file no longer matches the raw RGBA pixel data as it was in the computer memory.
Files often contain lots of extra bytes for things like a file header, metadata, compression information, or possibly even an index for blocks of data that are smaller files or images within a file.
When you use File.ReadAllBytes(), you are given all of the bytes that represent this data in an array and you have to know exactly what the meaning of the byte at each index is.
SFML understands how to decode many different image formats, and will read the bytes of the file and process that into an array of pixel data. This is what the constructor for Image that takes a file is doing in the background. Once you have an SFML.Graphics.Image instance, you can use its Pixels property to access that decoded RGBA pixel data.