BigGustave 1.0.0

Big Gustave

Open, read and create PNG images in fully managed C#.

Usage

To open a PNG image from file and get some pixel values:

using (var stream = File.OpenRead(@"C:\my\file\path\file.png"))
{
    Png image = Png.Open(stream);

    Pixel pixel = image.GetPixel(image.Width - 1, image.Height - 1);

    int pixelRedAverage = 0;

    pixelRedAverage += pixel.R;

    pixel = image.GetPixel(0, 0);

    pixelRedAverage += pixel.R;

    Console.WriteLine(pixelRedAverage / 2.0);       
    
}

The PNG object has methods to inspect the header and get the pixel values. The header has properties for:

png.Header.Width
png.Header.Height
png.Header.BitDepth
png.Header.ColorType
png.Header.CompressionMethod
png.Header.FilterMethod
png.Header.InterlaceMethod

The PNG also has width and height as convenience properties from the header information:

png.Width == png.Header.Width
png.Height == png.Header.Height

And a property that indicates if the image uses transparency:

png.HasAlphaChannel

To get a pixel use:

Pixel pixel = png.GetPixel(0, 7);

Where the first argument is x (column) and the second is y (row). The Pixel is used for all image types, e.g. Grayscale, Colour, with/without transparency.

Creation

Because of some issues with ZLib compatibility the created images work with most, but not all image viewers. Of the viewers tested the images work with all browsers, Paint, Gimp, Paint3D etc.

To create a PNG use:

var builder = PngBuilder.Create(2, 2, false);

var red = new Pixel(255, 0, 12, 255, false);
var black = new Pixel(0, 0, 0, 255, false);

builder.SetPixel(new Pixel(255, 0, 12, 255, false), 0, 0);
builder.SetPixel(new Pixel(255, 0, 12, 255, false), 1, 1);

using (var memory = new MemoryStream())
{
    builder.Save(memory);
    
    return memory.ToArray();
}