73 lines
1.8 KiB
Markdown
73 lines
1.8 KiB
Markdown
# Big Gustave #
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Open, read and create PNG images in fully managed C#.
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## Usage ##
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To open a PNG image from file and get some pixel values:
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using (var stream = File.OpenRead(@"C:\my\file\path\file.png"))
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{
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Png image = Png.Open(stream);
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Pixel pixel = image.GetPixel(image.Width - 1, image.Height - 1);
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int pixelRedAverage = 0;
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pixelRedAverage += pixel.R;
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pixel = image.GetPixel(0, 0);
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pixelRedAverage += pixel.R;
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Console.WriteLine(pixelRedAverage / 2.0);
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}
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The PNG object has methods to inspect the header and get the pixel values. The header has properties for:
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png.Header.Width
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png.Header.Height
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png.Header.BitDepth
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png.Header.ColorType
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png.Header.CompressionMethod
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png.Header.FilterMethod
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png.Header.InterlaceMethod
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The PNG also has width and height as convenience properties from the header information:
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png.Width == png.Header.Width
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png.Height == png.Header.Height
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And a property that indicates if the image uses transparency:
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png.HasAlphaChannel
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To get a pixel use:
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Pixel pixel = png.GetPixel(0, 7);
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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.
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## Creation ##
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To create a PNG use:
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var builder = PngBuilder.Create(2, 2, false);
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var red = new Pixel(255, 0, 0);
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builder.SetPixel(red, 0, 0);
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builder.SetPixel(255, 120, 16, 1, 1);
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using (var memory = new MemoryStream())
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{
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builder.Save(memory);
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return memory.ToArray();
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}
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You can also load a PNG into a builder which will copy all the pixel values into the builder for easy editing:
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var png = Png.Create(@"C:\files\my.png");
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var builder = PngBuilder.FromPng(png); |