49 lines
1.9 KiB
Markdown
49 lines
1.9 KiB
Markdown
# ReFuel.StbImage
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StbImage is a very common library that has been developed mainly by Sean Barett.
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It is one of the easiest to use image loading libraries on the planet
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especially for C and C++ users. It is relatively simple to load up and use in
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C#, however the C# build system makes it a bit difficult to manage native
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dependencies. Therefore this package makes it easy for you and everyone else
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who needs a cross platform way to load images.
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Intended OS targets are:
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* Windows (x86 and x64)
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* Linux (arm32, arm64, x86 and x64)
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* MacOS (arm64, x64)
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## Usage
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```cs
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using ReFuel.Stb;
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// Simply load an image from a Stream or Span<T> (T: unmanaged) source.
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using StbImage image = StbImage.Load(source);
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Console.WriteLine("{0}x{1}", image.Width, image.Height);
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// StbImage.ImagePointer is a pointer to the image data.
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// Pass the image to an unsafe library as is (e.g. OpenGL), or cast it to a span. Currently there is no "safe" way to do this.
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// OpenGL example
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GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, image.Width, image.Height, 0, StbiFormatToGLFormat(image.Format, image.IsFloat ? PixelFormat.Float : PixelFormat.UnsignedByte), image.ImagePointer);
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// C# example
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struct Pixel
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{
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int R, G, B, A;
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}
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Span<Pixel> pixels;
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unsafe
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{
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pixels = new Span<Pixel>(image.ImagePointer, image.Width * image.Height);
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}
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```
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### Global Options
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| Option | Description |
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|--------|-------------|
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| `bool StbImage.FlipVerticallyOnLoad` | Flips the image vertically after loading. Practical for uses where a right handed coordinate system is used (e.g. OpenGL) |
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| `bool UnpremultiplyOnLoad` | Applies to Apple iPhone PNG images, where the image is sometimes encoded with premultiplied alpha. Reverses this premultiplication. |
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## Calling Stbi directly.
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If you wish to call the native Stbi library, call functions in the static class `Stbi`. See `stb_image.h` documentation [online](https://github.com/nothings/stb/blob/master/stb_image.h).
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