README.md

NetVips

This NuGet package provides a .NET binding for the libvips image processing library.

This binding passes the vips test suite cleanly with no leaks on Windows, macOS and Linux.

We have formatted docs online here:

https://kleisauke.github.io/net-vips/

How it works

Programs that use NetVips don't manipulate images directly, instead they create pipelines of image processing operations building on a source image. When the end of the pipe is connected to a destination, the whole pipeline executes at once, streaming the image in parallel from source to destination a section at a time.

Because NetVips is parallel, it's quick, and because it doesn't need to keep entire images in memory, it's light. For example, the NetVips benchmark:

NetVips.Benchmarks

Loads a large image, shrinks by 10%, sharpens, and saves again. On this test NetVips is around 22 times faster than Magick.NET and 4 times faster than ImageSharp.

The libvips documentation has a chapter explaining how libvips opens files which gives some more background.

Supported platforms

• .NET Framework 4.5.2 and higher
• .NET 6.0 and higher

Install

You need the libvips shared library on your library search path, version 8.2 or later. There are separate NuGet packages that will contain the pre-compiled libvips binaries for the most common platforms (see this repo for details):

	NuGet Package1
Windows 64-bit
Windows 32-bit
Windows ARM64
Linux x64 glibc2
Linux x64 musl3
Linux ARM64v8 glibc2
Linux ARM64v8 musl3
Linux ARMv7
macOS x64
macOS ARM64

¹ The version number of these NuGet packages is in sync with libvips' version number.
² Uses glibc as the standard C library (Ubuntu, Debian, etc).
³ Uses musl as the standard C library (Alpine, Gentoo Linux, etc).

Then just install this package, perhaps:

Install-Package NetVips

To test your install, try this test program:

if (ModuleInitializer.VipsInitialized)
{
    Console.WriteLine($"Inited libvips {NetVips.Version(0)}.{NetVips.Version(1)}.{NetVips.Version(2)}");
}
else
{
    Console.WriteLine(ModuleInitializer.Exception.Message);
}
Console.ReadLine();

If NetVips was able to find the libvips shared library, you should see:

Inited libvips [VERSION_NUMBER]

However, if you see something else, NetVips was unable to initialize libvips. This can happen for a variety of reasons, even though most of the times it's because NetVips was not able to find libvips or due to x86/x64 architecture problems:

Inner exception	HRESULT	Solution
DllNotFoundException	0x8007007E	Make sure to add the bin folder of the libvips Windows build to your PATH environment variable (if you wish to not use the separate NuGet packages).
BadImageFormatException	0x8007000B	Make sure when you target the AnyCPU platform the Prefer 32-bit option is unchecked. Or try to target x64 instead.

Example

using NetVips;

using var im = Image.NewFromFile("image.jpg");

// put im at position (100, 100) in a 3000 x 3000 pixel image,
// make the other pixels in the image by mirroring im up / down /
// left / right, see
// https://www.libvips.org/API/current/libvips-conversion.html#vips-embed
using var embed = im.Embed(100, 100, 3000, 3000, extend: Enums.Extend.Mirror);

// multiply the green (middle) band by 2, leave the other two alone
using var multiply = embed * new[] { 1, 2, 1 };

// make an image from an array constant, convolve with it
using var mask = Image.NewFromArray(new[,]
{
    {-1, -1, -1},
    {-1, 16, -1},
    {-1, -1, -1}
}, 8);
using var convolve = multiply.Conv(mask, precision: Enums.Precision.Integer);

// finally, write the result back to a file on disk
convolve.WriteToFile("output.jpg");