Go Vips

Go Vips is a go bind to libvips C API.

Install

Check if pkg-config is able to find the right libvips include:

pkg-config --cflags --libs vips  

Package 'libffi', required by 'gobject-2.0', not found

# optional, use you libffi lib path  
export PKG_CONFIG_PATH="/usr/local/opt/libffi/lib/pkgconfig"  

Per the security update https://groups.google.com/forum/#!topic/golang-announce/X7N1mvntnoU you may need whitelist the -Xpreprocessor flag in your environment.

export CGO_CFLAGS_ALLOW='-Xpreprocessor'  

examples

func main() {
	img := vips.NewFromFile("./images/Landscape_2.jpg")
	wm := vips.NewFromFile("./images/away.webp")

	err := wm.ThumbnailImage(200)
	if err != nil {
		panic(err)
	}

	err = wm.Resize(float64(img.Width()) / float64(wm.Width()))
	if err != nil {
		panic(err)
	}

	err = wm.Rotate(30)
	if err != nil {
		panic(err)
	}

	err = wm.Replicate(img.Width()/wm.Width()+1, img.Height()/wm.Height()+1)
	if err != nil {
		panic(err)
	}
	img.Replicate(2, 2)

	fmt.Println(img.Height(), img.Width())

	imgCopy, err := img.Copy()
	if err != nil {
		panic(err)
	}
	fmt.Println(imgCopy.Width())

	err = img.Save2file("out.png")
	if err != nil {
		panic(err)
	}
}

Features

conversion

• Copy: Copy an image, optionally modifying the header.
• Replicate: repeats an image many times.
• Gravity: place in within an image of size width by height at a certain gravity.
• Composite2: composite overlay on top of base with mode .
• GetAngle: examine the metadata on im and return the VipsAngle
• AutoRot: look at the image metadata and rotate the image to make it upright.
• Embed: Embed *Image within an image of size width by height at position x , y .
• ExtractArea: extract an area from an image. The area must fit within *Image.
• Crop: Crop a synonym for ExtractArea
• Flip: Flip an image left-right or up-down.
• Grid: Grid chop a tall thin image up into a set of tiles, lay the tiles out in a grid.
• Scale: Scale search the image for the maximum and minimum value
• SubSample: SubSample an image by an integer fraction. This is fast, nearest-neighbour shrink.
• Zoom: Zoom an image by repeating pixels. This is fast nearest-neighbour zoom.
• Wrap: Wrap slice an image up and move the segments
• ExtractBand: SmartCrop crop an image down to a specified width and height by removing boring parts.

create

• Black: Black make a black unsigned char image of a specified size.
• Xyz: Xyz Create a two-band uint32 image where the elements in the first band have the value of their x coordinate and elements in the second band have their y coordinate.
• Grey: Grey create a one-band float image with the left-most column zero and the right-most 1.
• GaussMat: GaussMat Creates a circularly symmetric Gaussian image of radius sigma.
• LogMat: LogMat creates a circularly symmetric Laplacian of Gaussian mask of radius sigma.
• Text: Text draw the string text to an image.
• GaussNoise: GaussNoise make a one band float image of gaussian noise with the specified distribution.
• Eye: Eye create a test pattern with increasing spatial frequence in X and amplitude in Y.
• Sines: Sines creates a float one band image of the a sine waveform in two dimensions.
• Zone: Zone create a one-band image of a zone plate.
• Identity: Identity creates an identity lookup table.
• BuildLut: BuildLut this operation builds a lookup table from a set of points.
• InvertLut: InvertLut given a mask of target values and real values, generate a LUT which will map reals to targets.
• ToneLut: ToneLut generates a tone curve for the adjustment of image levels.
• MaskIdeal: MaskIdeal Make an ideal high- or low-pass filter.
• MaskIdealRing: MaskIdealRing make an ideal ring-pass or ring-reject filter.
• MaskIdealBand: MaskIdealBand make an ideal band-pass or band-reject filter.
• MaskButterWorth: MaskButterWorth make an butterworth high- or low-pass filter.
• MaskButterWorthRing: MaskButterWorthRing Make a butterworth ring-pass or ring-reject filter.
• MaskButterWorthBand: MaskButterWorthBand make an butterworth band-pass or band-reject filter
• MaskGaussian: MaskGaussian Make a gaussian high- or low-pass filter.
• MaskGaussianRing: MaskGaussianRing Make a gaussian ring-pass or ring-reject filter.
• MaskGaussianBand: MaskGaussianBand Make a gaussian band-pass or band-reject filter.
• MaskFractal: MaskFractal operation should be used to create fractal images by filtering the power spectrum of Gaussian white noise
• FractSurf: FractSurf Generate an image of size width by height and fractal dimension fractalDimension.
• Worley: Worley create a one-band float image of Worley noise.
• Perlin: Perlin create a one-band float image of Perlin noise.

draw

• DrawRect: DrawRect paint pixels within left , top , width , height in image with ink.
• DrawRect1: DrawRect1 as DrawRect, but just take a single float64 for ink.
• DrawPoint: DrawPoint draw a single pixel at x, y.
• DrawPoint1: DrawPoint1 as DrawPoint, but just take a single float64 for ink.
• DrawImage: DrawImage draw sub on top of image at position x, y.
• DrawMask: DrawMask draw mask on the image. mask is a monochrome 8-bit image with 0/255 for transparent or ink coloured points.
• DrawMask1: DrawMask1 as DrawMask, but just take a single float64 for ink.
• DrawLine: DrawLine draws a 1-pixel-wide line on an image.
• DrawLine1: DrawLine1 as DrawLine, but just take a single double for ink.
• DrawCircle: DrawCircle Draws a circle on image.
• DrawCircle1: DrawCircle1 as DrawCircle, but just take a single double for ink.
• DrawFlood: DrawFlood flood-fill image with ink, starting at position x , y.
• DrawFlood1: DrawFlood1 as DrawFlood, but just take a single double for ink.
• DrawSmudge: DrawSmudge smudge a section of image.

foreign_save

freqfilt

• FwFFT: FwFFT transform an image to Fourier space.
• InvFFT: InvFFT transform an image from Fourier space to real space.
• FreqMult: FreqMult transformed to Fourier space, multipled with mask.
• Spectrum: Spectrum make a displayable (ie. 8-bit unsigned int) power spectrum.
• Phasecor: Phasecor convert the two input images to Fourier space, calculate phase-correlation, back to real space.

header

mosaicing

• Merge: Merge joins two images left-right (with ref on the left) or up-down (with ref above) with a smooth seam.
• Mosaic: Mosaic joins two images left-right (with ref on the left) or top-bottom (with ref above) given an approximate overlap.
• Mosaic1: Mosaic1 This operation joins two images top-bottom (with sec on the right) or left-right (with sec at the bottom) given an approximate pair of tie-points.
• Match: Match scale, rotate and translate sec so that the tie-points line up.
• GlobalBalance: GlobalBalance can be used to remove contrast differences in an assembled mosaic.
• ReMosaic: ReMosaic takes apart the mosaiced image in and rebuilds it, substituting images.

resample

• Resize: Resize image
• Rotate: Rotate image
• Thumbnail: Thumbnail Make a thumbnail from a file
• ThumbnailBuffer: ThumbnailBuffer Make a thumbnail from []byte
• ThumbnailImage: ThumbnailImage Make a thumbnail from *Image

vip

• DefaultInit: DefaultInit init vips by default
• Init: Init starts up libvips
• Shutdown: Shutdown drop caches and close plugins. Run with "--vips-leak" to do a leak check too.
• LeakSet: LeakSet turn on or off vips leak checking
• VersionString: VersionString get the VIPS version as a static string, including a build date and time.
• Version: Version get the major, minor or micro library version, with flag values 0, 1 and 2.
• Error: Error Get a pointer to the start of the error buffer as a C string.

vipsimage

• New: New empty VipsImage
• NewMemory: NewMemory creates a new VipsImage.
• NewFromFile: NewFromFile opens filename for reading.
• NewFromBuffer: NewFromBuffer loads an image from the formatted area of memory buf.
• Height: Height return image height
• Width: Width return image width
• ProgressSet: ProgressSet ff set, vips will print messages about the progress of computation to stdout.
• ImageSetProgress: ImageSetProgress vips signals evaluation progress via the “preeval”

Contributing

We appreciate your help!