bimg

package module
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 Go to latest Published: Nov 21, 2020 License: MIT Imports: 12 Imported by: 0

README

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Small Go package for fast high-level image processing using libvips via C bindings, providing a simple programmatic API.

bimg was designed to be a small and efficient library supporting common image operations such as crop, resize, rotate, zoom or watermark. It can read JPEG, PNG, WEBP natively, and optionally TIFF, PDF, GIF and SVG formats if libvips@8.3+ is compiled with proper library bindings. Lastly AVIF is supported as of libvips@8.9+. For AVIF support libheif needs to be compiled with an applicable AVIF en-/decoder.

bimg is able to output images as JPEG, PNG and WEBP formats, including transparent conversion across them.

bimg uses internally libvips, a powerful library written in C for image processing which requires a low memory footprint and it's typically 4x faster than using the quickest ImageMagick and GraphicsMagick settings or Go native image package, and in some cases it's even 8x faster processing JPEG images.

If you're looking for an HTTP based image processing solution, see imaginary.

bimg was heavily inspired in sharp, its homologous package built for node.js. bimg is used in production environments processing thousands of images per day.

v1 notice: bimg introduces some minor breaking changes in v1 release. If you're using gopkg.in, you can still rely in the v0 without worrying about API breaking changes.

Contents

Supported image operations

  • Resize
  • Enlarge
  • Crop (including smart crop support, libvips 8.5+)
  • Rotate (with auto-rotate based on EXIF orientation)
  • Flip (with auto-flip based on EXIF metadata)
  • Flop
  • Zoom
  • Thumbnail
  • Extract area
  • Watermark (using text or image)
  • Gaussian blur effect
  • Custom output color space (RGB, grayscale...)
  • Format conversion (with additional quality/compression settings)
  • EXIF metadata (size, alpha channel, profile, orientation...)
  • Trim (libvips 8.6+)

Prerequisites

  • libvips 8.3+ (8.8+ recommended)
  • C compatible compiler such as gcc 4.6+ or clang 3.0+
  • Go 1.3+

Note:

  • libvips v8.3+ is required for GIF, PDF and SVG support.
  • libvips v8.9+ is required for AVIF support. libheif compiled with a AVIF en-/decoder also needs to be present.

Installation

go get -u github.com/h2non/bimg
libvips

Follow libvips installation instructions:

https://libvips.github.io/libvips/install.html

Installation script

Note: install script is officially deprecated, it might not work as expected. We recommend following libvips install instructions.

Run the following script as sudo (supports OSX, Debian/Ubuntu, Redhat, Fedora, Amazon Linux):

curl -s https://raw.githubusercontent.com/h2non/bimg/master/preinstall.sh | sudo bash -

If you want to take the advantage of OpenSlide, simply add --with-openslide to enable it:

curl -s https://raw.githubusercontent.com/h2non/bimg/master/preinstall.sh | sudo bash -s --with-openslide

The install script requires curl and pkg-config.

Performance

libvips is probably the fastest open source solution for image processing. Here you can see some performance test comparisons for multiple scenarios:

Benchmark

Tested using Go 1.5.1 and libvips-7.42.3 in OSX i7 2.7Ghz

BenchmarkRotateJpeg-8     	      20	  64686945 ns/op
BenchmarkResizeLargeJpeg-8	      20	  63390416 ns/op
BenchmarkResizePng-8      	     100	  18147294 ns/op
BenchmarkResizeWebP-8     	     100	  20836741 ns/op
BenchmarkConvertToJpeg-8  	     100	  12831812 ns/op
BenchmarkConvertToPng-8   	      10	 128901422 ns/op
BenchmarkConvertToWebp-8  	      10	 204027990 ns/op
BenchmarkCropJpeg-8       	      30	  59068572 ns/op
BenchmarkCropPng-8        	      10	 117303259 ns/op
BenchmarkCropWebP-8       	      10	 107060659 ns/op
BenchmarkExtractJpeg-8    	      50	  30708919 ns/op
BenchmarkExtractPng-8     	    3000	    595546 ns/op
BenchmarkExtractWebp-8    	    3000	    386379 ns/op
BenchmarkZoomJpeg-8       	      10	 160005424 ns/op
BenchmarkZoomPng-8        	      30	  44561047 ns/op
BenchmarkZoomWebp-8       	      10	 126732678 ns/op
BenchmarkWatermarkJpeg-8  	      20	  79006133 ns/op
BenchmarkWatermarPng-8    	     200	   8197291 ns/op
BenchmarkWatermarWebp-8   	      30	  49360369 ns/op

Examples

import (
  "fmt"
  "os"
  "github.com/h2non/bimg"
)
Resize
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Resize(800, 600)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

size, err := bimg.NewImage(newImage).Size()
if size.Width == 800 && size.Height == 600 {
  fmt.Println("The image size is valid")
}

bimg.Write("new.jpg", newImage)
Rotate
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Rotate(90)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)
Convert
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Convert(bimg.PNG)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

if bimg.NewImage(newImage).Type() == "png" {
  fmt.Fprintln(os.Stderr, "The image was converted into png")
}
Force resize

Force resize operation without perserving the aspect ratio:

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).ForceResize(1000, 500)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

size := bimg.Size(newImage)
if size.Width != 1000 || size.Height != 500 {
  fmt.Fprintln(os.Stderr, "Incorrect image size")
}
Custom colour space (black & white)
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Colourspace(bimg.INTERPRETATION_B_W)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

colourSpace, _ := bimg.ImageInterpretation(newImage)
if colourSpace != bimg.INTERPRETATION_B_W {
  fmt.Fprintln(os.Stderr, "Invalid colour space")
}
Custom options

See Options struct to discover all the available fields

options := bimg.Options{
  Width:        800,
  Height:       600,
  Crop:         true,
  Quality:      95,
  Rotate:       180,
  Interlace:    true,
}

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Process(options)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)
Watermark
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

watermark := bimg.Watermark{
  Text:       "Chuck Norris (c) 2315",
  Opacity:    0.25,
  Width:      200,
  DPI:        100,
  Margin:     150,
  Font:       "sans bold 12",
  Background: bimg.Color{255, 255, 255},
}

newImage, err := bimg.NewImage(buffer).Watermark(watermark)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)
Fluent interface
buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

image := bimg.NewImage(buffer)

// first crop image
_, err := image.CropByWidth(300)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

// then flip it
newImage, err := image.Flip()
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

// save the cropped and flipped image
bimg.Write("new.jpg", newImage)

Debugging

Run the process passing the DEBUG environment variable

DEBUG=bimg ./app

Enable libvips traces (note that a lot of data will be written in stdout):

VIPS_TRACE=1 ./app

You can also dump a core on failure, as John Cuppit said:

g_log_set_always_fatal(
                G_LOG_FLAG_RECURSION |
                G_LOG_FLAG_FATAL |
                G_LOG_LEVEL_ERROR |
                G_LOG_LEVEL_CRITICAL |
                G_LOG_LEVEL_WARNING );

Or set the G_DEBUG environment variable:

export G_DEBUG=fatal-warnings,fatal-criticals

API

See godoc reference for detailed API documentation.

Authors

Credits

People who recurrently contributed to improve bimg in some way.

Thank you!

License

MIT - Tomas Aparicio

views

Documentation

Index

Constants

View Source 
const (
	Make                    = "exif-ifd0-Make"
	Model                   = "exif-ifd0-Model"
	Orientation             = "exif-ifd0-Orientation"
	XResolution             = "exif-ifd0-XResolution"
	YResolution             = "exif-ifd0-YResolution"
	ResolutionUnit          = "exif-ifd0-ResolutionUnit"
	Software                = "exif-ifd0-Software"
	Datetime                = "exif-ifd0-DateTime"
	YCbCrPositioning        = "exif-ifd0-YCbCrPositioning"
	Compression             = "exif-ifd1-Compression"
	ExposureTime            = "exif-ifd2-ExposureTime"
	FNumber                 = "exif-ifd2-FNumber"
	ExposureProgram         = "exif-ifd2-ExposureProgram"
	ISOSpeedRatings         = "exif-ifd2-ISOSpeedRatings"
	ExifVersion             = "exif-ifd2-ExifVersion"
	DateTimeOriginal        = "exif-ifd2-DateTimeOriginal"
	DateTimeDigitized       = "exif-ifd2-DateTimeDigitized"
	ComponentsConfiguration = "exif-ifd2-ComponentsConfiguration"
	ShutterSpeedValue       = "exif-ifd2-ShutterSpeedValue"
	ApertureValue           = "exif-ifd2-ApertureValue"
	BrightnessValue         = "exif-ifd2-BrightnessValue"
	ExposureBiasValue       = "exif-ifd2-ExposureBiasValue"
	MeteringMode            = "exif-ifd2-MeteringMode"
	Flash                   = "exif-ifd2-Flash"
	FocalLength             = "exif-ifd2-FocalLength"
	SubjectArea             = "exif-ifd2-SubjectArea"
	MakerNote               = "exif-ifd2-MakerNote"
	SubSecTimeOriginal      = "exif-ifd2-SubSecTimeOriginal"
	SubSecTimeDigitized     = "exif-ifd2-SubSecTimeDigitized"
	ColorSpace              = "exif-ifd2-ColorSpace"
	PixelXDimension         = "exif-ifd2-PixelXDimension"
	PixelYDimension         = "exif-ifd2-PixelYDimension"
	SensingMethod           = "exif-ifd2-SensingMethod"
	SceneType               = "exif-ifd2-SceneType"
	ExposureMode            = "exif-ifd2-ExposureMode"
	WhiteBalance            = "exif-ifd2-WhiteBalance"
	FocalLengthIn35mmFilm   = "exif-ifd2-FocalLengthIn35mmFilm"
	SceneCaptureType        = "exif-ifd2-SceneCaptureType"
	GPSLatitudeRef          = "exif-ifd3-GPSLatitudeRef"
	GPSLatitude             = "exif-ifd3-GPSLatitude"
	GPSLongitudeRef         = "exif-ifd3-GPSLongitudeRef"
	GPSLongitude            = "exif-ifd3-GPSLongitude"
	GPSAltitudeRef          = "exif-ifd3-GPSAltitudeRef"
	GPSAltitude             = "exif-ifd3-GPSAltitude"
	GPSSpeedRef             = "exif-ifd3-GPSSpeedRef"
	GPSSpeed                = "exif-ifd3-GPSSpeed"
	GPSImgDirectionRef      = "exif-ifd3-GPSImgDirectionRef"
	GPSImgDirection         = "exif-ifd3-GPSImgDirection"
	GPSDestBearingRef       = "exif-ifd3-GPSDestBearingRef"
	GPSDestBearing          = "exif-ifd3-GPSDestBearing"
	GPSDateStamp            = "exif-ifd3-GPSDateStamp"
)

Common EXIF fields for data extraction

View Source 
const (
	// Quality defines the default JPEG quality to be used.
	Quality = 75
	// MaxSize defines the maximum pixels width or height supported.
	MaxSize = 16383
)
View Source 
const Version = "1.1.5"

Version represents the current package semantic version.

View Source 
const VipsMajorVersion = int(C.VIPS_MAJOR_VERSION)

VipsMajorVersion exposes the current libvips major version number

View Source 
const VipsMinorVersion = int(C.VIPS_MINOR_VERSION)

VipsMinorVersion exposes the current libvips minor version number

View Source 
const VipsVersion = string(C.VIPS_VERSION)

VipsVersion exposes the current libvips semantic version

Variables

View Source 
var ColorBlack = Color{0, 0, 0}

ColorBlack is a shortcut to black RGB color representation.

View Source 
var (
	// ErrExtractAreaParamsRequired defines a generic extract area error
	ErrExtractAreaParamsRequired = errors.New("extract area width/height params are required")
)
View Source 
var ImageTypes = map[ImageType]string{
	JPEG:   "jpeg",
	PNG:    "png",
	WEBP:   "webp",
	TIFF:   "tiff",
	GIF:    "gif",
	PDF:    "pdf",
	SVG:    "svg",
	MAGICK: "magick",
	HEIF:   "heif",
	AVIF:   "avif",
}

ImageTypes stores as pairs of image types supported and its alias names.

View Source 
var SupportedImageTypes = map[ImageType]SupportedImageType{}

SupportedImageTypes stores the optional image type supported by the current libvips compilation. Note: lazy evaluation as demand is required due to bootstrap runtime limitation with C/libvips world.

View Source 
var WatermarkFont = "sans 10"

WatermarkFont defines the default watermark font to be used.

Functions

func ColourspaceIsSupported 

func ColourspaceIsSupported(buf []byte) (bool, error)

ColourspaceIsSupported checks if the image colourspace is supported by libvips.

func DetermineImageTypeName 

func DetermineImageTypeName(buf []byte) string

DetermineImageTypeName determines the image type format by name (jpeg, png, webp or tiff)

func ImageTypeName 

func ImageTypeName(t ImageType) string

ImageTypeName is used to get the human friendly name of an image format.

func Initialize 

func Initialize()

Initialize is used to explicitly start libvips in thread-safe way. Only call this function if you have previously turned off libvips.

func IsSVGImage added in v1.0.3 

func IsSVGImage(buf []byte) bool

IsSVGImage returns true if the given buffer is a valid SVG image.

func IsTypeNameSupported 

func IsTypeNameSupported(t string) bool

IsTypeNameSupported checks if a given image type name is supported

func IsTypeNameSupportedSave added in v1.0.7 

func IsTypeNameSupportedSave(t string) bool

IsTypeNameSupportedSave checks if a given image type name is supported for saving

func IsTypeSupported 

func IsTypeSupported(t ImageType) bool

IsTypeSupported checks if a given image type is supported

func IsTypeSupportedSave added in v1.0.7 

func IsTypeSupportedSave(t ImageType) bool

IsTypeSupportedSave checks if a given image type is support for saving

func Read 

func Read(path string) ([]byte, error)

Read reads all the content of the given file path and returns it as byte buffer.

func Resize 

func Resize(buf []byte, o Options) ([]byte, error)

Resize is used to transform a given image as byte buffer with the passed options.

func Shutdown 

func Shutdown()

Shutdown is used to shutdown libvips in a thread-safe way. You can call this to drop caches as well. If libvips was already initialized, the function is no-op

func VipsCacheDropAll added in v1.0.10 

func VipsCacheDropAll()

VipsCacheDropAll drops the vips operation cache, freeing the allocated memory.

func VipsCacheSetMax added in v1.0.10 

func VipsCacheSetMax(maxCacheSize int)

VipsCacheSetMax sets the maximum number of operations to keep in the vips operation cache.

func VipsCacheSetMaxMem added in v1.0.10 

func VipsCacheSetMaxMem(maxCacheMem int)

VipsCacheSetMaxMem Sets the maximum amount of tracked memory allowed before the vips operation cache begins to drop entries.

func VipsDebugInfo 

func VipsDebugInfo()

VipsDebugInfo outputs to stdout libvips collected data. Useful for debugging.

func VipsIsTypeSupported added in v1.0.3 

func VipsIsTypeSupported(t ImageType) bool

VipsIsTypeSupported returns true if the given image type is supported by the current libvips compilation.

func VipsIsTypeSupportedSave added in v1.0.7 

func VipsIsTypeSupportedSave(t ImageType) bool

VipsIsTypeSupportedSave returns true if the given image type is supported by the current libvips compilation for the save operation.

func Write 

func Write(path string, buf []byte) error

Write writes the given byte buffer into disk to the given file path.

Types

type Angle 

type Angle int

Angle represents the image rotation angle value. 

const (
	// D0 represents the rotation angle 0 degrees.
	D0 Angle = 0
	// D45 represents the rotation angle 90 degrees.
	D45 Angle = 45
	// D90 represents the rotation angle 90 degrees.
	D90 Angle = 90
	// D135 represents the rotation angle 90 degrees.
	D135 Angle = 135
	// D180 represents the rotation angle 180 degrees.
	D180 Angle = 180
	// D235 represents the rotation angle 235 degrees.
	D235 Angle = 235
	// D270 represents the rotation angle 270 degrees.
	D270 Angle = 270
	// D315 represents the rotation angle 180 degrees.
	D315 Angle = 315
)

type Color 

type Color struct {
	R, G, B uint8
}

Color represents a traditional RGB color scheme.

type Direction 

type Direction int

Direction represents the image direction value. 

const (
	// Horizontal represents the orizontal image direction value.
	Horizontal Direction = C.VIPS_DIRECTION_HORIZONTAL
	// Vertical represents the vertical image direction value.
	Vertical Direction = C.VIPS_DIRECTION_VERTICAL
)

type EXIF added in v1.1.3 

type EXIF struct {
	Make                    string
	Model                   string
	Orientation             int
	XResolution             string
	YResolution             string
	ResolutionUnit          int
	Software                string
	Datetime                string
	YCbCrPositioning        int
	Compression             int
	ExposureTime            string
	FNumber                 string
	ExposureProgram         int
	ISOSpeedRatings         int
	ExifVersion             string
	DateTimeOriginal        string
	DateTimeDigitized       string
	ComponentsConfiguration string
	ShutterSpeedValue       string
	ApertureValue           string
	BrightnessValue         string
	ExposureBiasValue       string
	MeteringMode            int
	Flash                   int
	FocalLength             string
	SubjectArea             string
	MakerNote               string
	SubSecTimeOriginal      string
	SubSecTimeDigitized     string
	ColorSpace              int
	PixelXDimension         int
	PixelYDimension         int
	SensingMethod           int
	SceneType               string
	ExposureMode            int
	WhiteBalance            int
	FocalLengthIn35mmFilm   int
	SceneCaptureType        int
	GPSLatitudeRef          string
	GPSLatitude             string
	GPSLongitudeRef         string
	GPSLongitude            string
	GPSAltitudeRef          string
	GPSAltitude             string
	GPSSpeedRef             string
	GPSSpeed                string
	GPSImgDirectionRef      string
	GPSImgDirection         string
	GPSDestBearingRef       string
	GPSDestBearing          string
	GPSDateStamp            string
}

EXIF image metadata

type Extend added in v1.0.5 

type Extend int

Extend represents the image extend mode, used when the edges of an image are extended, you can specify how you want the extension done. See: https://libvips.github.io/libvips/API/current/libvips-conversion.html#VIPS-EXTEND-BACKGROUND:CAPS 

const (
	// ExtendBlack extend with black (all 0) pixels mode.
	ExtendBlack Extend = C.VIPS_EXTEND_BLACK
	// ExtendCopy copy the image edges.
	ExtendCopy Extend = C.VIPS_EXTEND_COPY
	// ExtendRepeat repeat the whole image.
	ExtendRepeat Extend = C.VIPS_EXTEND_REPEAT
	// ExtendMirror mirror the whole image.
	ExtendMirror Extend = C.VIPS_EXTEND_MIRROR
	// ExtendWhite extend with white (all bits set) pixels.
	ExtendWhite Extend = C.VIPS_EXTEND_WHITE
	// ExtendBackground with colour from the background property.
	ExtendBackground Extend = C.VIPS_EXTEND_BACKGROUND
	// ExtendLast extend with last pixel.
	ExtendLast Extend = C.VIPS_EXTEND_LAST
)

type GaussianBlur 

type GaussianBlur struct {
	Sigma   float64
	MinAmpl float64
}

GaussianBlur represents the gaussian image transformation values.

type Gravity 

type Gravity int

Gravity represents the image gravity value. 

const (
	// GravityCentre represents the centre value used for image gravity orientation.
	GravityCentre Gravity = iota
	// GravityNorth represents the north value used for image gravity orientation.
	GravityNorth
	// GravityEast represents the east value used for image gravity orientation.
	GravityEast
	// GravitySouth represents the south value used for image gravity orientation.
	GravitySouth
	// GravityWest represents the west value used for image gravity orientation.
	GravityWest
	// GravitySmart enables libvips Smart Crop algorithm for image gravity orientation.
	GravitySmart
)

type Image 

type Image struct {
	// contains filtered or unexported fields
}

Image provides a simple method DSL to transform a given image as byte buffer.

func NewImage 

func NewImage(buf []byte) *Image

NewImage creates a new Image struct with method DSL.

func (*Image) AutoRotate added in v1.1.3 

func (i *Image) AutoRotate() ([]byte, error)

AutoRotate automatically rotates the image with no additional transformation based on the EXIF oritentation metadata, if available.

func (*Image) Colourspace 

func (i *Image) Colourspace(c Interpretation) ([]byte, error)

Colourspace performs a color space conversion bsaed on the given interpretation.

func (*Image) ColourspaceIsSupported 

func (i *Image) ColourspaceIsSupported() (bool, error)

ColourspaceIsSupported checks if the current image color space is supported.

func (*Image) Convert 

func (i *Image) Convert(t ImageType) ([]byte, error)

Convert converts image to another format.

func (*Image) Crop 

func (i *Image) Crop(width, height int, gravity Gravity) ([]byte, error)

Crop crops the image to the exact size specified.

func (*Image) CropByHeight 

func (i *Image) CropByHeight(height int) ([]byte, error)

CropByHeight crops an image by height (auto width).

func (*Image) CropByWidth 

func (i *Image) CropByWidth(width int) ([]byte, error)

CropByWidth crops an image by width only param (auto height).

func (*Image) Enlarge 

func (i *Image) Enlarge(width, height int) ([]byte, error)

Enlarge enlarges the image by width and height. Aspect ratio is maintained.

func (*Image) EnlargeAndCrop 

func (i *Image) EnlargeAndCrop(width, height int) ([]byte, error)

EnlargeAndCrop enlarges the image by width and height with additional crop transformation.

func (*Image) Extract 

func (i *Image) Extract(top, left, width, height int) ([]byte, error)

Extract area from the by X/Y axis in the current image.

func (*Image) Flip 

func (i *Image) Flip() ([]byte, error)

Flip flips the image about the vertical Y axis.

func (*Image) Flop 

func (i *Image) Flop() ([]byte, error)

Flop flops the image about the horizontal X axis.

func (*Image) ForceResize 

func (i *Image) ForceResize(width, height int) ([]byte, error)

ForceResize resizes with custom size (aspect ratio won't be maintained).

func (*Image) Gamma added in v1.1.0 

func (i *Image) Gamma(exponent float64) ([]byte, error)

Gamma returns the gamma filtered image buffer.

func (*Image) Image 

func (i *Image) Image() []byte

Image returns the current resultant image buffer.

func (*Image) Interpretation 

func (i *Image) Interpretation() (Interpretation, error)

Interpretation gets the image interpretation type. See: https://libvips.github.io/libvips/API/current/VipsImage.html#VipsInterpretation

func (*Image) Length added in v1.0.10 

func (i *Image) Length() int

Length returns the size in bytes of the image buffer.

func (*Image) Metadata 

func (i *Image) Metadata() (ImageMetadata, error)

Metadata returns the image metadata (size, alpha channel, profile, EXIF rotation).

func (*Image) Process 

func (i *Image) Process(o Options) ([]byte, error)

Process processes the image based on the given transformation options, talking with libvips bindings accordingly and returning the resultant image buffer.

func (*Image) Resize 

func (i *Image) Resize(width, height int) ([]byte, error)

Resize resizes the image to fixed width and height.

func (*Image) ResizeAndCrop 

func (i *Image) ResizeAndCrop(width, height int) ([]byte, error)

ResizeAndCrop resizes the image to fixed width and height with additional crop transformation.

func (*Image) Rotate 

func (i *Image) Rotate(a Angle) ([]byte, error)

Rotate rotates the image by given angle degrees (0, 90, 180 or 270).

func (*Image) Size 

func (i *Image) Size() (ImageSize, error)

Size returns the image size as form of width and height pixels.

func (*Image) SmartCrop added in v1.0.8 

func (i *Image) SmartCrop(width, height int) ([]byte, error)

SmartCrop produces a thumbnail aiming at focus on the interesting part.

func (*Image) Thumbnail 

func (i *Image) Thumbnail(pixels int) ([]byte, error)

Thumbnail creates a thumbnail of the image by the a given width by aspect ratio 4:4.

func (*Image) Trim added in v1.0.14 

func (i *Image) Trim() ([]byte, error)

Trim removes the background from the picture. It can result in a 0x0 output if the image is all background.

func (*Image) Type 

func (i *Image) Type() string

Type returns the image type format (jpeg, png, webp, tiff).

func (*Image) Watermark 

func (i *Image) Watermark(w Watermark) ([]byte, error)

Watermark adds text as watermark on the given image.

func (*Image) WatermarkImage added in v1.0.8 

func (i *Image) WatermarkImage(w WatermarkImage) ([]byte, error)

WatermarkImage adds image as watermark on the given image.

func (*Image) Zoom 

func (i *Image) Zoom(factor int) ([]byte, error)

Zoom zooms the image by the given factor. You should probably call Extract() before.

type ImageMetadata 

type ImageMetadata struct {
	Orientation int
	Channels    int
	Alpha       bool
	Profile     bool
	Type        string
	Space       string
	Colourspace string
	Size        ImageSize
	EXIF        EXIF
}

ImageMetadata represents the basic metadata fields

func Metadata 

func Metadata(buf []byte) (ImageMetadata, error)

Metadata returns the image metadata (size, type, alpha channel, profile, EXIF orientation...).

type ImageSize 

type ImageSize struct {
	Width  int
	Height int
}

ImageSize represents the image width and height values

func Size 

func Size(buf []byte) (ImageSize, error)

Size returns the image size by width and height pixels.

type ImageType 

type ImageType int

ImageType represents an image type value. 

const (
	// UNKNOWN represents an unknow image type value.
	UNKNOWN ImageType = iota
	// JPEG represents the JPEG image type.
	JPEG
	// WEBP represents the WEBP image type.
	WEBP
	// PNG represents the PNG image type.
	PNG
	// TIFF represents the TIFF image type.
	TIFF
	// GIF represents the GIF image type.
	GIF
	// PDF represents the PDF type.
	PDF
	// SVG represents the SVG image type.
	SVG
	// MAGICK represents the libmagick compatible genetic image type.
	MAGICK
	// HEIF represents the HEIC/HEIF/HVEC image type
	HEIF
	// AVIF represents the AVIF image type.
	AVIF
)

func DetermineImageType 

func DetermineImageType(buf []byte) ImageType

DetermineImageType determines the image type format (jpeg, png, webp or tiff)

type Interpolator 

type Interpolator int

Interpolator represents the image interpolation value. 

const (
	// Bicubic interpolation value.
	Bicubic Interpolator = iota
	// Bilinear interpolation value.
	Bilinear
	// Nohalo interpolation value.
	Nohalo
	// Nearest neighbour interpolation value.
	Nearest
)

func (Interpolator) String 

func (i Interpolator) String() string

type Interpretation 

type Interpretation int

Interpretation represents the image interpretation type. See: https://libvips.github.io/libvips/API/current/VipsImage.html#VipsInterpretation 

const (
	// InterpretationError points to the libvips interpretation error type.
	InterpretationError Interpretation = C.VIPS_INTERPRETATION_ERROR
	// InterpretationMultiband points to its libvips interpretation equivalent type.
	InterpretationMultiband Interpretation = C.VIPS_INTERPRETATION_MULTIBAND
	// InterpretationBW points to its libvips interpretation equivalent type.
	InterpretationBW Interpretation = C.VIPS_INTERPRETATION_B_W
	// InterpretationCMYK points to its libvips interpretation equivalent type.
	InterpretationCMYK Interpretation = C.VIPS_INTERPRETATION_CMYK
	// InterpretationRGB points to its libvips interpretation equivalent type.
	InterpretationRGB Interpretation = C.VIPS_INTERPRETATION_RGB
	// InterpretationSRGB points to its libvips interpretation equivalent type.
	InterpretationSRGB Interpretation = C.VIPS_INTERPRETATION_sRGB
	// InterpretationRGB16 points to its libvips interpretation equivalent type.
	InterpretationRGB16 Interpretation = C.VIPS_INTERPRETATION_RGB16
	// InterpretationGREY16 points to its libvips interpretation equivalent type.
	InterpretationGREY16 Interpretation = C.VIPS_INTERPRETATION_GREY16
	// InterpretationScRGB points to its libvips interpretation equivalent type.
	InterpretationScRGB Interpretation = C.VIPS_INTERPRETATION_scRGB
	// InterpretationLAB points to its libvips interpretation equivalent type.
	InterpretationLAB Interpretation = C.VIPS_INTERPRETATION_LAB
	// InterpretationXYZ points to its libvips interpretation equivalent type.
	InterpretationXYZ Interpretation = C.VIPS_INTERPRETATION_XYZ
)

func ImageInterpretation 

func ImageInterpretation(buf []byte) (Interpretation, error)

ImageInterpretation returns the image interpretation type. See: https://libvips.github.io/libvips/API/current/VipsImage.html#VipsInterpretation

type Options 

type Options struct {
	Height         int
	Width          int
	AreaHeight     int
	AreaWidth      int
	Top            int
	Left           int
	Quality        int
	Compression    int
	Zoom           int
	Crop           bool
	SmartCrop      bool // Deprecated, use: bimg.Options.Gravity = bimg.GravitySmart
	Enlarge        bool
	Embed          bool
	Flip           bool
	Flop           bool
	Force          bool
	NoAutoRotate   bool
	NoProfile      bool
	Interlace      bool
	StripMetadata  bool
	Trim           bool
	Lossless       bool
	Extend         Extend
	Rotate         Angle
	Background     Color
	Gravity        Gravity
	Watermark      Watermark
	WatermarkImage WatermarkImage
	Type           ImageType
	Interpolator   Interpolator
	Interpretation Interpretation
	GaussianBlur   GaussianBlur
	Sharpen        Sharpen
	Threshold      float64
	Gamma          float64
	OutputICC      string
	InputICC       string
	Palette        bool
	// Speed defines the AVIF encoders CPU effort. Valid values are 0-8.
	Speed int
	// contains filtered or unexported fields
}

Options represents the supported image transformation options.

type Sharpen 

type Sharpen struct {
	Radius int
	X1     float64
	Y2     float64
	Y3     float64
	M1     float64
	M2     float64
}

Sharpen represents the image sharp transformation options.

type SupportedImageType added in v1.0.7 

type SupportedImageType struct {
	Load bool
	Save bool
}

SupportedImageType represents whether a type can be loaded and/or saved by the current libvips compilation.

func IsImageTypeSupportedByVips added in v1.0.3 

func IsImageTypeSupportedByVips(t ImageType) SupportedImageType

IsImageTypeSupportedByVips returns true if the given image type is supported by current libvips compilation.

type VipsMemoryInfo 

type VipsMemoryInfo struct {
	Memory          int64
	MemoryHighwater int64
	Allocations     int64
}

VipsMemoryInfo represents the memory stats provided by libvips.

func VipsMemory 

func VipsMemory() VipsMemoryInfo

VipsMemory gets memory info stats from libvips (cache size, memory allocs...)

type Watermark 

type Watermark struct {
	Width       int
	DPI         int
	Margin      int
	Opacity     float32
	NoReplicate bool
	Text        string
	Font        string
	Background  Color
}

Watermark represents the text-based watermark supported options.

type WatermarkImage added in v1.0.8 

type WatermarkImage struct {
	Left    int
	Top     int
	Buf     []byte
	Opacity float32
}

WatermarkImage represents the image-based watermark supported options.

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