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Package caire

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The latest major version is .

Published: Jul 2, 2020 | License: MIT | Module:


Package caire is a content aware image resize library, which can rescale the source image seamlessly both vertically and horizontally by eliminating the less important parts of the image.

The package provides a command line interface, supporting various flags for different types of rescaling operations. To check the supported commands type:

$ caire --help

In case you wish to integrate the API in a self constructed environment here is a simple example:

package main

import (

func main() {
	p := &caire.Processor{
		// Initialize struct variables

	if err := p.Process(in, out); err != nil {
		fmt.Printf("Error rescaling image: %s", err.Error())



var TempImage = fmt.Sprintf("%d.jpg", time.Now().Unix())

TempImage temporary image file.

func Grayscale

func Grayscale(src *image.NRGBA) *image.NRGBA

Grayscale converts the image to grayscale mode.

func RemoveTempImage

func RemoveTempImage(tmpImage string)

RemoveTempImage removes the temporary image generated during face detection process.

func Resize

func Resize(s SeamCarver, img *image.NRGBA) (image.Image, error)

Resize implements the Resize method of the Carver interface. It returns the concrete resize operation method.

func SobelFilter

func SobelFilter(img *image.NRGBA, threshold float64) *image.NRGBA

SobelFilter detects image edges. See

func StackBlur

func StackBlur(img *image.NRGBA, radius uint32) *image.NRGBA

StackBlur applies a blur filter to the provided image. The radius defines the bluring average.

type ActiveSeam

type ActiveSeam struct {
	Pix color.Color

ActiveSeam contains the current seam position and color.

type Carver

type Carver struct {
	Width  int
	Height int
	Points []float64

Carver is the main entry struct having as parameters the newly generated image width, height and seam points.

func NewCarver

func NewCarver(width, height int) *Carver

NewCarver returns an initialized Carver structure.

func (*Carver) AddSeam

func (c *Carver) AddSeam(img *image.NRGBA, seams []Seam, debug bool) *image.NRGBA

AddSeam add new seam.

func (*Carver) ComputeSeams

func (c *Carver) ComputeSeams(img *image.NRGBA, p *Processor)

ComputeSeams compute the minimum energy level based on the following logic:

- traverse the image from the second row to the last row
  and compute the cumulative minimum energy M for all possible
  connected seams for each entry (i, j).

- the minimum energy level is calculated by summing up the current pixel value
  with the minimum pixel value of the neighboring pixels from the previous row.

func (*Carver) FindLowestEnergySeams

func (c *Carver) FindLowestEnergySeams() []Seam

FindLowestEnergySeams find the lowest vertical energy seam.

func (*Carver) RemoveSeam

func (c *Carver) RemoveSeam(img *image.NRGBA, seams []Seam, debug bool) *image.NRGBA

RemoveSeam remove the least important columns based on the stored energy (seams) level.

func (*Carver) RotateImage270

func (c *Carver) RotateImage270(src *image.NRGBA) *image.NRGBA

RotateImage270 rotate the image by 270 degree counter clockwise.

func (*Carver) RotateImage90

func (c *Carver) RotateImage90(src *image.NRGBA) *image.NRGBA

RotateImage90 rotate the image by 90 degree counter clockwise.

type Processor

type Processor struct {
	SobelThreshold int
	BlurRadius     int
	NewWidth       int
	NewHeight      int
	Percentage     bool
	Square         bool
	Debug          bool
	Scale          bool
	FaceDetect     bool
	FaceAngle      float64
	Classifier     string

Processor options

func (*Processor) Process

func (p *Processor) Process(r io.Reader, w io.Writer) error

Process is the main function having as parameters an input reader and an output writer. We are using the io package, because this way we can provide different types of input and output source, as long as they implement the io.Reader and io.Writer interface.

func (*Processor) Resize

func (p *Processor) Resize(img *image.NRGBA) (image.Image, error)

Resize method takes the source image and rescales it using the parameters provided. The new image can be rescaled either horizontally or vertically (or both). Depending on the provided parameters the image can be either reduced or enlarged.

type Seam

type Seam struct {
	X int
	Y int

Seam struct contains the seam pixel coordinates.

type SeamCarver

type SeamCarver interface {
	Resize(*image.NRGBA) (image.Image, error)

SeamCarver interface defines the Resize method. This has to be implemented by every struct which declares a Resize method.

type UsedSeams

type UsedSeams struct {
	ActiveSeam []ActiveSeam

UsedSeams contains the already generated seams.

Package Files

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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