https://github.com/gographics/imagick/issues/72

imagick_leak_test.go

// Testing reported mem leak at: https://github.com/gographics/imagick/issues/72

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"runtime"

	"gopkg.in/gographics/imagick.v2/imagick"
)

const SrcImage = `/path/to/source/image.jpg`

func main() {

	imagick.Initialize()
	defer imagick.Terminate()

	i := 0
	var stats runtime.MemStats

	for {

		Process()

		runtime.ReadMemStats(&stats)

		i++
		fmt.Printf("After run #%04d: Alloc: %v, Idle: %v, InUse: %v, Objects: %v\n", i,
			stats.HeapAlloc, stats.HeapIdle, stats.HeapInuse, stats.HeapObjects)
	}
}

func Process() {

	f, err := os.Open(SrcImage)
	if err != nil {
		log.Fatalf("Failed to open source image: %v", err)
	}
	defer f.Close()

	img, err := ioutil.ReadAll(f)
	if err != nil {
		log.Fatalf("Failed to read image file: %v", err)
	}

	mw := imagick.NewMagickWand()
	defer mw.Destroy()

	err = mw.ReadImageBlob(img)
	if err != nil {
		log.Fatalf("Failed to read image blob: %v", err)
	}

	originalWidth := float64(mw.GetImageWidth())
	originalHeight := float64(mw.GetImageHeight())

	imageAspectRatio := originalWidth / originalHeight

	masterWidth := 320.0
	masterHeight := 180.0
	masterAspectRatio := masterWidth / masterHeight

	pwm := imagick.NewPixelWand()
	defer pwm.Destroy()

	tx := imagick.NewMagickWand()
	defer tx.Destroy()

	var w, h uint = 0, 0
	size := fmt.Sprintf("%dx%d^+0+0", w, h)
	if imageAspectRatio <= masterAspectRatio {
		// trim the height
		w = uint(originalWidth)
		h = (uint(originalWidth / masterAspectRatio))
		size = fmt.Sprintf("%dx%d^+0+0", w, h)
	} else {
		// trim the width
		w = uint(originalHeight * masterAspectRatio)
		h = uint(originalHeight)
		size = fmt.Sprintf("%dx%d^+0+0", w, h)
	}

	tx = mw.TransformImage("", size)
	tx.SetImageGravity(imagick.GRAVITY_CENTER)
	offsetX := -(int(w) - int(tx.GetImageWidth())) / 2
	offsetY := -(int(h) - int(tx.GetImageHeight())) / 2
	err = tx.ExtentImage(w, h, offsetX, offsetY)
	if err != nil {
		log.Fatalf("Failed calling ExtendImage(%v, %v, %v, %v): %v",
			w, h, offsetX, offsetY, err)
	}

	if float64(tx.GetImageWidth()) > masterWidth && float64(tx.GetImageHeight()) > masterHeight {

		err = tx.ResizeImage(uint(masterWidth), uint(masterHeight), imagick.FILTER_BOX, 1)
		if err != nil {
			log.Fatalf("Inside CreateMaster function Couldn't "+
				"resize the image %s: %s", SrcImage, err)
		}
	}

}