Merge branch '220_convert_command' into im-7

examples/convert_command/main.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+
+	"gopkg.in/gographics/imagick.v3/imagick"
+)
+
+func main() {
+	imagick.Initialize()
+	defer imagick.Terminate()
+
+	ret, err := imagick.ConvertImageCommand([]string{
+		"convert", "logo:", "-resize", "100x100", "/tmp/out.png",
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("Metadata:\n%s\n", ret.Meta)
+}

imagick/image.go

@@ -5,10 +5,14 @@
 package imagick
 
 /*
+#include <MagickWand/MagickWand.h>
 #include <MagickCore/MagickCore.h>
 */
 import "C"
-import "runtime"
+import (
+	"runtime"
+	"unsafe"
+)
 
 type Image struct {
 	img *C.Image
@@ -33,3 +37,61 @@ func NewMagickImage(info *ImageInfo, width, height uint,
 
 	return &Image{img: img}, nil
 }
+
+// ImageCommandResult is returned by a call to
+// ConvertImageCommand. It contains the ImageInfo
+// and Metadata string generated by the convert command.
+type ImageCommandResult struct {
+	Info *ImageInfo
+	Meta string
+}
+
+/*
+ConvertImageCommand reads one or more images, applies one or more image
+processing operations, and writes out the image in the same or differing
+format.
+The first item in the args list is expected to be the program name, ie "convert".
+*/
+func ConvertImageCommand(args []string) (*ImageCommandResult, error) {
+	size := len(args)
+
+	cmdArr := make([]*C.char, size)
+	for i, s := range args {
+		cmdArr[i] = C.CString(s)
+	}
+
+	empty := C.CString("")
+	metaStr := C.AcquireString(empty)
+	C.free(unsafe.Pointer(empty))
+
+	defer func() {
+		for i := range cmdArr {
+			C.free(unsafe.Pointer(cmdArr[i]))
+		}
+
+		C.DestroyString(metaStr)
+	}()
+
+	imageInfo := newImageInfo()
+
+	var exc *C.ExceptionInfo = C.AcquireExceptionInfo()
+	defer C.DestroyExceptionInfo(exc)
+
+	ok := C.ConvertImageCommand(
+		imageInfo.info,
+		C.int(size), // argc
+		&cmdArr[0],  // argv
+		&metaStr,    // metadata
+		exc,         // exception
+	)
+	if C.int(ok) == 0 {
+		imageInfo.Destroy()
+		return nil, newExceptionInfo(exc)
+	}
+
+	ret := &ImageCommandResult{
+		Info: imageInfo,
+		Meta: C.GoString(metaStr),
+	}
+	return ret, nil
+}

imagick/image_test.go

@@ -5,6 +5,9 @@
 package imagick
 
 import (
+	"fmt"
+	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -28,3 +31,32 @@ func TestNewMagickImage(t *testing.T) {
 		t.Fatal(err.Error())
 	}
 }
+
+func ExampleConvertImageCommand() {
+	ret, err := ConvertImageCommand([]string{
+		"convert", "logo:", "-resize", "100x100", "/tmp/out.png",
+	})
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println("Meta:", ret.Meta)
+}
+
+func TestConvertImageCommand(t *testing.T) {
+	tmp, err := ioutil.TempFile("", "imagick_test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(tmp.Name())
+
+	ret, err := ConvertImageCommand([]string{
+		"convert", "logo:", "-resize", "100x100", tmp.Name(),
+	})
+	if err != nil {
+		t.Fatalf("command failed: %v", err)
+	}
+
+	if ret.Meta == "" {
+		t.Fatal("got empty metadata string from command result")
+	}
+}