Golang C.DestroyImageInfo类(方法)实例源码

// Destroy frees the C memory for the image. Should be called after processing is done.
func (im *MagickImage) Destroy() (err error) {
	C.DestroyImage(im.Image)
	C.DestroyImageInfo(im.ImageInfo)
	im.Image = nil
	im.ImageInfo = nil
	return
}

func main() {
	// Some GraphicsMagick boilerplate
	C.InitializeMagick(nil)
	defer C.DestroyMagick()
	C.GetExceptionInfo(&exceptionInfo)
	imageInfo = C.CloneImageInfo(nil)
	defer C.DestroyExceptionInfo(&exceptionInfo)
	defer C.DestroyImageInfo(imageInfo)

	// main OMIT

	Show("./cgo/armed_gopher.jpg")

	img, err := Read("./cgo/armed_gopher.jpg")
	if err != nil {
		fmt.Println(err)
		return
	}

	if img, err = Resize(img, 200, 800); err != nil {
		fmt.Println("resize error:", err)
		return
	}

	if err = Save(img, "./cgo/resized_gopher.jpg"); err != nil {
		fmt.Println("save error:", err)
		return
	}

	Show("./cgo/resized_gopher.jpg")
}

// Destroy frees the C memory for the image. Should be called after processing is done.
func (im *MagickImage) Destroy() (err error) {
	if im.Image != nil {
		C.DestroyImage(im.Image)
	}
	if im.ImageInfo != nil {
		C.DestroyImageInfo(im.ImageInfo)
	}
	im.Image = nil
	im.ImageInfo = nil
	return
}

// NewInfo returns a newly allocated *Info structure. Do not
// create Info objects directly, since they need to allocate
// some internal structures while being created.
func NewInfo() *Info {
	cinfo := C.CloneImageInfo(nil)
	info := new(Info)
	info.info = cinfo
	runtime.SetFinalizer(info, func(i *Info) {
		if i.info != nil {
			C.DestroyImageInfo(i.info)
			i.info = nil
		}
	})
	return info
}

// NewFromFile loads a file at filename into a MagickImage.
// Exceptions are returned as MagickErrors.
func NewFromFile(filename string) (im *MagickImage, err error) {
	exception := C.AcquireExceptionInfo()
	defer C.DestroyExceptionInfo(exception)
	info := C.AcquireImageInfo()
	c_filename := C.CString(filename)
	defer C.free(unsafe.Pointer(c_filename))
	C.SetImageInfoFilename(info, c_filename)
	image := C.ReadImage(info, exception)
	if failed := C.CheckException(exception); failed == C.MagickTrue {
		C.DestroyImageInfo(info)
		return nil, ErrorFromExceptionInfo(exception)
	}
	return &MagickImage{Image: image, ImageInfo: info}, nil
}

func decodeData(data []byte, try int) (*Image, error) {
	if len(data) == 0 {
		return nil, ErrNoData
	}
	info := C.CloneImageInfo(nil)
	defer C.DestroyImageInfo(info)
	var ex C.ExceptionInfo
	C.GetExceptionInfo(&ex)
	defer C.DestroyExceptionInfo(&ex)
	im := C.BlobToImage(info, unsafe.Pointer(&data[0]), C.size_t(len(data)), &ex)
	if im == nil && try < maxGifTries && ex.severity == C.CorruptImageError && looksLikeGif(data) {
		return fixAndDecodeGif(data, try)
	}
	return checkImage(im, nil, &ex, "decoding")
}

// NewFromBlob takes a byte slice of image data and an extension that defines the
// image type (e.g. "png", "jpg", etc). It loads the image data and returns a MagickImage.
// The extension is required so that Magick knows what processor to use.
func NewFromBlob(blob []byte, extension string) (im *MagickImage, err error) {
	if len(blob) < 1 {
		return nil, &MagickError{"fatal", "", "zero length blob passed to NewFromBlob"}
	}
	if len(extension) < 1 {
		return nil, &MagickError{"fatal", "", "zero length extension passed to NewFromBlob"}
	}
	exception := C.AcquireExceptionInfo()
	defer C.DestroyExceptionInfo(exception)
	info := C.AcquireImageInfo()
	defer C.DestroyImageInfo(info)
	c_filename := C.CString("image." + extension)
	defer C.free(unsafe.Pointer(c_filename))
	C.SetImageInfoFilename(info, c_filename)
	var success (C.MagickBooleanType)
	success = C.SetImageInfo(info, 1, exception)
	if success != C.MagickTrue {
		return nil, ErrorFromExceptionInfo(exception)
	}
	cloned_info := C.CloneImageInfo(info)
	success = C.GetBlobSupport(info)
	if success != C.MagickTrue {
		// No blob support, lets try reading from a file
		file, err := ioutil.TempFile("", "image."+extension)
		if _, err = file.Write(blob); err != nil {
			return nil, &MagickError{"fatal", "", "image format " + extension + " does not support blobs and could not write temp file"}
		}
		file.Close()
		return NewFromFile(file.Name())
	}
	length := (C.size_t)(len(blob))
	if length == 0 {
		return nil, &MagickError{"fatal", "", "empty blob"}
	}
	blob_start := unsafe.Pointer(&blob[0])
	image := C.ReadImageFromBlob(info, blob_start, length)

	if image == nil {
		return nil, &MagickError{"fatal", "", "corrupt image, not a " + extension}
	}

	if failed := C.CheckException(exception); failed == C.MagickTrue {
		return nil, ErrorFromExceptionInfo(exception)
	}

	return &MagickImage{Image: image, ImageInfo: cloned_info}, nil
}

func (im *Image) AnnotateImage(x, y int, text string, fontSize int, color string) {
	image_info := C.CloneImageInfo(nil)
	defer C.DestroyImageInfo(image_info)

	draw_info := C.CloneDrawInfo(image_info, nil)
	defer C.DestroyDrawInfo(draw_info)

	textBytes := []byte(text)
	bytesPointer := unsafe.Pointer(&textBytes[0])

	textArray := (*C.uchar)(bytesPointer)

	colorArray := C.CString(color)
	defer C.free(unsafe.Pointer(colorArray))

	draw_context := C.DrawAllocateContext(draw_info, im.image)
	defer C.DrawDestroyContext(draw_context)

	C.DrawSetFontSize(draw_context, C.double(fontSize))
	C.DrawSetStrokeColorString(draw_context, colorArray)
	C.DrawSetFillColorString(draw_context, colorArray)
	C.DrawAnnotation(draw_context, C.double(x), C.double(y), textArray)
	C.DrawRender(draw_context)
}