photo

Documentation

Index

• Constants
• func DominantImageColor(ctx context.Context, img image.Image) (color.Color, error)
• func Encode(format string, w io.Writer, img image.Image, opts any) error
• func FilenameForFormat(format, path string) (string, error)
• func FilenameWithoutFormat(format, path string) string
• func PreferredExt(format string) string
• func RegisterEncoder(format string, ext []string, enc EncoderFunc)
• type Complete
  • func (i *Complete) Filename() string
  • func (i *Complete) Image() (image.Image, string, error)
  • func (i *Complete) Reader() (io.ReadCloser, error)
• type Creator
• type Descriptor
  • func (d *Descriptor) AddImage(key string, img Image)
  • func (d *Descriptor) GetColor() (color.Color, error)
  • func (d *Descriptor) GetImage(key string) ImageComplete
  • func (d *Descriptor) HasImage(key string) bool
  • func (d *Descriptor) RemoveImage(key string)
  • func (d *Descriptor) SetColor(c color.Color)
• type EncoderFunc
• type File
  • func NewFile(path string) *File
  • func (f *File) Filename() string
  • func (f *File) Reader() (io.ReadCloser, error)
• type Image
• type ImageComplete
  • func CompleteImage(img Image) ImageComplete
• type ImageDecoded
• type ImageReader
• type Memory
  • func NewMemory(name string, format string, img image.Image) *Memory
  • func (m *Memory) Filename() string
  • func (m *Memory) Image() (image.Image, string, error)
• type Option
  • func FromImage(img string) Option
  • func MaxHeight(h uint) Option
  • func MaxWidth(w uint) Option
• type Service
  • func NewService(s Source) *Service
  • func (s *Service) Photo(ctx context.Context, photoUrl string) (*Descriptor, error)
  • func (s *Service) ResizedImage(ctx context.Context, d *Descriptor, opts ...Option) (string, error)
• type Source

Constants

const (
	DefaultMaxWidth  uint = 3840
	DefaultMaxHeight uint = 3840
)

const DefaultFormat = "jpeg"

const (
	Original = "original"
)

Functions

func DominantImageColor

func DominantImageColor(
	ctx context.Context,
	img image.Image,
) (color.Color, error)

DominantImageColor returns the dominant color of the image. This is calculated by creating a histogram of all image pixels, then selecting the color that is used the most after excluding pure black and white (unless they are the only possible choices).

func Encode

func Encode(format string, w io.Writer, img image.Image, opts any) error

Encode encodes the image to the given format and writes it to the writer. If the format is empty, the default format is assumed. If the format is not registered, an error is returned.

func FilenameForFormat

func FilenameForFormat(format, path string) (string, error)

FilenameForFormat returns a filename for the given format. If the path already has an extension for the format, the path is returned as is. Otherwise, the path is returned with the extension for the format appended. If the format is empty, the default format is assumed. If the format is not registered, an error is returned.

func FilenameWithoutFormat

func FilenameWithoutFormat(format, path string) string

FilenameWithoutFormat returns a filename with the format extension removed.

func PreferredExt

func PreferredExt(format string) string

func RegisterEncoder

func RegisterEncoder(format string, ext []string, enc EncoderFunc)

Types

type Complete

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

Complete provides a complete implementation of the Image interface, providing ImageDecoded and ImageReader.

func (*Complete) Filename

func (i *Complete) Filename() string

func (*Complete) Image

func (i *Complete) Image() (image.Image, string, error)

func (*Complete) Reader

func (i *Complete) Reader() (io.ReadCloser, error)

type Creator

type Creator struct {
	Name string `yaml:"name" json:"name"`
	Link string `yaml:"link" json:"link"`
}

Creator contains the metadata about the creator of a photo.

type Descriptor

type Descriptor struct {
	Link    string  `yaml:"link" json:"link"`
	Type    string  `yaml:"type" json:"type"`
	Title   string  `yaml:"title,omitempty" json:"title,omitempty"`
	Color   string  `yaml:"color,omitempty" json:"color,omitempty"`
	Creator Creator `yaml:"creator" json:"creator"`
	// contains filtered or unexported fields
}

Descriptor provides metadata data about the image, which is stored in a serialization format on openscripture.today, and also includes a reference to the image file.

func (*Descriptor) AddImage

func (d *Descriptor) AddImage(key string, img Image)

AddImage adds an image to the descriptor.

func (*Descriptor) GetColor

func (d *Descriptor) GetColor() (color.Color, error)

GetColor returns a color.Color after decoding the CSS string stored. Returns nil and an error if the color cannot be decoded. Returns nil with no error if the color is not set.

func (*Descriptor) GetImage

func (d *Descriptor) GetImage(key string) ImageComplete

GetImage returns an image from the descriptor.

func (*Descriptor) HasImage

func (d *Descriptor) HasImage(key string) bool

HasImage returns true if the descriptor has an image with the given key.

func (*Descriptor) RemoveImage

func (d *Descriptor) RemoveImage(key string)

RemoveImage removes an image from the descriptor.

func (*Descriptor) SetColor

func (d *Descriptor) SetColor(c color.Color)

SetColor sets the color as a CSS string from a color.Color.

type EncoderFunc

type EncoderFunc func(w io.Writer, img image.Image, opts any) error

type File

type File struct {
	Path string
}

func NewFile

func NewFile(path string) *File

func (*File) Filename

func (f *File) Filename() string

func (*File) Reader

func (f *File) Reader() (io.ReadCloser, error)

type Image

type Image interface {
	// Filename is the filename for the image. This may include a directory path
	// as well. It may be useful as a cache key, so a unique name is preferred.
	Filename() string
}

Image is the interface for a photo image. Every Image must also implemented ImageDecoded or ImageReader.

type ImageComplete

type ImageComplete interface {
	Image
	ImageReader
	ImageDecoded
}

ImageComplete is the interface for images that implement Image, ImageReader, and ImageDecoded.

func CompleteImage

func CompleteImage(img Image) ImageComplete

type ImageDecoded

type ImageDecoded interface {
	// Image returns the image and the format of the image. The format is the
	// name of the format, like "jpeg" or "png". It should match the registered
	// format used to decode the image. If the image was not decoded, the format
	// should be empty. An error should be returned if there's a problem getting
	// the iamge data.
	Image() (img image.Image, format string, err error)
}

ImageDecoded is the interface that provides the image data in decoded form.

type ImageReader

type ImageReader interface {
	Reader() (io.ReadCloser, error)
}

ImageReader is the interface that provides the image data via io.Reader. After reading the image data, the caller must close the reader.

type Memory

type Memory struct {
	Name   string
	Format string
	Img    image.Image
}

func NewMemory

func NewMemory(name string, format string, img image.Image) *Memory

func (*Memory) Filename

func (m *Memory) Filename() string

func (*Memory) Image

func (m *Memory) Image() (image.Image, string, error)

type Option

type Option func(*options)

func FromImage

func FromImage(img string) Option

func MaxHeight

func MaxHeight(h uint) Option

func MaxWidth

func MaxWidth(w uint) Option

type Service

type Service struct {
	Source
	Client *http.Client
}

func NewService

func NewService(s Source) *Service

func (*Service) Photo

func (s *Service) Photo(
	ctx context.Context,
	photoUrl string,
) (*Descriptor, error)

Meta returns the photo info for a given photo URL. It will cache the photo info in the local filesystem and in S3.

func (*Service) ResizedImage

func (s *Service) ResizedImage(
	ctx context.Context,
	d *Descriptor,
	opts ...Option,
) (string, error)

ResizedImage returns a resized version of the photo if it is larger than the maximum width and height I have set.

type Source

type Source interface {
	// Meta returns the photo info for a given URL.
	Photo(ctx context.Context, url string) (desc *Descriptor, err error)
}

Source is the interface for a source of photo information.