zntg/ui/imagesource.go

package ui

import (
	"image"

	"github.com/nfnt/resize"
	"opslag.de/schobers/zntg"
)

type ImageSource interface {
	CreateImage() (image.Image, error)
}

type ImageSourceFile string

var _ ImageSource = ImageSourceFile("")

func (s ImageSourceFile) CreateImage() (image.Image, error) {
	return zntg.DecodeImage(string(s))
}

type ImageSourceGo struct {
	image.Image
}

var _ ImageSource = ImageSourceGo{}

func (s ImageSourceGo) CreateImage() (image.Image, error) {
	return s.Image, nil
}

type ImageSourceResource struct {
	Resources Resources
	Name      string
}

func (s ImageSourceResource) CreateImage() (image.Image, error) {
	src, err := s.Resources.OpenResource(s.Name)
	if err != nil {
		return nil, err
	}
	defer src.Close()
	value, err := zntg.ImageDecoder(src)
	if err != nil {
		return nil, err
	}
	return value.(image.Image), nil
}

func ImageSourceFromResources(res Resources, name string) ImageSourceResource {
	return ImageSourceResource{Resources: res, Name: name}
}

func Scaled(source ImageSource, width, height int) ImageSource {
	return scaledImageSource{ImageSource: source, width: width, height: height}
}

type scaledImageSource struct {
	ImageSource

	width, height int
}

func (s scaledImageSource) CreateImage() (image.Image, error) {
	im, err := s.ImageSource.CreateImage()
	if err != nil {
		return nil, err
	}
	return resize.Resize(uint(s.width), uint(s.height), im, resize.Bicubic), nil
}