go-imager/pkg/img/info.go

package img

import (
	"bytes"
	"encoding/base64"
	"image"
	"image/color"
	"image/jpeg"
	_ "image/jpeg"
	"image/png"
	_ "image/png"
	"math"
	"os"
	"strconv"

	"github.com/disintegration/imaging"
	"github.com/spf13/cast"
)

type ImageInfo struct {
	Path   string      `json:"path"`
	Base64 string      `json:"base64"`
	Type   string      `json:"type"`
	Width  int         `json:"width"`
	Height int         `json:"height"`
	Image  image.Image `json:"-"`
}

type ImageEffect struct {
	Name     string         `json:"name"`
	Settings map[string]any `json:"settings"`
}

func GetImageInfo(file string) *ImageInfo {
	content, err := os.ReadFile(file)

	if err != nil {
		return nil
	}

	reader, err := os.Open(file)

	if err != nil {
		return nil
	}

	defer reader.Close()

	i, t, err := image.Decode(reader)

	if err != nil {
		return nil
	}

	info := ImageInfo{
		Path:   file,
		Base64: base64.StdEncoding.EncodeToString(content),
		Type:   t,
		Width:  i.Bounds().Dx(),
		Height: i.Bounds().Dy(),
		Image:  i,
	}

	return &info
}

func ApplyFilters(src *ImageInfo, effects []ImageEffect) *ImageInfo {
	base := GetImageInfo(src.Path)
	result := base.Image
	quality := 100

	for _, effect := range effects {
		if effect.Name == "scale-width" {
			width := cast.ToFloat64(effect.Settings["value"])
			height := cast.ToInt(math.Round(float64(result.Bounds().Dy()) * width / float64(result.Bounds().Dx())))

			result = imaging.Resize(
				result,
				cast.ToInt(width),
				cast.ToInt(height),
				imaging.Lanczos,
			)
		} else if effect.Name == "scale-height" {
			height := cast.ToFloat64(effect.Settings["value"])
			width := cast.ToInt(math.Round(float64(result.Bounds().Dx()) * height / float64(result.Bounds().Dy())))

			result = imaging.Resize(
				result,
				cast.ToInt(width),
				cast.ToInt(height),
				imaging.Lanczos,
			)
		} else if effect.Name == "crop" {
			result = imaging.Crop(
				result,
				image.Rect(
					cast.ToInt(effect.Settings["x0"]),
					cast.ToInt(effect.Settings["y0"]),
					cast.ToInt(effect.Settings["x1"]),
					cast.ToInt(effect.Settings["y1"]),
				),
			)
		} else if effect.Name == "crop-center" {
			result = imaging.CropCenter(
				result,
				cast.ToInt(effect.Settings["width"]),
				cast.ToInt(effect.Settings["height"]),
			)
		} else if effect.Name == "resize" {
			result = imaging.Resize(
				result,
				cast.ToInt(effect.Settings["width"]),
				cast.ToInt(effect.Settings["height"]),
				imaging.Lanczos,
			)
		} else if effect.Name == "brightness" {
			result = imaging.AdjustBrightness(result, cast.ToFloat64(effect.Settings["value"]))
		} else if effect.Name == "contrast" {
			result = imaging.AdjustContrast(result, cast.ToFloat64(effect.Settings["value"]))
		} else if effect.Name == "saturation" {
			result = imaging.AdjustSaturation(result, cast.ToFloat64(effect.Settings["value"]))
		} else if effect.Name == "gamma" {
			result = imaging.AdjustGamma(result, cast.ToFloat64(effect.Settings["value"]))
		} else if effect.Name == "blur" {
			result = imaging.Blur(result, cast.ToFloat64(effect.Settings["value"]))
		} else if effect.Name == "flip-v" {
			result = imaging.FlipV(result)
		} else if effect.Name == "flip-h" {
			result = imaging.FlipH(result)
		} else if effect.Name == "rotate-90" {
			result = imaging.Rotate90(result)
		} else if effect.Name == "rotate-180" {
			result = imaging.Rotate180(result)
		} else if effect.Name == "rotate-270" {
			result = imaging.Rotate270(result)
		} else if effect.Name == "quality" {
			quality = cast.ToInt(effect.Settings["value"])
		} else if effect.Name == "rotate" {
			values, err := strconv.ParseUint(string(effect.Settings["backgroundColor"].(string)[1:]), 16, 32)

			if err == nil {
				result = imaging.Rotate(
					result,
					cast.ToFloat64(effect.Settings["value"]),
					color.RGBA{
						R: uint8(values >> 16),
						G: uint8((values >> 8) & 0xFF),
						B: uint8(values & 0xFF),
						A: 255,
					},
				)
			}
		}
	}

	buff := new(bytes.Buffer)

	if src.Type == "jpeg" {
		err := jpeg.Encode(buff, result, &jpeg.Options{
			Quality: quality,
		})

		if err != nil {
			return nil
		}
	} else {
		err := png.Encode(buff, result)

		if err != nil {
			return nil
		}
	}

	return &ImageInfo{
		Path:   "",
		Base64: base64.StdEncoding.EncodeToString(buff.Bytes()),
		Type:   base.Type,
		Width:  result.Bounds().Dx(),
		Height: result.Bounds().Dy(),
		Image:  result,
	}
}