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package converter
import (
"fmt"
"image"
"image/jpeg"
"image/png"
"io"
"log/slog"
"strings"
"golang.org/x/image/draw"
"github.com/SayaAndy/saya-today-thumbnail-generator/config"
"github.com/SayaAndy/saya-today-thumbnail-generator/internal/client/input"
"github.com/SayaAndy/saya-today-thumbnail-generator/internal/client/output"
"github.com/kolesa-team/go-webp/encoder"
"github.com/kolesa-team/go-webp/webp"
)
var _ Converter = (*WebpConverter)(nil)
type WebpConverter struct {
maxWidth int
maxHeight int
quality int
outputClient output.OutputClient
}
func NewWebpConverter(cfg *config.ConverterConfig) (Converter, error) {
if cfg.Type != "webp" {
return nil, fmt.Errorf("invalid storage type for WebpConverter")
}
webpCfg := cfg.Config.(*config.WebpConfig)
outputClient, err := output.NewOutputClientMap[cfg.Output.Storage.Type](&cfg.Output)
if err != nil {
return nil, fmt.Errorf("fail to initialize output client: %w", err)
}
return &WebpConverter{webpCfg.Size.MaxWidth, webpCfg.Size.MaxHeight, webpCfg.Quality, outputClient}, nil
}
func (p *WebpConverter) Process(inputMetadata *input.MetadataStruct, reader io.Reader, outputName string) error {
var src image.Image
writer, err := p.outputClient.GetWriter(outputName, inputMetadata, "image/webp")
if err != nil {
return fmt.Errorf("fail to initialize writer for output: %w", err)
}
defer writer.Close()
switch inputMetadata.ContentType {
case "image/jpeg":
src, err = jpeg.Decode(reader)
if err != nil {
return fmt.Errorf("decode jpeg: %w", err)
}
case "image/png":
src, err = png.Decode(reader)
if err != nil {
return fmt.Errorf("decode png: %w", err)
}
case "image/webp":
src, err = webp.Decode(reader, nil)
if err != nil {
return fmt.Errorf("decode webp: %w", err)
}
default:
return fmt.Errorf("unsupported content type: %s", inputMetadata.ContentType)
}
opts, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, float32(p.quality))
if err != nil {
return fmt.Errorf("create webp encoder options: %w", err)
}
xCoef := 1.0
if p.maxWidth > 0 {
xCoef = float64(p.maxWidth) / float64(src.Bounds().Max.X)
}
yCoef := 1.0
if p.maxHeight > 0 {
yCoef = float64(p.maxHeight) / float64(src.Bounds().Max.Y)
}
slog.Debug("calculated coefficients", slog.Float64("x_coef", xCoef), slog.Float64("y_coef", yCoef))
minCoef := xCoef
if yCoef < minCoef {
minCoef = yCoef
}
if minCoef >= 1.0 {
return webp.Encode(writer, src, opts)
}
dst := image.NewRGBA(image.Rect(0, 0, int(float64(src.Bounds().Max.X)*minCoef+0.5), int(float64(src.Bounds().Max.Y)*minCoef+0.5)))
draw.CatmullRom.Scale(dst, dst.Rect, src, src.Bounds(), draw.Over, nil)
return webp.Encode(writer, dst, opts)
}
func (p *WebpConverter) DeductOutputPath(inputPath string) string {
pathParts := strings.Split(inputPath, ".")
if len(pathParts) < 2 {
return inputPath + ".webp"
}
pathParts[len(pathParts)-1] = "webp"
return strings.Join(pathParts, ".")
}
func (p *WebpConverter) ReadMetadata(path string) (*output.MetadataStruct, error) {
return p.outputClient.ReadMetadata(path)
}
func (p *WebpConverter) IsMissing(path string) bool {
return p.outputClient.IsMissing(path)
}
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