effects

internal/effects/saturation/saturation.go

@@ -0,0 +1,38 @@
+package saturation
+
+import (
+	"fmt"
+	"image"
+	"strconv"
+
+	"github.com/anthonynsimon/bild/adjust"
+	"github.com/coalaura/ffwebp/internal/effects"
+	"github.com/coalaura/ffwebp/internal/logx"
+)
+
+type impl struct{}
+
+func init() {
+	effects.Register(impl{})
+}
+
+func (impl) String() string {
+	return "saturation"
+}
+
+func (impl) Apply(img image.Image, args string) (image.Image, error) {
+	var change float64 = 0.1
+
+	if args != "" {
+		f64, err := strconv.ParseFloat(args, 64)
+		if err != nil || f64 < -1 || f64 > 1 || f64 == 0 {
+			return nil, fmt.Errorf("invalid saturation change: %s", args)
+		}
+
+		change = f64
+	}
+
+	logx.Printf("  applying saturation (change=%.f)\n", change)
+
+	return adjust.Saturation(img, change), nil
+}