Backend: Add blackman resample filter and set default to cubic #157

Signed-off-by: Michael Mayer <michael@liquidbytes.net>

docker/demo/Dockerfile

@@ -12,6 +12,11 @@ ENV PHOTOPRISM_PUBLIC true
 ENV PHOTOPRISM_EXPERIMENTAL true
 ENV PHOTOPRISM_UPLOAD_NSFW false
 ENV PHOTOPRISM_HIDE_NSFW false
+ENV PHOTOPRISM_THUMB_QUALITY 95
+ENV PHOTOPRISM_THUMB_SIZE 3840
+ENV PHOTOPRISM_THUMB_LIMIT 3840
+ENV PHOTOPRISM_THUMB_ALGORITHM lanczos
+ENV PHOTOPRISM_GEOCODING_API places
 
 # Import example photos
 RUN photoprism import

internal/config/config.go

@@ -239,9 +239,11 @@ func (c *Config) ThumbLimit() int {
 	return c.config.ThumbLimit
 }
 
-// ThumbAlgorithm returns the thumbnail algorithm name (lanczos, cubic or linear).
+// ThumbAlgorithm returns the thumbnail resample algorithm (blackman, lanczos, cubic or linear).
 func (c *Config) ThumbAlgorithm() thumb.ResampleAlgorithm {
 	switch strings.ToLower(c.config.ThumbAlgorithm) {
+	case "blackman":
+		return thumb.ResampleBlackman
 	case "lanczos":
 		return thumb.ResampleLanczos
 	case "cubic":
@@ -249,7 +251,7 @@ func (c *Config) ThumbAlgorithm() thumb.ResampleAlgorithm {
 	case "linear":
 		return thumb.ResampleLinear
 	default:
-		return thumb.ResampleLanczos
+		return thumb.ResampleCubic
 	}
 }
 

internal/config/flags.go

@@ -238,20 +238,20 @@ var GlobalFlags = []cli.Flag{
 	},
 	cli.IntFlag{
 		Name:   "thumb-size, s",
-		Usage:  "pre-rendered thumbnail size limit in pixels (720-3840)",
+		Usage:  "pre-render size limit in pixels (720-3840)",
 		Value:  2048,
 		EnvVar: "PHOTOPRISM_THUMB_SIZE",
 	},
 	cli.IntFlag{
 		Name:   "thumb-limit, x",
-		Usage:  "on-demand thumbnail size limit in pixels (720-3840)",
+		Usage:  "on-demand size limit in pixels (720-3840)",
 		Value:  3840,
 		EnvVar: "PHOTOPRISM_THUMB_LIMIT",
 	},
 	cli.StringFlag{
 		Name:   "thumb-algorithm, a",
-		Usage:  "thumbnail algorithm (lanczos, cubic or linear)",
-		Value:  "lanczos",
+		Usage:  "resample algorithm (blackman, lanczos, cubic or linear)",
+		Value:  "cubic",
 		EnvVar: "PHOTOPRISM_THUMB_ALGORITHM",
 	},
 }

internal/thumb/types.go

@@ -11,15 +11,18 @@ var (
 )
 
 const (
-	ResampleLanczos ResampleAlgorithm = "lanczos"
-	ResampleCubic                     = "cubic"
-	ResampleLinear                    = "linear"
+	ResampleBlackman ResampleAlgorithm = "blackman"
+	ResampleLanczos  ResampleAlgorithm = "lanczos"
+	ResampleCubic    ResampleAlgorithm = "cubic"
+	ResampleLinear   ResampleAlgorithm = "linear"
 )
 
 type ResampleAlgorithm string
 
 func (a ResampleAlgorithm) Filter() imaging.ResampleFilter {
 	switch a {
+	case ResampleBlackman:
+		return imaging.Blackman
 	case ResampleLanczos:
 		return imaging.Lanczos
 	case ResampleCubic: