add new parameter - png compression value

config.example.yml

@@ -39,7 +39,14 @@ http:
 
 map:
   # Do not render map more than once within below specified interval
-  min_refresh_int: 1000ms
+  min_refresh_int: 5000ms
+
+  # Specify compression level for Golang's PNG library:
+  # 0 - Best speed
+  # 1 - Best compression
+  # 2 - Default compression
+  # 3 - No compression
+  png_compression: 0
 
   # 4 is default
   scale: 4

pkg/config/config.go

@@ -36,10 +36,11 @@ type TopicsConfig struct {
 }
 
 type MapConfig struct {
-	MinRefreshInt time.Duration `yaml:"min_refresh_int"`
-	Scale         float64       `yaml:"scale"`
-	RotationTimes int           `yaml:"rotate"`
-	CustomLimits  struct {
+	MinRefreshInt  time.Duration `yaml:"min_refresh_int"`
+	PNGCompression int           `yaml:"png_compression"`
+	Scale          float64       `yaml:"scale"`
+	RotationTimes  int           `yaml:"rotate"`
+	CustomLimits   struct {
 		StartX int `yaml:"start_x"`
 		StartY int `yaml:"start_y"`
 		EndX   int `yaml:"end_x"`
@@ -70,6 +71,7 @@ func NewConfig(configFile string) (*Config, error) {
 }
 
 func validate(c *Config) (*Config, error) {
+	// Check if any section is nil (missing)
 	if c.Mqtt == nil {
 		return nil, errors.New("missing mqtt section")
 	}
@@ -79,14 +81,32 @@ func validate(c *Config) (*Config, error) {
 	if c.Map == nil {
 		return nil, errors.New("missing map section")
 	}
-
 	if c.Mqtt.Connection == nil {
 		return nil, errors.New("missing mqtt.connection section")
 	}
 	if c.Mqtt.Topics == nil {
 		return nil, errors.New("missing mqtt.topics section")
 	}
 
+	// Check MQTT topics section
+	if c.Mqtt.Topics.ValetudoIdentifier == "" {
+		return nil, errors.New("missing mqtt.topics.valetudo_identifier value")
+	}
+	if c.Mqtt.Topics.ValetudoPrefix == "" {
+		return nil, errors.New("missing mqtt.topics.valetudo_prefix value")
+	}
+	if c.Mqtt.Topics.HaAutoconfPrefix == "" {
+		return nil, errors.New("missing mqtt.topics.ha_autoconf_prefix value")
+	}
+
+	// Check map section
+	if c.Map.Scale < 1 {
+		return nil, errors.New("missing map.scale cannot be lower than 1")
+	}
+	if c.Map.PNGCompression < 0 || c.Map.PNGCompression > 3 {
+		return nil, errors.New("invalid map.png_compression value")
+	}
+
 	// Everything else should fail when used (e.g. wrong IP/port will cause
 	// fatal error when starting http server)
 

pkg/renderer/renderer.go

@@ -18,15 +18,27 @@ type Renderer struct {
 }
 
 type Settings struct {
-	Scale         float64
-	RotationTimes int
+	Scale          float64
+	PNGCompression int
+	RotationTimes  int
 
 	// Hardcoded limits for a map within robot's coordinates system
 	StaticStartX, StaticStartY int
 	StaticEndX, StaticEndY     int
 }
 
 func New(s *Settings) *Renderer {
+	switch s.PNGCompression {
+	case 0:
+		pngEncoder.CompressionLevel = png.BestSpeed
+	case 1:
+		pngEncoder.CompressionLevel = png.BestCompression
+	case 2:
+		pngEncoder.CompressionLevel = png.DefaultCompression
+	case 3:
+		pngEncoder.CompressionLevel = png.NoCompression
+	}
+
 	r := &Renderer{
 		settings: s,
 	}

pkg/renderer/result.go

@@ -6,7 +6,8 @@ import (
 	"image/png"
 )
 
-var pngEncoder = png.Encoder{CompressionLevel: png.BestSpeed}
+// Set compression value from 'New' function.
+var pngEncoder = png.Encoder{}
 
 type Result struct {
 	Image       *image.Image

pkg/server/server.go

@@ -23,8 +23,9 @@ var (
 
 func Start(c *config.Config) {
 	r := renderer.New(&renderer.Settings{
-		Scale:         c.Map.Scale,
-		RotationTimes: c.Map.RotationTimes,
+		Scale:          c.Map.Scale,
+		PNGCompression: c.Map.PNGCompression,
+		RotationTimes:  c.Map.RotationTimes,
 
 		StaticStartX: c.Map.CustomLimits.StartX,
 		StaticStartY: c.Map.CustomLimits.StartY,