slideshow-api/internal/palette.go

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2023-11-28 15:52:53 +01:00
package internal
import (
"bytes"
"fmt"
"image"
"image/color"
"strconv"
"time"
"git.velvettear.de/velvettear/loggo"
"git.velvettear.de/velvettear/slideshow/internal/config"
color_thief "github.com/kennykarnama/color-thief"
)
// extract the given amount of dominant colors of raw image bytes
func GetColorPalette(data []byte) (string, error) {
var palette string
timestamp := time.Now().UnixMilli()
amount := config.PaletteColors
img, _, error := image.Decode(bytes.NewReader(data))
if error != nil {
loggo.ErrorTimed("encountered an error decoding the provided raw image bytes to an image", timestamp, error.Error())
return palette, error
}
colors, error := color_thief.GetPalette(img, amount, config.PaletteAlgorithm)
if error != nil {
loggo.ErrorTimed("encountered an error generating the color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
return palette, error
} else {
loggo.DebugTimed("generated color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
}
for index, color := range colors {
if index > 0 {
palette += "\n"
}
tmp := strconv.Itoa(index)
if len(tmp) < 2 {
tmp = "0" + tmp
}
tmp = "SLIDESHOW_COLOR" + tmp
palette += tmp + "=\"" + rgbToHex(color) + "\""
}
return palette, nil
}
// extract the given amount of dominant colors of an image
func getColorPalette(image string) ([]color.Color, error) {
var colors []color.Color
timestamp := time.Now().UnixMilli()
amount := config.PaletteColors
colors, error := color_thief.GetPaletteFromFile(image, amount, config.PaletteAlgorithm)
if error != nil {
loggo.ErrorTimed("encountered an error generating the color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
} else {
loggo.DebugTimed("generated color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
}
return colors, error
}
// parse rgb color values to hex
func rgbToHex(color color.Color) string {
r, g, b, _ := color.RGBA()
return fmt.Sprintf("#%02x%02x%02x", uint8(r>>8), uint8(g>>8), uint8(b>>8))
}