feat: implement main logic and implement webp support

README.md

@@ -1,10 +1,14 @@
-# ColorX (WIP)
+# ColorX
 ColorX is a library to determine the most prominent color in an image.
+ColorX doesn't use any sort of complex algorithms to calculate the prominent color, it simply loops over the image pixels and returns the color that occurs the most.
+
+The `getProminentColor` function returns the color in 2 formats, a hex string such as: `#abfecd` and a variable of type `color.Color`.
 
 # Example
-Example code is written in [example/example.go](https://github.com/illusionman1212/colorx/blob/master/example/example.go)
+An example on how to use this library is written in [example/example.go](https://github.com/illusionman1212/colorx/blob/master/example/example.go)
 
 # Supported Image Formats
 Currently ColorX supports these image formats:
 - png
 - jpeg
+- webp

color.go

@@ -20,28 +20,91 @@ import (
 	"bytes"
 	"fmt"
 	"image"
+	"strconv"
 
+	"image/color"
 	_ "image/jpeg"
 	_ "image/png"
+
+	_ "golang.org/x/image/webp"
 )
 
+// downsampleImage downsamples images larger than 20000px for faster image processing.
+func downsampleImage(img image.Image) image.Image {
+	// TODO: implement downsampling
+	return img
+}
+
+// calculateColorMap loops through the image pixels and creates a map-
+// of all unique pixel colors and how many times they occur.
+func calculateColorMap(img image.Image, width int, height int) map[color.Color]int {
+	colorMap := map[color.Color]int{}
+
+	for x := 0; x < width; x++ {
+		for y := 0; y < height; y++ {
+			color := img.At(x, y)
+			// if the alpha is bigger than 100 then add the color to the map
+			if _, _, _, a := color.RGBA(); a > 100 {
+				colorMap[color] = colorMap[color] + 1
+			}
+		}
+	}
+
+	return colorMap
+}
+
 // GetProminentColor gets the most prominent color in the image bytes reader that gets passed in.
 // returns a hex color as a string.
-func GetProminentColor(data []byte) (string, error) {
+func GetProminentColor(data []byte) (string, color.Color, error) {
 	buf := bytes.NewBuffer(data)
 	img, _, err := image.Decode(buf)
 	if err != nil {
-		return "", err
+		return "", nil, err
 	}
 
 	width := img.Bounds().Max.X
 	height := img.Bounds().Max.Y
 
+	// amount of pixels in image
 	pixels := height * width
 
-	fmt.Printf("Pixels in image: %v\n", pixels)
-	fmt.Printf("Width: %v\n", width)
-	fmt.Printf("Height: %v\n", height)
-
-	return "", nil
+	// image is too big, downsample to a reasonable size
+	if pixels > 20000 {
+		img = downsampleImage(img)
+	}
+
+	colorMap := calculateColorMap(img, width, height)
+
+	var maxColor color.Color
+	maxAmmount := 0
+
+	for color, amount := range colorMap {
+		if amount > maxAmmount {
+			maxColor = color
+			maxAmmount = amount
+		}
+	}
+
+	RGBAColor := color.RGBAModel.Convert(maxColor).(color.RGBA)
+
+	red := strconv.FormatUint(uint64(RGBAColor.R), 16)
+	green := strconv.FormatUint(uint64(RGBAColor.G), 16)
+	blue := strconv.FormatUint(uint64(RGBAColor.B), 16)
+
+	// prepend 0 if the hex number has less than 2 digits
+	if len(red) < 2 {
+		red = "0" + red
+	}
+
+	if len(green) < 2 {
+		green = "0" + green
+	}
+
+	if len(blue) < 2 {
+		blue = "0" + blue
+	}
+
+	hexColor := fmt.Sprintf("#%2s%2s%2s", red, green, blue)
+
+	return hexColor, maxColor, nil
 }

example/example.go

@@ -38,7 +38,7 @@ func main() {
 		log.Fatal(err)
 	}
 
-	color, err := colorx.GetProminentColor(data)
+	color, _, err := colorx.GetProminentColor(data)
 	if err != nil {
 		log.Fatal(err)
 	}

go.mod

@@ -1,3 +1,5 @@
 module github.com/illusionman1212/colorx
 
 go 1.16
+
+require golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d

go.sum

@@ -0,0 +1,4 @@
+golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d h1:RNPAfi2nHY7C2srAV8A49jpsYr0ADedCk1wq6fTMTvs=
+golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=