resize picture based on specified dimensions

blend.go

@@ -85,12 +85,19 @@ func (p *blendWorkerPool) SetImageWorker(newImage *image.RGBA) {
 func (p *blendWorkerPool) BlendImages(img1 image.Image, img2 image.Image) {
 	log.Println("Blending the images...")
 
-	dimensions := getDimensions(img1, img2)
+	// dimensions := getMaxDimensions(img1, img2)
 	// output image, ready to receive pixel values
+	dimensions := dimensionsToRectangle(ConfigRegister.OutputWidth, ConfigRegister.OutputHeight)
 	outImg := image.NewRGBA(dimensions)
+
+	// TODO: use a worker pool for those operations ?
+	// resize image
+	img1Resized := resize(img1)
+	img2Resized := resize(img2)
+
 	p.RunWorkers(outImg)
 
-	p.SendBlendJobs(dimensions, img1, img2)
+	p.SendBlendJobs(dimensions, img1Resized, img2Resized)
 
 	// first waitgroup to wait for the results to be ready before closing the channel
 	p.WorkerWG.Wait()
@@ -166,7 +173,7 @@ func blendColor(color1 color.Color, color2 color.Color) color.Color {
 }
 
 // creates a new rectangle with the min height and width from both images
-func getDimensions(img1 image.Image, img2 image.Image) image.Rectangle {
+func getMaxDimensions(img1 image.Image, img2 image.Image) image.Rectangle {
 	// get dimensions for both images
 	size1 := img1.Bounds().Size()
 	size2 := img2.Bounds().Size()
@@ -181,3 +188,30 @@ func getDimensions(img1 image.Image, img2 image.Image) image.Rectangle {
 
 	return image.Rectangle{upLeft, lowRight}
 }
+
+// resizes image using dimensions from config register (nearest neighbour interpolation)
+func resize(img image.Image) (resized *image.RGBA) {
+	imgSize := img.Bounds().Size()
+	dimensions := dimensionsToRectangle(ConfigRegister.OutputWidth, ConfigRegister.OutputHeight)
+	xscale := float64(imgSize.X) / float64(dimensions.Max.X)
+	yscale := float64(imgSize.Y) / float64(dimensions.Max.Y)
+	// creates new rescaled image based on a given image dimensions
+	resized = image.NewRGBA(dimensions)
+	// get pixels from the original image
+	for x := 0; x < dimensions.Max.X; x++ {
+		for y := 0; y < dimensions.Max.Y; y++ {
+			xp := int(math.Floor(float64(x) * xscale))
+			yp := int(math.Floor(float64(y) * yscale))
+			pixel := img.At(xp, yp)
+			resized.Set(x, y, pixel)
+		}
+	}
+	return
+}
+
+// returns a Rectangle of dimensions <width>x<height>
+func dimensionsToRectangle(width int, height int) image.Rectangle {
+	upLeft := image.Point{0, 0}
+	lowRight := image.Point{width, height}
+	return image.Rectangle{upLeft, lowRight}
+}

config.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"strconv"
+	"strings"
 )
 
 type Config struct {
@@ -11,6 +13,9 @@ type Config struct {
 	OutputDir    string `json:outputdir`
 	InputDir     string `json:inputdir`
 	BaseImage    string `json:baseimage`
+	Dimensions   string `json:dimensions`
+	OutputWidth  int    `json:output_width`
+	OutputHeight int    `json:output_height`
 }
 
 // loads configuration values from json file
@@ -27,5 +32,14 @@ func (c *Config) LoadConfigFromFile(filePath string) {
 	fmt.Println(configuration.OutputDir)
 }
 
+// Set output file dimensions using string symbol (<width>x<height>)
+func (c *Config) SetOutputDimensions() {
+	split := strings.Split(c.Dimensions, "x")
+	width, _ := strconv.Atoi(split[0])
+	height, _ := strconv.Atoi(split[1])
+	c.OutputWidth = width
+	c.OutputHeight = height
+}
+
 // global register to acccess configuration values
 var ConfigRegister Config

main.go

@@ -13,8 +13,12 @@ func main() {
 	flag.StringVar(&ConfigRegister.OutputDir, "output", "./", "Output directory")
 	flag.StringVar(&ConfigRegister.InputDir, "input", "/home/gator/Photos", "Input directory. Where to look the images from")
 	flag.StringVar(&ConfigRegister.BaseImage, "base-img", "", "Path to the base image to work with. Random image if not set")
+	flag.StringVar(&ConfigRegister.Dimensions, "dimensions", "800x600", "Out image dimensions. <width>x<height>")
 	flag.Parse()
 
+	// set output's width and height
+	ConfigRegister.SetOutputDimensions()
+
 	// get two random images and load them
 	var img1 image.Image
 	if ConfigRegister.BaseImage != "" {