From 6ee682ae1c41bfd64968d71334d72b52c8d29ca3 Mon Sep 17 00:00:00 2001
From: qeesung <1245712564@qq.com>
Date: Sat, 27 Oct 2018 22:05:34 +0800
Subject: [PATCH] add parallel convert

---
 convert/convert.go      | 105 ++++++++++++++++++++++++++++++++++++++--
 convert/convert_test.go |  19 ++++++++
 2 files changed, 119 insertions(+), 5 deletions(-)

diff --git a/convert/convert.go b/convert/convert.go
index 3a4e2ce..302b8d1 100644
--- a/convert/convert.go
+++ b/convert/convert.go
@@ -6,6 +6,7 @@ import (
 	"github.com/qeesung/image2ascii/ascii"
 	"image"
 	"image/color"
+	"runtime"
 	// Support decode jpeg image
 	_ "image/jpeg"
 	// Support deocde the png image
@@ -14,6 +15,13 @@ import (
 	"os"
 )
 
+type Pixel struct {
+	i              int
+	j              int
+	color          color.Color
+	convertedChars string
+}
+
 // Options to convert the image to ASCII
 type Options struct {
 	Ratio          float64
@@ -37,11 +45,11 @@ func Image2ASCIIMatrix(image image.Image, imageConvertOptions *Options) []string
 	// Resize the convert first
 	newImage := ScaleImage(image, imageConvertOptions)
 	sz := newImage.Bounds()
-	newWidth := sz.Max.Y
-	newHeight := sz.Max.X
-	rawCharValues := make([]string, 0, int(newWidth*newHeight+newWidth))
-	for i := 0; i < int(newWidth); i++ {
-		for j := 0; j < int(newHeight); j++ {
+	newWidth := sz.Max.X
+	newHeight := sz.Max.Y
+	rawCharValues := make([]string, 0, int(newWidth*newHeight+newHeight))
+	for i := 0; i < int(newHeight); i++ {
+		for j := 0; j < int(newWidth); j++ {
 			pixel := color.NRGBAModel.Convert(newImage.At(j, i))
 			// Convert the pixel to ascii char
 			pixelConvertOptions := ascii.NewOptions()
@@ -54,6 +62,65 @@ func Image2ASCIIMatrix(image image.Image, imageConvertOptions *Options) []string
 	return rawCharValues
 }
 
+func Image2ASCIIMatrixParallel(image image.Image, imageConvertOptions *Options) []string {
+	// Resize the convert first
+	newImage := ScaleImage(image, imageConvertOptions)
+	sz := newImage.Bounds()
+	newWidth := sz.Max.X
+	newHeight := sz.Max.Y
+	cap := int(newWidth*newHeight + newHeight)
+	rawCharValues := make([]string, cap, cap)
+
+	// set the new line string
+	for i := 0; i < newHeight; i++ {
+		newLineIndex := (i+1)*(newWidth+1) - 1
+		rawCharValues[newLineIndex] = "\n"
+	}
+
+	pixelChannel := make(chan Pixel, newWidth)
+	charChannel := make(chan Pixel, newWidth)
+	defer close(pixelChannel)
+	defer close(charChannel)
+
+	// schedule the convert task
+	go func() {
+		for i := 0; i < int(newHeight); i++ {
+			for j := 0; j < int(newWidth); j++ {
+				pixelColor := color.NRGBAModel.Convert(newImage.At(j, i))
+				pixelChannel <- Pixel{
+					i:              i,
+					j:              j,
+					color:          pixelColor,
+					convertedChars: "",
+				}
+			}
+		}
+	}()
+
+	// convert the pixel
+	pixelConvertOptions := ascii.NewOptions()
+	pixelConvertOptions.Colored = imageConvertOptions.Colored
+	coreCount := runtime.NumCPU()
+	for i := 0; i < coreCount; i++ {
+		go func() {
+			for pixel := range pixelChannel {
+				rawChar := ascii.ConvertPixelToASCII(pixel.color, &pixelConvertOptions)
+				pixel.convertedChars = rawChar
+				charChannel <- pixel
+			}
+		}()
+	}
+
+	// get the results
+	for k := 0; k < int(newWidth)*int(newHeight); k++ {
+		convertedPixel := <-charChannel
+		i, j := convertedPixel.i, convertedPixel.j
+		index := i*int(newWidth+1) + j
+		rawCharValues[index] = convertedPixel.convertedChars
+	}
+	return rawCharValues
+}
+
 // Image2ASCIIString converts a image to ascii matrix, and the join the matrix to a string
 func Image2ASCIIString(image image.Image, options *Options) string {
 	convertedPixelASCII := Image2ASCIIMatrix(image, options)
@@ -65,6 +132,16 @@ func Image2ASCIIString(image image.Image, options *Options) string {
 	return buffer.String()
 }
 
+func Image2ASCIIStringParallel(image image.Image, options *Options) string {
+	convertedPixelASCII := Image2ASCIIMatrixParallel(image, options)
+	var buffer bytes.Buffer
+
+	for i := 0; i < len(convertedPixelASCII); i++ {
+		buffer.WriteString(convertedPixelASCII[i])
+	}
+	return buffer.String()
+}
+
 // ImageFile2ASCIIMatrix converts a image file to ascii matrix
 func ImageFile2ASCIIMatrix(imageFilename string, option *Options) []string {
 	img, err := OpenImageFile(imageFilename)
@@ -74,6 +151,15 @@ func ImageFile2ASCIIMatrix(imageFilename string, option *Options) []string {
 	return Image2ASCIIMatrix(img, option)
 }
 
+// ImageFile2ASCIIMatrix converts a image file to ascii matrix
+func ImageFile2ASCIIMatrixParallel(imageFilename string, option *Options) []string {
+	img, err := OpenImageFile(imageFilename)
+	if err != nil {
+		log.Fatal("open image failed : " + err.Error())
+	}
+	return Image2ASCIIMatrixParallel(img, option)
+}
+
 // ImageFile2ASCIIString converts a image file to ascii string
 func ImageFile2ASCIIString(imageFilename string, option *Options) string {
 	img, err := OpenImageFile(imageFilename)
@@ -83,6 +169,15 @@ func ImageFile2ASCIIString(imageFilename string, option *Options) string {
 	return Image2ASCIIString(img, option)
 }
 
+// ImageFile2ASCIIString converts a image file to ascii string
+func ImageFile2ASCIIStringParallel(imageFilename string, option *Options) string {
+	img, err := OpenImageFile(imageFilename)
+	if err != nil {
+		log.Fatal("open image failed : " + err.Error())
+	}
+	return Image2ASCIIStringParallel(img, option)
+}
+
 // OpenImageFile open a image and return a image object
 func OpenImageFile(imageFilename string) (image.Image, error) {
 	f, err := os.Open(imageFilename)
diff --git a/convert/convert_test.go b/convert/convert_test.go
index 6710b66..247db40 100644
--- a/convert/convert_test.go
+++ b/convert/convert_test.go
@@ -64,6 +64,12 @@ func TestImage2ASCIIMatrix(t *testing.T) {
 				t.Errorf("image %s convert expected to %+v, but get %+v",
 					tt.imageFilename, tt.asciiMatrix, matrix)
 			}
+
+			matrixParallel := ImageFile2ASCIIMatrixParallel(tt.imageFilename, &convertOptions)
+			if !reflect.DeepEqual(matrixParallel, tt.asciiMatrix) {
+				t.Errorf("image %s convert expected to %+v, but get %+v",
+					tt.imageFilename, tt.asciiMatrix, matrixParallel)
+			}
 		})
 	}
 }
@@ -107,6 +113,19 @@ func BenchmarkBigImage2ASCIIMatrix(b *testing.B) {
 	}
 }
 
+// BenchmarkBigImage2ASCIIMatrix benchmark convert big image to ascii
+func BenchmarkBigImage2ASCIIMatrixParallel(b *testing.B) {
+	convertOptions := DefaultOptions
+	convertOptions.FitScreen = false
+	convertOptions.Colored = false
+	convertOptions.ExpectedWidth = 200
+	convertOptions.ExpectedHeight = 200
+
+	for i:=0; i< b.N; i++ {
+		_ = ImageFile2ASCIIMatrixParallel("testdata/cat_2000x1500.jpg", &convertOptions)
+	}
+}
+
 // BenchmarkSmallImage2ASCIIMatrix benchmark convert small image to ascii
 func BenchmarkSmallImage2ASCIIMatrix(b *testing.B) {
 	convertOptions := DefaultOptions
-- 
2.45.2