[gocv][golang-opencv]示例教程(2-1)矩阵创建、填充、访问元素，ROI操作

package main

import (
 "gocv.io/x/gocv"
 "log"
)

const (
 WIDTH   = 480
 HEIGHT  = 640
 CHANNEL = 3
)

type Matrix []uint8

func main() {
 matrix := make(Matrix, WIDTH*HEIGHT*CHANNEL)

 // white
 matrix.changeColor(255, 255, 255)

 mat, err := gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForWhite := gocv.NewWindow("White")
 defer windowForWhite.Close()
 windowForWhite.IMShow(mat)

 // red
 matrix.changeColor(0, 0, 255)

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForRed := gocv.NewWindow("Red")
 defer windowForRed.Close()
 windowForRed.IMShow(mat)

 // black
 matrix.changeColor(0, 0, 0)

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForBlack := gocv.NewWindow("Black")
 defer windowForBlack.Close()
 windowForBlack.IMShow(mat)

 // some white
 x := 240
 for _, y := range []int{160, 320, 480} {
  index := (WIDTH*y + x) * CHANNEL // getPixelIndex
  matrix[index] = 255
  matrix[index+1] = 255
  matrix[index+2] = 255
 }

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForSomeWhite := gocv.NewWindow("Some White")
 defer windowForSomeWhite.Close()
 windowForSomeWhite.IMShow(mat)

 // black to blue
 for i := 0; i < len(matrix); i += 3 {
  matrix[i] = 255
 }

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForBlackToBlue := gocv.NewWindow("Black to Blue")
 defer windowForBlackToBlue.Close()
 windowForBlackToBlue.IMShow(mat)

 // center vertical white line
 x = 320
 for y := 0; y < HEIGHT; y++ {
  index := (WIDTH*y + x) * CHANNEL // getPixelIndex
  matrix[index] = 255
  matrix[index+1] = 255
  matrix[index+2] = 255
 }

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForCenterVerticalWhiteLine := gocv.NewWindow("Center Vertical White Line")
 defer windowForCenterVerticalWhiteLine.Close()
 windowForCenterVerticalWhiteLine.IMShow(mat)

 // certain region
 x1, y1 := 100, 100
 x2, y2 := 200, 600

 for x = x1; x < x2; x++ {
  for y := y1; y < y2; y++ {
   index := (WIDTH*y + x) * CHANNEL // getPixelIndex
   matrix[index] = 255
   matrix[index+1] = 255
   matrix[index+2] = 255

  }
 }

 mat, err = gocv.NewMatFromBytes(HEIGHT, WIDTH, gocv.MatTypeCV8UC3, matrix)
 if err != nil {
  log.Panic("Can not change bytes to Mat")
  return
 }

 windowForCertainRegion := gocv.NewWindow("Certain region")
 defer windowForCertainRegion.Close()
 windowForCertainRegion.IMShow(mat)

 // wait
 for {
  key := gocv.WaitKey(3)
  if key == 27 {
   log.Println("Pressed ESC")
   break
  }
 }
}

func (matrix *Matrix) changeColor(blue, green, red uint8) {
 for i := 0; i < len(*matrix); i += 3 {
  (*matrix)[i] = blue    // Blue
  (*matrix)[i+1] = green // Green
  (*matrix)[i+2] = red   // Red
 }
}

Execute Result