horizontal_time_slicer.go

package main

import (
	"image"

	"gocv.io/x/gocv"
)

func main() {
	webcam, err := gocv.OpenVideoCapture(0)
	if err != nil {
		panic(err)
	}
	window := gocv.NewWindow("Horizontal Time Slicer")

	mb := NewMatBuffer(50)
	img := gocv.NewMat()
	resizedImg := gocv.NewMat()

	for {
		webcam.Read(&img)
		gocv.Resize(img, &resizedImg, image.Point{img.Cols() / 3, img.Rows() / 3}, 0.5, 0.5, gocv.InterpolationDefault)
		mb.Push(resizedImg.Clone())
		window.IMShow(mb.HorizontalTimeSliceMat())

		window.WaitKey(1)
	}
}

type MatBuffer struct {
	bufsize int
	buf     []gocv.Mat
}

func NewMatBuffer(bufsize int) *MatBuffer {
	return &MatBuffer{
		bufsize: bufsize,
		buf:     make([]gocv.Mat, 0, bufsize),
	}
}

func (mb *MatBuffer) Push(mat gocv.Mat) {
	if len(mb.buf) == mb.bufsize {
		mb.buf = mb.buf[1:mb.bufsize]
	}
	mb.buf = append(mb.buf, mat)
}

func (mb *MatBuffer) DelayMat() gocv.Mat {
	return mb.buf[0]
}

func (mb *MatBuffer) HorizontalTimeSliceMat() gocv.Mat {
	if len(mb.buf) != mb.bufsize {
		return mb.buf[0]
	}

	sizePerMat := 14

	originMat := mb.buf[mb.bufsize-1].Clone()
	originMa := NewMatAccessor(originMat)

	for i, mat := range mb.buf {
		ma := NewMatAccessor(mat)
		for j := 0; j < sizePerMat; j++ {
			rowData := ma.GetRowData(sizePerMat*i + j)
			originMa.SetRowData(sizePerMat*i+j, rowData)
		}
	}

	return originMa.ToMat()
}

type MatAccessor struct {
	mat  gocv.Mat
	rows int
	cols int
	mt   gocv.MatType
	data []byte
}

func NewMatAccessor(mat gocv.Mat) *MatAccessor {
	return &MatAccessor{
		mat:  mat,
		rows: mat.Rows(),
		cols: mat.Cols(),
		mt:   mat.Type(),
		data: mat.ToBytes(),
	}
}

func (ma *MatAccessor) GetRowData(row int) []byte {
	start := row * ma.cols
	end := start + ma.cols
	return ma.data[start:end]
}

func (ma *MatAccessor) SetRowData(row int, rowData []byte) {
	start := row * ma.cols
	for i := 0; i < ma.cols; i++ {
		ma.data[start+i] = rowData[i]
	}
}

func (ma *MatAccessor) ToMat() gocv.Mat {
	mat, _ := gocv.NewMatFromBytes(ma.rows, ma.cols, ma.mt, ma.data)
	return mat
}