Golang绘制数列趋势图的操作步骤

go get -u gonum.org/v1/plot/...

12
23
12
34
23
24

package main

import (
    "bufio"
    "log"
    "os"
    "strconv"
    "gonum.org/v1/plot"
    "gonum.org/v1/plot/plotter"
    "gonum.org/v1/plot/vg"
)

func main() {
    // 打开并读取数据文件
    f, err := os.Open("data.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer f.Close()

    scanner := bufio.NewScanner(f)
    points := make(plotter.XYs, 0)

    i := 0.0
    for scanner.Scan() {
        y, err := strconv.ParseFloat(scanner.Text(), 64)
        if err != nil {
            log.Fatalf("error parsing value: %v", err)
        }
        points = append(points, plotter.XY{X: i, Y: y})
        i++
    }

    if err := scanner.Err(); err != nil {
        log.Fatal(err)
    }

    // 创建图表
    p := plot.New()
    p.Title.Text = "数列趋势图"
    p.X.Label.Text = "序号"
    p.Y.Label.Text = "数值"

    // 添加线条
    line, err := plotter.NewLine(points)
    if err != nil {
        log.Fatal(err)
    }
    p.Add(line)

    // 保存图表
    if err := p.Save(10*vg.Inch, 4*vg.Inch, "trend.png"); err != nil {
        log.Fatal(err)
    }
}

go build main.go

./main

package main

import (
	"encoding/json"
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"log"
	"math"
	"reflect"
	"strings"

	"github.com/fogleman/gg"
)

// test_draw_rect_text 画图像矩形, 标注, 颜色; 返回保存图像路径
// ref: https://github.com/fogleman/gg/blob/master/examples/rotated-image.go
func test_draw_rect_text(im_path, font_path, detect_label, save_path string, x, y, w, h float64) {
	// Load image
	im, err := gg.LoadImage(im_path)
	if err != nil {
		log.Fatal(err)
	}

	// 1 method
	// iw, ih := im.Bounds().Dx(), im.Bounds().Dy()
	// Set Context
	// dc := gg.NewContext(iw, ih)

	// Draw image
	// dc.DrawImage(im, 0, 0)

	// 2 method
	dc := gg.NewContextForImage(im)

	// Set color and line width
	dc.SetHexColor("#FF0000")
	dc.SetLineWidth(1)

	// Draw rectangle
	dc.DrawRoundedRectangle(x, y, w, h, 0)
	// Store set
	dc.Stroke()

	// Set font and draw label
	var font_height float64 = 7
	if err := dc.LoadFontFace(font_path, font_height); err != nil {
		panic(err)
	}
	rect_center_x := x + w/2
	rect_center_y := y + h/2
	dc.DrawStringAnchored(detect_label, rect_center_x, rect_center_y, 0.5, 0.5)
	dc.Clip()

	// Save png image
	dc.SavePNG(save_path)
}

func main() {
	im_path := "/home/tianzx/Pictures/lena.jpeg"
	font_path := "/home/tianzx/ai_model/simsun.ttc"
	detect_label := "缺角/碎裂"
	save_path := "/home/tianzx/Pictures/lena_test.png"
	var x, y, w, h float64 = 50, 100, 50, 50
	test_draw_rect_text(im_path, font_path, detect_label, save_path, x, y, w, h)
}