feat: support line chart draw function

chart.go

@@ -0,0 +1,145 @@
+// MIT License
+
+// Copyright (c) 2022 Tree Xie
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package charts
+
+import (
+	"github.com/dustin/go-humanize"
+	"github.com/wcharczuk/go-chart/v2"
+	"github.com/wcharczuk/go-chart/v2/drawing"
+)
+
+type XAxisOption struct {
+	BoundaryGap *bool
+	Data        []string
+	// TODO split number
+}
+
+type SeriesData struct {
+	Value float64
+	Style chart.Style
+}
+type Point struct {
+	X int
+	Y int
+}
+
+type Range struct {
+	originalMin float64
+	originalMax float64
+	divideCount int
+	Min         float64
+	Max         float64
+	Size        int
+	Boundary    bool
+}
+
+func (r *Range) getHeight(value float64) int {
+	v := 1 - value/(r.Max-r.Min)
+	return int(v * float64(r.Size))
+}
+
+func (r *Range) getWidth(value float64) int {
+	v := value / (r.Max - r.Min)
+	// 移至居中
+	if r.Boundary &&
+		r.divideCount != 0 {
+		v += 1 / float64(r.divideCount*2)
+	}
+	return int(v * float64(r.Size))
+}
+
+type Series struct {
+	Type       string
+	Name       string
+	Data       []SeriesData
+	YAxisIndex int
+	Style      chart.Style
+}
+
+type ChartOption struct {
+	Theme           string
+	XAxis           XAxisOption
+	Width           int
+	Height          int
+	Parent          *Draw
+	Padding         chart.Box
+	SeriesList      []Series
+	BackgroundColor drawing.Color
+}
+
+func (o *ChartOption) getWidth() int {
+	if o.Width == 0 {
+		return 600
+	}
+	return o.Width
+}
+
+func (o *ChartOption) getHeight() int {
+	if o.Height == 0 {
+		return 400
+	}
+	return o.Height
+}
+
+func (o *ChartOption) getYRange(axisIndex int) Range {
+	min := float64(0)
+	max := float64(0)
+
+	for _, series := range o.SeriesList {
+		if series.YAxisIndex != axisIndex {
+			continue
+		}
+		for _, item := range series.Data {
+			if item.Value > max {
+				max = item.Value
+			}
+			if item.Value < min {
+				min = item.Value
+			}
+		}
+	}
+	// TODO 对于小数的处理
+
+	divideCount := 6
+	r := Range{
+		originalMin: min,
+		originalMax: max,
+		Min:         float64(int(min * 0.8)),
+		Max:         max * 1.2,
+		divideCount: divideCount,
+	}
+	value := int((r.Max - r.Min) / float64(divideCount))
+	r.Max = float64(int(float64(value*divideCount) + r.Min))
+	return r
+}
+
+func (r Range) Values() []string {
+	offset := (r.Max - r.Min) / float64(r.divideCount)
+	values := make([]string, 0)
+	for i := 0; i <= r.divideCount; i++ {
+		v := r.Min + float64(i)*offset
+		value := humanize.CommafWithDigits(v, 2)
+		values = append(values, value)
+	}
+	return values
+}