feat: support line chart render function

range.go

@@ -0,0 +1,127 @@
+// 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 (
+	"math"
+)
+
+const defaultAxisDivideCount = 6
+
+type axisRange struct {
+	divideCount int
+	min         float64
+	max         float64
+	size        int
+	boundary    bool
+}
+
+type AxisRangeOption struct {
+	Min         float64
+	Max         float64
+	Size        int
+	Boundary    bool
+	DivideCount int
+}
+
+func NewRange(opt AxisRangeOption) axisRange {
+	max := opt.Max
+	min := opt.Min
+
+	max += math.Abs(max * 0.1)
+	min -= math.Abs(min * 0.1)
+	divideCount := opt.DivideCount
+	r := math.Abs(max - min)
+
+	// 最小单位计算
+	unit := 2
+	if r > 10 {
+		unit = 4
+	}
+	if r > 30 {
+		unit = 5
+	}
+	if r > 100 {
+		unit = 10
+	}
+	if r > 200 {
+		unit = 20
+	}
+	unit = int((r/float64(divideCount))/float64(unit))*unit + unit
+
+	if min != 0 {
+		isLessThanZero := min < 0
+		min = float64(int(min/float64(unit)) * unit)
+		// 如果是小于0，int的时候向上取整了，因此调整
+		if min < 0 ||
+			(isLessThanZero && min == 0) {
+			min -= float64(unit)
+		}
+	}
+	max = min + float64(unit*divideCount)
+	return axisRange{
+		divideCount: divideCount,
+		min:         min,
+		max:         max,
+		size:        opt.Size,
+		boundary:    opt.Boundary,
+	}
+}
+
+func (r axisRange) 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 := commafWithDigits(v)
+		values = append(values, value)
+	}
+	return values
+}
+
+func (r *axisRange) getHeight(value float64) int {
+	v := (value - r.min) / (r.max - r.min)
+	return int(v * float64(r.size))
+}
+
+func (r *axisRange) getRestHeight(value float64) int {
+	return r.size - r.getHeight(value)
+}
+
+func (r *axisRange) GetRange(index int) (float64, float64) {
+	unit := float64(r.size) / float64(r.divideCount)
+	return unit * float64(index), unit * float64(index+1)
+}
+func (r *axisRange) AutoDivide() []int {
+	return autoDivide(r.size, r.divideCount)
+}
+
+func (r *axisRange) 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))
+}