vision/draw.go

package vision

import (
	"math"

	"apigo.cc/go/rand"
	"github.com/disintegration/imaging"
	"github.com/fogleman/gg"
)

// DrawStyle 定义图形绘制样式
type DrawStyle struct {
	StrokeColor  string
	StrokeWidth  float64
	LineCap      gg.LineCap
	LineJoin     gg.LineJoin
	Dash         []float64
	DashOffset   float64
	FillColor    string
	FillRule     gg.FillRule
	ShadowColor  string
	ShadowOffset float64
	ShadowBlur   float64
}

func (c *Canvas) draw(fn func(offset float64), opt *DrawStyle) {
	if opt == nil {
		opt = &DrawStyle{}
	}

	needFill := opt.FillColor != ""
	needStroke := !needFill || opt.StrokeColor != "" || opt.StrokeWidth >= 0.01

	// 绘制阴影
	if opt.ShadowColor != "" || opt.ShadowOffset >= 0.01 || opt.ShadowBlur >= 0.01 {
		shadowColor := opt.ShadowColor
		if shadowColor == "" {
			shadowColor = "#333333"
		}
		offset := opt.ShadowOffset
		if offset < 0.01 {
			offset = 2
		}

		if opt.ShadowBlur >= 0.01 {
			// 使用模糊阴影
			bounds := c.dc.Image().Bounds()
			tmpdc := gg.NewContext(bounds.Dx(), bounds.Dy())
			olddc := c.dc
			c.dc = tmpdc

			fn(offset)
			c.dc.SetColor(ParseColor(shadowColor))
			if needFill {
				c.dc.Fill()
			} else {
				if opt.StrokeWidth >= 0.01 {
					c.dc.SetLineWidth(opt.StrokeWidth)
				}
				c.dc.Stroke()
			}

			c.dc = olddc
			blurred := imaging.Blur(tmpdc.Image(), opt.ShadowBlur)
			c.dc.DrawImage(blurred, 0, 0)
		} else {
			// 直接绘制偏移阴影
			c.dc.Push()
			fn(offset)
			c.dc.SetColor(ParseColor(shadowColor))
			if needFill {
				c.dc.Fill()
			} else {
				if opt.StrokeWidth >= 0.01 {
					c.dc.SetLineWidth(opt.StrokeWidth)
				}
				c.dc.Stroke()
			}
			c.dc.Pop()
		}
	}

	// 绘制主体
	c.dc.Push()
	fn(0)
	if needFill {
		c.dc.SetColor(ParseColor(opt.FillColor))
		if opt.FillRule != 0 {
			c.dc.SetFillRule(opt.FillRule)
		}
		if needStroke {
			c.dc.FillPreserve()
		} else {
			c.dc.Fill()
		}
	}
	if needStroke {
		if opt.StrokeWidth >= 0.01 {
			c.dc.SetLineWidth(opt.StrokeWidth)
		}
		if opt.StrokeColor != "" {
			c.dc.SetColor(ParseColor(opt.StrokeColor))
		} else if c.lastColor != "" {
			c.dc.SetColor(ParseColor(c.lastColor))
		}

		c.dc.SetLineCap(opt.LineCap)
		c.dc.SetLineJoin(opt.LineJoin)
		if len(opt.Dash) > 0 {
			c.dc.SetDash(opt.Dash...)
			c.dc.SetDashOffset(opt.DashOffset)
		}
		c.dc.Stroke()
	}
	c.dc.Pop()
}

// Rect 绘制矩形
func (c *Canvas) Rect(x, y, w, h float64, opt *DrawStyle) {
	c.draw(func(offset float64) {
		c.dc.DrawRectangle(x+offset, y+offset, w, h)
	}, opt)
}

// RoundedRect 绘制圆角矩形
func (c *Canvas) RoundedRect(x, y, w, h, r float64, opt *DrawStyle) {
	c.draw(func(offset float64) {
		c.dc.DrawRoundedRectangle(x+offset, y+offset, w, h, r)
	}, opt)
}

// Circle 绘制圆形
func (c *Canvas) Circle(x, y, r float64, opt *DrawStyle) {
	c.draw(func(offset float64) {
		c.dc.DrawCircle(x+offset, y+offset, r)
	}, opt)
}

// Line 绘制直线
func (c *Canvas) Line(x1, y1, x2, y2 float64, opt *DrawStyle) {
	c.draw(func(offset float64) {
		c.dc.DrawLine(x1+offset, y1+offset, x2+offset, y2+offset)
	}, opt)
}

// Path 绘制 SVG 路径
func (c *Canvas) Path(path string, opt *DrawStyle) {
	// 这里的 Path 解析逻辑可以参考原实现，或者使用更强大的解析器
	// 为了保持精简并对齐原功能，我们先实现一个基础版本
	// 实际上 gg 并没有直接支持 SVG path 字符串，原代码手动解析了
	// 我将把原代码中的解析逻辑重构并放入此处
}

// Put 将另一个画布内容贴入当前画布
func (c *Canvas) Put(src *Canvas, x, y int) {
	c.dc.DrawImage(src.dc.Image(), x, y)
}

// RandBG 绘制随机干扰背景 (1-10 档)
func (c *Canvas) RandBG(level int) {
	if level < 1 { level = 1 }
	if level > 10 { level = 10 }

	w, h := float64(c.dc.Width()), float64(c.dc.Height())
	elements := 30 + level*150

	for i := 0; i < elements; i++ {
		x := rand.Float(0.0, 1.0) * w
		y := rand.Float(0.0, 1.0) * h
		color := RandColor()
		size := rand.Float(0.0, 1.0)*(7.0+float64(level)*1.5) + 1.0
		lineWidth := 0.5 + rand.Float(0.0, 1.0)*(0.5+float64(level)*0.3)

		t := rand.Int(0, 99)
		switch {
		case t < 20: // 点
			c.dc.Push()
			c.dc.SetColor(ParseColor(color))
			c.dc.DrawPoint(x, y, 1)
			c.dc.Stroke()
			c.dc.Pop()
		case t < 40: // 线
			angle := rand.Float(0.0, 1.0) * 2 * math.Pi
			length := 3 + rand.Float(0.0, 1.0)*float64(level)*3
			c.Line(x, y, x+math.Cos(angle)*length, y+math.Sin(angle)*length, &DrawStyle{
				StrokeColor: color,
				StrokeWidth: lineWidth,
			})
		case t < 60: // 圆
			c.Circle(x, y, rand.Float(0.0, 1.0)*size, &DrawStyle{
				StrokeColor: color,
				StrokeWidth: lineWidth,
			})
		case t < 80: // 矩形
			c.Rect(x, y, rand.Float(0.0, 1.0)*size*5, rand.Float(0.0, 1.0)*size*3, &DrawStyle{
				StrokeColor: color,
				StrokeWidth: lineWidth,
			})
		default:
			// 更多随机图形...
		}
	}
}