Files
ofdgo/ofdgo_text_position.go
T
2026-10-03 10:51:50 +08:00

100 lines
2.9 KiB
Go

// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ofdgo
import "slices"
// TextPositioner 按OFD坐标及增量定位连续字形,不依赖字体或绘图库
type TextPositioner struct {
xs, ys, dxs, dys []float64
direction Point
current Point
previous float64
index int
}
// textCodeOrigins 按标准继承文本段原点,首段缺失坐标时以零横坐标和字体上升高度容错恢复
// 入参: codes 文本段, ascent 对象坐标系下的字体上升高度
// 返回: []TextCode 定位文本段,不修改原始数据
func textCodeOrigins(codes []TextCode, ascent float64) []TextCode {
for i, code := range codes {
if code.X != "" && code.Y != "" {
continue
}
result := slices.Clone(codes)
var x, y string
if i > 0 {
x, y = codes[i-1].X, codes[i-1].Y
} else {
x, y = "0", ofdNumber(ascent)
}
for j := i; j < len(result); j++ {
if result[j].X == "" {
result[j].X = x
}
if result[j].Y == "" {
result[j].Y = y
}
x, y = result[j].X, result[j].Y
}
return result
}
return codes
}
// NewTextPositioner 创建单个TextCode的定位器,方向采用OFD角度
// 入参: code 文本定位数据, direction 阅读方向
// 返回: TextPositioner 字形定位器
func NewTextPositioner(code TextCode, direction int) TextPositioner {
result := TextPositioner{xs: parseFloats(code.X), ys: parseFloats(code.Y), dxs: parseFloats(code.DeltaX), dys: parseFloats(code.DeltaY), direction: Point{X: 1}}
switch direction {
case 90:
result.direction = Point{Y: 1}
case 180:
result.direction = Point{X: -1}
case 270:
result.direction = Point{Y: -1}
}
return result
}
// Next 返回下一个字形位置并保存其推进长度,显式坐标和增量优先
// 入参: advance 当前字形推进长度,单位为毫米
// 返回: Point 字形原点
func (p *TextPositioner) Next(advance float64) Point {
i := p.index
if i < len(p.xs) {
p.current.X = p.xs[i]
} else if i > 0 {
if dx, ok := textDelta(p.dxs, i-1); ok {
p.current.X += dx
} else if len(p.dys) == 0 {
p.current.X += p.previous * p.direction.X
}
}
if i < len(p.ys) {
p.current.Y = p.ys[i]
} else if i > 0 {
if dy, ok := textDelta(p.dys, i-1); ok {
p.current.Y += dy
} else if len(p.dxs) == 0 {
p.current.Y += p.previous * p.direction.Y
}
}
p.previous = advance
p.index++
return p.current
}