ofdgo/ofdgo_text.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 (
	"image/color"
	"strconv"
	"strings"

	"github.com/tdewolff/canvas"
)

// parseColor 解析颜色字符串
// 入参: val 颜色值(R G B)
// 返回: color.Color 颜色对象
func parseColor(val string) color.Color {
	return parseColorWithAlpha(val, nil)
}

// parseColorWithAlpha 解析带透明度的颜色
// 入参: val 颜色值, alpha 透明度
// 返回: color.Color 颜色对象
func parseColorWithAlpha(val string, alpha *int) color.Color {
	parts := strings.Fields(val)
	if len(parts) >= 3 {
		r, _ := strconv.Atoi(parts[0])
		g, _ := strconv.Atoi(parts[1])
		b, _ := strconv.Atoi(parts[2])
		a := 255
		if alpha != nil {
			a = *alpha
		}
		return color.RGBA{R: uint8(r), G: uint8(g), B: uint8(b), A: uint8(a)}
	}
	return color.Black
}

// parseFillColor 解析填充颜色
// 入参: fillColor 填充颜色节点
// 返回: color.Color 颜色对象
func parseFillColor(fillColor *FillColor) color.Color {
	if fillColor == nil {
		return nil
	}
	if strings.TrimSpace(fillColor.Value) != "" {
		return parseColorWithAlpha(fillColor.Value, fillColor.Alpha)
	}
	return parseAxialShdColor(fillColor.AxialShd, fillColor.Alpha)
}

// parseFillPaint 解析填充画刷
// 入参: fillColor 填充颜色节点, x X坐标, y Y坐标, pageH 页面高度, originX 原点X坐标, originY 原点Y坐标
// 返回: any 填充画刷
func parseFillPaint(fillColor *FillColor, x, y, pageH, originX, originY float64) any {
	if fillColor == nil {
		return nil
	}
	if strings.TrimSpace(fillColor.Value) != "" {
		return parseColorWithAlpha(fillColor.Value, fillColor.Alpha)
	}
	if gradient := parseAxialShdGradient(fillColor.AxialShd, fillColor.Alpha, x, y, pageH, originX, originY); gradient != nil {
		return gradient
	}
	return parseAxialShdColor(fillColor.AxialShd, fillColor.Alpha)
}

// parseStrokeColor 解析勾边颜色
// 入参: strokeColor 勾边颜色节点
// 返回: color.Color 颜色对象
func parseStrokeColor(strokeColor *StrokeColor) color.Color {
	if strokeColor == nil {
		return nil
	}
	if strings.TrimSpace(strokeColor.Value) != "" {
		return parseColorWithAlpha(strokeColor.Value, strokeColor.Alpha)
	}
	return parseAxialShdColor(strokeColor.AxialShd, strokeColor.Alpha)
}

// parseStrokePaint 解析勾边画刷
// 入参: strokeColor 勾边颜色节点, x X坐标, y Y坐标, pageH 页面高度, originX 原点X坐标, originY 原点Y坐标
// 返回: any 勾边画刷
func parseStrokePaint(strokeColor *StrokeColor, x, y, pageH, originX, originY float64) any {
	if strokeColor == nil {
		return nil
	}
	if strings.TrimSpace(strokeColor.Value) != "" {
		return parseColorWithAlpha(strokeColor.Value, strokeColor.Alpha)
	}
	if gradient := parseAxialShdGradient(strokeColor.AxialShd, strokeColor.Alpha, x, y, pageH, originX, originY); gradient != nil {
		return gradient
	}
	return parseAxialShdColor(strokeColor.AxialShd, strokeColor.Alpha)
}

// parseAxialShdColor 解析轴向渐变颜色
// 入参: axialShd 轴向渐变节点, alpha 透明度
// 返回: color.Color 颜色对象
func parseAxialShdColor(axialShd *AxialShd, alpha *int) color.Color {
	if axialShd != nil {
		for _, segment := range axialShd.Segment {
			if strings.TrimSpace(segment.Color.Value) == "" {
				continue
			}
			if alpha == nil {
				alpha = segment.Color.Alpha
			}
			return parseColorWithAlpha(segment.Color.Value, alpha)
		}
	}
	return color.Black
}

// parseAxialShdGradient 解析轴向渐变
// 入参: axialShd 轴向渐变节点, alpha 透明度, x X坐标, y Y坐标, pageH 页面高度, originX 原点X坐标, originY 原点Y坐标
// 返回: canvas.Gradient 渐变对象
func parseAxialShdGradient(axialShd *AxialShd, alpha *int, x, y, pageH, originX, originY float64) canvas.Gradient {
	if axialShd == nil {
		return nil
	}
	start := parseFloats(axialShd.StartPoint)
	end := parseFloats(axialShd.EndPoint)
	if len(start) < 2 || len(end) < 2 {
		return nil
	}
	grad := canvas.NewGradient()
	for _, segment := range axialShd.Segment {
		if strings.TrimSpace(segment.Color.Value) == "" {
			continue
		}
		segmentAlpha := alpha
		if segmentAlpha == nil {
			segmentAlpha = segment.Color.Alpha
		}
		grad.Add(segment.Position, colorToRGBA(parseColorWithAlpha(segment.Color.Value, segmentAlpha)))
	}
	if len(grad) == 0 {
		return nil
	}
	startPoint := canvas.Point{X: x + start[0] - originX, Y: pageH - (y + start[1]) - originY}
	endPoint := canvas.Point{X: x + end[0] - originX, Y: pageH - (y + end[1]) - originY}
	if startPoint.Equals(endPoint) {
		return nil
	}
	return grad.ToLinear(startPoint, endPoint)
}

// colorToRGBA 转换颜色对象
// 入参: c 颜色对象
// 返回: color.RGBA RGBA颜色
func colorToRGBA(c color.Color) color.RGBA {
	r, g, b, a := c.RGBA()
	return color.RGBA{R: uint8(r >> 8), G: uint8(g >> 8), B: uint8(b >> 8), A: uint8(a >> 8)}
}

// GetDeltaX 获取X轴偏移量数组
// 返回: []float64 偏移量数组
func (tc *TextCode) GetDeltaX() []float64 {
	return parseFloats(tc.DeltaX)
}

// GetDeltaY 获取Y轴偏移量数组
// 返回: []float64 偏移量数组
func (tc *TextCode) GetDeltaY() []float64 {
	return parseFloats(tc.DeltaY)
}