mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
94 lines
2.6 KiB
Go
94 lines
2.6 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"crypto/sha256"
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"fmt"
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"io"
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"strings"
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"github.com/tdewolff/canvas"
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"github.com/tdewolff/canvas/renderers/svg"
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)
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// SVGFont SVG引用的字体资源，Name为CSS字体族标识，Data为只读字体数据
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type SVGFont struct {
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Name string
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Weight int
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Style string
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Data []byte
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}
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// svgFontRenderer 分离字体资源的SVG渲染器
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type svgFontRenderer struct {
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*svg.SVG
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renderer *Renderer
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fonts []SVGFont
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seen map[string]bool
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styles strings.Builder
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}
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// RenderToSVGWithFonts 渲染为SVG并返回页面引用的字体资源，不在SVG中嵌入字体
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// 入参: page 页面内容, writer 输出流
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// 返回: []SVGFont 字体资源，可按Name复用并按Weight、Style注册，error 错误信息
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func (r *Renderer) RenderToSVGWithFonts(page *PageContent, writer io.Writer) ([]SVGFont, error) {
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c, err := r.renderPage(page)
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if err != nil {
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return nil, err
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}
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options := svg.DefaultOptions
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options.EmbedFonts = false
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s := &svgFontRenderer{
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SVG: svg.New(writer, c.W, c.H, &options),
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renderer: r,
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seen: make(map[string]bool),
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}
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c.RenderTo(s)
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s.SetCustomStyle(s.styles.String())
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return s.fonts, s.Close()
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}
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// RenderText 绘制文字并记录实际使用的字体资源
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// 入参: text 文字对象, m 变换矩阵
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func (s *svgFontRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
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if text.Empty() {
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return
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}
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font := text.MostCommonFontFace().Font
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resource, ok := s.renderer.svgFontCache[font]
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if !ok {
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data := font.SFNT.Write()
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resource = SVGFont{
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Name: fmt.Sprintf("ofdgo-%x-%d", sha256.Sum256(data), font.Style()),
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Weight: font.Style().CSS(),
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Style: "normal",
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Data: data,
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}
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if font.Style().Italic() {
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resource.Style = "italic"
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}
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s.renderer.svgFontCache[font] = resource
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}
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if !s.seen[resource.Name] {
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s.seen[resource.Name] = true
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s.fonts = append(s.fonts, resource)
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fmt.Fprintf(&s.styles, ".%s{font-family:%s!important}", resource.Name, resource.Name)
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}
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s.SetClass(resource.Name)
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s.SVG.RenderText(text, m)
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s.SetClass()
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}
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