mirror of
https://github.com/xiaoqidun/ofdgo.git
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105 lines
3.5 KiB
Go
105 lines
3.5 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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"fmt"
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"path"
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"github.com/tdewolff/canvas"
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"github.com/tdewolff/font"
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)
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// ResolveFont 按需加载字体资源，保留内嵌数据及外部字体的名称、样式和集合索引匹配
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// 入参: r 渲染器, id 字体标识, exact 是否禁止无关回退
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// 返回: ResolvedFont 字体与来源, error 字体不可用错误
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func (CanvasBackend) ResolveFont(r *Renderer, id string, exact bool) (ResolvedFont, error) {
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definition := r.Reader.fontCache[id]
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if definition == nil && !r.Reader.fontResourcesRead && r.Reader.OFD != nil {
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if _, err := r.Reader.Fonts(); err != nil {
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return ResolvedFont{}, err
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}
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definition = r.Reader.fontCache[id]
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}
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if definition == nil {
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if exact {
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return ResolvedFont{}, fmt.Errorf("font %q not found", id)
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}
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return r.canvasFallbackFont(), nil
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}
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if definition.FontFile != "" {
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data, err := r.Reader.FontData(id)
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if err != nil {
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return ResolvedFont{}, err
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}
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face, err := r.Reader.embeddedFontFace(*definition)
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if err != nil {
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return ResolvedFont{}, err
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}
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return ResolvedFont{Data: data, Source: path.Base(definition.FontFile), Face: face, Exact: true}, nil
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}
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style := canvasFontStyle(definition)
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if source, family := r.fontSourceMatch(id, definition, exact); family != nil {
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sfnt := family.Face(12, style).Font.SFNT
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face := fontFaceInfo(sfnt.Tables["name"], source.face)
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r.canvasState().fontSourceUsed[id] = source
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return ResolvedFont{Data: fontSFNTData(sfnt), Source: source.name, Face: &face, Exact: source.exact}, nil
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}
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if !exact {
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return r.canvasFallbackFont(), nil
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}
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return ResolvedFont{}, fmt.Errorf("font %q is unavailable", definition.FontName)
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}
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// canvasFallbackFont 按需加载默认阅读字体，不用于精确编辑匹配
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// 返回: ResolvedFont 默认字体，未安装时数据为空
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func (r *Renderer) canvasFallbackFont() ResolvedFont {
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if r.canvasState().fontFamily == nil {
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r.initCanvasFonts()
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}
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if r.canvasState().defaultFontLoaded {
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return ResolvedFont{Data: fontSFNTData(r.canvasState().fontFamily.Face(12, canvas.FontRegular).Font.SFNT)}
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}
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return ResolvedFont{}
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}
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// OpenFont 解析独立SFNT数据，度量与原有编辑排版保持一致
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// 入参: data 字体数据
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// 返回: FontMetrics 字体度量, error 解析错误
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func (CanvasBackend) OpenFont(data []byte) (FontMetrics, error) {
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sfnt, err := font.ParseSFNT(data, 0)
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if err != nil {
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return nil, err
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}
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return canvasFontMetrics{sfnt}, nil
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}
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// canvasFontMetrics 保留默认字体度量，写出时不更新原始时间
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type canvasFontMetrics struct {
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*font.SFNT
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}
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// Write 返回字体数据，不修改字体元信息
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// 返回: []byte 独立SFNT数据
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func (f canvasFontMetrics) Write() []byte {
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return fontSFNTData(f.SFNT)
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}
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// initCanvasFonts 初始化Canvas默认字体
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func (r *Renderer) initCanvasFonts() {
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r.canvasState().fontFamily = canvas.NewFontFamily("default")
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r.canvasState().defaultFontLoaded = r.loadDefaultFonts()
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}
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