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feat: rewrite markdown preview rendering pipeline - #4693
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[APPROVALNOTIFIER] This PR is NOT APPROVED This pull-request has been approved by: Johnson-zs The full list of commands accepted by this bot can be found here. DetailsNeeds approval from an approver in each of these files:Approvers can indicate their approval by writing |
Reviewer's GuideThe preview now parses Markdown with md4c into a QTextDocument-compatible, palette-themed HTML representation, performs per-code-block KSyntaxHighlighting using fence languages, resolves local resources, preserves reading position across theme changes, and adds corresponding build dependencies and extensive unit coverage. Sequence diagram for themed markdown renderingsequenceDiagram
participant Browser as MarkdownBrowser
participant Renderer as MarkdownRenderer
participant Builder as MarkdownHtmlBuilder
participant Parser as md4c
participant Document as QTextDocument
participant Highlighter as MarkdownCodeHighlighter
Browser->>Renderer: render(document, markdown, basePath, theme)
Renderer->>Builder: build(markdown)
Builder->>Parser: md_parse(...)
Parser-->>Builder: HTML fragment and codeLanguages
Builder-->>Renderer: HTML fragment
Renderer->>Document: setHtml(html)
Renderer->>Highlighter: highlightRun(blocks, language)
Highlighter->>Document: mergeCharFormat(...)
Sequence diagram for theme changes preserving reading positionsequenceDiagram
participant Browser as MarkdownBrowser
participant ThemeHelper as DGuiApplicationHelper
participant Renderer as MarkdownRenderer
participant Document as QTextDocument
participant ScrollBar as QScrollBar
ThemeHelper-->>Browser: themeTypeChanged()
Browser->>ScrollBar: value()
Browser->>Renderer: render(document, markdown, basePath, theme)
Renderer->>Document: setHtml(html)
Browser->>ScrollBar: setValue(scrollPosition)
Flow diagram for fenced code block highlightingflowchart TD
A[md4c parses fenced code block] --> B[Capture fence language]
B --> C[Import themed HTML into QTextDocument]
C --> D[Find code block QTextBlock run]
D --> E["definitionFor(language)"]
E --> F[highlightLine]
F --> G[QTextCursor.mergeCharFormat]
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Hey - I've found 1 issue
Prompt for AI Agents
Please address the comments from this code review:
## Individual Comments
### Comment 1
<location path="src/apps/dde-file-manager-preview/pluginpreviews/markdown-preview/markdownrenderer.cpp" line_range="88-89" />
<code_context>
+ continue;
+ }
+
+ QVector<QTextBlock> run;
+ while (block.isValid() && isCodeBlock(block, theme)) {
+ run.append(block);
+ block = block.next();
</code_context>
<issue_to_address>
**Adjacent fences share one language**
When two fenced code blocks with different languages are consecutive without a non-code block between them, `highlightCodeBlocks()` groups their code-formatted blocks into one run and advances `languageIndex` only once, so `highlightRun()` applies the first fence’s grammar to later fences and the preview shows incorrect highlighting.
Split runs at fence boundaries and advance the language index for each fenced block.
Also at `src/apps/dde-file-manager-preview/pluginpreviews/markdown-preview/markdownrenderer.cpp:94`.
</issue_to_address>
Comment on lines
+88
to
+89
| QVector<QTextBlock> run; | ||
| while (block.isValid() && isCodeBlock(block, theme)) { |
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🟠 High · Adjacent fences share one language
When two fenced code blocks with different languages are consecutive without a non-code block between them, highlightCodeBlocks() groups their code-formatted blocks into one run and advances languageIndex only once, so highlightRun() applies the first fence’s grammar to later fences and the preview shows incorrect highlighting.
Split runs at fence boundaries and advance the language index for each fenced block.
Also at src/apps/dde-file-manager-preview/pluginpreviews/markdown-preview/markdownrenderer.cpp:94.
Prompt for AI agents
In `src/apps/dde-file-manager-preview/pluginpreviews/markdown-preview/markdownrenderer.cpp` at lines 88-89:
**Adjacent fences share one language**
When two fenced code blocks with different languages are consecutive without a non-code block between them, `highlightCodeBlocks()` groups their code-formatted blocks into one run and advances `languageIndex` only once, so `highlightRun()` applies the first fence’s grammar to later fences and the preview shows incorrect highlighting.
Split runs at fence boundaries and advance the language index for each fenced block.
Also at `src/apps/dde-file-manager-preview/pluginpreviews/markdown-preview/markdownrenderer.cpp:94`.
|
Warning
详情 {
"unset": {
"autotests/apps/dde-file-manager-preview/markdown-preview/test_markdownrenderer.cpp": {
"b": [
"// Note that an unset QBrush still reports black, hence the style check."
]
}
}
} |
1. The markdown preview only called QTextDocument::setMarkdown(), which parses CommonMark but produces no visual formatting at all: no heading scale, no spacing, no code surface, no table borders. Rendering quality was far below expectations 2. Parse with md4c (the parser Qt uses internally, so the dialect still matches) and emit the HTML subset QTextHtmlParser actually honours - the same round-trip format QTextDocument::toHtml() produces. Inline style attributes carry the theme 3. md4c exposes the fence info string that Qt's reader discards, so code blocks are re-coloured per block with KSyntaxHighlighting (AbstractHighlighter::highlightLine + QTextCursor::mergeCharFormat), giving each block its own language 4. All colours derive from DGuiApplicationHelper/DPalette and the document is rebuilt on themeTypeChanged, so light/dark switch keeps the reading position 5. Work around four QtHTML limits found by rendering to PNG: h1-h6 ignore font-size (headings are emitted as sized bold paragraphs), block margins only honour px (pt is dropped), blockquote cannot draw a left bar and hr cannot take a colour (both use a one cell table with a border), and nested lists need margin-left on every level 6. Add libmd4c-dev to Build-Depends in both debian/control and debian/control.in; it is pure C with Architecture: any and present for amd64/arm64/loong64/riscv64 Log: Rewrite markdown preview with md4c parsing, themed rich text layout and per-block code syntax highlighting Influence: 1. Open any .md file in the file manager preview panel and confirm headings, paragraphs, lists, quotes, tables, images and fenced code blocks are properly typeset 2. Confirm fenced code blocks are syntax highlighted according to their info string (```cpp, ```python, ```json and so on) 3. Switch the system theme between light and dark and confirm the preview recolours without jumping back to the top 4. Open a markdown file with relative image references and confirm the images resolve against the file directory 5. Run ut-markdown-preview and confirm all cases pass feat: 重写 markdown 预览渲染管线 1. 原实现只调用了一句 QTextDocument::setMarkdown()，该接口只解析 CommonMark 语法，完全不产生任何排版样式：没有标题字号阶梯、没有 段间距、没有代码块底色、没有表格边框，观感很差 2. 改用 md4c 解析（Qt 内部 setMarkdown 用的就是它，方言保持一致）， 只生成 QtHtmlParser 真正支持的 HTML 子集——即 QTextDocument::toHtml() 自身的往返格式，配色通过内联样式属性携带 3. md4c 能给出 Qt 读取器丢弃的 fence 语言信息，因此导入后按块用 KSyntaxHighlighting 二次着色 （AbstractHighlighter::highlightLine + QTextCursor::mergeCharFormat）， 每个代码块都能使用自己的语言定义 4. 配色全部从 DGuiApplicationHelper/DPalette 派生，themeTypeChanged 时整体重渲染，明暗切换保留阅读位置 5. 通过离屏渲染 PNG 实测，绕开四处 QtHTML 限制：h1-h6 忽略字号 （标题改为带字号的粗体段落）、块边距只认 px（pt 被丢弃）、 blockquote 无法画左侧色条且 hr 无法设色（两者改用单格表格加边框）、 嵌套列表每一层都要写 margin-left 6. 在 debian/control 与 debian/control.in 的 Build-Depends 中新增 libmd4c-dev；该包为纯 C、Architecture: any， amd64/arm64/loong64/riscv64 均已提供 Log: 重写 markdown 预览，改用 md4c 解析、跟随主题的富文本排版，并支持 按代码块语言语法高亮 Influence: 1. 在文件管理器预览面板打开任意 .md 文件，确认标题、段落、列表、 引用、表格、图片与代码块排版正常 2. 确认 fenced 代码块按其 info string 语法高亮（```cpp、```python、 ```json 等） 3. 切换系统明暗主题，确认预览重新着色且不会跳回顶部 4. 打开含相对路径图片引用的 markdown 文件，确认图片按文件所在目录 正确解析 5. 运行 ut-markdown-preview，确认全部用例通过
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Warning
详情 {
"unset": {
"autotests/apps/dde-file-manager-preview/markdown-preview/test_markdownrenderer.cpp": {
"b": [
"// Note that an unset QBrush still reports black, hence the style check."
]
}
}
} |
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deepin pr auto review🤖 AI 代码审查报告总体评分： 📊 总体评价
🔍 详细分析1. 语法逻辑 ✅评价： 语法正确，逻辑清晰 ✅ 通过 潜在问题： 建议： [] 2. 代码质量 ✅评价： 代码结构清晰，注释完整 ✅ 通过 潜在问题： 建议： [] 3. 代码性能 ✅评价： 性能良好，资源使用合理 ✅ 通过 潜在问题： 建议： [] 4. 代码安全 🔒评价： 存在0个安全漏洞 ✅ 通过
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parses CommonMark but produces no visual formatting at all: no heading
scale, no spacing, no code surface, no table borders. Rendering quality
was far below expectations
matches) and emit the HTML subset QTextHtmlParser actually honours -
the same round-trip format QTextDocument::toHtml() produces. Inline
style attributes carry the theme
blocks are re-coloured per block with KSyntaxHighlighting
(AbstractHighlighter::highlightLine + QTextCursor::mergeCharFormat),
giving each block its own language
is rebuilt on themeTypeChanged, so light/dark switch keeps the reading
position
font-size (headings are emitted as sized bold paragraphs), block
margins only honour px (pt is dropped), blockquote cannot draw a left
bar and hr cannot take a colour (both use a one cell table with a
border), and nested lists need margin-left on every level
debian/control.in; it is pure C with Architecture: any and present for
amd64/arm64/loong64/riscv64
Log: Rewrite markdown preview with md4c parsing, themed rich text layout
and per-block code syntax highlighting
Influence:
headings, paragraphs, lists, quotes, tables, images and fenced code
blocks are properly typeset
info string (
cpp,python, ```json and so on)recolours without jumping back to the top
images resolve against the file directory
feat: 重写 markdown 预览渲染管线
CommonMark 语法，完全不产生任何排版样式：没有标题字号阶梯、没有
段间距、没有代码块底色、没有表格边框，观感很差
只生成 QtHtmlParser 真正支持的 HTML 子集——即
QTextDocument::toHtml() 自身的往返格式，配色通过内联样式属性携带
KSyntaxHighlighting 二次着色
（AbstractHighlighter::highlightLine + QTextCursor::mergeCharFormat），
每个代码块都能使用自己的语言定义
时整体重渲染，明暗切换保留阅读位置
（标题改为带字号的粗体段落）、块边距只认 px（pt 被丢弃）、
blockquote 无法画左侧色条且 hr 无法设色（两者改用单格表格加边框）、
嵌套列表每一层都要写 margin-left
libmd4c-dev；该包为纯 C、Architecture: any，
amd64/arm64/loong64/riscv64 均已提供
Log: 重写 markdown 预览，改用 md4c 解析、跟随主题的富文本排版，并支持
按代码块语言语法高亮
Influence:
引用、表格、图片与代码块排版正常
cpp、python、正确解析
Summary by Sourcery
Rewrite the Markdown preview pipeline to provide themed rich-text rendering with per-block syntax highlighting and reliable resource handling.
New Features:
Bug Fixes:
Enhancements:
Build:
Tests: