feat: Add newspaper-style text rendering engine

Implement text renderer with adaptive layout:
- Adaptive width with maximum 80 characters
- Center-aligned content for comfortable reading
- Smart text wrapping and paragraph spacing
- Color scheme optimized for terminal reading
- Support for headings, paragraphs, lists, and links
- Link indicators with numbering
- Horizontal rules and visual separators

The renderer creates a newspaper-like reading experience
optimized for terminal displays.

src/text_renderer.cpp

@@ -0,0 +1,300 @@
+#include "text_renderer.h"
+#include <sstream>
+#include <algorithm>
+#include <clocale>
+
+class TextRenderer::Impl {
+public:
+    RenderConfig config;
+
+    // 自动换行处理
+    std::vector<std::string> wrap_text(const std::string& text, int width) {
+        std::vector<std::string> lines;
+        if (text.empty()) {
+            return lines;
+        }
+
+        std::istringstream words_stream(text);
+        std::string word;
+        std::string current_line;
+
+        while (words_stream >> word) {
+            // 处理单个词超长的情况
+            if (word.length() > static_cast<size_t>(width)) {
+                if (!current_line.empty()) {
+                    lines.push_back(current_line);
+                    current_line.clear();
+                }
+                // 强制分割长词
+                for (size_t i = 0; i < word.length(); i += width) {
+                    lines.push_back(word.substr(i, width));
+                }
+                continue;
+            }
+
+            // 正常换行逻辑
+            if (current_line.empty()) {
+                current_line = word;
+            } else if (current_line.length() + 1 + word.length() <= static_cast<size_t>(width)) {
+                current_line += " " + word;
+            } else {
+                lines.push_back(current_line);
+                current_line = word;
+            }
+        }
+
+        if (!current_line.empty()) {
+            lines.push_back(current_line);
+        }
+
+        if (lines.empty()) {
+            lines.push_back("");
+        }
+
+        return lines;
+    }
+
+    // 添加缩进
+    std::string add_indent(const std::string& text, int indent) {
+        return std::string(indent, ' ') + text;
+    }
+};
+
+TextRenderer::TextRenderer() : pImpl(std::make_unique<Impl>()) {
+    pImpl->config = RenderConfig();
+}
+
+TextRenderer::~TextRenderer() = default;
+
+std::vector<RenderedLine> TextRenderer::render(const ParsedDocument& doc, int screen_width) {
+    std::vector<RenderedLine> lines;
+
+    // 计算实际内容宽度
+    int content_width = std::min(pImpl->config.max_width, screen_width - 4);
+    if (content_width < 40) {
+        content_width = screen_width - 4;
+    }
+
+    // 计算左边距（如果居中）
+    int margin = 0;
+    if (pImpl->config.center_content && content_width < screen_width) {
+        margin = (screen_width - content_width) / 2;
+    }
+    pImpl->config.margin_left = margin;
+
+    // 渲染标题
+    if (!doc.title.empty()) {
+        RenderedLine title_line;
+        title_line.text = std::string(margin, ' ') + doc.title;
+        title_line.color_pair = COLOR_HEADING1;
+        title_line.is_bold = true;
+        title_line.is_link = false;
+        title_line.link_index = -1;
+        lines.push_back(title_line);
+
+        // 标题下划线
+        RenderedLine underline;
+        underline.text = std::string(margin, ' ') + std::string(std::min((int)doc.title.length(), content_width), '=');
+        underline.color_pair = COLOR_HEADING1;
+        underline.is_bold = false;
+        underline.is_link = false;
+        underline.link_index = -1;
+        lines.push_back(underline);
+
+        // 空行
+        RenderedLine empty;
+        empty.text = "";
+        empty.color_pair = COLOR_NORMAL;
+        empty.is_bold = false;
+        empty.is_link = false;
+        empty.link_index = -1;
+        lines.push_back(empty);
+    }
+
+    // 渲染URL
+    if (!doc.url.empty()) {
+        RenderedLine url_line;
+        url_line.text = std::string(margin, ' ') + "URL: " + doc.url;
+        url_line.color_pair = COLOR_URL_BAR;
+        url_line.is_bold = false;
+        url_line.is_link = false;
+        url_line.link_index = -1;
+        lines.push_back(url_line);
+
+        RenderedLine empty;
+        empty.text = "";
+        empty.color_pair = COLOR_NORMAL;
+        empty.is_bold = false;
+        empty.is_link = false;
+        empty.link_index = -1;
+        lines.push_back(empty);
+    }
+
+    // 渲染内容元素
+    for (const auto& elem : doc.elements) {
+        int color = COLOR_NORMAL;
+        bool bold = false;
+        std::string prefix = "";
+
+        switch (elem.type) {
+            case ElementType::HEADING1:
+                color = COLOR_HEADING1;
+                bold = true;
+                prefix = "# ";
+                break;
+            case ElementType::HEADING2:
+                color = COLOR_HEADING2;
+                bold = true;
+                prefix = "## ";
+                break;
+            case ElementType::HEADING3:
+                color = COLOR_HEADING3;
+                bold = true;
+                prefix = "### ";
+                break;
+            case ElementType::PARAGRAPH:
+                color = COLOR_NORMAL;
+                bold = false;
+                break;
+            case ElementType::BLOCKQUOTE:
+                color = COLOR_DIM;
+                prefix = "> ";
+                break;
+            case ElementType::LIST_ITEM:
+                prefix = "  • ";
+                break;
+            case ElementType::HORIZONTAL_RULE:
+                {
+                    RenderedLine hr;
+                    std::string hrline(content_width, '-');
+                    hr.text = std::string(margin, ' ') + hrline;
+                    hr.color_pair = COLOR_DIM;
+                    hr.is_bold = false;
+                    hr.is_link = false;
+                    hr.link_index = -1;
+                    lines.push_back(hr);
+                    continue;
+                }
+            default:
+                break;
+        }
+
+        // 换行处理
+        auto wrapped_lines = pImpl->wrap_text(elem.text, content_width - prefix.length());
+        for (size_t i = 0; i < wrapped_lines.size(); ++i) {
+            RenderedLine line;
+            if (i == 0) {
+                line.text = std::string(margin, ' ') + prefix + wrapped_lines[i];
+            } else {
+                line.text = std::string(margin + prefix.length(), ' ') + wrapped_lines[i];
+            }
+            line.color_pair = color;
+            line.is_bold = bold;
+            line.is_link = false;
+            line.link_index = -1;
+            lines.push_back(line);
+        }
+
+        // 段落间距
+        if (elem.type == ElementType::PARAGRAPH ||
+            elem.type == ElementType::HEADING1 ||
+            elem.type == ElementType::HEADING2 ||
+            elem.type == ElementType::HEADING3) {
+            for (int i = 0; i < pImpl->config.paragraph_spacing; ++i) {
+                RenderedLine empty;
+                empty.text = "";
+                empty.color_pair = COLOR_NORMAL;
+                empty.is_bold = false;
+                empty.is_link = false;
+                empty.link_index = -1;
+                lines.push_back(empty);
+            }
+        }
+    }
+
+    // 渲染链接列表
+    if (!doc.links.empty() && pImpl->config.show_link_indicators) {
+        RenderedLine separator;
+        std::string sepline(content_width, '-');
+        separator.text = std::string(margin, ' ') + sepline;
+        separator.color_pair = COLOR_DIM;
+        separator.is_bold = false;
+        separator.is_link = false;
+        separator.link_index = -1;
+        lines.push_back(separator);
+
+        RenderedLine links_header;
+        links_header.text = std::string(margin, ' ') + "Links:";
+        links_header.color_pair = COLOR_HEADING3;
+        links_header.is_bold = true;
+        links_header.is_link = false;
+        links_header.link_index = -1;
+        lines.push_back(links_header);
+
+        RenderedLine empty;
+        empty.text = "";
+        empty.color_pair = COLOR_NORMAL;
+        empty.is_bold = false;
+        empty.is_link = false;
+        empty.link_index = -1;
+        lines.push_back(empty);
+
+        for (size_t i = 0; i < doc.links.size(); ++i) {
+            const auto& link = doc.links[i];
+            std::string link_text = "[" + std::to_string(i) + "] " + link.text;
+
+            auto wrapped = pImpl->wrap_text(link_text, content_width - 4);
+            for (size_t j = 0; j < wrapped.size(); ++j) {
+                RenderedLine link_line;
+                link_line.text = std::string(margin + 2, ' ') + wrapped[j];
+                link_line.color_pair = COLOR_LINK;
+                link_line.is_bold = false;
+                link_line.is_link = true;
+                link_line.link_index = i;
+                lines.push_back(link_line);
+            }
+
+            // URL on next line
+            auto url_wrapped = pImpl->wrap_text(link.url, content_width - 6);
+            for (const auto& url_line_text : url_wrapped) {
+                RenderedLine url_line;
+                url_line.text = std::string(margin + 4, ' ') + "→ " + url_line_text;
+                url_line.color_pair = COLOR_DIM;
+                url_line.is_bold = false;
+                url_line.is_link = false;
+                url_line.link_index = -1;
+                lines.push_back(url_line);
+            }
+
+            lines.push_back(empty);
+        }
+    }
+
+    return lines;
+}
+
+void TextRenderer::set_config(const RenderConfig& config) {
+    pImpl->config = config;
+}
+
+RenderConfig TextRenderer::get_config() const {
+    return pImpl->config;
+}
+
+void init_color_scheme() {
+    if (has_colors()) {
+        start_color();
+        use_default_colors();
+
+        init_pair(COLOR_NORMAL, COLOR_WHITE, -1);
+        init_pair(COLOR_HEADING1, COLOR_CYAN, -1);
+        init_pair(COLOR_HEADING2, COLOR_BLUE, -1);
+        init_pair(COLOR_HEADING3, COLOR_MAGENTA, -1);
+        init_pair(COLOR_LINK, COLOR_YELLOW, -1);
+        init_pair(COLOR_LINK_ACTIVE, COLOR_BLACK, COLOR_YELLOW);
+        init_pair(COLOR_STATUS_BAR, COLOR_BLACK, COLOR_WHITE);
+        init_pair(COLOR_URL_BAR, COLOR_GREEN, -1);
+        init_pair(COLOR_SEARCH_HIGHLIGHT, COLOR_BLACK, COLOR_YELLOW);
+        init_pair(COLOR_DIM, COLOR_BLACK, -1);
+    }
+}

src/text_renderer.h

@@ -0,0 +1,60 @@
+#pragma once
+
+#include "html_parser.h"
+#include <string>
+#include <vector>
+#include <curses.h>
+
+// 渲染后的行信息
+struct RenderedLine {
+    std::string text;
+    int color_pair;
+    bool is_bold;
+    bool is_link;
+    int link_index; // 如果是链接，对应的链接索引
+};
+
+// 渲染配置
+struct RenderConfig {
+    int max_width = 80;        // 内容最大宽度
+    int margin_left = 0;       // 左边距（居中时自动计算）
+    bool center_content = true; // 是否居中内容
+    int paragraph_spacing = 1;  // 段落间距
+    bool show_link_indicators = true; // 是否显示链接指示器
+};
+
+class TextRenderer {
+public:
+    TextRenderer();
+    ~TextRenderer();
+
+    // 渲染文档到行数组
+    std::vector<RenderedLine> render(const ParsedDocument& doc, int screen_width);
+
+    // 设置渲染配置
+    void set_config(const RenderConfig& config);
+
+    // 获取当前配置
+    RenderConfig get_config() const;
+
+private:
+    class Impl;
+    std::unique_ptr<Impl> pImpl;
+};
+
+// 颜色定义
+enum ColorScheme {
+    COLOR_NORMAL = 1,
+    COLOR_HEADING1,
+    COLOR_HEADING2,
+    COLOR_HEADING3,
+    COLOR_LINK,
+    COLOR_LINK_ACTIVE,
+    COLOR_STATUS_BAR,
+    COLOR_URL_BAR,
+    COLOR_SEARCH_HIGHLIGHT,
+    COLOR_DIM
+};
+
+// 初始化颜色方案
+void init_color_scheme();