zcatpdf/examples/markdown_demo.zig

//! Markdown Demo - Rendering styled text with Markdown syntax
//!
//! Run with: zig build markdown_demo && ./zig-out/bin/markdown_demo

const std = @import("std");
const zpdf = @import("zpdf");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    std.debug.print("=== zpdf Markdown Demo ===\n\n", .{});

    // Create PDF
    var pdf = zpdf.Pdf.init(allocator, .{});
    defer pdf.deinit();

    pdf.setTitle("Markdown Styled Document");
    pdf.setAuthor("zpdf Markdown Renderer");

    var page = try pdf.addPage(.{});

    // Sample markdown text
    const markdown_text =
        \\# Welcome to zpdf Markdown
        \\
        \\This is a demonstration of **Markdown-styled** text rendering in PDF.
        \\
        \\## Features
        \\
        \\The renderer supports the following formatting:
        \\
        \\- **Bold text** using double asterisks
        \\- *Italic text* using single asterisks
        \\- ***Bold and italic*** combined
        \\- ~~Strikethrough~~ using tildes
        \\- [Clickable links](https://github.com)
        \\
        \\### Code and Technical Content
        \\
        \\You can write technical documentation with styled text.
        \\For example, the *zpdf* library is written in **Zig** and provides
        \\a simple API for PDF generation.
        \\
        \\## Numbered Lists
        \\
        \\1. First item in the list
        \\2. Second item with **bold** text
        \\3. Third item with a [link](https://example.com)
        \\
        \\### Conclusion
        \\
        \\The Markdown renderer makes it easy to create styled documents
        \\without manually managing fonts and styles.
    ;

    // Parse markdown
    var renderer = zpdf.MarkdownRenderer.init(allocator);
    defer renderer.deinit();

    try renderer.parse(markdown_text);

    std.debug.print("Parsed {d} lines of Markdown\n", .{renderer.getLines().len});

    // Render to PDF
    const base_font_size: f32 = 11;
    const line_height: f32 = 16;
    const left_margin: f32 = 50;
    const bullet_indent: f32 = 20;
    var y: f32 = 780;

    var list_number: u32 = 0;

    for (renderer.getLines()) |line| {
        // Handle blank lines
        if (line.line_type == .blank) {
            y -= line_height;
            list_number = 0;
            continue;
        }

        // Calculate y position based on line type
        const extra_spacing: f32 = switch (line.line_type) {
            .heading1 => 20,
            .heading2 => 15,
            .heading3 => 10,
            else => 0,
        };
        y -= extra_spacing;

        // Handle list prefixes
        var x: f32 = left_margin;
        switch (line.line_type) {
            .bullet => {
                try page.setFont(.helvetica, base_font_size);
                page.setFillColor(zpdf.Color.black);
                try page.drawText(x, y, "\xe2\x80\xa2"); // Bullet point (UTF-8)
                // Note: PDF Type1 fonts don't support UTF-8, so we use a simple dash
                try page.drawText(x, y, "-");
                x += bullet_indent;
                list_number = 0;
            },
            .numbered => {
                list_number += 1;
                try page.setFont(.helvetica, base_font_size);
                page.setFillColor(zpdf.Color.black);
                var num_buf: [16]u8 = undefined;
                const num_str = std.fmt.bufPrint(&num_buf, "{d}.", .{list_number}) catch "?.";
                try page.drawText(x, y, num_str);
                x += bullet_indent;
            },
            else => {
                list_number = 0;
            },
        }

        // Render spans
        for (line.spans) |span| {
            // Set font based on style
            const font = zpdf.MarkdownRenderer.fontForStyle(span.style);
            const font_size = span.font_size orelse base_font_size;

            try page.setFont(font, font_size);

            // Set color
            if (span.color) |color| {
                page.setFillColor(zpdf.Color.hex(color));
            } else {
                page.setFillColor(zpdf.Color.black);
            }

            // Draw text
            try page.drawText(x, y, span.text);

            // Draw underline if needed
            if (span.style.underline) {
                const text_width = font.stringWidth(span.text, font_size);
                page.setStrokeColor(if (span.color) |c| zpdf.Color.hex(c) else zpdf.Color.black);
                try page.setLineWidth(0.5);
                try page.drawLine(x, y - 2, x + text_width, y - 2);
            }

            // Draw strikethrough if needed
            if (span.style.strikethrough) {
                const text_width = font.stringWidth(span.text, font_size);
                page.setStrokeColor(zpdf.Color.black);
                try page.setLineWidth(0.5);
                const strike_y = y + font_size * 0.3;
                try page.drawLine(x, strike_y, x + text_width, strike_y);
            }

            // Advance x position
            x += font.stringWidth(span.text, font_size);

            // Add link annotation if present
            if (span.url) |url| {
                const text_width = font.stringWidth(span.text, font_size);
                try page.addUrlLink(url, x - text_width, y - 2, text_width, font_size + 4);
            }
        }

        // Move to next line
        const line_font_size: f32 = if (line.spans.len > 0 and line.spans[0].font_size != null)
            line.spans[0].font_size.?
        else
            base_font_size;
        y -= line_font_size + 4;

        // Add extra space after headings
        y -= extra_spacing / 2;

        // Check for page break
        if (y < 80) {
            page = try pdf.addPage(.{});
            y = 780;
        }
    }

    // Save
    try pdf.save("markdown_demo.pdf");
    std.debug.print("Saved: markdown_demo.pdf\n", .{});
}