zcatpdf/examples/ttf_demo.zig

//! TrueType Font Demo
//!
//! Demonstrates loading and using TrueType fonts.

const std = @import("std");
const zpdf = @import("zpdf");
const Pdf = zpdf.Pdf;
const Color = zpdf.Color;
const TrueTypeFont = zpdf.TrueTypeFont;

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

    var pdf = Pdf.init(allocator, .{});
    defer pdf.deinit();

    pdf.setTitle("TrueType Font Demo");
    pdf.setAuthor("zpdf");

    // Try to load a system TTF font
    const font_paths = [_][]const u8{
        "/usr/share/fonts/google-carlito-fonts/Carlito-Regular.ttf",
        "/usr/share/fonts/adwaita-sans-fonts/AdwaitaSans-Regular.ttf",
        "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
        "/usr/share/fonts/dejavu/DejaVuSans.ttf",
    };

    var ttf_font: ?TrueTypeFont = null;
    var font_path: ?[]const u8 = null;
    var font_data: ?[]u8 = null;  // Keep font data alive

    for (font_paths) |path| {
        const file = std.fs.openFileAbsolute(path, .{}) catch continue;
        defer file.close();

        const data = file.readToEndAlloc(allocator, 10 * 1024 * 1024) catch continue;
        // Don't defer free - font needs to keep data alive

        ttf_font = TrueTypeFont.parse(allocator, data) catch {
            allocator.free(data);
            continue;
        };
        font_data = data;
        font_path = path;
        break;
    }
    defer if (font_data) |data| allocator.free(data);

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

    // Title
    try page.setFont(.helvetica_bold, 28);
    page.setFillColor(Color.hex(0x333333));
    try page.drawText(50, 780, "TrueType Font Demo");

    try page.setFont(.helvetica, 12);
    page.setFillColor(Color.hex(0x666666));
    try page.drawText(50, 760, "TrueType font parsing and information");

    if (ttf_font) |*font| {
        defer font.deinit();

        // Font information section
        try page.setFont(.helvetica_bold, 16);
        page.setFillColor(Color.hex(0x333333));
        try page.drawText(50, 720, "Loaded Font Information");

        try page.setFont(.courier, 10);
        page.setFillColor(Color.black);

        var y: f32 = 690;

        try page.drawText(50, y, "File:");
        try page.drawText(150, y, font_path.?);
        y -= 20;

        try page.drawText(50, y, "Family:");
        if (font.family_name.len > 0) {
            try page.drawText(150, y, font.family_name);
        } else {
            try page.drawText(150, y, "(not available)");
        }
        y -= 20;

        try page.drawText(50, y, "Subfamily:");
        if (font.subfamily_name.len > 0) {
            try page.drawText(150, y, font.subfamily_name);
        } else {
            try page.drawText(150, y, "(not available)");
        }
        y -= 20;

        try page.drawText(50, y, "PostScript:");
        if (font.postscript_name.len > 0) {
            try page.drawText(150, y, font.postscript_name);
        } else {
            try page.drawText(150, y, "(not available)");
        }
        y -= 20;

        // Font metrics
        var buf: [128]u8 = undefined;

        const units_str = std.fmt.bufPrint(&buf, "{d}", .{font.units_per_em}) catch "(error)";
        try page.drawText(50, y, "Units/EM:");
        try page.drawText(150, y, units_str);
        y -= 20;

        const ascender_str = std.fmt.bufPrint(&buf, "{d}", .{font.ascender}) catch "(error)";
        try page.drawText(50, y, "Ascender:");
        try page.drawText(150, y, ascender_str);
        y -= 20;

        const descender_str = std.fmt.bufPrint(&buf, "{d}", .{font.descender}) catch "(error)";
        try page.drawText(50, y, "Descender:");
        try page.drawText(150, y, descender_str);
        y -= 20;

        const glyphs_str = std.fmt.bufPrint(&buf, "{d}", .{font.num_glyphs}) catch "(error)";
        try page.drawText(50, y, "Num Glyphs:");
        try page.drawText(150, y, glyphs_str);
        y -= 20;

        // Bounding box
        const bbox_str = std.fmt.bufPrint(&buf, "[{d}, {d}, {d}, {d}]", .{
            font.bbox[0],
            font.bbox[1],
            font.bbox[2],
            font.bbox[3],
        }) catch "(error)";
        try page.drawText(50, y, "BBox:");
        try page.drawText(150, y, bbox_str);
        y -= 20;

        const angle_str = std.fmt.bufPrint(&buf, "{d:.2}", .{font.italic_angle}) catch "(error)";
        try page.drawText(50, y, "Italic Angle:");
        try page.drawText(150, y, angle_str);
        y -= 20;

        // Character width test
        y -= 20;
        try page.setFont(.helvetica_bold, 14);
        try page.drawText(50, y, "Character Widths (in font units):");
        y -= 20;

        try page.setFont(.courier, 10);

        const test_chars = "AaBbCcDdEeFf0123456789";
        for (test_chars) |c| {
            const glyph_id = font.getGlyphIndex(c);
            const width = font.getGlyphWidth(glyph_id);
            const char_str = std.fmt.bufPrint(&buf, "'{c}' -> glyph {d}, width {d}", .{ c, glyph_id, width }) catch "(error)";
            try page.drawText(50, y, char_str);
            y -= 15;

            if (y < 100) break;
        }

        // String width calculation
        y -= 20;
        try page.setFont(.helvetica_bold, 14);
        try page.drawText(50, y, "String Width Calculation:");
        y -= 20;

        try page.setFont(.courier, 10);
        const test_string = "Hello, World!";
        const width_12pt = font.stringWidth(test_string, 12.0);
        const width_str = std.fmt.bufPrint(&buf, "\"{s}\" at 12pt = {d:.2} points", .{ test_string, width_12pt }) catch "(error)";
        try page.drawText(50, y, width_str);
    } else {
        try page.setFont(.helvetica, 14);
        page.setFillColor(Color.red);
        try page.drawText(50, 700, "No TrueType font found on this system.");
        try page.drawText(50, 680, "Tried the following paths:");

        try page.setFont(.courier, 10);
        var y: f32 = 650;
        for (font_paths) |path| {
            try page.drawText(70, y, path);
            y -= 15;
        }
    }

    // Note about TTF embedding
    try page.setFont(.helvetica_oblique, 10);
    page.setFillColor(Color.hex(0x999999));
    try page.drawText(50, 50, "Note: Full TTF embedding in PDF requires additional implementation for CIDFont Type 2 output.");

    try pdf.save("ttf_demo.pdf");

    std.debug.print("Generated ttf_demo.pdf\n", .{});
}