zcatpdf/examples/image_demo.zig

//! Image Demo - Demonstrates JPEG and PNG image embedding
//!
//! Usage: ./image_demo [path_to_image]
//! Supports: JPEG (.jpg, .jpeg) and PNG (.png) images
//! If no path is provided, creates a simple PDF with text explaining the features.

const std = @import("std");
const pdf = @import("zcatpdf");

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

    std.debug.print("zcatpdf - Image Demo\n", .{});

    // Get command line args
    const args = try std.process.argsAlloc(allocator);
    defer std.process.argsFree(allocator, args);

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

    doc.setTitle("Image Demo");
    doc.setAuthor("zcatpdf");

    var page = try doc.addPage(.{});
    page.setMargins(50, 50, 50);
    page.setXY(50, 800);

    // Title
    try page.setFont(.helvetica_bold, 24);
    page.setFillColor(pdf.Color.rgb(41, 98, 255));
    try page.cell(0, 30, "Image Demo - JPEG & PNG Support", pdf.Border.none, .center, false);
    page.ln(40);

    // Check if an image path was provided
    if (args.len > 1) {
        const image_path = args[1];
        std.debug.print("Loading image: {s}\n", .{image_path});

        // Try to load the image (auto-detect format)
        const image_index = doc.addImageFromFile(image_path) catch |err| {
            std.debug.print("Error loading image: {any}\n", .{err});

            try page.setFont(.helvetica, 12);
            page.setFillColor(pdf.Color.red);
            try page.cell(0, 20, "Error: Could not load image file", pdf.Border.none, .left, false);
            page.ln(25);

            try page.setFont(.helvetica, 10);
            page.setFillColor(pdf.Color.black);
            const long_text =
                \\Make sure the file exists and is a valid JPEG or PNG image.
                \\
                \\Supported formats:
                \\- JPEG/JPG images (RGB, Grayscale, CMYK)
                \\- PNG images (RGB, RGBA, Grayscale, Indexed)
            ;
            try page.multiCell(450, null, long_text, pdf.Border.none, .left, false);

            const filename = "image_demo.pdf";
            try doc.save(filename);
            std.debug.print("Created: {s}\n", .{filename});
            return;
        };

        // Get image info
        const img_info = doc.getImage(image_index).?;

        // Show image info
        try page.setFont(.helvetica_bold, 14);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 20, "Image Information:", pdf.Border.none, .left, false);
        page.ln(25);

        try page.setFont(.helvetica, 11);

        // Display image properties
        var buf: [256]u8 = undefined;
        const size_text = std.fmt.bufPrint(&buf, "Dimensions: {d} x {d} pixels", .{ img_info.width, img_info.height }) catch "Error";
        try page.cell(0, 16, size_text, pdf.Border.none, .left, false);
        page.ln(18);

        const format_text = std.fmt.bufPrint(&buf, "Format: {s}", .{if (img_info.format == .jpeg) "JPEG" else "PNG"}) catch "Error";
        try page.cell(0, 16, format_text, pdf.Border.none, .left, false);
        page.ln(18);

        const color_text = std.fmt.bufPrint(&buf, "Color Space: {s}", .{img_info.color_space.pdfName()}) catch "Error";
        try page.cell(0, 16, color_text, pdf.Border.none, .left, false);
        page.ln(18);

        const bpc_text = std.fmt.bufPrint(&buf, "Bits per Component: {d}", .{img_info.bits_per_component}) catch "Error";
        try page.cell(0, 16, bpc_text, pdf.Border.none, .left, false);
        page.ln(18);

        const alpha_text = std.fmt.bufPrint(&buf, "Has Alpha Channel: {s}", .{if (img_info.hasAlpha()) "Yes" else "No"}) catch "Error";
        try page.cell(0, 16, alpha_text, pdf.Border.none, .left, false);
        page.ln(30);

        // Draw the image
        try page.setFont(.helvetica_bold, 14);
        try page.cell(0, 20, "Image Preview:", pdf.Border.none, .left, false);
        page.ln(25);

        // Calculate size to fit in available space (max 400x400)
        const max_w: f32 = 400;
        const max_h: f32 = 400;
        const img_w: f32 = @floatFromInt(img_info.width);
        const img_h: f32 = @floatFromInt(img_info.height);
        const scale = @min(max_w / img_w, max_h / img_h, 1.0);
        const display_w = img_w * scale;
        const display_h = img_h * scale;

        // Draw border around image area
        const img_x = page.getX();
        const img_y = page.getY() - display_h;

        page.setStrokeColor(pdf.Color.light_gray);
        try page.drawRect(img_x - 2, img_y - 2, display_w + 4, display_h + 4);

        // Draw the image
        try page.image(image_index, img_info, img_x, img_y, display_w, display_h);

        std.debug.print("Image embedded: {d}x{d} pixels, displayed at {d:.0}x{d:.0} points\n", .{ img_info.width, img_info.height, display_w, display_h });
        if (img_info.hasAlpha()) {
            std.debug.print("Alpha channel: embedded as soft mask\n", .{});
        }
    } else {
        // No image provided - show instructions
        try page.setFont(.helvetica_bold, 14);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 20, "How to Use Images:", pdf.Border.none, .left, false);
        page.ln(25);

        try page.setFont(.helvetica, 11);
        const instructions =
            \\To include an image in your PDF:
            \\
            \\1. Load the image file (auto-detects format):
            \\   const img_idx = try doc.addImageFromFile("photo.jpg");
            \\   // Or specifically:
            \\   const jpg_idx = try doc.addJpegImageFromFile("photo.jpg");
            \\   const png_idx = try doc.addPngImageFromFile("image.png");
            \\
            \\2. Get the image info:
            \\   const info = doc.getImage(img_idx).?;
            \\
            \\3. Draw on a page:
            \\   try page.image(img_idx, info, x, y, width, height);
            \\
            \\Or use imageFit to auto-scale:
            \\   try page.imageFit(img_idx, info, x, y, max_w, max_h);
            \\
            \\Run this example with an image file path:
            \\   ./image_demo photo.jpg
            \\   ./image_demo logo.png
        ;
        try page.multiCell(450, null, instructions, pdf.Border.all, .left, false);

        page.ln(30);

        // Supported features
        try page.setFont(.helvetica_bold, 14);
        try page.cell(0, 20, "Supported Features:", pdf.Border.none, .left, false);
        page.ln(25);

        try page.setFont(.helvetica, 11);

        // JPEG Features
        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "JPEG images (RGB, Grayscale, CMYK)", pdf.Border.none, .left, false);
        page.ln(18);

        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "JPEG direct passthrough (no re-encoding)", pdf.Border.none, .left, false);
        page.ln(18);

        // PNG Features
        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "PNG images (RGB, RGBA, Grayscale, Indexed)", pdf.Border.none, .left, false);
        page.ln(18);

        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "PNG transparency (alpha channel as soft mask)", pdf.Border.none, .left, false);
        page.ln(18);

        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "PNG filters (None, Sub, Up, Average, Paeth)", pdf.Border.none, .left, false);
        page.ln(18);

        // General features
        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "Automatic format detection", pdf.Border.none, .left, false);
        page.ln(18);

        page.setFillColor(pdf.Color.rgb(0, 128, 0));
        try page.cell(20, 16, "[OK]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "Aspect ratio preservation", pdf.Border.none, .left, false);
        page.ln(18);

        // Not yet supported
        page.setFillColor(pdf.Color.rgb(255, 165, 0));
        try page.cell(20, 16, "[--]", pdf.Border.none, .left, false);
        page.setFillColor(pdf.Color.black);
        try page.cell(0, 16, "PNG interlaced images (not supported)", pdf.Border.none, .left, false);
    }

    // Footer
    page.setXY(50, 50);
    try page.setFont(.helvetica, 9);
    page.setFillColor(pdf.Color.medium_gray);
    try page.cell(0, 15, "Generated with zcatpdf - Pure Zig PDF Library", pdf.Border.none, .center, false);

    // Save
    const filename = "image_demo.pdf";
    try doc.save(filename);

    std.debug.print("Created: {s}\n", .{filename});
    std.debug.print("Done!\n", .{});
}