mupdf annotation sample

annot.c

static void add_ink_annot_sample(const char *input_pdf)
{
    const char *output_pdf = next_file_name(input_pdf);
    fz_context *ctx = fz_new_context(NULL, NULL, FZ_STORE_UNLIMITED);

    fz_try(ctx)
    {
        pdf_document *doc = pdf_open_document(ctx, input_pdf);
        fz_page *page = fz_load_page(ctx, (fz_document *)doc, 0);
        pdf_page *pdfpage = (pdf_page *)page;

        fz_point points[3] = {
            {100, 500},
            {150, 520},
            {180, 580}};

        pdf_annot *annot = pdf_create_annot(ctx, pdfpage, PDF_ANNOT_INK);

        fz_colorspace *cs = fz_device_rgb(ctx);
        float color[3] = {0.57f, 0.25f, 0.67f};
        pdf_set_annot_color(ctx, annot, 3, color);

        pdf_set_annot_border(ctx, annot, 2.0f);

        pdf_obj *obj = pdf_annot_obj(ctx, annot);
        pdf_dict_puts(ctx, obj, PDF_NAME(CA), pdf_new_real(ctx, 0.5f));

        pdf_obj *inklist = pdf_new_array(ctx, doc, 1);
        pdf_obj *stroke = pdf_new_array(ctx, doc, 6);
        for (int i = 0; i < 3; i++)
        {
            pdf_array_push(ctx, stroke, pdf_new_real(ctx, points[i].x));
            pdf_array_push(ctx, stroke, pdf_new_real(ctx, points[i].y));
        }
        pdf_array_push(ctx, inklist, stroke);
        pdf_dict_puts(ctx, obj, PDF_NAME(InkList), inklist);

        pdf_update_annot(ctx, annot);

        fz_output *output = fz_new_output_with_path(ctx, output_pdf, 0);
        fz_document_writer *writer = fz_new_pdf_writer_with_output(ctx, output, NULL);
        fz_write_document(ctx, writer, (fz_document *)doc);
        fz_close_document_writer(ctx, writer);
        fz_close_output(ctx, output);

        fz_drop_page(ctx, page);
        fz_drop_document(ctx, &doc->super);
    }
    fz_catch(ctx)
    {
        d("Error: %s", fz_caught_message(ctx));
    }

    fz_drop_context(ctx);
}