cairo-renderer-pdf-out.cpp

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * A quick hack to use the Cairo renderer to write out a file.  This
 * then makes 'save as...' PDF.
 *
 * Authors:
 *   Ted Gould <ted@gould.cx>
 *   Ulf Erikson <ulferikson@users.sf.net>
 *   Johan Engelen <goejendaagh@zonnet.nl>
 *   Jon A. Cruz <jon@joncruz.org>
 *   Abhishek Sharma
 *
 * Copyright (C) 2004-2010 Authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#include <cairo.h>
#ifdef CAIRO_HAS_PDF_SURFACE
 
#include "cairo-renderer-pdf-out.h"
#include "cairo-render-context.h"
#include "cairo-renderer.h"
#include "latex-text-renderer.h"
#include "path-chemistry.h"
#include <print.h>
#include "extension/system.h"
#include "extension/print.h"
#include "extension/db.h"
#include "extension/output.h"
 
#include "display/drawing.h"
#include "display/curve.h"
 
#include "object/sp-item.h"
#include "object/sp-root.h"
#include "object/sp-page.h"
 
#include <2geom/affine.h>
#include "page-manager.h"
#include "document.h"
 
#include "util/units.h"
 
namespace Inkscape {
namespace Extension {
namespace Internal {
 
bool CairoRendererPdfOutput::check(Inkscape::Extension::Extension * /*module*/)
{
    bool result = true;
 
    if (nullptr == Inkscape::Extension::db.get("org.inkscape.output.pdf.cairorenderer")) {
        result = false;
    }
 
    return result;
}
 
// TODO: Make this function more generic so that it can do both PostScript and PDF; expose in the headers
static bool
pdf_render_document_to_file(SPDocument *doc, gchar const *filename, unsigned int level, PDFOptions flags,
                            int resolution)
{
    if (flags.text_to_path) {
        assert(!flags.text_to_latex);
        // Cairo's text-to-path method has numerical precision and font matching
        // issues (https://gitlab.com/inkscape/inkscape/-/issues/1979).
        // We get better results by using Inkscape's Object-to-Path method.
        Inkscape::convert_text_to_curves(doc);
    }
 
    doc->ensureUpToDate();
 
    SPRoot *root = doc->getRoot();
    if (!root) {
        return false;
    }
    
    /* Create new drawing */
    Inkscape::Drawing drawing;
    unsigned dkey = SPItem::display_key_new(1);
    drawing.setRoot(root->invoke_show(drawing, dkey, SP_ITEM_SHOW_DISPLAY));
    drawing.setExact();
 
    /* Create renderer and context */
    CairoRenderer renderer;
    CairoRenderContext ctx = renderer.createContext();
    ctx.setPDFLevel(level);
    ctx.setTextToPath(flags.text_to_path);
    ctx.setOmitText(flags.text_to_latex);
    ctx.setFilterToBitmap(flags.rasterize_filters);
    ctx.setBitmapResolution(resolution);
 
    bool ret = ctx.setPdfTarget(filename)
               && renderer.setupDocument(&ctx, doc, root)
               && renderer.renderPages(&ctx, doc, flags.stretch_to_fit);
    if (ret) {
        ctx.finish();
    }
 
    root->invoke_hide(dkey);
    return ret;
}
 
void
CairoRendererPdfOutput::save(Inkscape::Extension::Output *mod, SPDocument *doc, gchar const *filename)
{
    Inkscape::Extension::Extension * ext;
    unsigned int ret;
 
    ext = Inkscape::Extension::db.get("org.inkscape.output.pdf.cairorenderer");
    if (ext == nullptr)
        return;
 
    int level = 0;
    try {
        const gchar *new_level = mod->get_param_optiongroup("PDFversion");
        if((new_level != nullptr) && (g_ascii_strcasecmp("PDF-1.5", new_level) == 0)) {
            level = 1;
        }
    }
    catch(...) {
        g_warning("Parameter <PDFversion> might not exist");
    }
 
    PDFOptions flags;
    flags.text_to_path = false;
    try {
        flags.text_to_path = (strcmp(mod->get_param_optiongroup("textToPath"), "paths") == 0);
    }
    catch(...) {
        g_warning("Parameter <textToPath> might not exist");
    }
 
    flags.text_to_latex = false;
    try {
        flags.text_to_latex = (strcmp(mod->get_param_optiongroup("textToPath"), "LaTeX") == 0);
    }
    catch(...) {
        g_warning("Parameter <textToLaTeX> might not exist");
    }
 
    flags.rasterize_filters = false;
    try {
        flags.rasterize_filters = mod->get_param_bool("blurToBitmap");
    }
    catch(...) {
        g_warning("Parameter <blurToBitmap> might not exist");
    }
 
    int new_bitmapResolution  = 72;
    try {
        new_bitmapResolution = mod->get_param_int("resolution");
    }
    catch(...) {
        g_warning("Parameter <resolution> might not exist");
    }
 
    flags.stretch_to_fit = false;
    try {
        flags.stretch_to_fit = (strcmp(ext->get_param_optiongroup("stretch"), "relative") == 0);
    } catch(...) {
        g_warning("Parameter <stretch> might not exist");
    }
 
    // Create PDF file
    {
        gchar * final_name;
        final_name = g_strdup_printf("> %s", filename);
        ret = pdf_render_document_to_file(doc, final_name, level, flags, new_bitmapResolution);
        g_free(final_name);
 
        if (!ret)
            throw Inkscape::Extension::Output::save_failed();
    }
 
    // Create LaTeX file (if requested)
    if (flags.text_to_latex) {
        ret = latex_render_document_text_to_file(doc, filename, true);
 
        if (!ret)
            throw Inkscape::Extension::Output::save_failed();
    }
}
 
#include "clear-n_.h"
 
void
CairoRendererPdfOutput::init ()
{
    // clang-format off
    Inkscape::Extension::build_from_mem(
        "<inkscape-extension xmlns=\"" INKSCAPE_EXTENSION_URI "\">\n"
            "<name>Portable Document Format</name>\n"
            "<id>org.inkscape.output.pdf.cairorenderer</id>\n"
            "<param name=\"PDFversion\" gui-text=\"" N_("Restrict to PDF version:") "\" type=\"optiongroup\" appearance=\"combo\" >\n"
                "<option value='PDF-1.5'>" N_("PDF 1.5") "</option>\n"
                "<option value='PDF-1.4'>" N_("PDF 1.4") "</option>\n"
            "</param>\n"
            "<param name=\"textToPath\" gui-text=\"" N_("Text output options:") "\" type=\"optiongroup\" appearance=\"radio\">\n"
                "<option value=\"embed\">" N_("Embed fonts") "</option>\n"
                "<option value=\"paths\">" N_("Convert text to paths") "</option>\n"
                "<option value=\"LaTeX\">" N_("Omit text in PDF and create LaTeX file") "</option>\n"
            "</param>\n"
            "<param name=\"blurToBitmap\" gui-text=\"" N_("Rasterize filter effects") "\" type=\"bool\">true</param>\n"
            "<param name=\"resolution\" gui-text=\"" N_("Resolution for rasterization (dpi):") "\" type=\"int\" min=\"1\" max=\"10000\">96</param>\n"
            "<spacer size=\"10\" />"
            "<param name=\"stretch\" gui-text=\"" N_("Rounding compensation:") "\" gui-description=\""
                N_("Exporting to PDF rounds the document size to the next whole number in pt units. Compensation may stretch the drawing slightly (up to 0.35mm for width and/or height). When not compensating, object sizes will be preserved strictly, but this can sometimes cause white gaps along the page margins.")
                "\" type=\"optiongroup\" appearance=\"radio\" >\n"
                "<option value=\"relative\">" N_("Compensate for rounding (recommended)") "</option>"
                "<option value=\"absolute\">" N_("Do not compensate") "</option>"
            "</param><separator/>"
            "<hbox indent=\"1\"><image>info-outline</image><spacer/><vbox><spacer/>"
                "<label>" N_("When exporting from the Export dialog, you can choose objects to export. 'Save a copy' / 'Save as' will export all pages.") "</label>"
                "<spacer size=\"5\" />"
                "<label>" N_("The page bleed can be set with the Page tool.") "</label>"
            "</vbox></hbox>"
            "<output is_exported='true' priority='5'>\n"
                "<extension>.pdf</extension>\n"
                "<mimetype>application/pdf</mimetype>\n"
                "<filetypename>PDF (*.pdf)</filetypename>\n"
                "<filetypetooltip>PDF File</filetypetooltip>\n"
            "</output>\n"
        "</inkscape-extension>", std::make_unique<CairoRendererPdfOutput>());
    // clang-format on
 
    return;
}
 
} } }  /* namespace Inkscape, Extension, Internal */
 
#endif /* HAVE_CAIRO_PDF */