okular/generators/dvi/psgs.h

// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; c-brace-offset: 0; -*-
//
// ghostscript_interface
//
// Part of KDVI - A framework for multipage text/gfx viewers
//
// SPDX-FileCopyrightText: 2004 Stefan Kebekus
// SPDX-License-Identifier: GPL-2.0-or-later

#ifndef _PSGS_H_
#define _PSGS_H_

#include <QApplication>
#include <QColor>
#include <QEvent>
#include <QHash>
#include <QObject>

class QUrl;
class PageNumber;
class QPainter;

class pageInfo
{
public:
    pageInfo(const QString &_PostScriptString);
    ~pageInfo();

    pageInfo(const pageInfo &) = delete;
    pageInfo &operator=(const pageInfo &) = delete;

    QColor background;
    QColor permanentBackground;
    QString *PostScriptString;
};

class ghostscript_interface : public QObject
{
    Q_OBJECT

public:
    ghostscript_interface();
    ~ghostscript_interface() override;

    void clear();

    // sets the PostScript which is used on a certain page
    void setPostScript(const PageNumber page, const QString &PostScript);

    // sets path from additional postscript files may be read
    void setIncludePath(const QString &_includePath);

    // Sets the background color for a certain page. If permanent is false then the original
    // background color can be restored by calling restoreBackground(page).
    // The Option permanent = false is used when we want to display a different paper
    // color as the one specified in the dvi file.
    void setBackgroundColor(const PageNumber page, const QColor &background_color, bool permanent = true);

    // Restore the background to the color which was specified by the last call to setBackgroundColor()
    // With option permanent = true.
    void restoreBackgroundColor(const PageNumber page);

    // Draws the graphics of the page into the painter, if possible. If
    // the page does not contain any graphics, nothing happens
    void graphics(const PageNumber page, double dpi, long magnification, QPainter *paint);

    // Returns the background color for a certain page. If no color was
    // set, Qt::white is returned.
    QColor getBackgroundColor(const PageNumber page) const;

    QString *PostScriptHeaderString;

    /** This method tries to find the PostScript file 'filename' in the
        DVI file's directory (if the base-URL indicates that the DVI file
        is local), and, if that fails, uses kpsewhich to find the file. If
        the file is found, the full path (including file name) is
        returned. Otherwise, the method returns the first argument. TODO:
        use the DVI file's baseURL, once this is implemented.
    */
    static QString locateEPSfile(const QString &filename, const QUrl &base);

private:
    void gs_generate_graphics_file(const PageNumber page, const QString &filename, long magnification);
    QHash<quint16, pageInfo *> pageList;

    double resolution; // in dots per inch
    int pixel_page_w;  // in pixels
    int pixel_page_h;  // in pixels

    QString includePath;

    // Output device that ghostscript is supposed tp use. Default is
    // "png256". If that does not work, gs_generate_graphics_file will
    // automatically try other known device drivers. If no known output
    // device can be found, something is badly wrong. In that case,
    // "gsDevice" is set to an empty string, and
    // gs_generate_graphics_file will return immediately.
    QList<QString>::iterator gsDevice;

    // A list of known devices, set by the constructor. This includes
    // "png256", "pnm". If a device is found to not work, its name is
    // removed from the list, and another device name is tried.
    QStringList knownDevices;

Q_SIGNALS:
    /** Passed through to the top-level kpart. */
    void error(const QString &message, int duration);
};

#endif