/***************************************************************************
                          sq_pixmap.cpp  -  description
                             -------------------
    begin                : Apr 10 2005
    copyright            : (C) 2005 by Baryshev Dmitry
    email                : ksquirrel@tut.by
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include <qpaintdevice.h>
#include <qapplication.h>

#include <X11/Xutil.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#include "sq_pixmap.h"

SQ_Pixmap::SQ_Pixmap()
{
	QDesktopWidget *d = QApplication::desktop();

	SQ_Pixmap::SQ_Pixmap(d->width()+2, d->height()+2);
}

SQ_Pixmap::SQ_Pixmap(int iWidth, int iHeight) : m_w(0), m_h(0)
{
        m_width  = iWidth;
        m_height = iHeight;

        // create the shared segment
        m_pXShmSegmentInfo = new XShmSegmentInfo;

        // create the shared memory image
        m_pXImage = XShmCreateImage(QPaintDevice::x11AppDisplay(),
					(Visual *)QPaintDevice::x11AppVisual(),
					QPaintDevice::x11AppDepth(),
					ZPixmap, 0, 
					m_pXShmSegmentInfo, m_width, m_height);

        // create the shared memory segment
	m_pXShmSegmentInfo->shmid = shmget(IPC_PRIVATE, m_pXImage->bytes_per_line * m_pXImage->height, IPC_CREAT | 0777);

        // attach the shared memory segment to process
	data = (int *)shmat(m_pXShmSegmentInfo->shmid, 0, 0);
	m_pXShmSegmentInfo->shmaddr = m_pXImage->data = (char *)data;

        // make the shared memory segment writable
	m_pXShmSegmentInfo->readOnly = false;

        // attach the shared memory segment to server
        XShmAttach(QPaintDevice::x11AppDisplay(), m_pXShmSegmentInfo);

	memset(data, 0x80, m_width * m_height * 4);
}

SQ_Pixmap::~SQ_Pixmap()
{
        // detach the shared memory segment from server
        XShmDetach(QPaintDevice::x11AppDisplay(), m_pXShmSegmentInfo);

        // destroy the shared memory image
        XDestroyImage(m_pXImage);

        // destroy the shared memory segment
        shmdt(m_pXShmSegmentInfo->shmaddr);
        shmctl(m_pXShmSegmentInfo->shmid, IPC_RMID, 0);
}

void SQ_Pixmap::draw(QPaintDevice* pPaintDevice, int x, int y)
{
    // synchronize X server
    QApplication::syncX();

    // create device context
    GC gc = XCreateGC(pPaintDevice->x11Display(), pPaintDevice->handle(), 0, 0);

    // draw the shared memory image
    XShmPutImage(pPaintDevice->x11Display(), pPaintDevice->handle(), gc, 
			m_pXImage, 0, 0, x, y, m_w, m_h, true);

    // free device context
    XFreeGC(pPaintDevice->x11Display(), gc);
}

void SQ_Pixmap::fillPixmap(unsigned char *buf, const int w, const int h)
{
    m_w = w;
    m_h = h;

    const int row_stride = w << 2;

    if(w < m_width)
    {
	for(int i = 0;i < h;i++)
	    memcpy(data+m_width*i, buf + i*row_stride, row_stride);
    }
    else
	memcpy(data, buf, (m_width * m_height) << 2);

}