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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "dimensionxx.hpp"
#include <cstdio>
namespace Dimension
{
PNG_Canvas::PNG_Canvas(std::istream& istr)
: Canvas(), m_istr(&istr), m_ostr(0), m_written(false)
{
read();
}
PNG_Canvas::PNG_Canvas(unsigned int x, unsigned int y, std::ostream& ostr)
: Canvas(x, y), m_istr(0), m_ostr(&ostr), m_written(false)
{ }
PNG_Canvas::PNG_Canvas(std::istream& istr, std::ostream& ostr)
: Canvas(), m_istr(&istr), m_ostr(&ostr), m_written(false)
{
read();
}
// PNG_Canvas destructor. Call write() to write the PNG file if not already
// written, but catch any exceptions and instead report the error with
// dmnsn_error() to avoid throwing from a destructor.
PNG_Canvas::~PNG_Canvas()
{
if (m_ostr && !m_written) {
try {
write();
} catch (...) {
dmnsn_error(SEVERITY_MEDIUM,
"Writing canvas to PNG failed in PNG_Canvas destructor.");
}
}
}
// Write the PNG file. Uses the FILE_Cookie() interface to make a FILE*
// corresponding to an std::ostream (including std::ostringstream, etc).
void PNG_Canvas::write()
{
if (m_written) {
// Does writing a PNG file twice make sense?
throw Dimension_Error("Attempt to write canvas to PNG twice.");
}
if (!m_ostr) {
// Don't call write() if we're not an output PNG_Canvas...
throw Dimension_Error("Attempt to write canvas to PNG without an output"
" stream.");
}
// Make the C++/C I/O interface
FILE_Cookie cookie(*m_ostr);
// Write the PNG file
if (dmnsn_png_write_canvas(m_canvas, cookie.file())) {
// The actual write operation failed, for some reason
throw Dimension_Error("Writing canvas to PNG failed.");
}
m_written = true; // We've written the file now, don't do it again
}
// Write a PNG file in the background
Progress
PNG_Canvas::write_async()
{
if (m_written) {
// Does writing a PNG file twice make sense?
throw Dimension_Error("Attempt to write canvas to PNG twice.");
}
if (!m_ostr) {
// Don't call write_async() if we're not an output PNG_Canvas...
throw Dimension_Error("Attempt to write canvas to PNG without an output"
" stream.");
}
m_written = true; // We've written the file now, don't do it again
// Object to persist local variables past function return
Persister persister;
// Make the C++/C I/O interface
FILE_Cookie* cookie = new FILE_Cookie(*m_ostr);
persister.persist(cookie);
// Start the asynchronous task
dmnsn_progress *progress
= dmnsn_png_write_canvas_async(m_canvas, cookie->file());
if (!progress) {
throw Dimension_Error("Starting background PNG write failed.");
}
// Return the Progress object
return Progress(progress, persister);
}
// Read a PNG file in the background
Progress
PNG_Canvas::read_async(std::istream& istr)
{
// Object to persist local variables past function return
Persister persister;
// Store a pointer to a dmnsn_canvas* in the persister to later construct
// the PNG_Canvas
dmnsn_canvas** canvas = new dmnsn_canvas*;
persister.persist(canvas);
// Make the C++/C I/O interface
FILE_Cookie* cookie = new FILE_Cookie(istr);
persister.persist(cookie);
// Start the asynchronous task
dmnsn_progress *progress
= dmnsn_png_read_canvas_async(canvas, cookie->file());
if (!progress) {
throw Dimension_Error("Starting background PNG read failed.");
}
// Return the Progress object
return Progress(progress, persister);
}
// Construct an input PNG_Canvas from a background task
PNG_Canvas::PNG_Canvas(Progress& progress)
: Canvas(), m_istr(0), m_ostr(0), m_written(false)
{
// Will throw if progress is not from a PNG_Canvas::read_async call
dmnsn_canvas** canvas
= progress.persister().first<dmnsn_canvas*>().persisted();
try {
progress.finish();
} catch (...) {
dmnsn_delete_canvas(*canvas);
throw;
}
m_canvas = *canvas;
}
// Construct an I/O PNG_Canvas from a background task
PNG_Canvas::PNG_Canvas(Progress& progress, std::ostream& ostr)
: Canvas(), m_istr(0), m_ostr(&ostr), m_written(false)
{
// Will throw if progress is not from a PNG_Canvas::read_async call
dmnsn_canvas** canvas
= progress.persister().first<dmnsn_canvas*>().persisted();
try {
progress.finish();
} catch (...) {
dmnsn_delete_canvas(*canvas);
throw;
}
m_canvas = *canvas;
}
// Protected constructor which sets the canvas to NULL for now
PNG_Canvas::PNG_Canvas(std::ostream& ostr)
: Canvas(), m_istr(0), m_ostr(&ostr), m_written(false)
{ }
// Read a canvas from a PNG file. Uses the FILE_Cookie() interface to make a
// FILE* corresponding to an std::istream (including std::istringstream, etc).
void PNG_Canvas::read()
{
if (!m_istr) {
// read() is private, and only called from the appropriate constructors,
// so this REALLY shouldn't happen.
throw Dimension_Error("Attempt to read canvas from PNG without an input"
" stream.");
}
// Make the C++/C I/O interface
FILE_Cookie cookie(*m_istr);
// Read the canvas from a PNG file
if (!(m_canvas = dmnsn_png_read_canvas(cookie.file()))) {
// The read operation failed
throw Dimension_Error("Reading canvas from PNG failed.");
}
}
}
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