blob: 029e431648d0c994f924342258742f8ef5c25c8e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
/*************************************************************************
* 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>
#include <stdexcept>
namespace Dimension
{
// 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
}
// 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.");
}
}
}
|
