1//
2// This file is part of the aMule Project.
3//
4// Copyright (c) 2003-2011 aMule Team ( admin@amule.org / http://www.amule.org )
5// Copyright (c) 2002-2011 Merkur ( devs@emule-project.net / http://www.emule-project.net )
6//
7// Any parts of this program derived from the xMule, lMule or eMule project,
8// or contributed by third-party developers are copyrighted by their
9// respective authors.
10//
11// This program is free software; you can redistribute it and/or modify
12// it under the terms of the GNU General Public License as published by
13// the Free Software Foundation; either version 2 of the License, or
14// (at your option) any later version.
15//
16// This program is distributed in the hope that it will be useful,
17// but WITHOUT ANY WARRANTY; without even the implied warranty of
18// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19// GNU General Public License for more details.
20//
21// You should have received a copy of the GNU General Public License
22// along with this program; if not, write to the Free Software
23// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA
24//
25
26#include "CaptchaGenerator.h"
27#include "RandomFunctions.h"
28#include "MemFile.h"
29#include <wx/bitmap.h>
30#include <wx/dcmemory.h>
31#include <wx/font.h>
32
33
34#define LETTERSIZE  32
35#define CROWDEDSIZE 20
36
37// fairly simply captcha generator, might be improved is spammers think its really worth it solving captchas on aMule
38
39CCaptchaGenerator::CCaptchaGenerator(uint32 nLetterCount)
40{
41	ReGenerateCaptcha(nLetterCount);
42}
43
44void CCaptchaGenerator::ReGenerateCaptcha(uint32 nLetterCount)
45{
46	static wxString schCaptchaContent = wxT("ABCDEFGHJKLMNPQRSTUVWXYZ123456789");
47	m_strCaptchaText.Clear();
48	// Bitmap must be created with full depth, or it will fail on GTK
49	wxBitmap pimgResult(LETTERSIZE + (nLetterCount-1)*CROWDEDSIZE, 36);
50	wxMemoryDC dc(pimgResult);
51	dc.SetBackground(*wxWHITE_BRUSH);
52	dc.Clear();
53	dc.SetTextForeground(*wxBLACK);
54	dc.SetTextBackground(*wxWHITE);
55	double lastrotate = 15.0;
56
57	for (uint32 i = 0; i < nLetterCount; i++) {
58		wxString strLetter(schCaptchaContent[GetRandomUint16() % schCaptchaContent.length()]);
59		m_strCaptchaText += strLetter;
60
61		uint16 nRandomSize = 30 - GetRandomUint16() % 12;
62		wxFont font(nRandomSize, wxFONTFAMILY_SWISS, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD);
63		dc.SetFont(font);
64		uint16 nRandomOffset = 3 + GetRandomUint16() % 8;
65		uint16 maxRotate = 50 - nRandomSize; // rotate small letters more than large letters
66		double fRotate = (double)(maxRotate - (GetRandomUint16() % (maxRotate*2)));
67		// limit angle diff - it causes too much overlap since wx rotates at the corner
68		// (maybe I'll redo that with some coordinate transformation one day)
69		if (fRotate - lastrotate > 20) {
70			fRotate = lastrotate + 20;
71		} else if (fRotate - lastrotate < -20) {
72			fRotate = lastrotate - 20;
73		}
74		dc.DrawRotatedText(strLetter, nRandomOffset + i * CROWDEDSIZE, 0, fRotate);
75	}
76	m_pimgCaptcha = pimgResult.ConvertToImage();
77	// wx always saves as 24 bpp except when it gets this WELL DOCUMENTED option...
78	m_pimgCaptcha.SetOption(wxIMAGE_OPTION_BMP_FORMAT, wxBMP_1BPP);
79	// m_pimgCaptcha.SaveFile(wxT("captcha.bmp"), wxBITMAP_TYPE_BMP);
80}
81
82bool CCaptchaGenerator::WriteCaptchaImage(wxMemoryOutputStream& file)
83{
84	return m_pimgCaptcha.SaveFile(file, wxBITMAP_TYPE_BMP);
85}
86