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<h1>blackWhite.cpp</h1><a href="blackWhite_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">//==============================================</span>
<a name="l00002"></a>00002 <span class="comment">// copyright : (C) 2003-2005 by Will Stokes</span>
<a name="l00003"></a>00003 <span class="comment">//==============================================</span>
<a name="l00004"></a>00004 <span class="comment">// This program is free software; you can redistribute it</span>
<a name="l00005"></a>00005 <span class="comment">// and/or modify it under the terms of the GNU General</span>
<a name="l00006"></a>00006 <span class="comment">// Public License as published by the Free Software</span>
<a name="l00007"></a>00007 <span class="comment">// Foundation; either version 2 of the License, or</span>
<a name="l00008"></a>00008 <span class="comment">// (at your option) any later version.</span>
<a name="l00009"></a>00009 <span class="comment">//==============================================</span>
<a name="l00010"></a>00010
<a name="l00011"></a>00011 <span class="comment">//Systemwide includes</span>
<a name="l00012"></a>00012 <span class="preprocessor">#include <qimage.h></span>
<a name="l00013"></a>00013 <span class="preprocessor">#include <qstring.h></span>
<a name="l00014"></a>00014 <span class="preprocessor">#include <qapplication.h></span>
<a name="l00015"></a>00015
<a name="l00016"></a>00016 <span class="comment">//Projectwide includes</span>
<a name="l00017"></a>00017 <span class="preprocessor">#include "<a class="code" href="blackWhite_8h.html">blackWhite.h</a>"</span>
<a name="l00018"></a>00018 <span class="preprocessor">#include "<a class="code" href="manipulationOptions_8h.html">manipulationOptions.h</a>"</span>
<a name="l00019"></a>00019 <span class="preprocessor">#include "../../gui/statusWidget.h"</span>
<a name="l00020"></a>00020
<a name="l00021"></a>00021 <span class="comment">//----------------------------------------------</span>
<a name="l00022"></a>00022 <span class="comment">// Inputs:</span>
<a name="l00023"></a>00023 <span class="comment">// -------</span>
<a name="l00024"></a>00024 <span class="comment">// QString filename - location of original image on disk</span>
<a name="l00025"></a>00025 <span class="comment">// StatusWidget* status - widget for making progress visible to user</span>
<a name="l00026"></a>00026 <span class="comment">//</span>
<a name="l00027"></a>00027 <span class="comment">// Outputs:</span>
<a name="l00028"></a>00028 <span class="comment">// --------</span>
<a name="l00029"></a>00029 <span class="comment">// QImage* returned - constructed image</span>
<a name="l00030"></a>00030 <span class="comment">//</span>
<a name="l00031"></a>00031 <span class="comment">// Description:</span>
<a name="l00032"></a>00032 <span class="comment">// ------------</span>
<a name="l00033"></a>00033 <span class="comment">// This method constructs a grayscale version of</span>
<a name="l00034"></a>00034 <span class="comment">// the image by computing a gray value for each pixel. A naive</span>
<a name="l00035"></a>00035 <span class="comment">// approach would use the average the red, green, and blue components</span>
<a name="l00036"></a>00036 <span class="comment">// at each pixel for the new pixel component values, that is:</span>
<a name="l00037"></a>00037 <span class="comment">//</span>
<a name="l00038"></a>00038 <span class="comment">// gray = (r+g+b) / 3;</span>
<a name="l00039"></a>00039 <span class="comment">// r' = gray; g' = gray; b'= gray</span>
<a name="l00040"></a>00040 <span class="comment">//</span>
<a name="l00041"></a>00041 <span class="comment">// The problem with this approach is that image luminance </span>
<a name="l00042"></a>00042 <span class="comment">// (observed brightness) is not maintained. Instead, we conpute</span>
<a name="l00043"></a>00043 <span class="comment">// the brightness at each pixel using a weighted sum of the color</span>
<a name="l00044"></a>00044 <span class="comment">// components. Weights vary depending on display device.</span>
<a name="l00045"></a>00045 <span class="comment">// Old school NTSC TV's which came out in the 50's would</span>
<a name="l00046"></a>00046 <span class="comment">// tell us to use these r,b,g weights (which Gimp uses):</span>
<a name="l00047"></a>00047 <span class="comment">// (see http://www.gimp.org/tutorials/Color2BW)</span>
<a name="l00048"></a>00048 <span class="comment">// (0.3, 0.59, 0.11)</span>
<a name="l00049"></a>00049 <span class="comment">//</span>
<a name="l00050"></a>00050 <span class="comment">// But these days we're using modern monitors and the green phosphur </span>
<a name="l00051"></a>00051 <span class="comment">// is brigther or something so it's best to use these instead:</span>
<a name="l00052"></a>00052 <span class="comment">// http://lists.trolltech.com/qt-interest/1999-10/thread00337-0.html</span>
<a name="l00053"></a>00053 <span class="comment">// (0.2125, 0.7154, 0.0721)</span>
<a name="l00054"></a>00054 <span class="comment">//</span>
<a name="l00055"></a>00055 <span class="comment">// After weighting, the resulting gray value is clamped to fall within the </span>
<a name="l00056"></a>00056 <span class="comment">// [0-255] range and assigned to the pixel in the new image.</span>
<a name="l00057"></a>00057 <span class="comment">//----------------------------------------------</span>
<a name="l00058"></a>00058
<a name="l00059"></a>00059 <span class="comment">//==============================================</span>
<a name="l00060"></a><a class="code" href="blackWhite_8h.html#81188751080c22115720554f1ce6a30f">00060</a> QImage* <a class="code" href="blackWhite_8cpp.html#81188751080c22115720554f1ce6a30f">blackWhiteEffect</a>( QString filename, <a class="code" href="classManipulationOptions.html">ManipulationOptions</a>* options )
<a name="l00061"></a>00061 {
<a name="l00062"></a>00062 <span class="comment">//load image</span>
<a name="l00063"></a>00063 QImage* <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a> = <span class="keyword">new</span> QImage( filename );
<a name="l00064"></a>00064
<a name="l00065"></a>00065 <span class="comment">//convert to 32-bit depth if necessary</span>
<a name="l00066"></a>00066 <span class="keywordflow">if</span>( editedImage->depth() < 32 )
<a name="l00067"></a>00067 {
<a name="l00068"></a>00068 QImage* tmp = editedImage;
<a name="l00069"></a>00069 editedImage = <span class="keyword">new</span> QImage( tmp->convertDepth( 32, Qt::AutoColor ) );
<a name="l00070"></a>00070 <span class="keyword">delete</span> tmp; tmp=NULL;
<a name="l00071"></a>00071 }
<a name="l00072"></a>00072
<a name="l00073"></a>00073 <span class="comment">//determine if busy indicators will be used</span>
<a name="l00074"></a>00074 <span class="keywordtype">bool</span> useBusyIndicators = <span class="keyword">false</span>;
<a name="l00075"></a>00075 <a class="code" href="classStatusWidget.html">StatusWidget</a>* <a class="code" href="redEye__internal_8h.html#65b682074aef9e63bb1dad48c3e9e9df">status</a> = NULL;
<a name="l00076"></a>00076 <span class="keywordflow">if</span>( options != NULL && options-><a class="code" href="classManipulationOptions.html#9bc4d4123333012b705b599043406e68">getStatus</a>() != NULL )
<a name="l00077"></a>00077 {
<a name="l00078"></a>00078 useBusyIndicators = <span class="keyword">true</span>;
<a name="l00079"></a>00079 status = options-><a class="code" href="classManipulationOptions.html#9bc4d4123333012b705b599043406e68">getStatus</a>();
<a name="l00080"></a>00080 }
<a name="l00081"></a>00081
<a name="l00082"></a>00082 <span class="comment">//setup progress bar</span>
<a name="l00083"></a>00083 <span class="keywordflow">if</span>(useBusyIndicators)
<a name="l00084"></a>00084 {
<a name="l00085"></a>00085 QString statusMessage = qApp->translate( <span class="stringliteral">"blackWhiteEffect"</span>, <span class="stringliteral">"Applying Black + White Effect:"</span> );
<a name="l00086"></a>00086 status-><a class="code" href="classStatusWidget.html#57d461014070b9d651c36bd157cab9c1" title="Initializes the progress bar.">showProgressBar</a>( statusMessage, 100 );
<a name="l00087"></a>00087 qApp->processEvents();
<a name="l00088"></a>00088 }
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="comment">//update progress bar for every 1% of completion</span>
<a name="l00091"></a>00091 <span class="keyword">const</span> <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#32598f506d413f48cda8e1c930dae6b3">updateIncrement</a> = (int) ( 0.01 * editedImage->width() * editedImage->height() );
<a name="l00092"></a>00092 <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#caa08422437cae250a76ca488cbe1567">newProgress</a> = 0;
<a name="l00093"></a>00093
<a name="l00094"></a>00094 <span class="comment">//iterate over each selected scanline </span>
<a name="l00095"></a>00095 <span class="keywordtype">int</span> x, y, grayValue;
<a name="l00096"></a>00096 QRgb* rgb;
<a name="l00097"></a>00097 uchar* scanLine;
<a name="l00098"></a>00098 <span class="keywordflow">for</span>( y=0; y<editedImage->height(); y++)
<a name="l00099"></a>00099 {
<a name="l00100"></a>00100 <span class="comment">//iterate over each selected pixel in scanline</span>
<a name="l00101"></a>00101 scanLine = editedImage->scanLine(y);
<a name="l00102"></a>00102 <span class="keywordflow">for</span>( x=0; x<editedImage->width(); x++)
<a name="l00103"></a>00103 {
<a name="l00104"></a>00104 <span class="comment">//compute gray value based on the display luminance of color coordinates</span>
<a name="l00105"></a>00105 rgb = ((QRgb*)scanLine+x);
<a name="l00106"></a>00106 grayValue = (int) (0.2125*qRed(*rgb) + 0.7154*qGreen(*rgb) + 0.0721*qBlue(*rgb));
<a name="l00107"></a>00107
<a name="l00108"></a>00108 <span class="comment">//clamp to ensure it falls in the 0-255 range</span>
<a name="l00109"></a>00109 grayValue = QMIN( QMAX( grayValue, 0 ), 255 );
<a name="l00110"></a>00110
<a name="l00111"></a>00111 <span class="comment">//set pixel channel values using computed gray value</span>
<a name="l00112"></a>00112 *rgb = qRgb( grayValue, grayValue, grayValue );
<a name="l00113"></a>00113
<a name="l00114"></a>00114 <span class="comment">//update status bar if significant progress has been made since last update</span>
<a name="l00115"></a>00115 <span class="keywordflow">if</span>(useBusyIndicators)
<a name="l00116"></a>00116 {
<a name="l00117"></a>00117 newProgress++;
<a name="l00118"></a>00118 <span class="keywordflow">if</span>(newProgress >= updateIncrement)
<a name="l00119"></a>00119 {
<a name="l00120"></a>00120 newProgress = 0;
<a name="l00121"></a>00121 status-><a class="code" href="classStatusWidget.html#de18735223ae40506c32c96b9c9c5476" title="Updates the progress bar by one step.">incrementProgress</a>();
<a name="l00122"></a>00122 qApp->processEvents();
<a name="l00123"></a>00123 }
<a name="l00124"></a>00124 }
<a name="l00125"></a>00125
<a name="l00126"></a>00126 }
<a name="l00127"></a>00127 }
<a name="l00128"></a>00128
<a name="l00129"></a>00129 <span class="comment">//return pointer to edited image</span>
<a name="l00130"></a>00130 <span class="keywordflow">return</span> editedImage;
<a name="l00131"></a>00131 }
<a name="l00132"></a>00132 <span class="comment">//==============================================</span>
</pre></div></div>
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Mandriva
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2010.0
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