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<h1>emboss.cpp</h1><a href="emboss_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 <span class="preprocessor">#include <math.h></span>
<a name="l00016"></a>00016
<a name="l00017"></a>00017 <span class="comment">//Projectwide includes</span>
<a name="l00018"></a>00018 <span class="preprocessor">#include "<a class="code" href="emboss_8h.html">emboss.h</a>"</span>
<a name="l00019"></a>00019 <span class="preprocessor">#include "<a class="code" href="manipulationOptions_8h.html">manipulationOptions.h</a>"</span>
<a name="l00020"></a>00020 <span class="preprocessor">#include "../tools/imageTools.h"</span>
<a name="l00021"></a>00021 <span class="preprocessor">#include "../../gui/statusWidget.h"</span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="comment">//----------------------------------------------</span>
<a name="l00024"></a>00024 <span class="comment">// Inputs:</span>
<a name="l00025"></a>00025 <span class="comment">// -------</span>
<a name="l00026"></a>00026 <span class="comment">// QString filename - location of original image on disk</span>
<a name="l00027"></a>00027 <span class="comment">// StatusWidget* status - widget for making progress visible to user</span>
<a name="l00028"></a>00028 <span class="comment">//</span>
<a name="l00029"></a>00029 <span class="comment">// Outputs:</span>
<a name="l00030"></a>00030 <span class="comment">// --------</span>
<a name="l00031"></a>00031 <span class="comment">// QImage* returned - constructed image</span>
<a name="l00032"></a>00032 <span class="comment">//</span>
<a name="l00033"></a>00033 <span class="comment">// Description:</span>
<a name="l00034"></a>00034 <span class="comment">// ------------</span>
<a name="l00035"></a>00035 <span class="comment">// This method constructs an embossed version of</span>
<a name="l00036"></a>00036 <span class="comment">// the image by modifying the luminance of each pixel</span>
<a name="l00037"></a>00037 <span class="comment">// by taking a weighted average of pixel luminance within</span>
<a name="l00038"></a>00038 <span class="comment">// a local neighborhood. Most embossing algorithms convert an </span>
<a name="l00039"></a>00039 <span class="comment">// image to grayscale and then combine a pixel's gray value with</span>
<a name="l00040"></a>00040 <span class="comment">// its neighbors using the following convolution matrix:</span>
<a name="l00041"></a>00041 <span class="comment">//</span>
<a name="l00042"></a>00042 <span class="comment">// [ -1 -1 0</span>
<a name="l00043"></a>00043 <span class="comment">// -1 1 1</span>
<a name="l00044"></a>00044 <span class="comment">// 0 1 1 ]</span>
<a name="l00045"></a>00045 <span class="comment">//</span>
<a name="l00046"></a>00046 <span class="comment">// This apporach has two problems. First, all color information</span>
<a name="l00047"></a>00047 <span class="comment">// is lost. Second, the convolution filter is not a function of image</span>
<a name="l00048"></a>00048 <span class="comment">// size, and as a result embossing results on high resolution images are</span>
<a name="l00049"></a>00049 <span class="comment">// barely when viewed on a high resolution screen or printed at high DPI. </span>
<a name="l00050"></a>00050 <span class="comment">// </span>
<a name="l00051"></a>00051 <span class="comment">// My solution to this problem is to:</span>
<a name="l00052"></a>00052 <span class="comment">//</span>
<a name="l00053"></a>00053 <span class="comment">// 1.) Apply the emboss effect on pixel luminance and leave pixel</span>
<a name="l00054"></a>00054 <span class="comment">// color untouched. The varying lightness that results produces</span>
<a name="l00055"></a>00055 <span class="comment">// the same effect, and if a grayscale image is really desired the</span>
<a name="l00056"></a>00056 <span class="comment">// image can be converted to grayscale either before or after the </span>
<a name="l00057"></a>00057 <span class="comment">// emboss effect takes place.</span>
<a name="l00058"></a>00058 <span class="comment">// </span>
<a name="l00059"></a>00059 <span class="comment">// 2.) using neighboring pixels that are a distance D from the </span>
<a name="l00060"></a>00060 <span class="comment">// pixel being modified in the X or Y dimensions. This simply </span>
<a name="l00061"></a>00061 <span class="comment">// modification allows the embossing procedure to run at the </span>
<a name="l00062"></a>00062 <span class="comment">// same speed (larger convolution matrices would slow the algorithm </span>
<a name="l00063"></a>00063 <span class="comment">// to at best O(N^2 * M^2) where there are N^2 pixels in the image </span>
<a name="l00064"></a>00064 <span class="comment">// and the convolution matrix is M^2 in size) while providing the </span>
<a name="l00065"></a>00065 <span class="comment">// same effective emboss effect at any image resolution. This is </span>
<a name="l00066"></a>00066 <span class="comment">// done by computing distance D using the minimum image dimension:</span>
<a name="l00067"></a>00067 <span class="comment">//</span>
<a name="l00068"></a>00068 <span class="comment">// D = MIN( width, height )</span>
<a name="l00069"></a>00069 <span class="comment">//</span>
<a name="l00070"></a>00070 <span class="comment">// At each pixel, we compute an average luminance of the 6 </span>
<a name="l00071"></a>00071 <span class="comment">// neighbors and combine these values with a 50% luminance value for </span>
<a name="l00072"></a>00072 <span class="comment">// the pixel in question. This luminance value is used to replace </span>
<a name="l00073"></a>00073 <span class="comment">// the current pixel luminance before converting it back to RGB </span>
<a name="l00074"></a>00074 <span class="comment">// space and storing in the edited image object.</span>
<a name="l00075"></a>00075 <span class="comment">//</span>
<a name="l00076"></a>00076 <span class="comment">// Neighbor pixels that are clamped to be on the image plane to </span>
<a name="l00077"></a>00077 <span class="comment">// prevent lookups of neighbor pixels with negative coordinates or</span>
<a name="l00078"></a>00078 <span class="comment">// coordinates beyond the width/height of the image in question.</span>
<a name="l00079"></a>00079 <span class="comment">//----------------------------------------------</span>
<a name="l00080"></a>00080
<a name="l00081"></a>00081 <span class="comment">//==============================================</span>
<a name="l00082"></a><a class="code" href="emboss_8h.html#f8d48220a7a9b902041fcae5d6278e04">00082</a> QImage* <a class="code" href="emboss_8cpp.html#f8d48220a7a9b902041fcae5d6278e04">embossEffect</a>( QString filename, <a class="code" href="classManipulationOptions.html">ManipulationOptions</a>* options )
<a name="l00083"></a>00083 {
<a name="l00084"></a>00084 <span class="comment">//load original image </span>
<a name="l00085"></a>00085 QImage originalImage( filename );
<a name="l00086"></a>00086
<a name="l00087"></a>00087 <span class="comment">//convert to 32-bit depth if necessary</span>
<a name="l00088"></a>00088 <span class="keywordflow">if</span>( originalImage.depth() < 32 ) { originalImage = originalImage.convertDepth( 32, Qt::AutoColor ); }
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="comment">//create edited image</span>
<a name="l00091"></a>00091 QImage* <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a> = <span class="keyword">new</span> QImage( filename );
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <span class="comment">//convert to 32-bit depth if necessary</span>
<a name="l00094"></a>00094 <span class="keywordflow">if</span>( editedImage->depth() < 32 )
<a name="l00095"></a>00095 {
<a name="l00096"></a>00096 QImage* tmp = editedImage;
<a name="l00097"></a>00097 editedImage = <span class="keyword">new</span> QImage( tmp->convertDepth( 32, Qt::AutoColor ) );
<a name="l00098"></a>00098 <span class="keyword">delete</span> tmp; tmp=NULL;
<a name="l00099"></a>00099 }
<a name="l00100"></a>00100
<a name="l00101"></a>00101 <span class="comment">//determine if busy indicators will be used</span>
<a name="l00102"></a>00102 <span class="keywordtype">bool</span> useBusyIndicators = <span class="keyword">false</span>;
<a name="l00103"></a>00103 <a class="code" href="classStatusWidget.html">StatusWidget</a>* <a class="code" href="redEye__internal_8h.html#65b682074aef9e63bb1dad48c3e9e9df">status</a> = NULL;
<a name="l00104"></a>00104 <span class="keywordflow">if</span>( options != NULL && options-><a class="code" href="classManipulationOptions.html#9bc4d4123333012b705b599043406e68">getStatus</a>() != NULL )
<a name="l00105"></a>00105 {
<a name="l00106"></a>00106 useBusyIndicators = <span class="keyword">true</span>;
<a name="l00107"></a>00107 status = options-><a class="code" href="classManipulationOptions.html#9bc4d4123333012b705b599043406e68">getStatus</a>();
<a name="l00108"></a>00108 }
<a name="l00109"></a>00109
<a name="l00110"></a>00110 <span class="comment">//setup progress bar</span>
<a name="l00111"></a>00111 <span class="keywordflow">if</span>(useBusyIndicators)
<a name="l00112"></a>00112 {
<a name="l00113"></a>00113 QString statusMessage = qApp->translate( <span class="stringliteral">"embossEffect"</span>, <span class="stringliteral">"Applying Emboss Effect:"</span> );
<a name="l00114"></a>00114 status-><a class="code" href="classStatusWidget.html#57d461014070b9d651c36bd157cab9c1" title="Initializes the progress bar.">showProgressBar</a>( statusMessage, 100 );
<a name="l00115"></a>00115 qApp->processEvents();
<a name="l00116"></a>00116 }
<a name="l00117"></a>00117
<a name="l00118"></a>00118 <span class="comment">//update progress bar for every 1% of completion</span>
<a name="l00119"></a>00119 <span class="keyword">const</span> <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#32598f506d413f48cda8e1c930dae6b3">updateIncrement</a> = (int) ( 0.01 * originalImage.width() * originalImage.height() );
<a name="l00120"></a>00120 <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#caa08422437cae250a76ca488cbe1567">newProgress</a> = 0;
<a name="l00121"></a>00121
<a name="l00122"></a>00122 <span class="comment">//iterate over each selected scanline </span>
<a name="l00123"></a>00123 <span class="keywordtype">int</span> x, y;
<a name="l00124"></a>00124 QRgb* rgb;
<a name="l00125"></a>00125 uchar* scanLine;
<a name="l00126"></a>00126
<a name="l00127"></a>00127 <span class="keywordtype">int</span> yPrev, yNext, xPrev, xNext;
<a name="l00128"></a>00128
<a name="l00129"></a>00129 <span class="comment">//compute the radius using image resolution</span>
<a name="l00130"></a>00130 <span class="keywordtype">double</span> minDimen = (double) QMIN( editedImage->width(), editedImage->height() );
<a name="l00131"></a>00131 <span class="keyword">const</span> <span class="keywordtype">int</span> embossRadius = (int) QMAX( 1, (sqrt(minDimen)/8) );
<a name="l00132"></a>00132
<a name="l00133"></a>00133 <span class="keywordflow">for</span>( y=0; y<editedImage->height(); y++)
<a name="l00134"></a>00134 {
<a name="l00135"></a>00135 scanLine = originalImage.scanLine(y);
<a name="l00136"></a>00136
<a name="l00137"></a>00137 <span class="comment">//compute previous and next y pixel coordinates</span>
<a name="l00138"></a>00138 yPrev = QMAX( y-embossRadius, 0 );
<a name="l00139"></a>00139 yNext = QMIN( y+embossRadius, editedImage->height() - 1 );
<a name="l00140"></a>00140
<a name="l00141"></a>00141 <span class="comment">//iterate over each selected pixel in scanline</span>
<a name="l00142"></a>00142 <span class="keywordflow">for</span>( x=0; x<editedImage->width(); x++)
<a name="l00143"></a>00143 {
<a name="l00144"></a>00144 <span class="comment">//compute previous and next x pixel coordinates</span>
<a name="l00145"></a>00145 xPrev = QMAX( x-embossRadius, 0 );
<a name="l00146"></a>00146 xNext = QMIN( x+embossRadius, editedImage->width() - 1 );
<a name="l00147"></a>00147
<a name="l00148"></a>00148 <span class="comment">//start with a default luminance of 128 (50% luminance)</span>
<a name="l00149"></a>00149 <span class="keywordtype">int</span> sum = 128;
<a name="l00150"></a>00150
<a name="l00151"></a>00151 <span class="comment">//sum weighted gray values of neighbors</span>
<a name="l00152"></a>00152 scanLine = originalImage.scanLine( yPrev );
<a name="l00153"></a>00153 sum-= qGray( *((QRgb*)scanLine + xPrev ) );
<a name="l00154"></a>00154 sum-= qGray( *((QRgb*)scanLine + x ) );
<a name="l00155"></a>00155
<a name="l00156"></a>00156 scanLine = originalImage.scanLine( y );
<a name="l00157"></a>00157 sum-= qGray( *((QRgb*)scanLine + xPrev ) );
<a name="l00158"></a>00158 sum+= qGray( *((QRgb*)scanLine + xNext ) );
<a name="l00159"></a>00159
<a name="l00160"></a>00160 scanLine = originalImage.scanLine( yNext );
<a name="l00161"></a>00161 sum+= qGray( *((QRgb*)scanLine + x ) );
<a name="l00162"></a>00162 sum+= qGray( *((QRgb*)scanLine + xNext ) );
<a name="l00163"></a>00163
<a name="l00164"></a>00164 <span class="comment">//clamp sum to within 0-255 range</span>
<a name="l00165"></a>00165 sum = QMAX( QMIN( sum, 255), 0 );
<a name="l00166"></a>00166
<a name="l00167"></a>00167 <span class="comment">//get original pixel color in HSV space</span>
<a name="l00168"></a>00168 scanLine = editedImage->scanLine(y);
<a name="l00169"></a>00169 rgb = ((QRgb*)scanLine+x);
<a name="l00170"></a>00170 <span class="keywordtype">double</span> r = ((double)qRed(*rgb) )/255.0;
<a name="l00171"></a>00171 <span class="keywordtype">double</span> g = ((double)qGreen(*rgb) )/255.0;
<a name="l00172"></a>00172 <span class="keywordtype">double</span> <a class="code" href="jpegInternal_8h.html#f320905358fa78701e4cc60b6135601f">b</a> = ((double)qBlue(*rgb) )/255.0;
<a name="l00173"></a>00173
<a name="l00174"></a>00174 <span class="comment">//convert to hsv</span>
<a name="l00175"></a>00175 <span class="keywordtype">double</span> h,s,v;
<a name="l00176"></a>00176 <a class="code" href="imageTools_8cpp.html#7769c25727d6caedf20321d238b3828d" title="Convert a RGB color triplet to HSV.">RGBtoHSV</a>(r,g,b,&h,&s,&v);
<a name="l00177"></a>00177
<a name="l00178"></a>00178 <span class="comment">//reset v</span>
<a name="l00179"></a>00179 v = ((double)sum)/255;
<a name="l00180"></a>00180
<a name="l00181"></a>00181 <span class="comment">//convert adjusted color back to rgb colorspace and clamp</span>
<a name="l00182"></a>00182 <a class="code" href="imageTools_8cpp.html#a4ea508b635b1a7648bb5834132d4681" title="Convert a HSV color triplet to RGB.">HSVtoRGB</a>( &r,&g,&b, h,s,v);
<a name="l00183"></a>00183 <span class="keywordtype">int</span> rp = (int) QMIN( QMAX((r*255), 0), 255 );
<a name="l00184"></a>00184 <span class="keywordtype">int</span> gp = (int) QMIN( QMAX((g*255), 0), 255 );
<a name="l00185"></a>00185 <span class="keywordtype">int</span> bp = (int) QMIN( QMAX((b*255), 0), 255 );
<a name="l00186"></a>00186
<a name="l00187"></a>00187 <span class="comment">//set adjusted color value</span>
<a name="l00188"></a>00188 *rgb = qRgb(rp,gp,bp);
<a name="l00189"></a>00189
<a name="l00190"></a>00190 <span class="comment">//update status bar if significant progress has been made since last update</span>
<a name="l00191"></a>00191 <span class="keywordflow">if</span>(useBusyIndicators)
<a name="l00192"></a>00192 {
<a name="l00193"></a>00193 newProgress++;
<a name="l00194"></a>00194 <span class="keywordflow">if</span>(newProgress >= updateIncrement)
<a name="l00195"></a>00195 {
<a name="l00196"></a>00196 newProgress = 0;
<a name="l00197"></a>00197 status-><a class="code" href="classStatusWidget.html#de18735223ae40506c32c96b9c9c5476" title="Updates the progress bar by one step.">incrementProgress</a>();
<a name="l00198"></a>00198 qApp->processEvents();
<a name="l00199"></a>00199 }
<a name="l00200"></a>00200 }
<a name="l00201"></a>00201
<a name="l00202"></a>00202 }
<a name="l00203"></a>00203 }
<a name="l00204"></a>00204
<a name="l00205"></a>00205 <span class="comment">//return pointer to edited image</span>
<a name="l00206"></a>00206 <span class="keywordflow">return</span> editedImage;
<a name="l00207"></a>00207 }
<a name="l00208"></a>00208 <span class="comment">//==============================================</span>
</pre></div></div>
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