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sepia.cpp

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00001 //============================================== 00002 // copyright : (C) 2003-2005 by Will Stokes 00003 //============================================== 00004 // This program is free software; you can redistribute it 00005 // and/or modify it under the terms of the GNU General 00006 // Public License as published by the Free Software 00007 // Foundation; either version 2 of the License, or 00008 // (at your option) any later version. 00009 //============================================== 00010 00011 //Systemwide includes 00012 #include <qimage.h> 00013 #include <qstring.h> 00014 #include <qapplication.h> 00015 00016 //Projectwide includes 00017 #include "sepia.h" 00018 #include "manipulationOptions.h" 00019 #include "../../gui/statusWidget.h" 00020 00021 //---------------------------------------------- 00022 // Inputs: 00023 // ------- 00024 // QString filename - location of original image on disk 00025 // StatusWidget* status - widget for making progress visible to user 00026 // 00027 // Outputs: 00028 // -------- 00029 // QImage* returned - constructed image 00030 // 00031 // Description: 00032 // ------------ 00033 // This method constructs a sepia version of 00034 // the image by computing a sepia value for each pixel. 00035 // The sepia effect is intended to mimick sepia coloring 00036 // obtained during traditional film development. 00037 // 00038 // First, a sepia color is chosen with a nice yellowy-orange tone 00039 // (r,g,b = 162,128,101). This color is next converted to HSL 00040 // (hue, saturation, luminance) space and used during sepia coloring. 00041 // 00042 // For each pixel, we construct a modified sepia color where the original 00043 // luminance (brightness) is replaced with that pixels luminance using 00044 // a weighted sum of the color channels. (For more information on image 00045 // luminance see the blackWhite effect). This modified sepia color is 00046 // converted back to RGB color space and used for the pixel color 00047 // in the modified image. This way image brightness is maintained 00048 // while color information is replaced with the sepia color. The 00049 // sepia color can be adjusted to produce a differnt overall color 00050 // feeling by changing the original sepia color. 00051 //---------------------------------------------- 00052 00053 //============================================== 00054 QImage* sepiaEffect( QString filename, ManipulationOptions* options ) 00055 { 00056 //load image 00057 QImage* editedImage = new QImage( filename ); 00058 00059 //convert to 32-bit depth if necessary 00060 if( editedImage->depth() < 32 ) 00061 { 00062 QImage* tmp = editedImage; 00063 editedImage = new QImage( tmp->convertDepth( 32, Qt::AutoColor ) ); 00064 delete tmp; tmp=NULL; 00065 } 00066 00067 //determine if busy indicators will be used 00068 bool useBusyIndicators = false; 00069 StatusWidget* status = NULL; 00070 if( options != NULL && options->getStatus() != NULL ) 00071 { 00072 useBusyIndicators = true; 00073 status = options->getStatus(); 00074 } 00075 00076 //setup progress bar 00077 if(useBusyIndicators) 00078 { 00079 QString statusMessage = qApp->translate( "sepiaEffect", "Applying Sepia Effect:" ); 00080 status->showProgressBar( statusMessage, 100 ); 00081 qApp->processEvents(); 00082 } 00083 00084 //update progress bar for every 1% of completion 00085 const int updateIncrement = (int) ( 0.01 * editedImage->width() * editedImage->height() ); 00086 int newProgress = 0; 00087 00088 //compute the hsl/hsv coordinates of sepia color 00089 int sepiaH, sepiaS, sepiaL; 00090 QColor(162,128,101).getHsv( &sepiaH, &sepiaS, &sepiaL ); 00091 00092 //iterate over each selected scanline 00093 int x, y, pixelLuminance; 00094 QRgb* rgb; 00095 QColor sepiaColor; 00096 uchar* scanLine; 00097 00098 for( y=0; y<editedImage->height(); y++) 00099 { 00100 //iterate over each selected pixel in scanline 00101 scanLine = editedImage->scanLine(y); 00102 for( x=0; x<editedImage->width(); x++) 00103 { 00104 //compute gray value based on the display luminance of color coordinates 00105 rgb = ((QRgb*)scanLine+x); 00106 pixelLuminance = (int) (0.2125*qRed(*rgb) + 0.7154*qGreen(*rgb) + 0.0721*qBlue(*rgb)); 00107 00108 //compute and set sepia color 00109 sepiaColor.setHsv( sepiaH, sepiaS, pixelLuminance ); 00110 *rgb = sepiaColor.rgb(); 00111 00112 //update status bar if significant progress has been made since last update 00113 if(useBusyIndicators) 00114 { 00115 newProgress++; 00116 if(newProgress >= updateIncrement) 00117 { 00118 newProgress = 0; 00119 status->incrementProgress(); 00120 qApp->processEvents(); 00121 } 00122 } 00123 00124 } 00125 } 00126 00127 //return pointer to edited image 00128 return editedImage; 00129 } 00130 //==============================================

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