[TASK] Implement brightness slider logic.

imageviewer-qt4.cpp

@@ -45,8 +45,9 @@
  * @brief ImageViewer::ImageViewer
  */
 ImageViewer::ImageViewer() {
-  image=NULL;
+  original_image = NULL;
-  histogramm=NULL;
+  image = NULL;
+  histogramm = NULL;
   startLogging();
   generateMainGui();
   renewLogging();
@@ -56,6 +57,23 @@ ImageViewer::ImageViewer() {
   resize(1600, 600);
  }
 
+/**
+ * Once an image is loaded, automatically perform these operations.
+ * 
+ * analyze the image
+ * allocate brightness map
+ * 
+ * @brief ImageViewer::initializeImage
+ */
+void ImageViewer::initializeImage() {
+  if(image==NULL) {
+    std::cout << "Error! No image provided!" << std::endl;
+    return;
+  }
+  analyzeImage();
+}
+
+
 /**
  * Draws a simple, black line.
  * @brief ImageViewer::drawBlackLine
@@ -176,7 +194,7 @@ void ImageViewer::analyzeImage() {
     logFile << "done" << std::endl;
     renewLogging();
 
-    QString result = QString("Intensity - average : %1, variance: %2").arg(getAverageIntensity()).arg(getIntensityVariance());
+    QString result = QString("Intensity: Average: %1, Variance: %2").arg(getAverageIntensity()).arg(getIntensityVariance());
     task_tab2_stats->setText(result);
 
     updateHistogramm();
@@ -244,6 +262,30 @@ void ImageViewer::updateHistogramm() {
   histogramm_label->setPixmap(QPixmap::fromImage(*histogramm));
 }
 
+/**
+ * Fired by the brightness_slider, this one adjusts the brightness on image.
+ * @brief ImageViewer::adjustBrightness
+ */
+void ImageViewer::adjustBrightness(int b) {
+  int h, s, old_l;
+  int new_l = 0;
+  int delta = b - 255;
+  for(int x=0; x<image->width(); x++) {
+    for(int y=0; y<image->height(); y++) {
+      QColor color = QColor::fromRgb(original_image->pixel(x, y));
+      color.getHsl(&h, &s, &old_l);
+      new_l = old_l + delta;
+      if(new_l > 255) new_l = 255;
+      if(new_l < 0) new_l = 0;
+      color.setHsl(h, s, new_l);
+      image->setPixel(x, y, color.rgba());
+    }
+  }
+  updateImageDisplay();
+  logFile << "Brightness adjusted to: " << old_l << " + " << delta << " -> (" << h << ", " << s << ", " << new_l << ")" << std::endl;
+  renewLogging();
+}
+
 /**************************************************************************************** 
 *   
 *  GUI elements related to the tasks are set up here.
@@ -295,13 +337,9 @@ void ImageViewer::generateControlPanels() {
   task_tab2 = new QVBoxLayout();
   task_tab_widget2->setLayout(task_tab2);
  
-  task_tab2_button1 = new QPushButton();
-  task_tab2_button1->setText("Analyze image");
-  QObject::connect(task_tab2_button1, SIGNAL(clicked()), this, SLOT (analyzeImage()));
-  
   histogramm_label = new QLabel();
   histogramm_label->setBackgroundRole(QPalette::Base);
-  histogramm_label->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
+  histogramm_label->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
   histogramm_label->setScaledContents(false);
 
   task_tab2_stats = new QLabel();
@@ -309,15 +347,15 @@ void ImageViewer::generateControlPanels() {
   
   brightness_slider = new QSlider(Qt::Horizontal);
   brightness_slider->setMinimum(0);
-  brightness_slider->setMaximum(255);
+  brightness_slider->setMaximum(510);
-  brightness_slider->setValue(127);
+  brightness_slider->setValue(255);
+  QObject::connect(brightness_slider, SIGNAL(valueChanged(int)), this, SLOT (adjustBrightness(int)));
   
   contrast_slider = new QSlider(Qt::Horizontal);
   contrast_slider->setMinimum(0);
   contrast_slider->setMaximum(255);
   contrast_slider->setValue(127);
 
-  task_tab2->addWidget(task_tab2_button1);
   task_tab2->addWidget(task_tab2_stats);
   task_tab2->addWidget(new QLabel("Histogramm"));
   task_tab2->addWidget(histogramm_label);
@@ -344,7 +382,7 @@ void ImageViewer::generateControlPanels() {
 
 /**************************************************************************************** 
 *
-* The following methods are about the generic image viewer application and do not contain
+* The following methods are about the adjustBrightness(int)generic image viewer application and do not contain
 * any special graphics logic.
 *
 *****************************************************************************************/
@@ -442,8 +480,13 @@ void ImageViewer::open() {
     if(image->isNull()) {
       QMessageBox::information(this, tr("Image Viewer"), tr("Cannot load %1.").arg(fileName));
       return;
+    } else {
+      if(original_image!=NULL) {
+	delete original_image;
+	original_image = NULL;
+      }
+      original_image = new QImage(fileName);
     }
-
     scaleFactor = 1.0;
     updateImageDisplay();
     printAct->setEnabled(true);
@@ -453,6 +496,7 @@ void ImageViewer::open() {
     setWindowFilePath(fileName);
     logFile << "geladen: " << fileName.toStdString().c_str()  << std::endl;
     renewLogging();
+    initializeImage(); //Now hook to prepare certain datastructures after loading.
   }
 }
 

imageviewer-qt4.h

@@ -51,6 +51,7 @@
 
 #include <cmath>
 #include "fstream"
+#include <iostream>
 
 class QAction;
 class QLabel;
@@ -82,7 +83,6 @@ class ImageViewer : public QMainWindow {
     QWidget* task_tab_widget2;
     QVBoxLayout* task_tab2;
 
-    QPushButton* task_tab2_button1;
     QLabel* task_tab2_stats;
     QLabel* histogramm_label;
     
@@ -97,6 +97,7 @@ class ImageViewer : public QMainWindow {
     int grayscale_absolute_histogramm[256];
     double grayscale_relative_histogramm[256];
     QImage* histogramm;
+    QImage* original_image;
 
   private slots:
     // Custom slots
@@ -106,6 +107,7 @@ class ImageViewer : public QMainWindow {
     void acidTrippin();
     void analyzeImage();
     void updateHistogramm();
+    void adjustBrightness(int b);
 
     void open();
     void print();
@@ -138,6 +140,7 @@ class ImageViewer : public QMainWindow {
     void scaleImage(double factor);
     void adjustScrollBar(QScrollBar *scrollBar, double factor);
 
+    void initializeImage();
     void renewLogging();
 
     QTabWidget* tabWidget;