Qt/Images/Pixmap

main.cpp

#include <QApplication>
 
#include "form.h"
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);
  Form form;
 
  form.show();
  return app.exec();
}

form.h

#ifndef FORM_H
#define FORM_H
 
#include "ui_form.h"
 
class Form : public QWidget, private Ui::Form
{
    Q_OBJECT
 
public:
    Form(QWidget *parent = 0);
 
};
 
#endif

form.cpp

#include <QtGui>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QPixmap>
 
#include "form.h"
 
Form::Form(QWidget *parent)
    : QWidget(parent)
{
  setupUi(this);
 
  //QPixmap pixmap;
  //pixmap.load("test.jpg");
 
  // Manual:
  //pixmap = pixmap.scaled(20,20);
 
  // Works
//   QPixmap pixmap(20,20);
//   QColor black(0,0,0);
//   pixmap.fill(black);
 
  //QPixmap pixmap; // Doesn't work (probably because the default size is (0,0) so scaling 0 to anything doesn't make sense)
  QPixmap pixmap(1,1); // Works
  pixmap = pixmap.scaled(20,20);
  QColor black(0,0,0);
  pixmap.fill(black);
 
  QGraphicsScene* scene = new QGraphicsScene;
  scene->addPixmap(pixmap);
 
  this->graphicsView->setScene(scene);
 
}

form.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Form</class>
 <widget class="QWidget" name="Form">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <widget class="QGraphicsView" name="graphicsView">
   <property name="geometry">
    <rect>
     <x>60</x>
     <y>50</y>
     <width>256</width>
     <height>192</height>
    </rect>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)
 
PROJECT(QPixmap)
 
FIND_PACKAGE(Qt4 REQUIRED)
INCLUDE(${QT_USE_FILE})
 
QT4_WRAP_UI(UISrcs form.ui)
QT4_WRAP_CPP(MOCSrcs form.h)
 
include_directories(${include_directories} ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
 
ADD_EXECUTABLE(QPixmap main.cpp form.h form.cpp ${MOCSrcs} ${UISrcs})
TARGET_LINK_LIBRARIES(QPixmap ${QT_LIBRARIES})