(C++) QtExample21

 

 

This Qt example shows a way to develop a transparent-like dialog. The trick used is to take a screenshot of the desktop before the dialog is shown. The illusion fades if the dialog is moved.

 

• Download the 'CppQtExample21' source code (zip)
• View a screenshot of 'CppQtExample21' (png)

Technical facts

 

Application type(s)

• Desktop application

Operating system(s) or programming environment(s)

• Lubuntu 15.04 (vivid)

IDE(s):

• Qt Creator 3.1.1

Project type:

• GUI application

C++ standard:

• C++11

Compiler(s):

• G++ 4.9.2

Libraries used:

• Qt: version 5.4.1 (32 bit)
• STL: GNU ISO C++ Library, version 4.9.2

 

 

 

 

 

Qt project file: ./CppQtExample21/CppQtExample21.pro

 

---

exists(../../DesktopApplication.pri) {   include(../../DesktopApplication.pri) } !exists(../../DesktopApplication.pri) {   QT += core gui   greaterThan(QT_MAJOR_VERSION, 4): QT += widgets   TEMPLATE = app   CONFIG(debug, debug|release) {     message(Debug mode)   }   CONFIG(release, debug|release) {     message(Release mode)     DEFINES += NDEBUG NTRACE_BILDERBIKKEL   }   QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra   unix {     QMAKE_CXXFLAGS += -Werror   } } exists(../../Libraries/Boost.pri) {   include(../../Libraries/Boost.pri) } !exists(../../Libraries/Boost.pri) {   win32 {     INCLUDEPATH += \       ../../../Projects/Libraries/boost_1_55_0   } } SOURCES += \   main.cpp \   transparentdialog.cpp HEADERS  += transparentdialog.h FORMS    += transparentdialog.ui #CONFIG += mobility #MOBILITY = #symbian { #    TARGET.UID3 = 0xe7de6653 #    # TARGET.CAPABILITY += #    TARGET.EPOCSTACKSIZE = 0x14000 #    TARGET.EPOCHEAPSIZE = 0x020000 0x800000 #}

 

 

 

 

 

./CppQtExample21/main.cpp

 

---

#pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QApplication> #include "transparentdialog.h" #pragma GCC diagnostic pop int main(int argc, char *argv[]) {   QApplication a(argc, argv);   TransparentDialog w;   w.show();   return a.exec(); }

 

 

 

 

 

./CppQtExample21/transparentdialog.h

 

---

#ifndef TRANSPARENTDIALOG_H #define TRANSPARENTDIALOG_H #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QDialog> #pragma GCC diagnostic pop namespace Ui {   class TransparentDialog; } class TransparentDialog : public QDialog {   Q_OBJECT public:   explicit TransparentDialog(QWidget *parent = 0);   TransparentDialog(const TransparentDialog&) = delete;   TransparentDialog& operator=(const TransparentDialog&) = delete;   ~TransparentDialog(); protected:   void paintEvent(QPaintEvent *); private:   Ui::TransparentDialog *ui;   QPixmap m_pixmap; private slots: }; #endif // TRANSPARENTDIALOG_H

 

 

 

 

 

./CppQtExample21/transparentdialog.cpp

 

---

#include "transparentdialog.h" #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QApplication> #include <QDesktopWidget> #include <QPainter> #include "ui_transparentdialog.h" #pragma GCC diagnostic pop TransparentDialog::TransparentDialog(QWidget *parent)   : QDialog(parent),     ui(new Ui::TransparentDialog),     m_pixmap(QPixmap::grabWindow(QApplication::desktop()->winId())) {   ui->setupUi(this); } TransparentDialog::~TransparentDialog() {   delete ui; } void TransparentDialog::paintEvent(QPaintEvent *) {   QPainter painter(this);   painter.drawPixmap(     this->rect(),     m_pixmap,     this->geometry()); }