init

.gitignore

@@ -0,0 +1,3 @@
+make
+.swp
+.git

README.md

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 # slide
 Simple slideshow showing random images from specified directory
+
+## Usage
+
+```
+slide /path/to/images
+```
+
+## Build
+
+```
+mkdir -p make
+cd make
+qmake ../slide.pro
+make
+sudo make install
+```

imageselector.cpp

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+#include "imageselector.h"
+#include "mainwindow.h"
+#include <QTimer>
+#include <QApplication>
+#include <QDir>
+#include <iostream>
+#include <stdlib.h>     /* srand, rand */
+#include <time.h>       /* time */
+
+ImageSelector::ImageSelector(MainWindow& w, unsigned int timeout, std::string path):
+    QObject::QObject(),
+    window(w),
+    timeout(timeout),
+    path(path),
+    timer(this)
+{
+    srand (time(NULL));
+}
+
+void ImageSelector::updateImage()
+{
+    QDir directory(path.c_str());
+    QStringList images = directory.entryList(QStringList() << "*.jpg" << "*.JPG",QDir::Files);
+    unsigned int selectedImage = rand() % images.size();
+    std::string filename = directory.filePath(images.at(selectedImage)).toStdString();
+    std::cout << "updating image: " << filename << std::endl;
+    window.setImage(filename);
+}
+
+void ImageSelector::start(){
+    updateImage();
+    connect(&timer, SIGNAL(timeout()), this, SLOT(updateImage()));
+    timer.start(timeout);
+}

imageselector.h

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+#ifndef IMAGESELECTOR_H
+#define IMAGESELECTOR_H
+
+#include <QObject>
+#include <QTimer>
+#include <iostream>
+class MainWindow;
+class ImageSelector : public QObject
+{
+    Q_OBJECT
+public:
+    ImageSelector(MainWindow& w, unsigned int timeout, std::string path);
+    void start();
+
+public slots:
+    void updateImage();
+private:
+    MainWindow& window;
+    unsigned int timeout;
+    std::string path;
+    QTimer timer;
+};
+
+#endif // IMAGESELECTOR_H

main.cpp

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+#include "mainwindow.h"
+#include "imageselector.h"
+#include <QApplication>
+#include <iostream>
+#include <sys/file.h>
+#include <errno.h>
+
+int main(int argc, char *argv[])
+{
+
+    int pid_file = open("/tmp/slide.pid", O_CREAT | O_RDWR, 0666);
+    int rc = flock(pid_file, LOCK_EX | LOCK_NB);
+    if(rc) {
+        if(EWOULDBLOCK == errno) {
+            std::cout << "Already running. Exiting" << std::endl;
+            return 0;
+        }
+    }
+    if (argc < 2) {
+        std::cout << "Error: Path expected." << std::endl;
+        return 1;
+    }
+    QApplication a(argc, argv);
+
+    MainWindow w;
+    w.show();
+
+    ImageSelector is(w, 30000, argv[1]);
+    is.start();
+    return a.exec();
+}

mainwindow.cpp

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+#include "mainwindow.h"
+#include "ui_mainwindow.h"
+#include <QLabel>
+#include <QPixmap>
+#include <QBitmap>
+#include <QKeyEvent>
+#include <QGraphicsBlurEffect>
+
+MainWindow::MainWindow(QWidget *parent) :
+    QMainWindow(parent),
+    ui(new Ui::MainWindow),
+    image(new QLabel)
+{
+    ui->setupUi(this);
+    setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint);
+
+    QMainWindow::showFullScreen();
+    QApplication::setOverrideCursor(Qt::BlankCursor);
+    QLabel *label = this->findChild<QLabel*>("image");
+    setCentralWidget(label);
+    label->setStyleSheet("QLabel {  background-color: rgba(0, 0, 0, 230);}");
+    label->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
+    update();
+
+}
+
+MainWindow::~MainWindow()
+{
+    delete ui;
+}
+
+void MainWindow::keyPressEvent(QKeyEvent* event)
+{
+    if(event->key() == Qt::Key_Escape)
+    {
+         QCoreApplication::quit();
+    }
+    else
+        QWidget::keyPressEvent(event);
+}
+
+void MainWindow::resizeEvent(QResizeEvent* event)
+{
+   QMainWindow::resizeEvent(event);
+    updateImage();
+}
+
+void MainWindow::setImage(std::string path)
+{
+    currentImage = path;
+    updateImage();
+}
+
+void MainWindow::updateImage()
+{
+    if (currentImage == "")
+    {
+        return;
+    }
+    QLabel *label = this->findChild<QLabel*>("image");
+    QPixmap p( currentImage.c_str() );
+    int w = label->width();
+    int h = label->height();
+    QPixmap scaled = p.scaled(w,h,Qt::KeepAspectRatio);
+    label->setPixmap(scaled);
+
+
+    QPalette palette;
+    if (scaled.width() < width()) {
+        QPixmap background = p.scaledToWidth(width());
+        QRect rect(0, (background.height() - height())/2, width(), height());
+        background = background.copy(rect);
+        palette.setBrush(QPalette::Background, background);
+    } else {
+        QPixmap background = p.scaledToHeight(height());
+        QRect rect((background.width() - width())/2, 0, width(), height());
+        background = background.copy(rect);
+        palette.setBrush(QPalette::Background, background);
+    }
+    this->setPalette(palette);
+    update();
+}

mainwindow.h

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+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+
+namespace Ui {
+class MainWindow;
+}
+class QLabel;
+class QKeyEvent;
+
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    explicit MainWindow(QWidget *parent = 0);
+    void keyPressEvent(QKeyEvent* event);
+    void resizeEvent(QResizeEvent* event);
+    ~MainWindow();
+    void setImage(std::string path);
+
+private:
+    Ui::MainWindow *ui;
+    QLabel *image;
+    std::string currentImage;
+    void updateImage();
+};
+
+#endif // MAINWINDOW_H

mainwindow.ui

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+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MainWindow</class>
+ <widget class="QMainWindow" name="MainWindow">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>1500</width>
+    <height>945</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Maximum" vsizetype="Maximum">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>MainWindow</string>
+  </property>
+  <widget class="QWidget" name="centralWidget">
+   <layout class="QGridLayout" name="gridLayout">
+    <item row="0" column="0">
+     <widget class="QLabel" name="image">
+      <property name="text">
+       <string>TextLabel</string>
+      </property>
+     </widget>
+    </item>
+   </layout>
+  </widget>
+ </widget>
+ <layoutdefault spacing="6" margin="11"/>
+ <resources/>
+ <connections/>
+</ui>

run_once.sh

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+#!/bin/bash
+
+me="$(basename "$0")";
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+running=$(ps h -C "$me" | grep -wv $$ | wc -l);
+[[ $running > 1 ]] && exit;
+slide $@

slide.pro

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+#-------------------------------------------------
+#
+# Project created by QtCreator 2019-01-20T10:45:40
+#
+#-------------------------------------------------
+
+QT       += core gui
+
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
+
+TARGET = slide
+TEMPLATE = app
+
+# The following define makes your compiler emit warnings if you use
+# any feature of Qt which has been marked as deprecated (the exact warnings
+# depend on your compiler). Please consult the documentation of the
+# deprecated API in order to know how to port your code away from it.
+DEFINES += QT_DEPRECATED_WARNINGS
+
+# You can also make your code fail to compile if you use deprecated APIs.
+# In order to do so, uncomment the following line.
+# You can also select to disable deprecated APIs only up to a certain version of Qt.
+#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
+
+
+SOURCES += \
+        main.cpp \
+        mainwindow.cpp \
+    imageselector.cpp
+
+HEADERS += \
+        mainwindow.h \
+    imageselector.h
+
+FORMS += \
+        mainwindow.ui
+
+target.path = /usr/local/bin/
+INSTALLS += target