- Add support for display time windows for images in folder.options

- the times are defined in a JSON array with start and end times, if inside the window the image is valid to display

src/imagestructs.h

@@ -1,16 +1,25 @@
 #ifndef IMAGESTRUCTS_H
 #define IMAGESTRUCTS_H
 
+#include <QTime>
+#include <QVector>
 #include <string>
 
 // possible aspect ratios of an image
 enum ImageAspect { ImageAspect_Landscape = 0, ImageAspect_Portrait, ImageAspect_Any, ImageAspect_Monitor /* match monitors aspect */ };
 
+struct DisplayTimeWindow
+{
+    QTime startDisplay = QTime(0,0,0,0);
+    QTime endDisplay = QTime(23,59,59,0);
+};
+
 // options to consider when displaying an image
 struct ImageDisplayOptions
 {
     ImageAspect onlyAspect = ImageAspect_Any;
     bool fitAspectAxisToWindow = false;
+    QVector<DisplayTimeWindow> timeWindows;
 };
 
 // details of a particular image