Branding: expand documentation

- Auto-advance the default presentation
 - Add more example slides to the fancy presentation
 - Expand README.md explaining what the default classes can do

src/branding/README.md

@@ -28,9 +28,67 @@ There are two examples of branding content:
    the default Calamares icons and a as start-page splash it provides a
    tag-cloud view of languages. The slideshow is a basic one with a few
    slides of text and a single image. No translations are provided.
+ - `fancy/` uses translations and offers navigation arrows. These are
+   provided by the standard Calamares QML classes.
  - `samegame/` is a similarly simple branding setup for Generic Linux,
    but instead of a slideshow, it lets the user play Same Game (clicking
    colored balls) during the installation. The game is taken from the
    QML examples provided by the Qt Company.
- - `fancy/` uses translations and offers navigation arrows.
 
+Since the slideshow can be **any** QML, it is limited only by your designers
+imagination and your QML experience. For straightforward presentations,
+see the documentation below.
+
+## Presentation
+
+The default QML classes provided by Calamares can be used for a simple
+and straightforward "slideshow" presentation with static text and
+pictures. To use the default slideshow classes, start with a `show.qml`
+file with the following content:
+
+```
+import QtQuick 2.5;
+import calamares.slideshow 1.0;
+
+Presentation
+{
+    id: presentation
+}
+```
+
+After the *id*, set properties of the presentation as a whole. These include:
+ - *loopSlides* (default true) When set, clicking past the last slide
+   returns to the very first slide.
+ - *mouseNavigation*, *arrowNavigation*, *keyShortcutsEnabled* (all default
+   true) enable different ways to navigate the slideshow.
+ - *titleColor*, *textColor* change the look of the presentation.
+ - *fontFamily*, *codeFontFamily* change the look of text in the presentation.
+ 
+After setting properties, you can add elements to the presentation.
+Generally, you will add a few presentation-level elements first,
+then slides.
+ - For visible navigation arrows, add elements of class *ForwardButton* and
+   *BackwardButton*. Set the *source* property of each to a suitable
+   image. See the `fancy/` example. It is recommended to turn off other
+   kinds of navigation when visible navigation is used.
+ - To indicate where the user is, add an element of class *SlideCounter*.
+   This indicates in "n / total" form where the user is in the slideshow.
+ - To automatically advance the presentation (for a fully passive slideshow), 
+   add a timer that calls the `goToNextSlide()` function of the presentation.
+   See the `default/` example -- remember to start the timer when the 
+   presentation is completely loaded.
+
+After setting the presentation elements, add one or more Slide elements.
+The presentation framework will make a slideshow out of the Slide 
+elements, displaying only one at a time. Each slide is an element in itself,
+so you can put whatever visual elements you like in the slide. They have
+standard properties for a boring "static text" slideshow, though:
+ - *title* is text to show as slide title
+ - *centeredText* is displayed in a large-ish font
+ - *writeInText* is displayed by "writing it in" to the slide,
+   one letter at a time.
+ - *content* is a list of things which are displayed as a bulleted list.
+ 
+The presentation classes can be used to produce a fairly dry slideshow
+for the installation process; it is recommended to experiment with the
+visual effects and classes available in QtQuick.

src/branding/default/show.qml

@@ -24,6 +24,7 @@ Presentation
     id: presentation
 
     Timer {
+        id: advanceTimer
         interval: 5000
         running: false
         repeat: true
@@ -60,4 +61,6 @@ Presentation
     Slide {
         centeredText: "This is a third Slide element."
     }
+
+    Component.onCompleted: advanceTimer.running = true
 }

src/branding/fancy/show.qml

@@ -93,4 +93,20 @@ Presentation
         }
         centeredText: qsTr("This is a fourth Slide element.")
     }
+    
+    Slide {
+        title: qsTr("Slide number five")
+        writeInText: qsTr("This is example branding for your GNU/Linux distribution. " +
+                "Long texts in the slideshow are translated and word-wrapped appropriately. " +
+                "Calamares is a distribution-independent installer framework. ")
+    }
+    
+    Slide {
+        title: qsTr("Slide number five")
+        content: [ 
+            qsTr("Welcome to Fancy GNU/Linux."), 
+            qsTr("This is a customizable QML slideshow."),
+            qsTr("This is a third Slide element.")
+            ]
+    }
 }