Made parallax factor scriptable and documented it

docs/manual/layers.rst

@@ -9,9 +9,10 @@ foreground or background graphics. The order of the layers determines
 the rendering order of your content.
 
 Layers can be hidden, made only partially visible and can be locked. Layers
-also have an offset, which can be used to position them independently of each
-other, for example to fake depth. Finally their contents can be tinted by
-multiplying with a custom :ref:`tint color <tint-color>`.
+also have an offset and a :ref:`parallax scrolling factor <parallax-factor>`,
+which can be used to position them independently of each other, for example to
+fake depth. Finally their contents can be tinted by multiplying with a custom
+:ref:`tint color <tint-color>`.
 
 .. figure:: images/layers/lock-visibility-toggle.png
    :alt: Layers View
@@ -125,6 +126,35 @@ Layers can be easily dragged in and out of groups with the mouse. The
 Raise Layer / Lower Layer actions also allow moving layers in and out of
 groups.
 
+.. raw:: html
+
+   <div class="new">New in Tiled 1.5</div>
+
+.. _parallax-factor:
+
+Parallax Scrolling Factor
+-------------------------
+
+The parallax scrolling factor determines the amount by which the layer moves in
+relation to the camera.
+
+By default its value is 1, which means its position on the screen changes at
+the same rate as the position of the camera (in opposite direction). A lower
+value makes it move slower, simulating a layer that is further away, whereas
+a higher value makes it move faster, simulating a layer positioned in between
+the screen and the camera.
+
+A value of 0 makes the layer not move at all, which can be useful to include
+some pieces of your ingame UI or to mark its general viewport boundaries.
+
+Negative values make the layer move in opposite direction, though this is rarely
+useful.
+
+When the parallax scrolling factor is set on a group layer, it applies to all
+its child layers. The effective parallax scrolling factor of a layer is
+determined by multiplying the parallax scrolling factor by the scrolling
+factors of all parent layers.
+
 .. raw:: html
 
    <div class="new">New in Tiled 1.4</div>

docs/reference/json-map-format.rst

@@ -94,10 +94,12 @@ Layer
     offsetx,          double,           "Horizontal layer offset in pixels (default: 0)"
     offsety,          double,           "Vertical layer offset in pixels (default: 0)"
     opacity,          double,           "Value between 0 and 1"
+    parallaxx,        double,           "Horizontal :ref:`parallax factor <parallax-factor>` for this layer (default: 1). (since Tiled 1.5)"
+    parallaxy,        double,           "Vertical :ref:`parallax factor <parallax-factor>` for this layer (default: 1). (since Tiled 1.5)"
     properties,       array,            "Array of :ref:`Properties <json-property>`"
     startx,           int,              "X coordinate where layer content starts (for infinite maps)"
     starty,           int,              "Y coordinate where layer content starts (for infinite maps)"
-    tintcolor,        string,           "Hex-formatted color (#RRGGBB or #AARRGGBB) that is multiplied with any graphics drawn by this layer or any child layers (optional)."
+    tintcolor,        string,           "Hex-formatted :ref:`tint color <tint-color>` (#RRGGBB or #AARRGGBB) that is multiplied with any graphics drawn by this layer or any child layers (optional)."
     transparentcolor, string,           "Hex-formatted color (#RRGGBB) (optional). ``imagelayer`` only."
     type,             string,           "``tilelayer``, ``objectgroup``, ``imagelayer`` or ``group``"
     visible,          bool,             "Whether layer is shown or hidden in editor"

docs/reference/scripting.rst

@@ -920,7 +920,8 @@ Properties
     **visible** : bool, Whether the layer is visible (affects child layer visibility for group layers).
     **locked** : bool, Whether the layer is locked (affects whether child layers are locked for group layers).
     **offset** : :ref:`script-point`, Offset in pixels that is applied when this layer is rendered.
-    **map** : :ref:`script-map`, Map that this layer is part of (or ``null`` in case of a standalone layer).
+    **parallaxFactor** : :ref:`script-point`, The parallax factor of the layer (since Tiled 1.5).
+    **map** : :ref:`script-map` |ro|, Map that this layer is part of (or ``null`` in case of a standalone layer).
     **selected** : bool, Whether the layer is selected.
     **isTileLayer** : bool |ro|, Whether this layer is a :ref:`script-tilelayer`.
     **isObjectLayer** : bool |ro|, Whether this layer is an :ref:`script-objectgroup`.

docs/reference/tmx-map-format.rst

@@ -380,11 +380,13 @@ tiles.
 -  **height:** The height of the layer in tiles. Always the same as the map height for fixed-size maps.
 -  **opacity:** The opacity of the layer as a value from 0 to 1. Defaults to 1.
 -  **visible:** Whether the layer is shown (1) or hidden (0). Defaults to 1.
--  **tintcolor:** A color that is multiplied with any tiles drawn by this layer in ``#AARRGGBB`` or ``#RRGGBB`` format (optional).
+-  **tintcolor:** A :ref:`tint color <tint-color>` that is multiplied with any tiles drawn by this layer in ``#AARRGGBB`` or ``#RRGGBB`` format (optional).
 -  **offsetx:** Horizontal offset for this layer in pixels. Defaults to 0.
    (since 0.14)
 -  **offsety:** Vertical offset for this layer in pixels. Defaults to 0.
    (since 0.14)
+-  **parallaxx:** Horizontal :ref:`parallax factor <parallax-factor>` for this layer. Defaults to 1. (since 1.5)
+-  **parallaxy:** Vertical :ref:`parallax factor <parallax-factor>` for this layer. Defaults to 1. (since 1.5)
 
 Can contain at most one: :ref:`tmx-properties`, :ref:`tmx-data`
 

src/tiled/editablelayer.cpp

@@ -146,6 +146,14 @@ void EditableLayer::setOffset(QPointF offset)
         layer()->setOffset(offset);
 }
 
+void EditableLayer::setParallaxFactor(QPointF factor)
+{
+    if (auto doc = document())
+        asset()->push(new SetLayerParallaxFactor(doc, layer(), factor));
+    else if (!checkReadOnly())
+        layer()->setParallaxFactor(factor);
+}
+
 void EditableLayer::setSelected(bool selected)
 {
     auto document = mapDocument();

src/tiled/editablelayer.h

@@ -40,6 +40,7 @@ class EditableLayer : public EditableObject
     Q_PROPERTY(bool visible READ isVisible WRITE setVisible)
     Q_PROPERTY(bool locked READ isLocked WRITE setLocked)
     Q_PROPERTY(QPointF offset READ offset WRITE setOffset)
+    Q_PROPERTY(QPointF parallaxFactor READ parallaxFactor WRITE setParallaxFactor)
     Q_PROPERTY(Tiled::EditableMap *map READ map)
     Q_PROPERTY(bool selected READ isSelected WRITE setSelected)
     Q_PROPERTY(bool isTileLayer READ isTileLayer CONSTANT)
@@ -62,6 +63,7 @@ class EditableLayer : public EditableObject
     bool isVisible() const;
     bool isLocked() const;
     QPointF offset() const;
+    QPointF parallaxFactor() const;
     EditableMap *map() const;
     bool isSelected() const;
     bool isTileLayer() const;
@@ -83,6 +85,7 @@ public slots:
     void setVisible(bool visible);
     void setLocked(bool locked);
     void setOffset(QPointF offset);
+    void setParallaxFactor(QPointF factor);
     void setSelected(bool selected);
 
 protected:
@@ -123,6 +126,11 @@ inline QPointF EditableLayer::offset() const
     return layer()->offset();
 }
 
+inline QPointF EditableLayer::parallaxFactor() const
+{
+    return layer()->parallaxFactor();
+}
+
 inline bool EditableLayer::isTileLayer() const
 {
     return layer()->isTileLayer();