# Displaying Images

The defining aspect of a visual novel, lending its name to the form, are the visuals. Ren'Py contains four statements that control the display of images, and a model that determines the order in which the images are displayed. This makes it convenient to display images in a manner that is suitable for use in visual novels and other storytelling games.

The four statements that work with images are:

- `image` - defines a new image.
- `show` - shows an image on a layer.
- `scene` - clears a layer, and optionally shows an image on that layer.
- `hide` - removes an image from a layer.

As abrupt changes of image can be disconcerting to the user, Ren'Py has the `with` statement, which allows effects to be applied when the scene is changed.

## Concepts

### Image

An image is something that can be show to the screen using the show statement. An image consists of a name and a displayable. When the image is shown on a layer, the displayable associated with it is displayed on that layer.

An image name consists of one or more names, separated by spaces. The first component of the image name is called the image tag. The second and later components of the name are the image attributes.

For example, take the image name `mary beach night happy`. The image tag is `mary`, while the image attributes are `beach`, `night`, and `happy`.

A displayable is something that can be shown on the screen. The most common thing to show is a static image, which can be specified by giving the filename of the image, as a string. In the example above, we might use "mary_beach_night_happy.png" as the filename. However, an image may refer to any displayable Ren'Py supports, not just static images. Thus, the same statements that are used to display images can also be used for animations, solid colors, and the other types of displayables.

### Layer

A layer is a list of displayables that are shown on the screen. Ren'Py supports multiple layers, including user-defined layers. The order of the layers is fixed within a game (controlled by the `config.layers` variable), while the order of displayables within a layer is controlled by the order in which the scene and show statements are called, and the properties given to those statements.

The following layers are defined as part of Ren'Py:

master
  This is the default layer that is used by the scene, show, and hide statements. It's generally used for backgrounds and character sprites.
transient
  The default layer used by ui functions. This layer is cleared at the end of each interaction.
screens
  This layer is used by the screen system.
overlay
  The default layer used when a ui function is called from within an overlay function. This layer is cleared when an interaction is restarted.

Additional layers can be defined by updating `config.layers`, and the various other layer-related config variables. Using `renpy.show_layer_at()`, one or more transforms can be applied to a layer.

## Defining Images

There are two ways to define images. You can either place an image file in the image directory, or an image can be defined using the image statement. The former is simple, as it involves placing properly named files in a directory, while the latter a allows more control over how the image is defined, and allows images that are not image files.

Images defined using the image statement take precedence over those defined by the image directory.

### Images Directory

The image directory is named "images", and is placed under the game directory. When a file with the .jpg or .png extension is placed underneath this directory, the extension is stripped, the rest of the filename is forced to lower case, and the resulting filename is used as the image name if an image with that name has not been previously defined.

This process takes place in all directories underneath the image directory. For example, all of these files will define the image `eileen happy`:

    game/images/eileen happy.png
    game/images/Eileen Happy.jpg
    game/images/eileen/eileen happy.png

### Image Statement

The `image` statement is used to define an image. An image statement consists of a single logical line beginning with the keyword `image`, followed by an image name, an equals sign `=`, and a displayable. For example:

    image eileen happy = "eileen_happy.png"
    image black = "#000"
    image bg tiled = LiveTile("tile.jpg")

    image eileen happy question = VBox(
        "question.png",
        "eileen_happy.png",
        )

When an image is not directly in the game directory, you'll need to give the directories underneath it. For example, if the image is in game/eileen/happy.png, then you can write:

    image eileen happy = "eileen/happy.png"

The image statement is run at init time, before the menus are shown or the start label runs. When not contained inside an `init` block, image statements are run as if they were placed inside an `init` block of priority 500.

See also the ATL variant of the image statement.

## Show Statement

The `show` statement is used to display an image on a layer. A show statement consists of a single logical line beginning with the keyword `show`, followed by an image name, followed by zero or more properties.

If the show statement is given the exact name of an existing image, that image is the one that is shown. Otherwise, Ren'Py will attempt to find a unique image that:

- Has the same tag as the one specified in the show statement.
- Has all of the attributes given in the show statement.
- If an image with the same tag is already showing, shares the largest number of attributes with that image.

If a unique image cannot be found, an exception occurs.

If an image with the same image tag is already showing on the layer, the new image replaces it. Otherwise, the image is placed above all other images in the layer. (That is, closest to the user.) This order may be modified by the `zorder` and `behind` properties.

The show statement does not cause an interaction to occur. For the image to actually be displayed to the user, a statement that causes an interaction (like the say, menu, pause, and with statements) must be run.

The show statement takes the following properties:

`as`
  The `as` property takes a name. This name is used in place of the image tag when the image is shown. This allows the same image to be on the screen twice.
`at`

  The `at` property takes one or more comma-separated simple expressions. Each expression must evaluate to a transform. The transforms are applied to the image in left-to-right order.

  If no at clause is given, Ren'Py will retain any existing transform that has been applied to the image. If no transform exists, the image will be displayed using the `default` transform.

`behind`
  Takes a comma-separated list of one or more names. Each name is taken as an image tag. The image is shown behind all images with the given tags that are currently being shown.
`onlayer`
  Takes a name. Shows the image on the named layer.
`zorder`
  Takes an integer. The integer specifies the relative ordering of images within a layer, with larger numbers being closer to the user. This isn't generally used by Ren'Py games, but can be useful when porting visual novels from other engines.

Assuming we have the following images defined:

    image mary night happy = "mary_night_happy.png"
    image mary night sad = "mary_night_sad.png"
    image moon = "moon.png"

Some example show statements are:

    # Basic show.
    show mary night sad

    # Since 'mary night happy' is showing, the following statement is
    # equivalent to:
    # show mary night happy
    show mary happy

    # Show an image on the right side of the screen.
    show mary night happy at right

    # Show the same image twice.
    show mary night sad as mary2 at left

    # Show an image behind another.
    show moon behind mary, mary2

    # Show an image on a user-defined layer.
    show moon onlayer user_layer

Show Expression. A variant of the show statement replaces the image name with the keyword `expression`, followed by a simple expression. The expression must evaluate to a displayable, and the displayable is shown on the layer. To hide the displayable, a tag must be given with the as statement.

For example:

    show expression "moon.png" as moon

Show Layer. The show layer statement allows one to apply a transform or ATL transform to an entire layer (such as "master"), using syntax like:

    show layer master at flip

or:

    show layer master:
        xalign 0.5 yalign 0.5 rotate 180

To stop applying transforms to the layer, use:

    show layer master

## Scene Statement

The `scene` statement removes all displayables from a layer, and then shows an image on that layer. It consists of the keyword `scene`, followed by an image name, followed by zero or more properties. The image is shown in the same way as in the show statement, and the scene statement takes the same properties as the show statement.

The scene statement is often used to show an image on the background layer. For example:

    scene bg beach

Scene Expression. Like the show statement, the scene statement can take expressions instead of image names.

Clearing a layer. When the image name is omitted entirely, the scene statement clears all displayables from a layer without showing another displayable.

## Hide Statement

The `hide` statement removes an image from a layer. It consists of the keyword `hide`, followed by an image name, followed by an optional property. The hide statement takes the image tag from the image name, and then hides any image on the layer with that tag.

Hide statements are rarely necessary. If a sprite represents a character, then a hide statement is only necessary when the character leaves the scene. When the character changes her emotion, it is preferable to use the show statement instead, as the show statement will automatically replace an image with the same tag.

The hide statement takes the following property:

`onlayer`
  Takes a name. Hides the image from the named layer.

For example:

    e "I'm out of here."

    hide eileen

You should never write:

    hide eileen
    show eileen happy

Instead, just write:

    show eileen happy

## With Statement

The `with` statement is used to apply a transition effect when the scene is changed, making showing and hiding images less abrupt. The with statement consists of the keyword `with`, followed by a simple expression that evaluates either to a transition object or the special value `None`.

The transition effect is applied between the contents of the screen at the end of the previous interaction (with transient screens and displayables hidden), and the current contents of the scene, after the show and hide statements have executed.

The with statement causes an interaction to occur. The duration of this interaction is controlled by the user, and the user can cause it to terminate early.

For a full list of transitions that can be used, see the chapter on transitions.

An example of the with statement is:

    show bg washington
    with dissolve

    show eileen happy at left
    show lucy mad at right
    with dissolve

This causes two transitions to occur. The first with statement uses the `dissolve` transition to change the screen from what was previously shown to the washington background. (The `dissolve` transition is, by default, defined as a .5 second dissolve.)

The second transition occurs after the Eileen and Lucy images are shown. It causes a dissolve from the scene consisting solely of the background to the scene consisting of all three images – the result is that the two new images appear to dissolve in simultaneously.

### With None

In the above example, there are two dissolves. But what if we wanted the background to appear instantly, followed by a dissolve of the two characters? Simply omitting the first with statement would cause all three images to dissolve in – we need a way to say that the first should be show instantly.

The with statement changes behavior when given the special value `None`. The `with None` statement causes an abbreviated interaction to occur, without changing what the user sees. When the next transition occurs, it will start from the scene as it appears at the end of this abbreviated interaction.

For example, in:

    show bg washington
    with None

    show eileen happy at left
    show lucy mad at right
    with dissolve

Only a single transition occurs, from the washington background to the scene consisting of all three images.

### With Clause of Scene, Show, and Hide Statements

The show, scene, and hide statements can take an optional `with` clause, which allows a transition to be combined with showing or hiding an image. This clause follows the statements at the end of the same logical line. It begins with the keyword `with`, followed by a simple expression.

The with clause is equivalent to preceding the line with a `with None` statement, and following it by a with statement containing the text of the with clause. For example:

    show eileen happy at left with dissolve
    show lucy mad at right with dissolve

is equivalent to:

    with None
    show eileen happy at left
    with dissolve

    with None
    show lucy mad at right
    with dissolve

## Hide and Show Window

The `window` statement is used to control if a window is shown when a character is not speaking (for example, during transitions and pauses). The `window show` statement causes the window to be shown, while the `window hide` statement hides the window.

If the optional transition is given, it's used to show and hide the window. If not given, it defaults to `config.window_show_transition` and `config.window_hide_transition`. Giving None as the transition prevents it from occurring.

The window itself is displayed by calling `config.empty_window`. It defaults to having the narrator say an empty string.

    show bg washington
    show eileen happy
    with dissolve

    window show dissolve

    "I can say stuff..."

    show eileen happy at right
    with move

    "... and move, while keeping the window shown."

    window hide dissolve

## Image Functions

`renpy.``can_show`(name, layer=None, tag=None)

  Determines if name can be used to show an image. This interprets name as a tag and attributes. This is combined with the attributes of the currently-showing image with tag on layer to try to determine a unique image to show. If a unique image can be show, returns the name of that image as a tuple. Otherwise, returns None.

  tag
    The image tag to get attributes from. If not given, defaults to the first component of name.
  layer
    The layer to check. If None, uses the default layer for tag.

`renpy.``check_image_attributes`(tag, attributes)

  Checks to see if there is a unique image with the given tag and attributes. If there is, returns the attributes in order. Otherwise, returns None.

`renpy.``copy_images`(old, new)

  Copies images beginning with one prefix to images beginning with another. For example:

      renpy.copy_images("eileen", "eileen2")

  will create an image beginning with "eileen2" for every image beginning with "eileen". If "eileen happy" exists, "eileen2 happy" will be created.

  old
    A space-separated string giving the components of the old image name.
  new
    A space-separated string giving the components of the new image name.

`renpy.``get_attributes`(tag, layer=None, if_hidden=None)

  Return a tuple giving the image attributes for the image tag. If the image tag has not had any attributes associated since the last time it was hidden, returns if_hidden.

  layer
    The layer to check. If None, uses the default layer for tag.

`renpy.``get_available_image_tags`()

  Returns a list of image tags that have been defined.

`renpy.``get_hidden_tags`(layer='master')

  Returns the set of image tags on layer that are currently hidden, but still have attribute information associated with them.

`renpy.``get_image_bounds`(tag, width=None, height=None, layer='master')

  If an image with tag exists on layer, returns the bounding box of that image. Returns None if the image is not found.

  The bounding box is an (x, y, width, height) tuple. The components of the tuples are expressed in pixels, and may be floating point numbers.

  width, height
    The width and height of the area that contains the image. If None, defaults the width and height of the screen, respectively.
  layer
    If None, uses the default layer for tag.

`renpy.``get_ordered_image_attributes`(tag, attributes=(), sort=None)

  Returns a list of image tags, ordered in a way that makes sense to present to the user.

  attributes
    If present, only attributes that are compatible with the given attributes are considered. (Compatible means that the attributes can be in a single image at the same time.)
  sort
    If not None, the returned list of attributes is sorted. This is a function that should be used as a tiebreaker.

`renpy.``get_placement`(d)

  This gets the placement of displayable d. There's very little warranty on this information, as it might change when the displayable is rendered, and might not exist until the displayable is first rendered.

  This returns an object with the following fields, each corresponding to a style property:

  - pos
  - xpos
  - ypos
  - anchor
  - xanchor
  - yanchor
  - offset
  - xoffset
  - yoffset
  - subpixel

`renpy.``get_registered_image`(name)

  If an image with the same name has been registered with renpy.register_image, returns it. Otherwise, returns None.

`renpy.``get_say_image_tag`()

  Returns the tag corresponding to the currently speaking character (the image argument given to that character). Returns None if no character is speaking or the current speaking character does not have a corresponding image tag.

`renpy.``get_showing_tags`(layer='master', sort=False)

  Returns the set of image tags that are currently being shown on layer. If sort is true, returns a list of the tags from back to front.

`renpy.``has_image`(name, exact=False)

  Return true if an image with name exists, and false if no such image exists.

  name
    Either a string giving an image name, or a tuple of strings giving the name components.
  exact
    Returns true if and only if an image with the exact name exists - parameterized matches are not included.

`renpy.``list_images`()

  Returns a list of images that have been added to Ren'Py, as a list of strings with spaces between the name components.

`renpy.``seen_image`(name)

  Returns True if the named image has been seen at least once on the user's system. An image has been seen if it's been displayed using the show statement, scene statement, or `renpy.show()` function. (Note that there are cases where the user won't actually see the image, like a show immediately followed by a hide.)

`renpy.``showing`(name, layer='master')

  Returns true if an image with the same tag as name is showing on layer.

  image
    May be a string giving the image name or a tuple giving each component of the image name. It may also be a string giving only the image tag.
  layer
    The layer to check. If None, uses the default layer for tag.

`renpy.``start_predict`(*args)

  This function takes one or more displayables as arguments. It causes Ren'Py to predict those displayables during every interaction until the displayables are removed by `renpy.stop_predict()`.

  If a displayable name is a string containing one or more * characters, the asterisks are used as a wildcard pattern. If there is at least one . in the string, the pattern is matched against filenames, otherwise it is matched against image names.

  For example:

      $ renpy.start_predict("eileen *")

  starts predicting all images with the name eileen, while:

      $ renpy.start_predict("images/concert*.*")

  matches all files starting with concert in the images directory.

`renpy.``stop_predict`(*args)

  This function takes one or more displayables as arguments. It causes Ren'Py to stop predicting those displayables during every interaction.

  Wildcard patterns can be used as described in `renpy.start_predict()`.