# Substance look and feel - watermarks

### Overview

Every Substance skin has an associated watermark. The watermark of the current skin is painted over the background of most of the containers (such as panels, tool bars etc). While most child components (such as buttons or combo boxes) do not show the watermark overlay, a specific skin can define a custom alpha value for certain component states (mostly disabled). In this case, the watermark painting from the parent will be partially displayed on the child component.

There is no need to mark your containers as non-opaque to get the watermark painting. The core library comes with four watermarks. Additional watermarks are bundled with the extras pack.

Due to performance considerations, it is recommended not to use any watermark at all. This results in about 20-30% improvement for both static and dynamic scenarios.

### Watermark

A watermark must implement org.jvnet.substance.watermark.SubstanceWatermark interface. This interface defines the following methods:

`/**
* Draws the watermark on the specified graphics context in the specified
* region.
*
* @param graphics
* Graphics context.
* @param c
* Component that is painted.
* @param x
* Left X of the region.
* @param y
* Top Y of the region.
* @param width
* Region width.
* @param height
* Region height.
*/
public void drawWatermarkImage(Graphics graphics, Component c, int x,
int y, int width, int height);
/**
* Updates the current watermark image.
*
* @param skin
* Skin for the watermark.
* @return <code>true</code> if the watermark has been updated successfully,
* <code>false</code> otherwise.
*/
public boolean updateWatermarkImage(SubstanceSkin skin);
/**
* Draws the preview of the watermark image.
*
* @param g
* Graphic context.
* @param x
* the <i>x</i> coordinate of the watermark to be drawn.
* @param y
* The <i>y</i> coordinate of the watermark to be drawn.
* @param width
* The width of the watermark to be drawn.
* @param height
* The height of the watermark to be drawn.
*/
public void previewWatermark(Graphics g, int x, int y, int width, int height);
/**
* Disposes the memory associated with <code>this</code> watermark.
*/
public void dispose();`

These methods are used at runtime to paint watermarks on the corresponding components.

Substance provides four core watermarks. The `Null` watermark in `org.jvnet.substance.watermark.SubstanceNullWatermark` draws a translucent fill:

The `Stripes` watermark in `org.jvnet.substance.watermark.SubstanceStripeWatermark` overlays a pattern of one-pixel stripes:

The `Crosshatch` watermark in `org.jvnet.substance.watermark.SubstanceCrosshatchWatermark` overlays a pattern of diagonal hatches:

The noise-based `Plankton` watermark in `org.jvnet.substance.watermark.SubstancePlanktonWatermark` overlays a random pattern of quasi aquatic life:

### Image-based watermarks

The `org.jvnet.substance.watermark.SubstanceImageWatermark` class provides an option to use an image-based watermark. To construct an image watermark, use one of the following constructors:

`/**
* Creates an instance with specified image.
*
* @param imageLocation
* Image location. Can point to a local file or HTTP URL (needs
* to start with <code>http</code> in the later case).
*/
@SubstanceApi
public SubstanceImageWatermark(String imageLocation)
/**
* Creates an instance from the specified input stream.
*
* @param inputStream
* Input stream.
*/
@SubstanceApi
public SubstanceImageWatermark(InputStream inputStream)`

Here are examples of image-based watermarks:

By default, the image is centered in the screen and scaled down if necessary. To change the default behavior, use the following API in the `SubstanceImageWatermark` class:

`/**
* Sets image watermark kind.
*
* @param kind
* Image watermark kind.
*/
@SubstanceApi
public void setKind(ImageWatermarkKind kind)`

Where `SubstanceConstants.ImageWatermarkKind` enum defines the following kinds of image watermark:

- SCREEN_CENTER_SCALE - the default behaviour. The image is centered in the screen and scaled down if necessary.
- SCREEN_TILE - the image is tiled starting from the screen top-left corner and not scaled.
- APP_ANCHOR - the image is anchored to the top-left corner of the application frame and not scaled.
- APP_CENTER - the image is anchored to the center of the application frame and not scaled.
- APP_TILE - the image is tiled starting from the top-left corner of the application frame and not scaled.

Here is an example of APP_TILE image watermark kind:

The default opacity of the image watermark is 0.2 and can be changed by using the following API in the `SubstanceImageWatermark` class:

`/**
* Sets image watermark opacity.
*
* @param opacity
* Image watermark opacity.
* @throws IllegalArgumentException
* if the argument is not in 0.0-1.0 range.
*/
@SubstanceApi
public void setOpacity(float opacity)`

Here are examples of default opacity (0.2) and custom opacity (0.6):

### Using watermarks

The available core watermarks are located in `org.jvnet.substance.watermark` package. You can also use additional watermark from the extras pack.

The recommended way to specify a watermark is to set the `watermark` field in the constructor of your custom skin. The public `withWatermark` may also be used to create a clone of an existing skin and change its watermark.

### Miscellaneous

If you wish to use the watermark of the current skin to provide additional custom painting in your application, call:

- `SubstanceLookAndFeel.getCurrentSkin()` to retrieve the current skin.
- `SubstanceSkin.getWatermark()` to retrieve the watermark of the current skin.
- `SubstanceWatermark.drawWatermarkImage()` to paint the watermark on the specific graphics context.

Note that some Swing core components do not show the watermark by default. Currently, the watermark is not shown on trees, tables, lists and text components. To enable the watermark painting on these components, read the documentation on the WATERMARK_VISIBLE client property.