com.codename1.ui.util

Class Effects

java.lang.Object

com.codename1.ui.util.Effects

public class Effects
extends Object

Static utility class useful for simple visual effects that don't quite fit anywhere else in the core API.

Author:

Shai Almog

Method Summary

Modifier and Type	Method and Description
static Image	dropshadow(Image source, int blurRadius, float opacity) Generates a shadow for the source image and returns either the shadow itself or the image merged with the shadow.
static Image	dropshadow(Image source, int blurRadius, float opacity, int xDistance, int yDistance) Generates a shadow for the source image and returns a new larger image containing the shadow
static Image	gaussianBlurImage(Image image, float radius) Create a blur image from the given image.
static void	growShrink(Component c, int duration) Deprecated. use Component.growShrink instead
static boolean	isGaussianBlurSupported() Returns true if gaussian blur is supported on this platform
static Image	reflectionImage(Image source) Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them.
static Image	reflectionImage(Image source, float mirrorRatio, int alphaRatio) Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them.
static Image	reflectionImage(Image source, float mirrorRatio, int alphaRatio, int spacing) Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them.
static Image	squareShadow(int width, int height, int blurRadius, float opacity) Generates a square shadow and returns it
static Image	verticalPerspective(Image i, float topScaleRatio, float bottomScaleRatio, float verticalShrink) Skews an image in a faux perspective transform on the vertical axis, this is effectively a fast scale algorithm that both shrinks the image vertically and reduces the width

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

reflectionImage

public static Image reflectionImage(Image source)

Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them. This method shouldn't be used when numAlpha is very low.

Parameters:

source - image to add the reflection effect to

Returns:

new image with a reflection effect for the source image

reflectionImage

public static Image reflectionImage(Image source,
                                    float mirrorRatio,
                                    int alphaRatio)

Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them. This method shouldn't be used when numAlpha is very low.

Parameters:

source - image to add the reflection effect to

mirrorRatio - generally less than 1, a mirror ration of 0.5f will create a mirror image half the height of the image, 0.75f will create a 3 quarter height mirror etc.

alphaRatio - starting point for the alpha value in the mirror, this should be a number between 0 - 255 (recommended larger than 0) indicating the opacity of the closest pixel. For a mirror thats completely opaque use 255. A recommended value would be between 128 to 90.

Returns:

new image with a reflection effect for the source image

reflectionImage

public static Image reflectionImage(Image source,
                                    float mirrorRatio,
                                    int alphaRatio,
                                    int spacing)

Takes the given image and appends an effect of reflection below it that is similar to the way elements appear in water beneath them. This method shouldn't be used when numAlpha is very low.

Parameters:

source - image to add the reflection effect to

mirrorRatio - generally less than 1, a mirror ration of 0.5f will create a mirror image half the height of the image, 0.75f will create a 3 quarter height mirror etc.

alphaRatio - starting point for the alpha value in the mirror, this should be a number between 0 - 255 (recommended larger than 0) indicating the opacity of the closest pixel. For a mirror thats completely opaque use 255. A recommended value would be between 128 to 90.

spacing - the distance in pixels between the image and its reflection

Returns:

new image with a reflection effect for the source image

growShrink

public static void growShrink(Component c,
                              int duration)

Deprecated. use Component.growShrink instead

Grows or shrinks the given component to its new preferred size, this method essentially takes a component whose preferred size has changed and creates a "growing" effect that lasts for the duration. Notice that some components (such as text areas) don't report proper preferred size untill they are laid out once. Hence the first time around a text area (or container containing a text area) will not produce the expected effect. This can be solved by invoking revalidate before the call to this method only the first time around!

Parameters:

c - the component to grow/shrink, its size must be different from its preferred size

duration - the duration in milliseconds for the grow/shrink animation

verticalPerspective

public static Image verticalPerspective(Image i,
                                        float topScaleRatio,
                                        float bottomScaleRatio,
                                        float verticalShrink)

Skews an image in a faux perspective transform on the vertical axis, this is effectively a fast scale algorithm that both shrinks the image vertically and reduces the width

Parameters:

topScaleRatio - the amount by which the top portion should be scaled where 1.0 means none

bottomScaleRatio - the amount by which the bottom portion should be scaled where 1.0 means none

verticalShrink - the scale ratio for the image height where 1.0 means none

Returns:

the perspective translated image

gaussianBlurImage

public static Image gaussianBlurImage(Image image,
                                      float radius)

Create a blur image from the given image. The algorithm is gaussian blur - https://en.wikipedia.org/wiki/Gaussian_blur

Parameters:

image - the image to blur

radius - the radius to be used in the algorithm

isGaussianBlurSupported

public static boolean isGaussianBlurSupported()

Returns true if gaussian blur is supported on this platform

Returns:

true if gaussian blur is supported.

dropshadow

public static Image dropshadow(Image source,
                               int blurRadius,
                               float opacity,
                               int xDistance,
                               int yDistance)

Generates a shadow for the source image and returns a new larger image containing the shadow

Parameters:

source - the source image for whom the shadow should be generated

blurRadius - a shadow is blurred using a gaussian blur when available, a value of 10 is often satisfactory

opacity - the opacity of the shadow between 0 - 1 where 1 is completely opaque

xDistance - the distance on the x axis from the main image body in pixels e.g. a negative value will represent a lightsource from the right (shadow on the left)

yDistance - the distance on the y axis from the main image body in pixels e.g. a negative value will represent a lightsource from the bottom (shadow on top)

Returns:

a new image whose size incorporates x/yDistance

dropshadow

public static Image dropshadow(Image source,
                               int blurRadius,
                               float opacity)

Generates a shadow for the source image and returns either the shadow itself or the image merged with the shadow.

Parameters:

source - the source image for whom the shadow should be generated

blurRadius - a shadow is blurred using a gaussian blur when available, a value of 10 is often satisfactory

opacity - the opacity of the shadow between 0 - 1 where 1 is completely opaque

Returns:

an image containing the shadow for source

squareShadow

public static Image squareShadow(int width,
                                 int height,
                                 int blurRadius,
                                 float opacity)

Generates a square shadow and returns it

Parameters:

width - the width of the shadow image

height - the height of the shadow image

blurRadius - a shadow is blurred using a gaussian blur when available, a value of 10 is often satisfactory

opacity - the opacity of the shadow between 0 - 1 where 1 is completely opaque

Returns:

an image containing the shadow for source