org.jdesktop.swingx.graphics.ShadowRenderer Maven / Gradle / Ivy
/*
* $Id: ShadowRenderer.java 3742 2010-08-05 03:25:09Z kschaefe $
*
* Copyright 2006 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.jdesktop.swingx.graphics;
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
/**
* A shadow renderer generates a drop shadow for any given picture, respecting
* the transparency channel if present. The resulting picture contains the
* shadow only and to create a drop shadow effect you will need to stack the
* original picture and the shadow generated by the renderer.
* Shadow Properties
* A shadow is defined by three properties:
*
* - size: The size, in pixels, of the shadow. This property also
* defines the fuzziness.
* - opacity: The opacity, between 0.0 and 1.0, of the shadow.
* - color: The color of the shadow. Shadows are not meant to be
* black only.
*
* You can set these properties using the provided mutators or the appropriate
* constructor. Here are two ways of creating a green shadow of size 10 and
* with an opacity of 50%:
*
* ShadowRenderer renderer = new ShadowRenderer(10, 0.5f, Color.GREEN);
* // ..
* renderer = new ShadowRenderer();
* renderer.setSize(10);
* renderer.setOpacity(0.5f);
* renderer.setColor(Color.GREEN);
*
* The default constructor provides the following default values:
*
* - size: 5 pixels
* - opacity: 50%
* - color: Black
*
* Generating a Shadow
* A shadow is generated as a BufferedImage from another
* BufferedImage. Once the renderer is set up, you must call
* {@link #createShadow} to actually generate the shadow:
*
* ShadowRenderer renderer = new ShadowRenderer();
* // renderer setup
* BufferedImage shadow = renderer.createShadow(bufferedImage);
*
* The generated image dimensions are computed as following:
*
* width = imageWidth + 2 * shadowSize
* height = imageHeight + 2 * shadowSize
*
* Properties Changes
* This renderer allows to register property change listeners with
* {@link #addPropertyChangeListener}. Listening to properties changes is very
* useful when you embed the renderer in a graphical component and give the API
* user the ability to access the renderer. By listening to properties changes,
* you can easily repaint the component when needed.
* Threading Issues
* ShadowRenderer is not guaranteed to be thread-safe.
*
* @author Romain Guy
* @author Sebastien Petrucci
*/
public class ShadowRenderer {
/**
* Identifies a change to the size used to render the shadow.
* When the property change event is fired, the old value and the new
* value are provided as Integer instances.
*/
public static final String SIZE_CHANGED_PROPERTY = "shadow_size";
/**
* Identifies a change to the opacity used to render the shadow.
* When the property change event is fired, the old value and the new
* value are provided as Float instances.
*/
public static final String OPACITY_CHANGED_PROPERTY = "shadow_opacity";
/**
* Identifies a change to the color used to render the shadow.
*/
public static final String COLOR_CHANGED_PROPERTY = "shadow_color";
// size of the shadow in pixels (defines the fuzziness)
private int size = 5;
// opacity of the shadow
private float opacity = 0.5f;
// color of the shadow
private Color color = Color.BLACK;
// notifies listeners of properties changes
private PropertyChangeSupport changeSupport;
/**
* Creates a default good looking shadow generator.
* The default shadow renderer provides the following default values:
*
* - size: 5 pixels
* - opacity: 50%
* - color: Black
*
* These properties provide a regular, good looking shadow.
*/
public ShadowRenderer() {
this(5, 0.5f, Color.BLACK);
}
/**
* A shadow renderer needs three properties to generate shadows.
* These properties are:
*
* - size: The size, in pixels, of the shadow. This property also
* defines the fuzziness.
* - opacity: The opacity, between 0.0 and 1.0, of the shadow.
* - color: The color of the shadow. Shadows are not meant to be
* black only.
*
* @param size the size of the shadow in pixels. Defines the fuzziness.
* @param opacity the opacity of the shadow.
* @param color the color of the shadow.
*/
public ShadowRenderer(final int size, final float opacity, final Color color) {
//noinspection ThisEscapedInObjectConstruction
changeSupport = new PropertyChangeSupport(this);
setSize(size);
setOpacity(opacity);
setColor(color);
}
/**
* Add a PropertyChangeListener to the listener list. The listener is
* registered for all properties. The same listener object may be added
* more than once, and will be called as many times as it is added. If
* listener is null, no exception is thrown and no action
* is taken.
* @param listener the PropertyChangeListener to be added
*/
public void addPropertyChangeListener(PropertyChangeListener listener) {
changeSupport.addPropertyChangeListener(listener);
}
/**
* Remove a PropertyChangeListener from the listener list. This removes
* a PropertyChangeListener that was registered for all properties. If
* listener was added more than once to the same event source,
* it will be notified one less time after being removed. If
* listener is null, or was never added, no exception is thrown
* and no action is taken.
* @param listener the PropertyChangeListener to be removed
*/
public void removePropertyChangeListener(PropertyChangeListener listener) {
changeSupport.removePropertyChangeListener(listener);
}
/**
* Gets the color used by the renderer to generate shadows.
* @return this renderer's shadow color
*/
public Color getColor() {
return color;
}
/**
* Sets the color used by the renderer to generate shadows.
* Consecutive calls to {@link #createShadow} will all use this color
* until it is set again.
* If the color provided is null, the previous color will be retained.
* @param shadowColor the generated shadows color
*/
public void setColor(final Color shadowColor) {
if (shadowColor != null) {
Color oldColor = this.color;
this.color = shadowColor;
changeSupport.firePropertyChange(COLOR_CHANGED_PROPERTY,
oldColor,
this.color);
}
}
/**
* Gets the opacity used by the renderer to generate shadows.
* The opacity is comprised between 0.0f and 1.0f; 0.0f being fully
* transparent and 1.0f fully opaque.
* @return this renderer's shadow opacity
*/
public float getOpacity() {
return opacity;
}
/**
* Sets the opacity used by the renderer to generate shadows.
* Consecutive calls to {@link #createShadow} will all use this opacity
* until it is set again.
* The opacity is comprised between 0.0f and 1.0f; 0.0f being fully
* transparent and 1.0f fully opaque. If you provide a value out of these
* boundaries, it will be restrained to the closest boundary.
* @param shadowOpacity the generated shadows opacity
*/
public void setOpacity(final float shadowOpacity) {
float oldOpacity = this.opacity;
if (shadowOpacity < 0.0) {
this.opacity = 0.0f;
} else if (shadowOpacity > 1.0f) {
this.opacity = 1.0f;
} else {
this.opacity = shadowOpacity;
}
changeSupport.firePropertyChange(OPACITY_CHANGED_PROPERTY,
oldOpacity,
this.opacity);
}
/**
* Gets the size in pixel used by the renderer to generate shadows.
* @return this renderer's shadow size
*/
public int getSize() {
return size;
}
/**
* Sets the size, in pixels, used by the renderer to generate shadows.
* The size defines the blur radius applied to the shadow to create the
* fuzziness.
* There is virtually no limit to the size. The size cannot be negative.
* If you provide a negative value, the size will be 0 instead.
* @param shadowSize the generated shadows size in pixels (fuzziness)
*/
public void setSize(final int shadowSize) {
int oldSize = this.size;
if (shadowSize < 0) {
this.size = 0;
} else {
this.size = shadowSize;
}
changeSupport.firePropertyChange(SIZE_CHANGED_PROPERTY,
new Integer(oldSize),
new Integer(this.size));
}
/**
* Generates the shadow for a given picture and the current properties
* of the renderer.
* The generated image dimensions are computed as following:
*
* width = imageWidth + 2 * shadowSize
* height = imageHeight + 2 * shadowSize
*
* @param image the picture from which the shadow must be cast
* @return the picture containing the shadow of image
*/
public BufferedImage createShadow(final BufferedImage image) {
// Written by Sesbastien Petrucci
int shadowSize = size * 2;
int srcWidth = image.getWidth();
int srcHeight = image.getHeight();
int dstWidth = srcWidth + shadowSize;
int dstHeight = srcHeight + shadowSize;
int left = size;
int right = shadowSize - left;
int yStop = dstHeight - right;
int shadowRgb = color.getRGB() & 0x00FFFFFF;
int[] aHistory = new int[shadowSize];
int historyIdx;
int aSum;
BufferedImage dst = new BufferedImage(dstWidth, dstHeight,
BufferedImage.TYPE_INT_ARGB);
int[] dstBuffer = new int[dstWidth * dstHeight];
int[] srcBuffer = new int[srcWidth * srcHeight];
GraphicsUtilities.getPixels(image, 0, 0, srcWidth, srcHeight, srcBuffer);
int lastPixelOffset = right * dstWidth;
float hSumDivider = 1.0f / shadowSize;
float vSumDivider = opacity / shadowSize;
int[] hSumLookup = new int[256 * shadowSize];
for (int i = 0; i < hSumLookup.length; i++) {
hSumLookup[i] = (int) (i * hSumDivider);
}
int[] vSumLookup = new int[256 * shadowSize];
for (int i = 0; i < vSumLookup.length; i++) {
vSumLookup[i] = (int) (i * vSumDivider);
}
int srcOffset;
// horizontal pass : extract the alpha mask from the source picture and
// blur it into the destination picture
for (int srcY = 0, dstOffset = left * dstWidth; srcY < srcHeight; srcY++) {
// first pixels are empty
for (historyIdx = 0; historyIdx < shadowSize; ) {
aHistory[historyIdx++] = 0;
}
aSum = 0;
historyIdx = 0;
srcOffset = srcY * srcWidth;
// compute the blur average with pixels from the source image
for (int srcX = 0; srcX < srcWidth; srcX++) {
int a = hSumLookup[aSum];
dstBuffer[dstOffset++] = a << 24; // store the alpha value only
// the shadow color will be added in the next pass
aSum -= aHistory[historyIdx]; // substract the oldest pixel from the sum
// extract the new pixel ...
a = srcBuffer[srcOffset + srcX] >>> 24;
aHistory[historyIdx] = a; // ... and store its value into history
aSum += a; // ... and add its value to the sum
if (++historyIdx >= shadowSize) {
historyIdx -= shadowSize;
}
}
// blur the end of the row - no new pixels to grab
for (int i = 0; i < shadowSize; i++) {
int a = hSumLookup[aSum];
dstBuffer[dstOffset++] = a << 24;
// substract the oldest pixel from the sum ... and nothing new to add !
aSum -= aHistory[historyIdx];
if (++historyIdx >= shadowSize) {
historyIdx -= shadowSize;
}
}
}
// vertical pass
for (int x = 0, bufferOffset = 0; x < dstWidth; x++, bufferOffset = x) {
aSum = 0;
// first pixels are empty
for (historyIdx = 0; historyIdx < left;) {
aHistory[historyIdx++] = 0;
}
// and then they come from the dstBuffer
for (int y = 0; y < right; y++, bufferOffset += dstWidth) {
int a = dstBuffer[bufferOffset] >>> 24; // extract alpha
aHistory[historyIdx++] = a; // store into history
aSum += a; // and add to sum
}
bufferOffset = x;
historyIdx = 0;
// compute the blur avera`ge with pixels from the previous pass
for (int y = 0; y < yStop; y++, bufferOffset += dstWidth) {
int a = vSumLookup[aSum];
dstBuffer[bufferOffset] = a << 24 | shadowRgb; // store alpha value + shadow color
aSum -= aHistory[historyIdx]; // substract the oldest pixel from the sum
a = dstBuffer[bufferOffset + lastPixelOffset] >>> 24; // extract the new pixel ...
aHistory[historyIdx] = a; // ... and store its value into history
aSum += a; // ... and add its value to the sum
if (++historyIdx >= shadowSize) {
historyIdx -= shadowSize;
}
}
// blur the end of the column - no pixels to grab anymore
for (int y = yStop; y < dstHeight; y++, bufferOffset += dstWidth) {
int a = vSumLookup[aSum];
dstBuffer[bufferOffset] = a << 24 | shadowRgb;
aSum -= aHistory[historyIdx]; // substract the oldest pixel from the sum
if (++historyIdx >= shadowSize) {
historyIdx -= shadowSize;
}
}
}
GraphicsUtilities.setPixels(dst, 0, 0, dstWidth, dstHeight, dstBuffer);
return dst;
}
}