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org.springframework.boot.ImageBanner Maven / Gradle / Ivy
/*
* Copyright 2012-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.boot;
import java.awt.Color;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import javax.imageio.ImageIO;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.boot.ansi.AnsiBackground;
import org.springframework.boot.ansi.AnsiColor;
import org.springframework.boot.ansi.AnsiColors;
import org.springframework.boot.ansi.AnsiElement;
import org.springframework.boot.ansi.AnsiOutput;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.core.env.Environment;
import org.springframework.core.env.PropertyResolver;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
/**
* Banner implementation that prints ASCII art generated from an image resource
* {@link Resource}.
*
* @author Craig Burke
* @author Phillip Webb
* @since 1.4.0
*/
public class ImageBanner implements Banner {
private static final Log log = LogFactory.getLog(ImageBanner.class);
private static final double[] RGB_WEIGHT = { 0.2126d, 0.7152d, 0.0722d };
private static final char[] PIXEL = { ' ', '.', '*', ':', 'o', '&', '8', '#', '@' };
private static final int LUMINANCE_INCREMENT = 10;
private static final int LUMINANCE_START = LUMINANCE_INCREMENT * PIXEL.length;
private final Resource image;
public ImageBanner(Resource image) {
Assert.notNull(image, "Image must not be null");
Assert.isTrue(image.exists(), "Image must exist");
this.image = image;
}
@Override
public void printBanner(Environment environment, Class sourceClass,
PrintStream out) {
String headless = System.getProperty("java.awt.headless");
try {
System.setProperty("java.awt.headless", "true");
printBanner(environment, out);
}
catch (Throwable ex) {
log.warn("Image banner not printable: " + this.image + " (" + ex.getClass()
+ ": '" + ex.getMessage() + "')");
log.debug("Image banner printing failure", ex);
}
finally {
if (headless == null) {
System.clearProperty("java.awt.headless");
}
else {
System.setProperty("java.awt.headless", headless);
}
}
}
private void printBanner(Environment environment, PrintStream out)
throws IOException {
PropertyResolver properties = new RelaxedPropertyResolver(environment,
"banner.image.");
int width = properties.getProperty("width", Integer.class, 76);
int height = properties.getProperty("height", Integer.class, 0);
int margin = properties.getProperty("margin", Integer.class, 2);
boolean invert = properties.getProperty("invert", Boolean.class, false);
BufferedImage image = readImage(width, height);
printBanner(image, margin, invert, out);
}
private BufferedImage readImage(int width, int height) throws IOException {
InputStream inputStream = this.image.getInputStream();
try {
BufferedImage image = ImageIO.read(inputStream);
return resizeImage(image, width, height);
}
finally {
inputStream.close();
}
}
private BufferedImage resizeImage(BufferedImage image, int width, int height) {
if (width < 1) {
width = 1;
}
if (height <= 0) {
double aspectRatio = (double) width / image.getWidth() * 0.5;
height = (int) Math.ceil(image.getHeight() * aspectRatio);
}
BufferedImage resized = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Image scaled = image.getScaledInstance(width, height, Image.SCALE_DEFAULT);
resized.getGraphics().drawImage(scaled, 0, 0, null);
return resized;
}
private void printBanner(BufferedImage image, int margin, boolean invert,
PrintStream out) {
AnsiElement background = (invert ? AnsiBackground.BLACK : AnsiBackground.DEFAULT);
out.print(AnsiOutput.encode(AnsiColor.DEFAULT));
out.print(AnsiOutput.encode(background));
out.println();
out.println();
AnsiColor lastColor = AnsiColor.DEFAULT;
for (int y = 0; y < image.getHeight(); y++) {
for (int i = 0; i < margin; i++) {
out.print(" ");
}
for (int x = 0; x < image.getWidth(); x++) {
Color color = new Color(image.getRGB(x, y), false);
AnsiColor ansiColor = AnsiColors.getClosest(color);
if (ansiColor != lastColor) {
out.print(AnsiOutput.encode(ansiColor));
lastColor = ansiColor;
}
out.print(getAsciiPixel(color, invert));
}
out.println();
}
out.print(AnsiOutput.encode(AnsiColor.DEFAULT));
out.print(AnsiOutput.encode(AnsiBackground.DEFAULT));
out.println();
}
private char getAsciiPixel(Color color, boolean dark) {
double luminance = getLuminance(color, dark);
for (int i = 0; i < PIXEL.length; i++) {
if (luminance >= (LUMINANCE_START - (i * LUMINANCE_INCREMENT))) {
return PIXEL[i];
}
}
return PIXEL[PIXEL.length - 1];
}
private int getLuminance(Color color, boolean inverse) {
double luminance = 0.0;
luminance += getLuminance(color.getRed(), inverse, RGB_WEIGHT[0]);
luminance += getLuminance(color.getGreen(), inverse, RGB_WEIGHT[1]);
luminance += getLuminance(color.getBlue(), inverse, RGB_WEIGHT[2]);
return (int) Math.ceil((luminance / 0xFF) * 100);
}
private double getLuminance(int component, boolean inverse, double weight) {
return (inverse ? 0xFF - component : component) * weight;
}
}