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防止设置色差过大，导致循环次数过多，增加默认色差方法

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This commit is contained in:
chenzecheng 2024-08-09 09:40:28 +08:00
parent 4c00f6adb2
commit a6f0193e19
4 changed files with 80 additions and 6 deletions
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40
hutool-captcha/src/test/java/cn/hutool/captcha/CaptchaUtilTest.java
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@ -26,17 +26,26 @@ public class CaptchaUtilTest {
@Test
@Ignore
public void drawStringColourfulTest() {
public void drawStringColourfulColorDistanceTest() {
for(int i = 0; i < 10; i++) {
AbstractCaptcha lineCaptcha = new TestLineCaptcha(200, 100, 5, 10);
lineCaptcha.write("d:/captcha/line"+i+".png");
AbstractCaptcha lineCaptcha = new TestLineCaptchaColorDistance(200, 100, 5, 10);
lineCaptcha.write("d:/captcha/line1-"+i+".png");
}
}
static class TestLineCaptcha extends AbstractCaptcha{
@Test
@Ignore
public void drawStringColourfulDefaultColorDistanceTest() {
for(int i = 0; i < 10; i++) {
AbstractCaptcha lineCaptcha = new TestLineCaptchaColorDistanceDefaultColorDistance(200, 100, 5, 10);
lineCaptcha.write("d:/captcha/line2-"+i+".png");
}
}
static class TestLineCaptchaColorDistance extends AbstractCaptcha{
private static final long serialVersionUID = -558846929114465692L;
public TestLineCaptcha(int width, int height, int codeCount, int interfereCount) {
public TestLineCaptchaColorDistance(int width, int height, int codeCount, int interfereCount) {
super(width, height, codeCount, interfereCount);
}
@ -62,11 +71,12 @@ public class CaptchaUtilTest {
* @param g {@link Graphics}画笔
* @param code 验证码
*/
private void drawString(Graphics2D g, String code) {
protected void drawString(Graphics2D g, String code) {
// 指定透明度
if (null != this.textAlpha) {
g.setComposite(this.textAlpha);
}
// 自定义与背景颜色的色差值，200是基于Color.WHITE较为居中的值
GraphicsUtil.drawStringColourful(g, code, this.font, this.width, this.height,Color.WHITE,200);
}
@ -89,4 +99,22 @@ public class CaptchaUtilTest {
}
// ----------------------------------------------------------------------------------------------------- Private method start
}
static class TestLineCaptchaColorDistanceDefaultColorDistance extends TestLineCaptchaColorDistance {
public TestLineCaptchaColorDistanceDefaultColorDistance(int width, int height, int codeCount, int interfereCount) {
super(width, height, codeCount, interfereCount);
}
@Override
protected void drawString(Graphics2D g, String code) {
// 指定透明度
if (null != this.textAlpha) {
g.setComposite(this.textAlpha);
}
// 使用默认色差设置
GraphicsUtil.drawStringColourful(g, code, this.font, this.width, this.height,Color.WHITE);
}
}
}

18
hutool-core/src/main/java/cn/hutool/core/img/ColorUtil.java
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@ -1,6 +1,7 @@
package cn.hutool.core.img;
import cn.hutool.core.convert.Convert;
import cn.hutool.core.lang.Assert;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.core.util.RandomUtil;
import cn.hutool.core.util.StrUtil;
@ -178,6 +179,9 @@ public class ColorUtil {
* @since 5.8.30
*/
public static Color randomColor(Color compareColor,int minDistance) {
// 注意minDistance太大会增加循环次数，保证至少1/3的概率生成成功
Assert.isTrue(minDistance < maxDistance(compareColor) / 3 * 2,
"minDistance is too large, there are too few remaining colors!");
Color color = randomColor();
while (computeColorDistance(compareColor,color) < minDistance) {
color = randomColor();
@ -195,6 +199,20 @@ public class ColorUtil {
return randomColor(null);
}
/**
* 计算给定点与其他点之间的最大可能距离。
*
* @param color 指定颜色
* @return 其余颜色与color的最大距离
* @since 6.0.0-M16
*/
public static int maxDistance(final Color color) {
final int maxX = RGB_COLOR_BOUND - 2 * color.getRed();
final int maxY = RGB_COLOR_BOUND - 2 * color.getGreen();
final int maxZ = RGB_COLOR_BOUND - 2 * color.getBlue();
return (int)Math.sqrt(maxX * maxX + maxY * maxY + maxZ * maxZ);
}
/**
* 计算两个颜色之间的色差，按三维坐标距离计算
*

17
hutool-core/src/main/java/cn/hutool/core/img/GraphicsUtil.java
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@ -101,6 +101,23 @@ public class GraphicsUtil {
return drawString(g, str, font, null, width, height, compareColor, minColorDistance);
}
/**
* 绘制字符串，使用随机颜色，并且与背景颜色保持一定色差，默认抗锯齿
*
* @param g {@link Graphics}画笔
* @param str 字符串
* @param font 字体
* @param width 字符串总宽度
* @param height 字符串背景高度
* @param backgroundColor 背景颜色
* @return 画笔对象
* @since 4.5.10
*/
public static Graphics drawStringColourful(Graphics g, String str, Font font, int width, int height, Color backgroundColor) {
// 默认色差为最大色差的1/2
return drawString(g, str, font, null, width, height, backgroundColor, ColorUtil.maxDistance(backgroundColor) / 2);
}
/**
* 绘制字符串，默认抗锯齿
*

11
hutool-core/src/main/java/cn/hutool/core/img/ImgUtil.java
View File

@ -2237,6 +2237,17 @@ public class ImgUtil {
return ColorUtil.randomColor(compareColor,minDistance);
}
/**
* 生成随机颜色，与指定颜色有一定的区分度
*
* @param compareColor 比较颜色
* @return 与指定颜色有一定的区分度的随机颜色，默认是最大可能的三维距离的一半
* @since 5.8.30
*/
public static Color randomColor(Color compareColor) {
return ColorUtil.randomColor(compareColor,ColorUtil.maxDistance(compareColor) / 2);
}
/**
* 生成随机颜色
*