使用drawString（）java时会跳过Color.White(Color.White is getting skipped when using drawString() java)

使用drawString（）java时会跳过Color.White(Color.White is getting skipped when using drawString() java)

当我试图在黑色背景上画白色字母时，我注意到一些奇怪的东西。

public WhiteOnBlackPanel() { setBackground(Color.BLACK); } public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(new Color(255,255,255)); g.drawString("Hello World",100,100); g.drawLine(0,0,100,100); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.add(new WhiteOnBlackPanel()); frame.setTitle("Hello World"); frame.setSize(600,400); frame.setLocation(100,100); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); // The frame is visible from now on }

！ 不要看图像中的代码，只看框架！

给我这个：

然而，线条画得很好。

当我采用不同但非常接近的颜色（254,255,255）时，我得到了这个

为什么java.awt.Graphics阻止绘制纯白色（255,255,255）字母（即使它是在黑色背景上）？

蒂亚，查理

When I was trying to draw white letters on a black background I noticed something weird.

public WhiteOnBlackPanel() { setBackground(Color.BLACK); } public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(new Color(255,255,255)); g.drawString("Hello World",100,100); g.drawLine(0,0,100,100); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.add(new WhiteOnBlackPanel()); frame.setTitle("Hello World"); frame.setSize(600,400); frame.setLocation(100,100); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); // The frame is visible from now on }

! Don't look at the code in the images, just look at the frame !

Gave me this:

Lines, however, were being drawn well.

When I took a different, but very close, color (254, 255, 255), I got this

Why is java.awt.Graphics blocking pure white (255,255,255) letters from being drawn (even when it is on a black background) ?

Tia, Charlie

最满意答案

jdk1.8.0_20中的一个错误，至少在Linux（Ubuntu）中：0xFFFFFFFF显示为BLACK。 更改alpha或其中一个RGB值会导致“几乎为白色”。

jdk1.7.0_67在同一系统上运行正常。

检查所有形式的setColor。

后来发现bug报告： JDK-8054638：没有涂上白色

受影响的版本：8u11,8u25

这个bug只影响Linux; 在Windows上一切正常。

A bug in jdk1.8.0_20, at least in Linux (Ubuntu): 0xFFFFFFFF appears as BLACK. Changing alpha or one of the RGB values results in "almost white".

jdk1.7.0_67 works fine on the same system.

Checked all forms of setColor.

Later Found that bug is reported: JDK-8054638 : White color is not painted

Affected Versions: 8u11,8u25

This bug only affects Linux; on Windows everything works fine.