我想在我的应用程序上画一个红色阴影的矩形,但我需要使它透明,这样它下面的组件仍然会显示。但是我仍然希望一些颜色仍然可以显示出来。我绘制的方法如下:
protected void paintComponent(Graphics g) {
if (point != null) {
int value = this.chooseColour(); // used to return how bright the red is needed
if(value !=0){
Color myColour = new Color(255, value,value );
g.setColor(myColour);
g.fillRect(point.x, point.y, this.width, this.height);
}
else{
Color myColour = new Color(value, 0,0 );
g.setColor(myColour);
g.fillRect(point.x, point.y, this.width, this.height);
}
}
}
有谁知道我怎么能使红色阴影有点透明吗?我不需要完全透明
int alpha = 127; // 50% transparent
Color myColour = new Color(255, value, value, alpha);
请参阅Color
构造函数,该构造函数接受4个参数(int
或float
)以了解更多详细信息。
试试这个(但它将适用于Graphics2D对象而不是Graphics)
protected void paintComponent(Graphics2D g) {
if (point != null) {
int value = this.chooseColour(); // used to return how bright the red is needed
g.setComposite(AlphaComposite.SrcOver.derive(0.8f));
if(value !=0){
Color myColour = new Color(255, value,value );
g.setColor(myColour);
g.fillRect(point.x, point.y, this.width, this.height);
}
else{
Color myColour = new Color(value, 0,0 );
g.setColor(myColour);
g.fillRect(point.x, point.y, this.width, this.height);
}
g.setComposite(AlphaComposite.SrcOver);
}
}