如何在图形中以透明颜色制作矩形？

发布于 2024-12-15 12:08:12 字数 682 浏览 3 评论 0原文

我试图在我的应用程序上以红色阴影绘制一个矩形，但我需要将其设置为透明，以便其下方的组件仍会显示。然而我仍然希望一些颜色仍然会显示出来。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);
        }
    }
}

有谁知道如何使红色阴影有点透明？但我不需要它完全透明。

原文

I'm trying to paint a rectangle on my application in a red shade but I need to make it sort of transparent so that the component under it will still show. However I still want that some colour will still show. The method where I'm drawing is the following:

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);
        }
    }
}

Does anyone know how I can make the red shade a bit transparent? I don't need it completely transparent though.

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烧了回忆取暖 2024-12-22 12:08:12

int alpha = 127; // 50% transparent
Color myColour = new Color(255, value, value, alpha);

请参阅 Color 构造函数，采用 4 个参数（int 或 float）以了解更多详细信息。

int alpha = 127; // 50% transparent
Color myColour = new Color(255, value, value, alpha);

See the Color constructors that take 4 arguments (of either int or float) for further details.

回复收藏 0 原文

我爱人 2024-12-22 12:08:12

试试这个：（但它适用于 Graphics2D 对象，不适用于 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); 
    }
}

Try this: (but it will works for Graphics2D objeccts not for 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); 
    }
}

回复收藏 0 原文

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