C# System.Drawing.RectangleF 到 Java 的對應轉換：使用 Rectangle2D.Float

C# 原始代碼

RectangleF rf = new RectangleF(
    new PointF(p0.X - width, p0.Y - width),
    new SizeF(width * 2, width * 2));

Java 對應實現

import java.awt.geom.Rectangle2D;
import java.awt.geom.Point2D;

// 直接構造
Rectangle2D.Float rect = new Rectangle2D.Float(
    (float)(p0.x - width),
    (float)(p0.y - width),
    (float)(width * 2),
    (float)(width * 2)
);

// 或分步
Point2D.Float location = new Point2D.Float((float)(p0.x - width), (float)(p0.y - width));
java.awt.geom.Dimension2D size = new java.awt.geom.Dimension2D() {
    public double getWidth()  { return width * 2; }
    public double getHeight() { return width * 2; }
};
Rectangle2D.Float rect2 = new Rectangle2D.Float(
    (float)location.getX(), (float)location.getY(),
    (float)size.getWidth(), (float)size.getHeight()
);

類對應表

注意事項

• Java 2D 使用 float 單精度，C# float 同，精度一致
• Rectangle2D 為抽象基類，Rectangle2D.Float / .Double 為具體實現
• 若需整數矩形，用 java.awt.Rectangle (x, y, w, h 均為 int)