从左、右、上、下创建矩形

Question

我有一个包含矩形的左、右、底部和顶部的列表。

如何将其转换为 Rectangle[] 数组？

Answer 1

定义矩形

Rectangle(left,top,width,height)
Rectangle[] rectangles = new Rectangle[2]
{
    new Rectangle(0,0,100,50),
    new Rectangle(200,100,200,50),
};



List<Rectangle> rectangles = new List<Rectangle>();
Rectangle rect = new Rectangle();
rect.X = 5;
rect.Y = 10;
rect.Width = 100;
rect.Height = 50;
rectangles.Add(rect);

通过底部和右侧获取高度和宽度

int left = 100;
int top = 50;
int right = 400;
int bottom = 250;

int width = right - left;
int heigth = bottom - top;
Rectangle rect = new Rectangle(left, top, width, heigth);

绘制矩形数组

private void DrawRectangle()
{
    Rectangle[] rectangles = new Rectangle[]
    {
       new Rectangle(0,0,100,50),
       new Rectangle(200,100,200,50),
       new Rectangle(300,200,160,60)
    };
    foreach(var rect in rectangles)
    {
       System.Drawing.SolidBrush myBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Blue);
       System.Drawing.Graphics formGraphics;
       formGraphics = this.CreateGraphics();
       formGraphics.FillRectangle(myBrush, rect);
       myBrush.Dispose();
       formGraphics.Dispose();
    }
}

Answer 2

因此您需要从矩形坐标对象列表中创建一个 Rectangle 对象数组。

public class LTRB
{
    public int Left { get; set; }
    public int Top { get; set; }
    public int Right { get; set; }
    public int Bottom { get; set; }

    public override string ToString() =>
        $"Left: {Left}, Top: {Top}, Right: {Right}, Bottom: {Bottom}";
}

Rectangle.FromLTRB 方法正是您所需要的，它根据坐标返回一个新的 Rectangle。

var rects = ltrbList.Select(x => Rectangle.FromLTRB(x.Left, x.Top, x.Right, x.Bottom)).ToArray();

理想情况下，创建扩展方法以获取 Rectangle 表单 LTRB 对象，以及 IEnumerable<Rectangle> 中的 IEnumerable<LTRB>：

public static class LtrbExtensions
{
    public static Rectangle ToRectangle(this LTRB ltrb) =>
        Rectangle.FromLTRB(ltrb.Left, ltrb.Top, ltrb.Right, ltrb.Bottom);

    public static IEnumerable<Rectangle> ToRectangles(this IEnumerable<LTRB> ltrbList) =>
        ltrbList.Select(x => Rectangle.FromLTRB(x.Left, x.Top, x.Right, x.Bottom));
}

ToRectangle

var ltrb = new LTRB { Left = 0, Top = 0, Right = 50, Bottom = 200 };
var rec = ltrb.ToRectangle();

ToRectangles

var ltrbList = new List<LTRB>()
{
    new LTRB {Left = 0, Top = 0, Right = 50, Bottom = 20},
    new LTRB {Left = 20, Top = 30, Right = 100, Bottom = 50},
};

// To get IEnumerable<Rectangle>
var rects = ltrbList.ToRectangles();

// To get Rectangle[]
var rects = ltrbList.ToRectangles().ToArray();

// To get List<Rectangle>
var rects = ltrbList.ToRectangles().ToList();