从左、右、上、下创建矩形

问题描述

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？

解决方法

定义矩形

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



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,heigth);

绘制矩形数组

private void DrawRectangle()
{
    Rectangle[] rectangles = new Rectangle[]
    {
       new Rectangle(0,new Rectangle(300,160,60)
    };
    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();
    }
}

,

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.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,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();