如何在图像上填充旋转的矩形

Question

如何填充旋转的矩形？我只能填充一个不旋转的矩形，而且效果很好。但我最近需要填充一个任意角度的旋转矩形。

这是我的代码

using (ImageMagick.MagickImage img = new ImageMagick.MagickImage())
{
img.Read(image.FullPath);
foreach (var item in ListofCoordinates)
{
ImageMagick.DrawableFillColor fillColor = new ImageMagick.DrawableFillColor(System.Drawing.Color.LightGray);
var d = int.Parse(Math.Round(((item.Rotation * img.Density.X) / 96)).ToString());
var x = int.Parse(Math.Round(((item.X * img.Density.X) / 96)).ToString());
var y = int.Parse(Math.Round(((item.Y * img.Density.X) / 96)).ToString());
var w = int.Parse(Math.Round(((item.Width * img.Density.X) / 96)).ToString());
var h = int.Parse(Math.Round(((item.Height * img.Density.X) / 96)).ToString());
var r = new System.Drawing.Rectangle(x, y, w, h);
ImageMagick.DrawableRectangle rect = new ImageMagick.DrawableRectangle(r);
img.Draw(fillColor, rect);
}
img.Write(System.IO.Path.Combine(OutputPath, image.FileName));
}

这是我应该实现的一个例子

这是示例图像这是的第一张照片

这是输出这是输出的第二张图片

Answer 1

虽然您可以使用ImageMagic，但.Net库就足够了。

有几种方法可以绘制像旋转矩形这样的形状。

1(画4个点(你可以用这种方式画任何形状，而不仅仅是矩形(，旋转它

C#

Dim Img As Image = New Bitmap(Me.Picturebox1.Width, Me.Picturebox1.Height)
Dim g As Graphics = Graphics.FromImage(Img)
Dim bgBrush As SolidBrush = New SolidBrush(Color.LightSlateGray)
Dim shPen As Pen = New Pen(Color.Black)
Dim pts() As Point
pts = {New Point(150, 100),         ' 1
New Point(200, 100),         ' 2
New Point(150, 200),         ' 3
New Point(200, 200)}         ' 4
Dim pth As New GraphicsPath
pth = ShapeData(0)
g.FillPath(bgBrush, pth)            ' fill
g.DrawPath(shPen, pth)              ' border
Dim Angle As Int16 = 30
Dim RotMatrix As New Matrix                       ' rotate matrix to put the shape back to initial coordinates (with bottom left point as reference)
RotMatrix.Rotate(Angle, MatrixOrder.Append)       ' Rotate the pattern to the desired angle
RotMatrix.TransformPoints(pts)                    ' carry out matrix transformation over the shape points

VB.NET

Image Img = new Bitmap(this.Picturebox1.Width, this.Picturebox1.Height);
Graphics g = Graphics.FromImage(Img);
SolidBrush bgBrush = new SolidBrush(Color.LightSlateGray);
Pen shPen = new Pen(Color.Black);
Point[] pts;
pts = new[] { new Point(150, 100), new Point(200, 100), new Point(150, 200), new Point(200, 200) };         // 4
GraphicsPath pth = new GraphicsPath();
pth = ShapeData(0);
g.FillPath(bgBrush, pth);            // fill
g.DrawPath(shPen, pth);              // border
Int16 Angle = 30;
Matrix RotMatrix = new Matrix();                    // rotate matrix to put the shape back to initial coordinates (with bottom left point as reference)
RotMatrix.Rotate(Angle, MatrixOrder.Append);        // Rotate the pattern to the desired angle
RotMatrix.TransformPoints(pts);                     // carry out matrix transformation over the shape points

2(绘制4个已旋转的点

C#

Dim Img As Image = New Bitmap(Me.Picturebox1.Width, Me.Picturebox1.Height)
Dim g As Graphics = Graphics.FromImage(Img)
Dim bgBrush As SolidBrush = New SolidBrush(Color.LightSlateGray)
Dim shPen As Pen = New Pen(Color.Black)
Dim pts() As Point
pts = {New Point(150, 100),         ' 1 - rotated coordinates
New Point(210, 110),         ' 2 - rotated coordinates
New Point(140, 200),         ' 3 - rotated coordinates
New Point(200, 210)}         ' 4 - rotated coordinates
Dim pth As New GraphicsPath
pth = ShapeData(0)
g.FillPath(bgBrush, pth)            ' fill
g.DrawPath(shPen, pth)              ' border

VB.NET

Image Img = new Bitmap(this.Picturebox1.Width, this.Picturebox1.Height);
Graphics g = Graphics.FromImage(Img);
SolidBrush bgBrush = new SolidBrush(Color.LightSlateGray);
Pen shPen = new Pen(Color.Black);
Point[] pts;
pts = new[] { new Point(150, 100), new Point(210, 110), new Point(140, 200), new Point(200, 210) };         // 4
GraphicsPath pth = new GraphicsPath();
pth = ShapeData(0);
g.FillPath(bgBrush, pth);            // fill
g.DrawPath(shPen, pth);              // border

3(绘制矩形并旋转图形。这可能有点棘手。

C#

Image Img = new Bitmap(this.Picturebox1.Width, this.Picturebox1.Height);
Graphics g = Graphics.FromImage(Img);
SolidBrush bgBrush = new SolidBrush(Color.LightSlateGray);
Pen shPen = new Pen(Color.Black);
Int16 dDimX = 75;
Int16 dDimY = 150;
Int16 dLocX = 200;
Int16 dLocY = 100;
Rectangle rect = new Rectangle(dLocX, dLocY, dDimX, dDimY);
g.RotateTransform(30);

VB.NET

Dim Img As Image = New Bitmap(Me.Picturebox1.Width, Me.Picturebox1.Height)
Dim g As Graphics = Graphics.FromImage(Img)
Dim bgBrush As SolidBrush = New SolidBrush(Color.LightSlateGray)
Dim shPen As Pen = New Pen(Color.Black)
Dim dDimX As Int16 = 75
Dim dDimY As Int16 = 150
Dim dLocX As Int16 = 200
Dim dLocY As Int16 = 100
Dim rect As Rectangle = New Rectangle(dLocX, dLocY, dDimX, dDimY)
g.RotateTransform(30)