c# GDI+ simple drawing (1)

Recently I have been exposed to GDI+ a lot, and I have also done some simple examples, such as drawing tablets, imitating QQ screenshots, etc.

The first time I came into contact with this class was because I wanted to imitate the effect of QQ screenshots. Coincidentally, after I learned how to make screenshots, the teacher in the .NET class happened to be teaching about C# drawing, and I also used this class when I studied online at Teacher Jin's training class. I have some experiences while studying, so I am going to write down these experiences. Because the content is quite large, I may write it in several times.

Without further ado, let’s first get to know this GDI+ and see what it looks like.

GDI+: Graphics Device Interface Plus is the graphics device interface, which provides a variety of rich graphics and image processing functions; in In C#.NET, GDI+ is used to process two-dimensional (2D) graphics and images, and DirectX is used to process three-dimensional (3D) graphics and images. The main namespace used in graphics and image processing is System. Drawing: Provides basic graphics functions of GDI+ Access mainly includes Graphics class, Bitmap class, classes inherited from Brush class, Font class, Icon class, Image class, Pen class, Color class, etc.

After roughly understanding what GDI+ is, let’s take a look at the drawing requirements The main tool used is to draw pictures, and you must use a drawing board. In C#, a drawing board can be created through the Graphics class. With a drawing board, you have to get a pen or something, otherwise how can you draw? Is it possible that we use our fingers? Drawing pens can be divided into many types, such as pencils, brushes, etc. The main difference between them is that pencils can be used to draw lines, and brushes, hey, think about it yourself. In c# we can use Pen and Brush classes. To achieve similar functions. Paint naturally uses the Color class.

With the tools, we can start! (Required namespace: using System.Drawing;)

Achieve the effect: draw basic drawings in a blank form Graphics

First prepare a drawing board:
There are three main ways to create a drawing board:
A: Directly reference the Graphics object in the Paint event of the form or control
B: Use the CreateGraphics method of the form or a control
C: Create a Graphics object from any object that inherits from an image
This time we will take A as an example to illustrate the problem:

 private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics; //创建画板,这里的画板是由Form提供的.
        }

Then, we only need a pen:

private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics; //创建画板,这里的画板是由Form提供的.
            Pen p = new Pen(Color.Blue, 2);//定义了一个蓝色,宽度为的画笔
        }

Next we can draw.

private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics; //创建画板,这里的画板是由Form提供的.
            Pen p = new Pen(Color.Blue, 2);//定义了一个蓝色,宽度为的画笔
            g.DrawLine(p, 10, 10, 100, 100);//在画板上画直线,起始坐标为(10,10),终点坐标为(100,100)
            g.DrawRectangle(p, 10, 10, 100, 100);//在画板上画矩形,起始坐标为(10,10),宽为,高为
            g.DrawEllipse(p, 10, 10, 100, 100);//在画板上画椭圆,起始坐标为(10,10),外接矩形的宽为,高为
        }

The rendering is as follows:

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