[Winform] supports color collection.

Today, someone in a group asked how the color collection function () in the drawing software was implemented. I only provide a simple idea.

There are two ideas in total.

Idea 1: Use GDI to capture desktop images and display them in a borderless form. You can get the corresponding color value through the mouse event to get the click position.

Train of Thought 2: Do not use a false window. Register an underlying hook to monitor the mouse. Then obtain the color of the corresponding position. (May be regarded as a virus)

 

The first idea is simpler to implement. After the second idea is implemented, the app can interact with the app during color collection.

 

Here we will post the code for the first idea.

using System.Drawing;using System.Windows.Forms;namespace ColorPickerDemo{    public class PickColorForm : Form    {        public PickColorForm()        {            Bitmap bmp = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);            using (Graphics g = Graphics.FromImage(bmp))            {                g.CopyFromScreen(0, 0, 0, 0, bmp.Size);            }            this.FormBorderStyle = FormBorderStyle.None;            this.SetStyle(ControlStyles.DoubleBuffer, true);            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);            this.DesktopLocation = new Point(0, 0);            this.Size = bmp.Size;            this.Cursor = Cursors.Cross;            this.MouseUp += (ss, ee) =>            {                if (ee.Button == MouseButtons.Left)                {                    this.Color = bmp.GetPixel(ee.X, ee.Y);                    this.DialogResult = DialogResult.OK;                }                else                {                    Color = null;                    this.DialogResult = DialogResult.Cancel;                }                this.Close();            };            this.KeyDown += (ss, ee) =>            {                if (ee.KeyCode == Keys.Escape)                    this.Close();            };            this.BackgroundImage = bmp;        }        public Color? Color { get; private set; }    }}

Call method:

        private void Form1_MouseClick(object sender, MouseEventArgs e)        {            PickColorForm f = new PickColorForm();            if (f.ShowDialog() == DialogResult.OK)            {                this.BackColor = f.Color.Value;            }        }

PS: I wrote this article only when I was bored tonight, so the content of this article is very simple. If you do not understand it, leave a message.

When will this blog post be updated if I have implemented idea 2.