C# :: Aufgabe #208

1 Lösung Lösung öffentlich

Screenshots erstellen und abspeichern

Anfänger - C# von Exception - 17.05.2018 um 15:36 Uhr
Aufgaben:
1) Erstelle ein Windows Forms Programm, welches via Buttonklick einen Screenshot erstellen kann.
2) Zusätzlich soll dieser Screenshot dann in einem beliebigen Ordner abgespeichert werden können, aber nur, falls dies der Nutzer auch möchte.
3) Das Bild kann dann dementsprechend in verschiedenen Formaten abgespeichert werden (png, jpg, …)

Optional:
- Gib dem Nutzer zusätzlich die Möglichkeit nur einen gewissen Bereich des Bildschirms als Screenshot abspeichern zu können (man möchte ja ggf. nur ein Fenster o.ä. aufnehmen)
- Möglichkeit das Bild um x Grad drehen
- Möglichkeit etwas in das Bild zeichnen, z.B. einen roten Rahmen
- Farbverläufe?
- etc. etc. etc.

Was ist ein Screenshot? Klicke hier!

Lösungen:

vote_ok
von Z3RP (1020 Punkte) - 31.05.2018 um 09:07 Uhr
Der Form Designer
Quellcode ausblenden C#-Code
namespace Screenshot
{
    partial class Form1
    {
        /// <summary>
        /// Erforderliche Designervariable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Verwendete Ressourcen bereinigen.
        /// </summary>
        /// <param name="disposing">True, wenn verwaltete Ressourcen gelöscht werden sollen; andernfalls False.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Vom Windows Form-Designer generierter Code

        /// <summary>
        /// Erforderliche Methode für die Designerunterstützung.
        /// Der Inhalt der Methode darf nicht mit dem Code-Editor geändert werden.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.screenshotBox = new System.Windows.Forms.PictureBox();
            this.screenshotBtn = new System.Windows.Forms.Button();
            this.selectionTim = new System.Windows.Forms.Timer(this.components);
            this.selectionBtn = new System.Windows.Forms.Button();
            this.saveImageBtn = new System.Windows.Forms.Button();
            this.imageSaveFileDlg = new System.Windows.Forms.SaveFileDialog();
            this.imageRotateTb = new System.Windows.Forms.TrackBar();
            this.label1 = new System.Windows.Forms.Label();
            this.rotateImageBtn = new System.Windows.Forms.Button();
            this.gradTbox = new System.Windows.Forms.TextBox();
            ((System.ComponentModel.ISupportInitialize)(this.screenshotBox)).BeginInit();
            ((System.ComponentModel.ISupportInitialize)(this.imageRotateTb)).BeginInit();
            this.SuspendLayout();
            // 
            // screenshotBox
            // 
            this.screenshotBox.Location = new System.Drawing.Point(12, 12);
            this.screenshotBox.Name = "screenshotBox";
            this.screenshotBox.Size = new System.Drawing.Size(753, 343);
            this.screenshotBox.TabIndex = 0;
            this.screenshotBox.TabStop = false;
            // 
            // screenshotBtn
            // 
            this.screenshotBtn.Location = new System.Drawing.Point(12, 370);
            this.screenshotBtn.Name = "screenshotBtn";
            this.screenshotBtn.Size = new System.Drawing.Size(93, 23);
            this.screenshotBtn.TabIndex = 1;
            this.screenshotBtn.Text = "Make Screen!";
            this.screenshotBtn.UseVisualStyleBackColor = true;
            this.screenshotBtn.Click += new System.EventHandler(this.screenshotBtn_Click);
            // 
            // selectionTim
            // 
            this.selectionTim.Enabled = true;
            this.selectionTim.Interval = 1;
            this.selectionTim.Tick += new System.EventHandler(this.selectionTim_Tick);
            // 
            // selectionBtn
            // 
            this.selectionBtn.Location = new System.Drawing.Point(12, 399);
            this.selectionBtn.Name = "selectionBtn";
            this.selectionBtn.Size = new System.Drawing.Size(183, 29);
            this.selectionBtn.TabIndex = 2;
            this.selectionBtn.Text = "Make Screen With Selection";
            this.selectionBtn.UseVisualStyleBackColor = true;
            this.selectionBtn.Click += new System.EventHandler(this.selectionBtn_Click);
            // 
            // saveImageBtn
            // 
            this.saveImageBtn.Location = new System.Drawing.Point(12, 434);
            this.saveImageBtn.Name = "saveImageBtn";
            this.saveImageBtn.Size = new System.Drawing.Size(75, 23);
            this.saveImageBtn.TabIndex = 3;
            this.saveImageBtn.Text = "Save Image";
            this.saveImageBtn.UseVisualStyleBackColor = true;
            this.saveImageBtn.Click += new System.EventHandler(this.saveImageBtn_Click);
            // 
            // imageRotateTb
            // 
            this.imageRotateTb.Location = new System.Drawing.Point(12, 488);
            this.imageRotateTb.Maximum = 360;
            this.imageRotateTb.Minimum = 1;
            this.imageRotateTb.Name = "imageRotateTb";
            this.imageRotateTb.Size = new System.Drawing.Size(753, 45);
            this.imageRotateTb.TabIndex = 4;
            this.imageRotateTb.Value = 1;
            this.imageRotateTb.Scroll += new System.EventHandler(this.imageRotateTb_Scroll);
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(12, 472);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(71, 13);
            this.label1.TabIndex = 5;
            this.label1.Text = "Rotate Image";
            // 
            // rotateImageBtn
            // 
            this.rotateImageBtn.Location = new System.Drawing.Point(121, 519);
            this.rotateImageBtn.Name = "rotateImageBtn";
            this.rotateImageBtn.Size = new System.Drawing.Size(75, 23);
            this.rotateImageBtn.TabIndex = 7;
            this.rotateImageBtn.Text = "Rotate Image";
            this.rotateImageBtn.UseVisualStyleBackColor = true;
            this.rotateImageBtn.Click += new System.EventHandler(this.rotateImageBtn_Click);
            // 
            // gradTbox
            // 
            this.gradTbox.Location = new System.Drawing.Point(15, 522);
            this.gradTbox.Name = "gradTbox";
            this.gradTbox.Size = new System.Drawing.Size(100, 20);
            this.gradTbox.TabIndex = 8;
            this.gradTbox.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.gradTbox_KeyPress);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(777, 580);
            this.Controls.Add(this.gradTbox);
            this.Controls.Add(this.rotateImageBtn);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.imageRotateTb);
            this.Controls.Add(this.saveImageBtn);
            this.Controls.Add(this.selectionBtn);
            this.Controls.Add(this.screenshotBtn);
            this.Controls.Add(this.screenshotBox);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            ((System.ComponentModel.ISupportInitialize)(this.screenshotBox)).EndInit();
            ((System.ComponentModel.ISupportInitialize)(this.imageRotateTb)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.PictureBox screenshotBox;
        private System.Windows.Forms.Button screenshotBtn;
        private System.Windows.Forms.Timer selectionTim;
        private System.Windows.Forms.Button selectionBtn;
        private System.Windows.Forms.Button saveImageBtn;
        private System.Windows.Forms.SaveFileDialog imageSaveFileDlg;
        private System.Windows.Forms.TrackBar imageRotateTb;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Button rotateImageBtn;
        private System.Windows.Forms.TextBox gradTbox;
    }
}



Die Form Klasse
Quellcode ausblenden C#-Code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace Screenshot
{
    public partial class Form1 : Form
    {
        Image currentImage;
        public Form1()
        {
            InitializeComponent();
        }
        Form selectionForm;
        private void Form1_Load(object sender, EventArgs e)
        {
            screenshotBox.SizeMode = PictureBoxSizeMode.StretchImage;
            InitSelectionForm();
        }

        private void InitSelectionForm()
        {
            selectionForm = new Form();
            selectionForm.BackColor = Color.Black;
            selectionForm.TransparencyKey = Color.Black;
            selectionForm.FormBorderStyle = FormBorderStyle.None;
            selectionForm.Bounds = Screen.PrimaryScreen.Bounds;
            selectionForm.TopMost = true;
        }

        #region NativeStuff
        [Flags]
        private enum KeyStates
        {
            None = 0,
            Down = 1,
            Toggled = 2
        }
        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }
        private const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter
        [DllImport("user32.dll")]
        private static extern IntPtr GetDesktopWindow();
        [DllImport("user32.dll")]
        private static extern IntPtr GetWindowDC(IntPtr hWnd);
        [DllImport("user32.dll")]
        private static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);
        [DllImport("gdi32.dll")]
        private static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,int nHeight);
        [DllImport("gdi32.dll")]
        private static extern IntPtr CreateCompatibleDC(IntPtr hDC);
        [DllImport("gdi32.dll")]
        private static extern bool DeleteDC(IntPtr hDC);
        [DllImport("User32.dll")]
        public static extern void ReleaseDC(IntPtr hwnd, IntPtr dc);
        [DllImport("gdi32.dll")]
        private static extern bool DeleteObject(IntPtr hObject);
        [DllImport("gdi32.dll")]
        private static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
        [DllImport("gdi32.dll")]
        private static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,int nWidth, int nHeight, IntPtr hObjectSource,int nXSrc, int nYSrc, int dwRop);
        [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
        private static extern short GetKeyState(int keyCode);
        private static KeyStates GetKeyState(Keys key)
        {
            KeyStates state = KeyStates.None;

            short retVal = GetKeyState((int)key);

            //If the high-order bit is 1, the key is down
            //otherwise, it is up.
            if ((retVal & 0x8000) == 0x8000)
                state |= KeyStates.Down;

            //If the low-order bit is 1, the key is toggled.
            if ((retVal & 1) == 1)
                state |= KeyStates.Toggled;

            return state;
        }
        private static Image CaptureScreen()
        {
            return CaptureSelection(GetDesktopWindow());
        }

        private static Image CaptureSelection(IntPtr handle)
        {
            // get te hDC of the target window
            IntPtr hdcSrc = GetWindowDC(handle);
            // get the size
            RECT windowRect = new RECT();
            GetWindowRect(handle, ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;
            // create a device context we can copy to
            IntPtr hdcDest = CreateCompatibleDC(hdcSrc);
            // create a bitmap we can copy it to,
            // using GetDeviceCaps to get the width/height
            IntPtr hBitmap = CreateCompatibleBitmap(hdcSrc, width, height);
            // select the bitmap object
            IntPtr hOld = SelectObject(hdcDest, hBitmap);
            // bitblt over
            BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, SRCCOPY);
            // restore selection
            SelectObject(hdcDest, hOld);
            // clean up 
            DeleteDC(hdcDest);
            ReleaseDC(handle, hdcSrc);

            // get a .NET image object for it
            Image img = Image.FromHbitmap(hBitmap);
            // free up the Bitmap object
            DeleteObject(hBitmap);

            return img;
        }

        private static Image CropImage(Image img, Rectangle cropRect)
        {
            Image returnImage = new Bitmap(cropRect.Width, cropRect.Height);
            using (Graphics g = Graphics.FromImage(returnImage))
            {
                g.DrawImage(img, new Rectangle(0, 0, returnImage.Width, returnImage.Height),
                                 cropRect,
                                 GraphicsUnit.Pixel);
            }
            return returnImage;
        }
        private static bool IsKeyDown(Keys key)
        {
            return KeyStates.Down == (GetKeyState(key) & KeyStates.Down);
        }

        private static Image RotateImage(Image img, float rotationAngle)
        {
            //create an empty Bitmap image
            Bitmap bmp = new Bitmap(img.Width, img.Height);

            //turn the Bitmap into a Graphics object
            Graphics gfx = Graphics.FromImage(bmp);

            //now we set the rotation point to the center of our image
            gfx.TranslateTransform((float)bmp.Width / 2, (float)bmp.Height / 2);

            //now rotate the image
            gfx.RotateTransform(rotationAngle);

            gfx.TranslateTransform(-(float)bmp.Width / 2, -(float)bmp.Height / 2);

            //set the InterpolationMode to HighQualityBicubic so to ensure a high
            //quality image once it is transformed to the specified size
            gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;

            //now draw our new image onto the graphics object
            gfx.DrawImage(img, new Point(0, 0));

            //dispose of our Graphics object
            gfx.Dispose();

            //return the image
            return bmp;
        }

        #endregion

        private bool inSelection = false;
        private bool inSelectionSetting = false;

        PictureBox selectionBox = new PictureBox();
        private void DrawOnDesktop()
        {
            InitSelectionForm();
            selectionBox.BorderStyle = BorderStyle.FixedSingle;
            selectionBox.SetBounds(0, 0, 0, 0);
            selectionForm.Controls.Add(selectionBox);
            selectionForm.ShowDialog();
        }

        private void screenshotBtn_Click(object sender, EventArgs e)
        {
            currentImage = CaptureScreen();
            screenshotBox.Image = currentImage;
        }

        private void selectionTim_Tick(object sender, EventArgs e)
        {
            
            if (inSelection)
            {
                if (IsKeyDown(Keys.LButton))
                {
                    selectionBox.Location = Cursor.Position;
                    inSelection = false;
                    inSelectionSetting = true;
                }
            }

            if (inSelectionSetting)
            {
                if(Cursor.Position.X > selectionBox.Location.X)
                    selectionBox.Width = Cursor.Position.X- selectionBox.Location.X;
                else
                    selectionBox.Width = selectionBox.Location.X - Cursor.Position.X;

                if (Cursor.Position.Y > selectionBox.Location.Y)
                    selectionBox.Height = Cursor.Position.Y - selectionBox.Location.Y;
                else
                    selectionBox.Height = selectionBox.Location.Y - Cursor.Position.Y;

                if (!IsKeyDown(Keys.LButton))
                {
                    inSelectionSetting = false;
                    selectionBox.BorderStyle = BorderStyle.None;
                    currentImage = CropImage(CaptureScreen(),new Rectangle(selectionBox.Location.X, selectionBox.Location.Y, selectionBox.Width, selectionBox.Height));
                    screenshotBox.Image = currentImage;
                    selectionForm.Close();
                    selectionForm = null;
                }
            }
            selectionBox.Refresh();
        }

        private void selectionBtn_Click(object sender, EventArgs e)
        {
            inSelection = true;
            DrawOnDesktop();
        }

        private void saveImageBtn_Click(object sender, EventArgs e)
        {
            imageSaveFileDlg.Filter = "JPeg Image|*.jpg|PNG Image|*.png|Bitmap Image|*.bmp|Gif Image|*.gif";
            imageSaveFileDlg.Title = "Save an Image File";
            imageSaveFileDlg.ShowDialog();

            if (imageSaveFileDlg.FileName != "" && currentImage != null)
            {
                // Saves the Image via a FileStream created by the OpenFile method.  
                System.IO.FileStream fs =
                   (System.IO.FileStream)imageSaveFileDlg.OpenFile();
                // Saves the Image in the appropriate ImageFormat based upon the  
                // File type selected in the dialog box.  
                // NOTE that the FilterIndex property is one-based.  
                switch (imageSaveFileDlg.FilterIndex)
                {
                    case 1:
                        currentImage.Save(fs,
                           System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;

                    case 2:
                        currentImage.Save(fs,
                           System.Drawing.Imaging.ImageFormat.Png);
                        break;

                    case 3:
                        currentImage.Save(fs,
                           System.Drawing.Imaging.ImageFormat.Bmp);
                        break;
                    case 4:
                        currentImage.Save(fs,
                           System.Drawing.Imaging.ImageFormat.Gif);
                        break;
                }

                fs.Close();
            }
        }

        private void imageRotateTb_Scroll(object sender, EventArgs e)
        {
            gradTbox.Text = imageRotateTb.Value.ToString();
        }

        private void rotateImageBtn_Click(object sender, EventArgs e)
        {
            if (currentImage != null)
            {
                currentImage = RotateImage(currentImage, float.Parse(gradTbox.Text));
                screenshotBox.Image = currentImage;
            }
        }

        private void gradTbox_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) &&
                (e.KeyChar != '.'))
            {
                e.Handled = true;
            }

            // only allow one decimal point
            if ((e.KeyChar == '.') && ((sender as TextBox).Text.IndexOf('.') > -1))
            {
                e.Handled = true;
            }
        }
    }
}
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