Simple and Effective Magnifier Using Very Easy Logic in C#

Introduction

While I working in GUI design I need to ensure each and every pixel of the application, so I need a magnifier. I used the default Windows magnifier but it will not meet my zoom level and this requires implementing this magnifier with very simple logic.

Concept behind the approach

Here the actual need is to zoom in a specific region. We get the screenshot of the image and zoom it using the BitMap value and display. For lens representation we used a Form and PictureBox in which we have used "i" to zoom in and "o" to zoom out and "Esc" to close the form.

C# Code behind the approach

PictureBox pictureBox1 = new PictureBox(); // Have a picture box

int zoom = 1; // Variable for zoom value

public Form1()

{

pictureBox1.Dock = DockStyle.Fill; // Occupy the full area of the form

pictureBox1.BorderStyle = BorderStyle.FixedSingle; // Have a single border of clear representation

Controls.Add(pictureBox1); // Add the control to the form

FormBorderStyle = FormBorderStyle.None; // Make the form borderless to make it as lens look

Timer timer = new Timer(); // Have a timer for frequent update

timer.Interval = 100; // Set the interval for the timer

timer.Tick += timer_Tick; // Hool the event to perform desire action

timer.Start(); //Start the timer

printscreen = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height); // Have a bitmap to store the image of the screen

}

void timer_Tick(object sender, EventArgs e)

{

var graphics = Graphics.FromImage(printscreen as Image); // Get the image of the captured screen

graphics.CopyFromScreen(0, 0, 0, 0, printscreen.Size); // Get the copy of screen

var position = Cursor.Position; // Get the position of cursor

var lensbmp = new Bitmap(50, 50); // Have a bitmap for lens

var i = 0; // Variable for row count

var j = 0; // Variable for column count

for (int row = position.X - 25; row < position.X + 25; row++) // Indicates row number

{

j = 0; // Set column value '0' for new column

for (int column = position.Y - 25; column < position.Y + 25; column++) // Indicate column number

{

lensbmp.SetPixel(i, j, printscreen.GetPixel(row, column)); // Place current region pixel to lens bitmap

j++; // Increase row count

}

i++; // Increase column count

}

this.pictureBox1.Image = new Bitmap(lensbmp, lensbmp.Width * zoom, lensbmp.Height * zoom); // Assign lens bitmap with zoom level to the picture box

Size = pictureBox1.Image.Size; // Assign optimal value to the form

Left = position.X + 20; // Place form nearer to cursor X value

Top = position.Y + 20; // Place form nearer to cursor Y value

TopMost = true; // Keep the form top level

}

// Override OnKeyDown for zoom in and zoom out actions

protected override void OnKeyDown(KeyEventArgs e)

{

if (e.KeyValue == 73) // Set "i" as the key for Zoom In.

zoom++; // Increase zoom by 1 item greater

else if (e.KeyValue == 79) // Set "o" as the key for Zoom Out

zoom--; // Decrease zoom by 1 item smaller

else if (e.KeyValue == 27) // Set "Esc" to close the magnifier

{

Close(); // Close the form

Dispose(); // Dispose the form

}

base.OnKeyDown(e);

}

Conclusion

Hence this simple logic gives you an efficient magnifier.