You know, we can easily to make line cursor for Chart (ex: Fig). But with PictureBox, how can I do it? Is there anyone has the solution?
You can intercept the MouseMove and the Paint events. Just draw the cross on the paint.
The advantage of using the Paint method, is that the original image is not changed, so no need to restore the overwritten pixels by the crosshair.
Here's an example:
I dropped a picturebox on a winform and linked some events.
using System;
using System.Drawing;
using System.Windows.Forms;
namespace MouseCrosshair
{
public partial class Form1 : Form
{
// to store the latest mouse position
private Point? _mousePos;
// the pen to draw the crosshair.
private Pen _pen = new Pen(Brushes.Red);
public Form1()
{
InitializeComponent();
}
private void pictureBox1_MouseEnter(object sender, EventArgs e)
{
// when the mouse enters the picturebox, we just hide it.
Cursor.Hide();
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
var pictureBox = (PictureBox)sender;
// on a mouse move, save the current location (to be used when drawing the crosshair)
_mousePos = e.Location;
// force an update to the picturebox.
pictureBox.Invalidate();
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
// if the mousepos is assigned (meaning we have a mouse pos, draw the crosshair)
if (_mousePos.HasValue)
{
var pictureBox = (PictureBox)sender;
// draw a vertical line
e.Graphics.DrawLine(_pen, new Point(_mousePos.Value.X, 0), new Point(_mousePos.Value.X, pictureBox.Height));
// draw a horizontal line
e.Graphics.DrawLine(_pen, new Point(0, _mousePos.Value.Y), new Point(pictureBox.Width, _mousePos.Value.Y));
}
}
private void pictureBox1_MouseLeave(object sender, EventArgs e)
{
// when the mouse is outside the picturebox, clear the mousepos
_mousePos = null;
// repaint the picturebox
pictureBox1.Invalidate();
// show the mouse cursor again.
Cursor.Show();
}
}
}
Because the events are using the sender, you can link multiple pictureboxes to these events.
It's also possible to inherit from the PictureBox, and write a new CrosshairPictureBox control, which has a crosshair by default.
If you want to draw charts in a PictureBox, use a Bitmap and draw on that using the Graphics.FromImage(bitmap) and put it in the PictureBox.Image. Don't forget to dispose the Graphics object.
You can achieve this by storing the position of the last point received, and then draw a line using the Graphics.DrawLine method between the old position and the new one.
Please also note, that when the mouse is moving, the Control.MouseMove event for every single pixel traveled by the mouse pointer isn't received for every single move. You do receive the Control.MouseMove events at a fairly consistent time interval. That means that the faster the mouse moves, the further apart the points you'll be actually receiving.
Check out this walkthrough for some examples - https://www.c-sharpcorner.com/UploadFile/mahesh/drawing-lines-in-gdi/
If I understand the question correctly, you are interested to draw x-axis and y-axis for a chart, but not using a chat control.
In this case, what you need to do is: Handle the Paint event of the PictureBox and draw the line from top middle to bottom middle and from left middle to right middle.
Here is the code which I write to produce above chart, y = Sin(x)
:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
var axisWidth = 3;
var axisColor = Color.Red;
var chartLineWidth = 2;
var chartLineColor = Color.Blue;
var scale = 90;
var gridSize = 45;
var gridLineWidth = 1;
var gridLineColor = Color.LightGray;
var g = e.Graphics;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
var w = pictureBox1.ClientRectangle.Width / 2;
var h = pictureBox1.ClientRectangle.Height / 2;
g.TranslateTransform(w, h);
g.ScaleTransform(1, -1);
//Draw grid
for (int i = -w / gridSize; i <= w / gridSize; i++)
using (var axisPen = new Pen(gridLineColor, gridLineWidth))
g.DrawLine(axisPen, i * gridSize, -h, i * gridSize, h);
for (int i = -h / gridSize; i <= h / gridSize; i++)
using (var axisPen = new Pen(gridLineColor, gridLineWidth))
g.DrawLine(axisPen, -w, i * gridSize, w, i * gridSize);
//Draw axis
using (var axisPen = new Pen(axisColor, axisWidth))
{
g.DrawLine(axisPen, -w, 0, w, 0); //X-Asxis
g.DrawLine(axisPen, 0, -h, 0, h); //Y-Asxis
}
//Draw y = Sin(x)
var points = new List<PointF>();
for (var x = -w; x < w; x++)
{
var y = System.Math.Sin(x * Math.PI / 180);
points.Add(new PointF(x, scale * (float)y));
}
using (var chartLinePen = new Pen(chartLineColor, chartLineWidth))
{
g.DrawCurve(chartLinePen, points.ToArray());
}
g.ResetTransform();
}
You also need the following piece of code to handle resizing of the picture box:
private void MyForm_Load(object sender, EventArgs e)
{
this.pictureBox1.GetType().GetProperty("ResizeRedraw",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Instance).SetValue(
this.pictureBox1, true);
}
You can also add a crosshair and rubber-band rectangle to the control, like the following image:
Related
I am trying to put a movable needle (pointer) on a fixed graphic of a gauge (meter). The needle is moved by using a matrix rotate on a buffered graphics. I can get the fixed graphic and the needle to show. But when I render to the screen the last placed image deletes the prior graphic. I am using a timer to get the needle animation and a track bar input to produce the movement. The needle does the exact movement I am looking for.
I just cannot get the fixed background and needle to appear at the same time.
Any ideas?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Resources;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Dial01
{
public partial class dial01Form : Form
{
// Establishes timer for graphics animation
private Timer timer01 = new Timer();
/* Establishes a graphic buffer to write to
* prior display on screen */
private Graphics myGraphics;
private BufferedGraphics myBufferedGraphics1;
// Establishes manager for embedded resources (Images)
private System.Resources.ResourceManager myRM = new
System.Resources.ResourceManager("Resources.resx",
System.Reflection.Assembly.GetExecutingAssembly());
int y = 0; // Rotation value
Graphics g,g1; // Graphics objects
public dial01Form()
{
// Establishes size of Dial01Form
this.Width = 500;
this.Height = 500;
// Gets reference to the current BufferedGraphicsContext
BufferedGraphicsContext myContext1 = BufferedGraphicsManager.Current;
// Specifically sets maximum buffer size
myContext1.MaximumBuffer = new Size(this.Width + 1, this.Height + 1);
// Sets the buffer size
myBufferedGraphics1 = myContext1.Allocate(this.CreateGraphics(),
new Rectangle(0, 0, this.Width, this.Height));
// Actvates timer and sets interval
timer01.Enabled = true;
timer01.Tick += onTimer;
timer01.Interval = 20;
timer01.Start();
// Initializes form components
InitializeComponent();
}
private void onTimer(object sender, System.EventArgs e)
{
myGraphics = this.CreateGraphics();
// Initializes graphics buffer variable
g1 = myBufferedGraphics1.Graphics;
// Clears graphic buffer with a color
g1.Clear(SystemColors.Control);
// Initializes an image variable for Dial Outline
Image dial01Outline = Dial01.Properties.Resources.DialOutline250x250;
// Draw Dial Outline to graphics buffer
myGraphics.DrawImage(dial01Outline, (ClientSize.Width / 2) - 100,
(ClientSize.Height / 2) - 100);
// Goto drawPointer method passing trackBar1 value
drawPointer(trackBar1.Value);
// Render buffered graphics to screen
// myBufferedGraphics.Render(Graphics.FromHwnd(this.Handle));
myBufferedGraphics1.Render();
}
public int drawPointer(int trkBarValue)
{
int x = trkBarValue;
y = 0;
if (225 + x <= 360) { y = 222 + x; }
else if (225 + x > 360) { y = x - 135; }
// These two labels are for testing purposes
label1.Text = ("Trk Bar Val = " + x).ToString();
label2.Text = ("Ptr value = " + y).ToString();
y = y + 180;
// Matrix rotation to pointer
Matrix myMatrix = new Matrix();
myMatrix.Rotate(y, MatrixOrder.Append);
myMatrix.Translate(this.ClientSize.Width / 2,
this.ClientSize.Height / 2, MatrixOrder.Append);
g1.Transform = myMatrix;
// Pointer polygon
PointF point1 = new PointF(0.0F, 0.0F);
PointF point2 = new PointF(0.0F, 50.0F);
PointF point3 = new PointF(3.0F, 55.0F);
PointF point4 = new PointF(7.0F, 50.0F);
PointF point5 = new PointF(7.0F, 0.0F);
PointF[] polyPoints =
{
point1,
point2,
point3,
point4,
point5
};
g1.FillPolygon(Brushes.Black, polyPoints);
return y;
}
private void dial01Form_Load(object sender, EventArgs e)
{
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
}
}
}
The general graphics approach you've taken is not appropriate for a winforms app.
The way graphics works in winforms, whenever the form is covered/uncovered/resized/etc, Windows tells it to repaint itself. Anything you've done with CreateGraphics will be overwritten at this point. This is why you shouldn't call CreateGraphics.
Instead, you should intercept the repainting process via the Paint event, and do all your custom painting there. You can still repaint on a timer, you just call Invalidate() inside the timer, which causes the form to repaint as soon as it can.
This is the general shape of the "right way" to do it:
public partial class dial01Form : Form
{
private Timer timer01 = new Timer();
int y = 0; // Rotation value
public dial01Form()
{
// Establishes size of Dial01Form
this.Width = 500;
this.Height = 500;
// Actvates timer and sets interval
timer01.Enabled = true;
timer01.Tick += onTimer;
timer01.Interval = 20;
timer01.Start();
// handle the paint event
this.Paint += OnPaint;
// Initializes form components
InitializeComponent();
}
private void OnPaint(object sender, PaintEventArgs e)
{
// all painting here, targeting e.Graphics
e.Graphics.Clear(SystemColors.Control);
Image dial01Outline = Dial01.Properties.Resources.DialOutline250x250;
e.Graphics.DrawImage(dial01Outline, (ClientSize.Width / 2) - 100,
(ClientSize.Height / 2) - 100);
drawPointer(e.Graphics, trackBar1.Value);
}
private void onTimer(object sender, System.EventArgs e)
{
this.Invalidate();
}
public int drawPointer(Graphics g1, int trkBarValue)
{
// elided: same code as before, but using the g1 parameter instead of a field
}
}
You shouldn't have problems with flickering, I think - double-buffering is enabled by default. Make sure your form's DoubleBuffered property is set to True though.
In the designer I have two TextBoxes.
And also a Chart control.
I want that when I type in the first textBox the number 120 and in the second one type the number 1 it will draw a point on the chart in 120,1 but I mean 120 and 1 as axis x and axis y values.
The red filled circle is not at 120 and 1.
I mean that the red circle should be drawn on the left axis on 120.
And if I will put instead 120 116 and instead 1 25 then the circle should be drawn at the left axis 116 and on the bottom axis on 25.
But now the circle is drawn out of the chart.
This is my code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;
using System.Drawing.Drawing2D;
using System.Collections;
namespace Test
{
public partial class Form1 : Form
{
private Point startPoint = new Point();
private Point endPoint = new Point();
private int X = 0;
private int Y = 0;
private List<Point> points = new List<Point>();
private Point lastPoint = Point.Empty;
private ArrayList myPts = new ArrayList();
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Random rdn = new Random();
for (int i = 120; i > 0; i--)
{
chart1.Series["Series1"].Points.AddXY
(rdn.Next(0, 10), rdn.Next(0, 10));
}
chart1.Series["Series1"].ChartType = SeriesChartType.FastLine;
chart1.Series["Series1"].Color = Color.Red;
ChartArea area = chart1.ChartAreas[0];
area.AxisX.Minimum = 1;
area.AxisX.Maximum = 30;
area.AxisY.Minimum = 1;
area.AxisY.Maximum = 120;
LineAnnotation line = new LineAnnotation();
Point p1 = new Point(1, 120);
chart1.Annotations.Add(line);
line.AxisX = area.AxisX;
line.AxisY = area.AxisY;
line.IsSizeAlwaysRelative = false;
line.X = 1; line.Y = 120;
line.Right = 30; line.Bottom = 1;
line.LineColor = Color.Blue;
line.LineWidth = 3;
}
SolidBrush myBrush = new SolidBrush(Color.Red);
private void chart1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
foreach (Point p in myPts)
g.FillEllipse(myBrush, p.X, p.Y, 10, 10);
}
private void chart1_MouseClick(object sender, MouseEventArgs e)
{
myPts.Add(new Point(X,Y));
chart1.Invalidate();
}
private void txtT_TextChanged(object sender, EventArgs e)
{
X = int.Parse(txtWeight.Text);
}
private void txtDays_TextChanged(object sender, EventArgs e)
{
Y = int.Parse(txtDays.Text);
}
}
}
What I did is that after I enter both textBoxes values then when I click anywhere on the Chart control area with the mouse it should draw the circule on the coordinates from the TextBoxes.
But the circle is not drawing on the right place.
The textBox name txtT is the left one the axis on the left values.
The textBox txtDays should is the axis on the bottom values.
The task of translating drawing coordinates into DataPoints and back is not exactly intuitive.
It is possible but you need to know the rules and pay a certain price.
I have outlined the way in this post and it is worth looking into..
But as the problem is coming up repeatedly, here is a more general solution.
Here is how to call it:
private void button11_Click(object sender, EventArgs e)
{
valuePoints.Add(new PointF(640, 1));
valuePoints.Add(new PointF(670, 10));
paintToCalaculate = true;
chart1.Invalidate();
}
And here is the result: Two red points drawn at the values 640, 1 and 670, 10:
The points are placed correctly event though I have zoomed and scrolled in the chart and also resized it..
To make it work we need three class level variables: A flag and two point lists. One list is the input with the values in the chart where the points are, the other is the output, receiving the current pixel coordinates.
bool paintToCalaculate = false;
List<Point> drawPoints = new List<Point>();
List<PointF> valuePoints = new List<PointF>();
I use a flag to avoid recalculating the Points when the system causes redraws. And after setting it I trigger the Paint event by Invalidating the Chart. During the Paint event I reset the flag.
Please note that these values are very volatile: They change:
Whenever you zoom or scroll
Whenever you resize the chart
Whenever the layout changes, maybe because new points need room or trigger a change in a label format..
Therefore those drawing coordinates will have to be updated on each such event!
Here is one example, that takes care of zoom and scrolling:
private void chart1_AxisViewChanged(object sender, ViewEventArgs e)
{
paintToCalaculate = true;
chart1.Invalidate();
}
You need to add these two lines, or a function to wrap them, to a few other spots in your program, depending what things you allow to happen in the chart.. Resize is also an obvious candidate..
Now for the actual caculation. It is using the ValueToPixelPosition, which does all the work. Unfortunately is only works inside of any of the three paint events of a chart (PrePaint,Paint and PostPaint) . Here I use the normal Paint event.
private void chart1_Paint(object sender, PaintEventArgs e)
{
if (paintToCalaculate)
{
Series s = chart1.Series.FindByName("dummy");
if (s == null) s = chart1.Series.Add("dummy");
drawPoints.Clear();
s.Points.Clear();
foreach (PointF p in valuePoints)
{
s.Points.AddXY(p.X, p.Y);
DataPoint pt = s.Points[0];
double x = chart1.ChartAreas[0].AxisX.ValueToPixelPosition(pt.XValue);
double y = chart1.ChartAreas[0].AxisY.ValueToPixelPosition(pt.YValues[0]);
drawPoints.Add(new Point((int)x, (int)y));
s.Points.Clear();
}
paintToCalaculate = false;
chart1.Series.Remove(s);
}
//..
// now we can draw our points at the current positions:
foreach (Point p in drawPoints)
e.Graphics.FillEllipse(Brushes.Red, p.X - 2, p.Y - 2, 4, 4);
}
Note that I add and remove a dummy Series and add and clear one Point to it for each data point, just to calculate its pixel coordinates. Yes, a bit involved, but the results are worth it..
I assume you can change the Button_Click code to read in the values from your TextBoxes instead of the using my hard-coded numbers..
so am implementing a project that can read image pan it, zoom it and do other stuff.. everything was going well until i tried implementing a draw with right mouse button.
the problem is when i draw a line, the line that appears on the image does not correspond to the line i drew on screen, meaning its shifted and i know its because of the re-sizing and zooming of the image, but when i draw lines on the image with its original size(the image) and with panning also ; i have no problem.
here's the code.
so first here is how i load the image when i click browse and select image
Myimage = new Bitmap(ImagePath);
resized = myImage.Size;
imageResize();
pictureBox.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox_Paint);
pictureBox.Invalidate();
the imageResize function does the following:
void imageResize()
{
//calculated the size to fit the control i will draw the image on
resized.Height = someMath;
resized.Width = someMath;
}
then in the event handler for the pictureBox_Paint event i wrote:
private void pictureBox_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
// Create a local version of the graphics object for the PictureBox.
Graphics PboxGraphics = e.Graphics;
PboxGraphics.DrawImage(myImage, imageULcorner.X, imageULcorner.Y, resized.Width, resized.Height);
}
as you can see the resized size is not the original image size i did this because i wanted the image to show on the picturebox control centralized and filled now the next part IS WHERE MY PROBLEM BEGINS
i have to draw lines on image using right mouse button so i implemented pictureBox_MouseDown & pictureBox_MouseUp event handlers
// mouse down event handler
private void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
else if (mouse.Button == MouseButtons.Right)
{
mouseDown = mouse.Location;
mouseDown.X = mouseDown.X - imageULcorner.X;
mouseDown.Y = mouseDown.Y - imageULcorner.Y;
draw = true;
}
}
here is the mouse up event handler
//Mouse UP
private void pictureBox_MouseUp(object sender, MouseEventArgs e)
{
else if (mouse.Button == MouseButtons.Right)
{
if (draw)
{
mouseLocationNow.X = mouse.X - imageULcorner.X;
mouseLocationNow.Y = mouse.Y - imageULcorner.Y;
//
// get graphics object of the image ( the original not the resized)
// as the resized image only appears when i draw on the graphics of the
// pictureBox control
// i know the problem lies here but how can i fix it
//
Graphics image = Graphics.FromImage(myImage);
Pen pen = new Pen(Color.Red, 2);
image.DrawLine(pen, mouseLocationNow, mouseDown);
pictureBox.Invalidate();
}
draw = false;
}
so in the end i want to be able to draw on the re-sized image and make it correspond to the real image and also to the screen where i draw the line
thanks and sorry for the long post but this problem has been driving me crazy.
Here is a PictureBox subclass that supports the ability to apply zooming not only to the Image but also to graphics you draw onto its surface.
It includes a SetZoom function to zoom in by scaling both itself and a Matrix.
It also has a ScalePoint function you can use to calculate the unscaled coordinates from the pixel coordinates you receive in the mouse events.
The idea is to use a Transformation Matrix to scale any pixels the Graphics object will draw in the Paint event.
I include a little code for the form for testing.
public partial class ScaledPictureBox : PictureBox
{
public Matrix ScaleM { get; set; }
float Zoom { get; set; }
Size ImgSize { get; set; }
public ScaledPictureBox()
{
InitializeComponent();
ScaleM = new Matrix();
SizeMode = PictureBoxSizeMode.Zoom;
}
public void InitImage()
{
if (Image != null)
{
ImgSize = Image.Size;
Size = ImgSize;
SetZoom(100);
}
}
public void SetZoom(float zoomfactor)
{
if (zoomfactor <= 0) throw new Exception("Zoom must be positive");
float oldZoom = Zoom;
Zoom = zoomfactor / 100f;
ScaleM.Reset();
ScaleM.Scale(Zoom , Zoom );
if (ImgSize != Size.Empty) Size = new Size((int)(ImgSize.Width * Zoom),
(int)(ImgSize.Height * Zoom));
}
public PointF ScalePoint(PointF pt)
{ return new PointF(pt.X / Zoom , pt.Y / Zoom ); }
}
Here is the code in the Form that does the testing:
public List<PointF> somePoints = new List<PointF>();
private void scaledPictureBox1_MouseClick(object sender, MouseEventArgs e)
{
somePoints.Add(scaledPictureBox1.ScalePoint(e.Location) );
scaledPictureBox1.Invalidate();
}
private void scaledPictureBox1_Paint(object sender, PaintEventArgs e)
{
// here we apply the scaling matrix to the graphics object:
e.Graphics.MultiplyTransform(scaledPictureBox1.ScaleM);
using (Pen pen = new Pen(Color.Red, 10f))
{
PointF center = new PointF(scaledPictureBox1.Width / 2f,
scaledPictureBox1.Height / 2f);
center = scaledPictureBox1.ScalePoint(center);
foreach (PointF pt in somePoints)
{
DrawPoint(e.Graphics, pt, pen);
e.Graphics.DrawLine(Pens.Yellow, center, pt);
}
}
}
public void DrawPoint(Graphics G, PointF pt, Pen pen)
{
using (SolidBrush brush = new SolidBrush(pen.Color))
{
float pw = pen.Width;
float pr = pw / 2f;
G.FillEllipse(brush, new RectangleF(pt.X - pr, pt.Y - pr, pw, pw));
}
}
Here are the results after drawing a few points showing the same points in four different zoom settings; the ScaledPictureBox is obviously placed in an AutoScroll-Panel. The lines show how to use the regular drawing commands..
I have small Image for a circle and I want to make the following:
Whenever some place on my form is clicked, I want to add a new instance of that circle in that place if there is no other circle there already.
I was thinking about a list of Circles and when that click happens i check the list to see if none of its circles is overlapping before adding the new one but I don't have any experience with forms so i don't know what would be the best approach for that.
You can build up a GraphicsPath and check if the clicked point is inside any of its parts with the IsVisible method.
This code also builds up a list of the points and to draws the image to each of it in the Paint event. If you let the GraphicsPath do the drawing you uncomment the DrawPath line and delete these //** list related lines.
GraphicsPath GP = new GraphicsPath();
List<Point> PL = new List<Point>(); //**
private void Form1_MouseClick(object sender, MouseEventArgs e)
{
int diameter = 22; // put in the size of your circle
Size s = new Size(diameter, diameter);
if (!GP.IsVisible(e.Location))
{
Point middle = new Point(e.X - diameter / 2, e.Y - diameter / 2);
GP.AddEllipse(new Rectangle(middle, s));
PL.Add(middle); //**
}
this.Invalidate();
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
// e.Graphics.DrawPath(Pens.Firebrick, GP);
Image img = new Bitmap("D:\\circle22.png"); //**
foreach(Point pt in PL) e.Graphics.DrawImage(img, pt); //**
img.Dispose(); //**
}
I'm making instrument to select part of image. I have PictrureBox, and simple way to make it :
void StartPanel(object sender, MouseEventArgs args)
{
xStart = args.X;
yStart = args.Y;
panelStarted = true;
pan.Location = new Point(xStart, yStart);
}
void FinishPanel(object sender, MouseEventArgs args)
{
xFinish = args.X;
yFinish = args.Y;
panelStarted = false;
}
void UpdatePanel(object sender, MouseEventArgs args)
{
if (panelStarted)
{
int x = args.X;
int y = args.Y;
int newxstart = xStart;
int newystart = yStart;
int neww = 0;
int newh = 0;
if (x >= xStart)
neww = x - xStart;
else
{
neww = xStart - x;
newxstart = x;
}
if (y >= yStart)
newh = y - yStart;
else
{
newh = yStart - y;
newystart = y;
}
pan.Size = new Size(neww, newh);
pan.Location = new Point(newxstart, newystart);
}
}
When I move mouse right and down, it is absolutely ok. But when I move it left or up I can see blinks at my area. So I have understood, that it is because when I move mouse left or up, my panel is redrawed, because Panel.Location is changed, and when I move mouse right and down, location is not changed, only size is changed, so it is not redrawed, just some pixels are added to panel. What is standart solution for this?
It's not easy trying to see what you are trying to do, but I guess you are using a panel as a draggable control to drag over the picturebox surface capturing the portion of image below (like a lens) - yes?
If so, then this is not the best way to do it. It is better to just draw a rectangle on the picturebox surface and "drag" that around - this is simple with just using the mouse events to sets the top left corner and use the onpaint to draw the unfilled rectangle over the image. Capturing the image when you are ready is simple too using whatever event you wish, then copy the image giving the same positions to the new bitmap.
Putting one control over another often causes flickers - even with double buffering. It also takes far more code.
Since you are describing a drawing issue when resizing the panel, probably the easiest fix is to replace the panel you are using with one that is double buffered and will invalidate on resize a event:
public class BufferedPanel : Panel {
public BufferedPanel() {
this.DoubleBuffered = true;
this.ResizeRedraw = true;
}
}