Develop Reference

Set Boundaries in Mouse move

How do I prevent my Mouse from getting out my pictureBox (500 x 500 pixels) when dragging an image inside it?
Here's the mouse events:
private void pictureBox_Canvass_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
drag = true;
//start = new Point(e.Location.X + (int)imageRect.Location.X, e.Location.Y + (int)imageRect.Location.Y);
start = new Point((int)Shape.center.X - ((int)imageRect.Location.X - e.X), (int)Shape.center.Y - ((int)imageRect.Location.Y - e.Y));
}
}
private void pictureBox_Canvass_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left && drag == true)
{
Point loc = new Point((int)((e.X - start.X) - (imageRect.Width / 2)), (int)((e.Y - start.Y) - (imageRect.Height / 2)));
start.Offset(loc.X, loc.Y);
imageRect.Location = start;
Debug.WriteLine(start);
pictureBox_Canvass.Invalidate();
}
}
private void pictureBox_Canvass_MouseUp(object sender, MouseEventArgs e)
{
drag = false;
}

How to move a pictureBox inside a Panel by Mouse

How to move a pictureBox inside a Panel by Mouse.
Visual Studio 2015 C# Winsows Forms Application.
I've made a primitive slider to control the volume of my WindowsMediaPlayer.
A panel as the background and a pictureBox inside as the slider-knopf.
And it works well.
But purely visually it does not work that good.
I'v searched all around, but can't I find an answer to this little funny problem.
Here is my code:
int posY;
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
posY = e.Y; ;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
PictureBox box = sender as PictureBox;
if (e.Button == MouseButtons.Left)
{
box.Top += e.Y - posY;
}
if (box.Top < 0)
{
box.Top = 0;
}
if (box.Top > 100)
{
box.Top = 100;
}
int n = box.Top;
n = n * - 1 + 100;
label1.Text = n.ToString();
}
When I move the pictureBox out of the edge of the little panel, the pictureBox somehow 'shrinks' in the panel.
But when I release the mouse, the pictureBox restore its size.
Slider.gif
Why is that.?
And how can I avoid it.?
Thanks.

I found a solution.
It's not optimal, but it can be used.
I changed the code to:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
dragging = true;
startPoint = e.Location;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (dragging)
{
Debug.WriteLine("mousemove X: " + e.X + " Y: " + e.Y);
pictureBox1.Location = new Point(0, pictureBox1.Top + e.Location.Y - startPoint.Y);
if (pictureBox1.Location.Y < 0)
{
pictureBox1.Location = new Point(0, 0);
dragging = false;
}
if (pictureBox1.Location.Y > 100)
{
pictureBox1.Location = new Point(0, 100);
dragging = false;
}
this.Refresh();
}
int n = pictureBox1.Location.Y;
n = n * -1 + 100;
label1.Text = n.ToString();
mediaPlayer1.settings.volume = n;
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
}
gif
I still need to put an 'if' to correct, when the pictureBox1 is pulled out of the panel.
And to avoid flicker, I have had to put a 'dragging = false'.
However, it results in the pictureBox1 is getting frozen to the edge, so I have to release the mouse, and re-click to continue.
But well - it's to live with.
Thanks.

MouseKeyHook c# path of relocation of a mouse

How to receive a path of relocation of a mouse between the 1st clicking and the 2nd?
private void OnMouseDown(object sender, MouseEventArgs e)
{
Log(string.Format("MouseDown \t\t {0}\n", e.Button));
LogMousePosition(string.Format("\n\nx={0:0000}\ny={1:0000}", e.X, e.Y));
if (lastX != -100 && lastY != -100)
{
shortestDistanse = Convert.ToInt64(Math.Sqrt((Math.Pow(e.X - lastX, 2)) + (Math.Pow(e.Y - lastY, 2))));
LogMousePosition(string.Format("\nshortDistanse\t\t {0}\n", shortestDistanse));
}
lastX = e.X;
lastY = e.Y;
}

If you just want the distance between the two points use pythagora.
Example:
private double GetDistance(Point p1, Point p2) {
int x = Math.Abs(p1.X - p2.X);
int y = Math.Abs(p1.Y - p2.Y);
return Math.Sqrt( Math.Pow(x, 2) + Math.Pow(y, 2));
}

You may try something like
// form fields
bool pressed;
List<Point> path;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
if (!pressed)
{
pressed = true;
path = new List<Point>();
path.Add(e.Location);
}
else
{
pressed = false;
// calculate distance from List
// log distance
}
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (pressed)
{
path.Add(e.Location);
}
}
However, the MouseMove event will be triggered only above the form. If the mouse is outside of it - distance is not taken into account. It also doesn't work when moving over other controls, but we can add to them MouseMove handlers too.

I could make
string pathMList = "C:\\logs/testMList.txt";`
private void HookManager_MouseMove(object sender, MouseEventArgs e)
{
labelMousePosition.Text = string.Format("x={0:0000}; y={1:0000}", e.X, e.Y);
if (mouseDownMove == 2)
{
LogMList(string.Format("\nx={0:0000} y={1:0000}", e.X, e.Y));
}
}
private void OnMouseDown(object sender, MouseEventArgs e)
{
Log(string.Format("MouseDown \t\t {0}\n", e.Button));
LogMousePosition(string.Format("\n\nx={0:0000}\ny={1:0000}", e.X, e.Y));
if (lastX != -100 && lastY != -100)
{
shortestDistanse = Convert.ToInt64(Math.Sqrt((Math.Pow(e.X - lastX, 2)) + (Math.Pow(e.Y - lastY, 2))));
LogMousePosition(string.Format("\nshortDistanse\t\t {0}\n", shortestDistanse));
LogMList(string.Format("\n\n NEW CLICK\n\nx={0:0000} y={1:0000}", e.X, e.Y));
}
lastX = e.X;
lastY = e.Y;
mouseDownMove = 2;
}

Move form relative to location clicked

I have a form which can be moved when the user clicks and drags in a border area. The implementations I've seen all lock to the current mouse position, so that when the form is moved, the form jumps so that the mouse is in the upper-left corner. I'd like to change it so that it behaves like a normal windows form, and the form stays at the same position relative to the mouse when moved. My current code looks like this:
Point locationClicked;
bool isMouseDown = false;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
isMouseDown = true;
locationClicked = new Point(e.Location.X, e.Location.Y);
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
isMouseDown = false;
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (isMouseDown && targetCell == new Point(-1, -1) && (mouseLocation.X < margin.X || mouseLocation.Y < margin.Y ||
mouseLocation.X > margin.X + cellSize.Width * gridSize.Width ||
mouseLocation.Y > margin.Y + cellSize.Height * gridSize.Height))
{
this.Location = new Point(e.Location.X - locationClicked.X, e.Location.Y - locationClicked.Y);
}
}
When I drag the window, it behaves similarly to what I want. The form flickers between two locations on the screen, one of which moves at about half the rate of the mouse. Is there a way I can fix this?

Try this out...
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Point locationClicked;
bool dragForm = false;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
locationClicked = new Point(e.Location.X, e.Location.Y);
if (isMouseDown && targetCell == new Point(-1, -1) && (mouseLocation.X < margin.X || mouseLocation.Y < margin.Y ||
mouseLocation.X > margin.X + cellSize.Width * gridSize.Width ||
mouseLocation.Y > margin.Y + cellSize.Height * gridSize.Height))
{
dragForm = true;
}
}
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (dragForm)
{
this.Location = new Point(this.Location.X + (e.X - locationClicked.X), this.Location.Y + (e.Y - locationClicked.Y));
}
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
dragForm = false;
}
}

DragDrop to move a picture box at run time

I have a PictureBox called pic, placed inside another PictureBox called picTrack.
My goal is to be able to let the user, at run time, change the position of pic by draging it.
This is what I have so far:
int x_offset = 0; // any better to do this without having a global variable?
int y_offset = 0;
void pic_MouseDown(object sender, MouseEventArgs e)
{
PictureBox me = (PictureBox)sender;
x_offset = me.Left - e.X;
y_offset = me.Top - e.Y;
}
void pic_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
PictureBox me = (PictureBox)sender;
me.Left = e.X + x_offset;
me.Top = e.Y + y_offset;
picTrack.Invalidate();
}
}
This code only works at a very basic level. I have 2 problems with it:
1.) picTrack is not updated if the user does not let go of the mouse button. Ghost images of pic can be seen while pic is getting moved around (it's like pic is having a tail).
2.) pic is "giggling" (i.e. rapidly shaking left and right, up and down, around its location).
How should I solve these 2 problems and create a more smooth drag & drop? Thanks.

Here this actually works, I've written quite a few dragging things before.. it may not be perfect but this should give you something to work with.
Point dragPoint = Point.Empty;
bool dragging = false;
private void pic_MouseDown(object sender, MouseEventArgs e)
{
dragging = true;
dragPoint = new Point(e.X, e.Y);
}
private void pic_MouseMove(object sender, MouseEventArgs e)
{
if (dragging)
pic.Location = new Point(pic.Location.X + e.X - dragPoint.X, pic.Location.Y + e.Y - dragPoint.Y);
}
private void pic_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
}
See, if you were dragging a local picture that you were just rendering yourself, this wouldn't be right.. but since you are moving a control after you move it, the new move coordinates are relative to the control. Therefore, you do not need to update dragPoint to the last position on move. If you were just moving a shape/image you were rendering OnPaint, you'd have to do update the drag point each movement.
There's one improvement you could make, if desired, which is to only start dragging if the user moves the cursor a certain distance D. For example, something like this:
Point dragPoint = Point.Empty;
bool dragging = false;
bool mouseDown = false;
private void pic_MouseDown(object sender, MouseEventArgs e)
{
mouseDown = true;
dragPoint = new Point(e.X, e.Y);
}
private void pic_MouseMove(object sender, MouseEventArgs e)
{
int deltaX = e.X - dragPoint.X;
int deltaY = e.Y - dragPoint.Y;
if (!dragging && mouseDown && deltaX * deltaX + deltaY * deltaY > 100)
dragging = true;
if (dragging)
pic.Location = new Point(pic.Location.X + deltaX, pic.Location.Y + deltaY);
}
private void pic_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
mouseDown = false;
}
Which checks if the user has moved the mouse 10 pixels (sqrt of 100).
If you don't want a global, you could try implementing your own behavior system and creating a reusable piece of code that you can attach to things you want to move. Something like this:
public class Behavior<T> where T : class
{
public T AssociatedObject
{
get;
private set;
}
public Behavior(T associatedObject)
{
this.AssociatedObject = associatedObject;
}
public virtual void Attach() { }
public virtual void Detach() { }
}
public class DragBehavior : Behavior<Control>
{
Point dragPoint = Point.Empty;
bool dragging = false;
bool mouseDown = false;
public DragBehavior(Control c) : base(c)
{
}
public override void Attach()
{
AssociatedObject.MouseDown += new MouseEventHandler(control_MouseDown);
AssociatedObject.MouseMove += new MouseEventHandler(control_MouseMove);
AssociatedObject.MouseUp += new MouseEventHandler(control_MouseUp);
}
private void control_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
mouseDown = false;
}
private void control_MouseMove(object sender, MouseEventArgs e)
{
int deltaX = e.X - dragPoint.X;
int deltaY = e.Y - dragPoint.Y;
if (mouseDown && deltaX * deltaX + deltaY * deltaY > 100)
dragging = true;
if (dragging)
AssociatedObject.Location = new Point(AssociatedObject.Location.X + deltaX, AssociatedObject.Location.Y + deltaY);
}
private void control_MouseDown(object sender, MouseEventArgs e)
{
mouseDown = true;
dragPoint = new Point(e.X, e.Y);
}
public override void Detach()
{
AssociatedObject.MouseDown -= new MouseEventHandler(control_MouseDown);
AssociatedObject.MouseMove -= new MouseEventHandler(control_MouseMove);
AssociatedObject.MouseUp -= new MouseEventHandler(control_MouseUp);
}
}
public partial class Form1 : Form
{
DragBehavior dragger;
public Form1()
{
InitializeComponent();
DoubleBuffered = true;
dragger = new DragBehavior(pic);
dragger.Attach();
}
}
Maybe that is better than "creating a global variable" (or more like creating a member variable in your form. =)

Try this
int x_offset = 0; // any better to do this without having a global variable?
int y_offset = 0;
private void pic_MouseDown(object sender, MouseEventArgs e)
{
PictureBox me = (PictureBox)sender;
x_offset = e.X;
y_offset = e.Y;
}
private void pic_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
PictureBox me = (PictureBox)sender;
me.Left = e.X + me.Left - x_offset;
me.Top = e.Y + me.Top - y_offset;
}
}