Develop Reference

How to detect if user is shaking form c# (detect shake),

I've made a paint clone and want to clear the bord when you shake the form, (so by holding mouse1 down on the top bar and moving it right and left fast).
I tried to compare two points on the x-axis, the points are set based on the mouse position and tested against a treshold. And I added a combo so you need to overcome the treshold multiple times to avoid accidental activation, to help with this there is also a timer that resets the combo.
The problem is that it sees fast movement to one side as a shake I still want the user to be able to move the form without clearing the canvas.
int firstpos = 0;
int secondpos = 0;
bool isfirst = true;
int combo = 0;
int threshold = 50;
Point lastPoint;
private void TopBar_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)//to move the form
{
this.Left += e.X - lastPoint.X;
this.Top += e.Y - lastPoint.Y;
}
if (isfirst)
{
firstpos = e.X;
isfirst = false;
}
else
{
secondpos = e.X;
int diff = secondpos - firstpos;
if (diff < 0) diff *= -1;//make positive
if (diff >= threshold)
{
combo++;
Thread t = new Thread(startdecay);
t.Start();
}
if (combo == 4)
{
canvas.Invalidate();//clear the canvas
combo = 0;
}
isfirst = true;
}
}
void startdecay()
{
Thread.Sleep(1000);
combo = 0;
}
private void TopBar_MouseDown(object sender, MouseEventArgs e)
{
lastPoint = new Point(e.X, e.Y);
}
the form

isfirst == true: Save firstpos.
Set isfirst = false.
isfirst == false: Get secondpos.
Get diff.
if Math.Sign(diff) != saveddiff {
increment shakecounter.
Set saveddiff = Math.Sign(diff).
}
Set firstpos = secondpos.
Accept when shakecounter over some value desired.
Don't forget to reset everything when Mouse Button goes up.

I want to set limit scrolling to a scrollable panel

I made a scrollable panel like this:
private void button3_Click(object sender, EventArgs e)
{
Form f2 = new Form();
f2.Size = new Size(400, 300);
f2.AutoScroll = false;
Panel pan = new Panel();
pan.Size = new Size(600, 100);
pan.AutoScroll = false;
for (int i = 1; i <= 10; i++)
{
Button b = new Button();
b.Text = "B" + (i);
b.Name = "button_" + (i);
b.Left = (b.Width + 12) * (i - 1);
b.Parent = pan;
pan.Parent = f2;
f2.Show();
}
}
private void panel1_MouseWheel(object sender, MouseEventArgs e)
{
Form2 frm = new Form2();
panel1.Top += e.Delta > 0 ? 10 : -10;
if (panel1.Top > 0)
panel1.Top = 0;
else if (panel1.Top <= panel1.Parent.Height)
panel1.Top = panel1.Parent.Height;
Console.WriteLine("panel2.top:" + panel1.Top);
}
This is the full code of that panel, panel1 = pan...
private void panel1_MouseDown(object sender, MouseEventArgs e)
{
pPt = e.Location;
}
public void panel1_MouseMove(object sender, MouseEventArgs e)
{
Console.WriteLine("panel2.top:" + panel1.Top);
if (e.Button.HasFlag(MouseButtons.Left))
{
Form2 frm = new Form2();
panel1.Top += e.Y - pPt.Y;
if (panel1.Top > 0)
panel1.Top = 0;
else if (panel1.Top <= panel1.Parent.Height)
panel1.Top = panel1.Parent.Height;
}
}
And you can scroll it by dragging the panel with the mouse but the problem is it looks like this:
And I want to don't go higher than button1 or lower than the last button.

Tweak this method: you need to "pin" the panel so it doesn't move below the top and above the bottom - because mouse wheel deltas are events you will continuously receive. You have to manually decide when to ignore them
private void panel1_MouseWheel(object sender, MouseEventArgs e)
{
Form2 frm = new Form2();
panel1.Top += e.Delta > 0 ? 10 : -10;
// tweak this
if (panel1.Top > 0) panel1.Top = 0;
else if (panel1.Bottom <= panel1.Parent.Height) panel1.Bottom = panel1.Parent.Height;
Console.WriteLine("panel2.top:" + panel1.Top);
}
Also, the above will work when the panel you are scrolling is "Taller" than the viewport (the form itself). You might need to tweak further when the panel is smaller than the form - so just test a few cases.
You also need to pay attention to the Resize event so your panel has the correct Top property when someone expands the container form.

We can Get or set the upper limit of values of the scrollable range with
ScrollBar.Maximum Property
An example is as follows.
The following example assumes that you have created a Form, added a PictureBox to the Form, and added a horizontal HScrollBar and a vertical VScrollBar to the PictureBox. This code example is part of a larger example provided for the ScrollBar class overview.
In this example, the Maximum property is set to the size of the Image plus the size of the scrollbar if it is visible plus an adjustment factor of the size of the LargeChange property.
You must add references to the System.Drawing and System.Windows.Forms namespaces to run this example.
public void SetScrollBarValues()
{
//Set the following scrollbar properties:
//Minimum: Set to 0
//SmallChange and LargeChange: Per UI guidelines, these must be set
// relative to the size of the view that the user sees, not to
// the total size including the unseen part. In this example,
// these must be set relative to the picture box, not to the image.
//Maximum: Calculate in steps:
//Step 1: The maximum to scroll is the size of the unseen part.
//Step 2: Add the size of visible scrollbars if necessary.
//Step 3: Add an adjustment factor of ScrollBar.LargeChange.
//Configure the horizontal scrollbar
//---------------------------------------------
if (this.hScrollBar1.Visible)
{
this.hScrollBar1.Minimum = 0;
this.hScrollBar1.SmallChange = this.pictureBox1.Width / 20;
this.hScrollBar1.LargeChange = this.pictureBox1.Width / 10;
this.hScrollBar1.Maximum = this.pictureBox1.Image.Size.Width - pictureBox1.ClientSize.Width; //step 1
if (this.vScrollBar1.Visible) //step 2
{
this.hScrollBar1.Maximum += this.vScrollBar1.Width;
}
this.hScrollBar1.Maximum += this.hScrollBar1.LargeChange; //step 3
}
//Configure the vertical scrollbar
//---------------------------------------------
if (this.vScrollBar1.Visible)
{
this.vScrollBar1.Minimum = 0;
this.vScrollBar1.SmallChange = this.pictureBox1.Height / 20;
this.vScrollBar1.LargeChange = this.pictureBox1.Height / 10;
this.vScrollBar1.Maximum = this.pictureBox1.Image.Size.Height - pictureBox1.ClientSize.Height; //step 1
if (this.hScrollBar1.Visible) //step 2
{
this.vScrollBar1.Maximum += this.hScrollBar1.Height;
}
this.vScrollBar1.Maximum += this.vScrollBar1.LargeChange; //step 3
}
}
Hope you can change the code accordingly to set the maximum scrollable space.:)

How to move label's text right to left,when a character hides in left it shows on right?

Here is my key code:
using System;
using System.Windows.Forms;
namespace Scroller
{
public partial class Form1 : Form
{
int i, j;
bool k = false;
public Form1()
{
InitializeComponent();
}
private void timer1_Tick(object sender, EventArgs e)
{
label1.Text = "Time:"+ System.DateTime.Now.ToString();
i--;
j = i + this.Width;
if (i < this.Width && i > 0)
{
label1.Left = i;
}
else
if (i < 0 && k == false)
{
label1.Left = i;
k = true;
}
else
if (i < 0 && k == true)
{
label1.Left = j;
k = false;
}
if (i < 0 - label1.Width)
{
i = this.Width - label1.Width;
}
}
private void Form1_Load(object sender, EventArgs e)
{
label1.Text = "Time:"+ System.DateTime.Now.ToString();
i = this.Width - label1.Width;
label1.Left = i;
}
}
}
The effect that I want to make is the whole time string move right to left. When a pixel of the text disappear on the left side (because it is out of the form's left border),the pixel will shows on the right side.
In other words, the effect can't be make by delete the first character of string and append it to the last.
I knew that it will be easier to use two label to do it. Set one's location in the form and hide the other right by the form. Move them in the same time.
When the first label hit the left border of the form, the second hit the right border of the form. And the first one move out, the second move in. Until the second totally move in, reset their x location.
But I just want to use one label. So I chose to quickly switch the label's location, and try to "cheat" user's eye. The problem is when the label switch between left and right, it flash very obviously. Even though I set timer's interval below 20,the problem still exist.
Could you help me dissolve the flash problem or enlighten me other ways which can just use one label and one timer to make the effect I need?
Thanks. If I didn't describer my problem clear enough or need more code, please let me know.

I don't think you can work out the flashing problem changing the label's location in a windows form.
Another solution would be to set the label width the same size as the form width, make the label text fill all the width using spaces and make the timer always get the last character and put it on the beginning of the string.
Sample code below.
private void timer1_Tick(object sender, EventArgs e)
{
label1.Text = label1.Text.Substring(label1.Text.Length - 1) + label1.Text.Remove(label1.Text.Length - 1);
}
private void Form1_Load(object sender, EventArgs e)
{
// The total spaces required to fill the form vary from form.width and the initial label.text.width
// Width | Spaces
// 177 | 13
// 228 | 30
// 297 | 53
// 318 | 60
// The spacesEnd = 60 work for a form with width 319
int spacesBegin = 0, spacesEnd = 60;
label1.Text = "Time:" + System.DateTime.Now.ToString();
label1.AutoSize = false;
label1.Left = -3;
label1.Width = this.Width - 1;
label1.Height = 15;
label1.BorderStyle = BorderStyle.FixedSingle;
for (int i = 0; i < spacesBegin; i++)
label1.Text = " " + label1.Text;
for (int i = 0; i < spacesEnd; i++)
label1.Text += " ";
Timer timer = new Timer();
timer.Tick += timer1_Tick;
timer.Interval = 50;
timer.Start();
}

Change fontSize of ListView with ctrl + mousewheel

I have a ListView (auftraegeView). Of this ListView I whish to change the FontSize of its Items through Ctrl + MouseWheel aka. a simple zoom like in excel or a browser.
In the form's ctor I subscribed my method to the event
this.MouseWheel += scrollZoom;
My EventHandler calculates the new FontHeight and applies it, if it doesn't exceed the bounds. The RowHeight is always kept a little bigger, finally I resize the columns so the zoom also works on the horizontal scale.
private void scrollZoom(object sender, MouseEventArgs e)
{
if(Control.ModifierKeys != Keys.Control)
return;
int currFontHeight = ListViewFontHeight;
int delta = (e.Delta)/120;
int newFontHeight = currFontHeight + delta;
if(newFontHeight < 1 || newFontHeight > 150)
return;
ListViewFontHeight = newFontHeight;
ListViewRowHeight = ListViewFontHeight + 4;
auftraegeView.AutoResizeColumns(ColumnHeaderAutoResizeStyle.ColumnContent);
}
ListViewFontHeight gets the Font.Height of the first Item. (Value is identical across all Items, so the first is as good as any.)
The set is where the issue seems to be (see below). My idea is that I just go through each Item and change the Font.
private int ListViewFontHeight
{
get { return auftraegeView.Items[0].Font.Height; }
set
{
foreach (ListViewItem line in auftraegeView.Items)
{
line.Font = new Font(line.Font.FontFamily, value);
}
}
}
ISSUE / QUESTION
Regardless of the direction I scroll in, the FontSize only increases till it hits the ceiling. The rest works fine (setting ListViewRowHeight, detecting the event at all,...).
What might be causing this?

Try this:
delta = (e.Delta > 0? 1 : -1);
to be on the safe side for different mouse settings.
This works for me:
float delta = (e.Delta > 0 ? 2f : -2f);
listView1.Font = new Font (listView1.Font.FontFamily, listView1.Font.Size + delta);

Found it myself:
In the ListViewFontHeight - property the get accessor used Item.Font.Height instead of Item.Font.Size
private int ListViewFontHeight
{
get { return (int)auftraegeView.Items[0].Font.Size; } //works now

C# Click source detection

I have a GroupBox that has multiple controls, specifically 4 PictureBoxes.
These are pieces of an image puzzle. Please note that the number of images can change. I want to allow a drag and drop effect to each of them. To mark the source and the destination I did the following:
foreach (var box in boxes)
{
box.DragEnter += new DragEventHandler(box_DragEnter);
box.MouseDown += new MouseEventHandler(box_MouseDown);
box.DragDrop += new DragEventHandler(box_DragDrop);
box.AllowDrop = true;
}
When a box is clicked it will be marked to a global variable (that will be the source) and when a box raises the DragDrop event that will be the destination.
As I previously mentioned, since the number of the boxes can be changed I do not want to add separate methods as handlers for each event.
My issue here is that I do not know how to "detect" which box has raised what event.
Example:
*If I press on the left-top image I want to know that I pressed on it to mark the source (let's say global picSource = 1) and if I drop on right-bottom image I want to know that as a destination (picDestination = 4). All that must occur in the handlers. *
Tests:
Adding a parent panel (same size as the GroupBox) with a Click event & doing a comparison between a Point issued with the X&Y provided by the event handler and a rectangle designated with the X,Y, width, height of the panel.
Adding handlers to the GroupBox (does not work either)
Notes:
e.X and e.Y refer to the position of the mouse
void box_MouseDown(object sender, MouseEventArgs e)
The purpose of this is to switch boxes (source <--> destination)

You can just detect puzzle element by mouse's coordinates in the controls container's MouseDown and MouseUp event as follows:
public partial class PuzzleForm : Form
{
private readonly Image[,] Images;
private readonly int Nx;
private readonly int Ny;
private int sourceIndexX;
private int sourceIndexY;
private int destinationIndexX;
private int destinationIndexY;
private PuzzleForm()
{
SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.ResizeRedraw, true);
InitializeComponent();
}
public PuzzleForm(Image[,] images)
: this()
{
Images = images;
Nx = Images.GetLength(0);
Ny = Images.GetLength(1);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
using (Graphics g = e.Graphics)
{
for (int j = 0; j < Ny; j++)
for (int i = 0; i < Nx; i++)
{
Rectangle rect = new Rectangle(ClientSize.Width * i / Nx, ClientSize.Height * j / Ny, ClientSize.Width / Nx - 1, ClientSize.Height / Ny - 1);
g.DrawImage(Images[i, j], rect);
}
}
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
if (e.Button != MouseButtons.Left)
return;
sourceIndexX = e.X * Nx / ClientSize.Width;
sourceIndexY = e.Y * Ny / ClientSize.Height;
Cursor = Cursors.Hand;
}
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
if (e.Button != MouseButtons.Left)
return;
destinationIndexX = e.X * Nx / ClientSize.Width;
destinationIndexY = e.Y * Ny / ClientSize.Height;
Cursor = Cursors.Default;
if (sourceIndexX != destinationIndexX || sourceIndexY != destinationIndexY)
{
swapImages();
MessageBox.Show(String.Format("From [{0}, {1}] to [{2}, {3}]", sourceIndexX, sourceIndexY, destinationIndexX, destinationIndexY));
}
}
private void swapImages()
{
Image tmp = Images[sourceIndexX, sourceIndexY];
Images[sourceIndexX, sourceIndexY] = Images[destinationIndexX, destinationIndexY];
Images[destinationIndexX, destinationIndexY] = tmp;
Invalidate();
}
}
Usage:
Image[,] images = new Image[2, 2];
// Fill array with images:
images[0, 0] = Bitmap.FromFile(#"...");
images[0, 1] = Bitmap.FromFile(#"...");
images[1, 0] = Bitmap.FromFile(#"...");
images[1, 1] = Bitmap.FromFile(#"...");
PuzzleForm puzzleForm = new PuzzleForm(images);
// Show form or whatever you want.
...