Develop Reference

Grow picturebox to top direction

Is it possible to give a picturebox a new size but instead of it growing down and right i want it to grow up and right. So basicaly I want the left bottom corner to be locked in the same position all the time.
As you can see in the image i want the green box to be above the line.
I have tried to make a formula to calculate the new position but cant figure out how to write it.

If you're assigning size at runtime, for example:
private void button1_Click(object sender, EventArgs e)
{
this.pictureBox1.Size = new Size( 200, 200 );
}
then just handle the PictureBox Resize event:
private void pictureBox1_Resize(object sender, EventArgs e)
{
var padding = 12; //Forms designer snap-to padding.
var titleBarHeight = 41;
this.pictureBox1.Location = new Point(padding, this.Height - this.pictureBox1.Height - titleBarHeight - padding);
}
This will handle the size assignment, as well as if you've anchored the PictureBox and are resizing the form.
If you're just resizing at design time, then just anchor the PictureBox:
It'll resize where ever it's sitting on the form. As mentioned above, it'll also work automatically for form resize at run time.

scrolling in a ScrollableControl: is there a .NET variant of MFC ViewPort?

I'm learning how to draw in Winforms. I've created a Form, with a panel with scrollbars. Upone Event Paint I draw an ellipse. This is fairly straightforward:
this.panel1.AutoScroll = true;
this.panel1.AutoScrollMinSize = = new System.Drawing.Size(500, 300);
private void OnPaint(object sender, PaintEventArgs e)
{
Rectangle ellipse = new Rectangle(Point.Empty, new Size(400, 400));
ellipse.Offset(this.panel1.AutoScrollPosition);
using (Pen myPen = new System.Drawing.Pen(System.Drawing.Color.Red))
{
e.Graphics.DrawEllipse(myPen, ellipse);
}
}
private void OnPanelScroll(object sender, ScrollEventArgs e)
{
this.panel1.Invalidate();
}
This works fine, but the complete image is redrawn when resizing or scrolling the panel.
A long time ago, in the time of MFC there was the notion of ViewPort / SetViewPortOrg / mapping modes / etc.. Scrolling and resizing did not require a recalculation of the complete image. Once you had drawn the image you didn't have to redraw as long as the complete image was not changed. All you had to do was move the viewport, or change the mapping mode
Does .NET have something similar that can do the scrolling for me? Maybe I should not draw on a panel, but on another subclass of a ScrollableControl?

C# transparent image above 2 images

I have make a playbar for my new MP3 player but I have a problem as shown in attachement
and this is my simple code :
public void setpercent(int percent)
{
pic1.Width = pic2.Width / 100 * percent;
pic3.Left = pic1.Width - ( pic3.Width /2);
}
I thought to use Graphics but I can't move it after.
and the method of ".Parent" doesn't work in this case.

In the Load() event of your Form, modify the Region() property of pic3 so that it becomes circular instead of rectangular. This can be done by construction a GraphicsPath and adding an Ellipse to it. If this doesn't line up properly with your image, then manually determine the correct bounding box for the ellipse and use that instead:
private void Form1_Load(object sender, EventArgs e)
{
System.Drawing.Drawing2D.GraphicsPath GP = new System.Drawing.Drawing2D.GraphicsPath();
GP.AddEllipse(pic3.ClientRectangle);
pic3.Region = new Region(GP);
}

Efficiently moving a WinForms button on a form with a background image

I am creating an application for an industrial touch screen computer with no hardware to brag about. The operator of this touch screen computer is among other things supposed to be able to unlock and drag buttons around on a form with a background image.
However, as many of you already might know, moving controls on a parent control with a background image isn't pretty. The dragging is slow and instead of experiencing a smooth dragging, the operator will see a button jumping after through hoops in the wake of the mouse pointer as you move the pointer across the screen.
This is the current code for moving the button:
private void btnButton_MouseMove(object sender, MouseEventArgs e)
{
// Do not proceed unless it is allowed to move buttons
if (!this._AllowButtonsToBeMoved)
return;
if (this._IsBeingDragged)
{
var btn = (sender as Button);
var newPoint = btn.PointToScreen(new Point(e.X, e.Y));
newPoint.Offset(this._ButtonOffset);
btn.Location = newPoint;
}
}
I am not looking to solve this exact problem, I'd rather eliminate it to save some time. What I wish to implement in order to eliminate this, is a more resource efficient way to move the box around. I'm thinking that moving a dotted rectangle instead of the button, then dropping it where I want the button must be way more efficient than dragging the button around the screen, causing who knows how many repaint operations.
Does anyone have any better suggestions? If not, then I would very much appreciate pointers on how to proceed with creating and moving this rectangle around the screen, as I am having some difficulty finding good sources of information regarding how to approach this on good ol' Google.
Update, 26/11/13
I'm attempting Luaan's suggestion regarding overriding the form's OnPaint, however I am unsure as to how exactly I can add the rendering of the button in this code. Any ideas?
protected override void OnPaint(PaintEventArgs e)
{
if (_IsBeingDragged)
{
e.Graphics.DrawImage(this._FormPaintBuffer, new Point(0, 0));
}
else
{
base.OnPaint(e);
}
}

This is a standard case of Winforms being too programmer-friendly. Details that any game programmer pays careful attention to but are way too easy to miss. It allows you to set a BackgroundImage and it will take anything you throw at it. That usually works just fine, except when you need the image to render quickly. Like you do in this case.
Two things you need to do to make it draw ~fifty times quicker:
Resize the bitmap yourself to fit the form's ClientSize so it doesn't have to be done repeatedly every time the image needs to be painted. The default Graphics.InterpolationMode property value produces very nice looking images but it is not cheap. Do note that this can take a significant memory hit, the reason it isn't done automatically.
Pay attention to the pixel format of the image. There's only one that draws fast, the one that can be blitted directly to the video adapter without having the value of every single pixel converted to the frame buffer format. That is PixelFormat.Format32bppPArgb on all video adapters in use in the past 10+ years. Big difference, it is ten times faster than all the other ones. You never get that format out of a bitmap that you created with a painting program so explicitly converting it is required. Again heed the memory hit.
It takes but a little scrap of code to get both:
private static Bitmap Resample(Image img, Size size) {
var bmp = new Bitmap(size.Width, size.Height,
System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
using (var gr = Graphics.FromImage(bmp)) {
gr.DrawImage(img, new Rectangle(Point.Empty, size));
}
return bmp;
}
In the somewhat unlikely case you still have painting trails or stuttering you need to consider a very different approach. Like the one that's used in the Winforms designer. You use layers, an extra borderless transparent window on top of the original. You get one with the TransparencyKey property.

1) If you want to keep everything the way it is, you might want to implement some sort of double buffering for the background. When the form is redrawn, it always has to redraw pretty much the whole thing, while actually doing some logic (ie. JPG/PNG is slower to draw than a BMP). If you store the Paint canvas in a Bitmap, you can draw the whole form except for that one button in a Bitmap and draw only that as background while you're dragging the button - this way you get around all the draw logic of the form and its controls, which should be vastly faster.
2) You can only draw an outline of the button being moved. The trick is that you draw lines in XOR mode - the first time you draw the rectangle it adds the outline, and the next time you draw it in the same location, it disappears. This way you don't have to redraw the form all the time, just the few pixels that form the rectangle. The support for XOR lines in C# isn't the best, but you can use the ControlPaint.DrawReversibleLine method.

To drag a control you need to use the .DrawToBitmap function of the control and set the appropriate styles of the form. I haven't done it in the sample code but you'll need a "design mode" and a "normal mode". To drag the control you simply click it, drag it and click again. You can get fancy and make the Bitmap holding the control transparent so as to accommodate rounded edges.
For this example, make a standard C# Windows Forms application (Form1) and drop a button (button1) onto the form then place this code after the Form1 constructor in your Form class. Make sure to change the location of the background bitmap in code.
private Bitmap b = null;
private bool IsDragging = false;
private Point down = Point.Empty;
private Point offset = Point.Empty;
private void button1_MouseUp(object sender, MouseEventArgs e)
{
IsDragging = true;
button1.Visible = false;
down = button1.PointToScreen(e.Location);
offset = e.Location;
this.Invalidate();
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
if (IsDragging)
{
IsDragging = false;
down = new Point(down.X - offset.X, down.Y - offset.Y);
button1.Location = down;
button1.Visible = true;
down = Point.Empty;
this.Invalidate();
}
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (IsDragging)
{
down.X += (e.X - down.X);
down.Y += (e.Y - down.Y);
this.Invalidate();
}
}
private void Form1_Load(object sender, EventArgs e)
{
try
{
b = new Bitmap(button1.Width, button1.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
button1.DrawToBitmap(b, new Rectangle(0, 0, button1.Width, button1.Height));
button1.MouseUp += new MouseEventHandler(button1_MouseUp);
this.MouseUp += new MouseEventHandler(Form1_MouseUp);
this.MouseMove += new MouseEventHandler(Form1_MouseMove);
this.DoubleBuffered = true;
this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.UserPaint, true);
this.UpdateStyles();
this.BackgroundImage = Image.FromFile(#"C:\Users\Public\Pictures\Sample Pictures\desert.jpg");
this.BackgroundImageLayout = ImageLayout.Stretch;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
protected override void OnPaint(PaintEventArgs e)
{
if (IsDragging)
{
e.Graphics.DrawImage(b, new Point(down.X - offset.X, down.Y - offset.Y));
}
base.OnPaint(e);
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (b != null)
{
b.Dispose();
}
}

How to do Free hand Image Cropping in C# window application?

How to do Free hand Image Cropping in C# window application??

Okay, you provided very small amount of information, but I'll assume that you are using winforms. There are some tasks dealing with freehand-technique such as:
Drawing
Drag-n-dropping
Cropping
Selecting
They all are very similar. Let's assume that you have a PictureBox and want to crop an image inside it.
// Current selection
private Rectangle _cropRectangle;
// Starting point
private Point _cropStart;
// Dragging flag
private bool _isDragging;
private void pBox_MouseDown(object sender, MouseEventArgs e)
{
_cropRectangle = new Rectangle(e.X, e.Y, 0, 0);
_isDragging = true;
}
private void pBox_MouseUp(object sender, MouseEventArgs e)
{
_isDragging = false;
}
private void pBox_MouseMove(object sender, MouseEventArgs e)
{
if (!_isDragging)
return;
_cropRectangle = new Rectangle(Math.Min(_cropStart.X, e.X),
Math.Min(_cropStart.Y, e.Y),
Math.Abs(e.X - _cropStart.X),
Math.Abs(e.Y - _cropStart.Y));
pBox.Invalidate();
}
private void pBox_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawRectangle(Pens.Red, _cropRectangle);
}
What happens: I make use of three mouse events (MouseDown, MouseUp, MoseMove) and the Paint event. Basically, whenever you want to do anything from the above list, you'll have handle these four events.
I tried to keep the code short and self-explanatory. There are four event handlers working with three instance fields. The fields are used to store the current state of dragging process.
Feel free to customize the code, especially the pBox_Paint handler. Mine just draws a thin red rectangle around selected area. You might want to do something more elaborate here.
Whenever you're done with your rectangle, you can call the Crop method:
private Image Crop()
{
Bitmap croppedImage = new Bitmap(_cropRectangle.Width, _cropRectangle.Height);
using (Graphics g = Graphics.FromImage(croppedImage))
{
g.DrawImage(pBox.Image, 0, 0, _cropRectangle, GraphicsUnit.Pixel);
}
return croppedImage;
}
It creates a new Bitmap and put the selected portion of source image into it. The returned Image object might be used in any manner you like.
EDIT: trying to simplify the code I made some mistakes earlier, fixed now.

You can use Graphics.DrawImage to draw a cropped image onto the graphics object from a bitmap.
Rectangle cropRect = new Rectangle(...);
Bitmap src = Image.FromFile(fileName) as Bitmap;
Bitmap target = new Bitmap(cropRect.Width, cropRect.Height);
using(Graphics g = Graphics.FromImage(target))
{
g.DrawImage(src, cropRect,
new Rectangle(0, 0, target.Width, target.Height),
GraphicsUnit.Pixel);
}
You can also refer the full code for this....
Refer this *Link*