I was nicely supplied a code from Alex M, for painting the background image to a panel but realized that if a PictureBox's BackgroundImage has its Center image property set, the drawn image becomes stretched but not centered. I so far have this code:
private void panel1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(pictureBox1.BackgroundImage,
new Rectangle(pictureBox1.Location, pictureBox1.Size));
}
This draws the background image to the panel but if pictureBox1's background image property is set to CENTER, it does not paint the image in the Center of the Rectangle, but instead stretches the image to fit the rectangle.
The only possible solution I've found is here but I can't make any sense of it.
The reason the image is being stretched is because the second parameter to DrawImage specifies the location and size of where you're drawing the image, and you're specifying the entire area of the picture box, not the area of the image itself.
If you want to center it, try something like this:
private void panel1_Paint(object sender, PaintEventArgs e)
{
var hPadding = (pictureBox1.Width - pictureBox1.BackgroundImage.Width) / 2;
var vPadding = (pictureBox1.Height - pictureBox1.BackgroundImage.Height) / 2;
var imgRect = new Rectangle(pictureBox1.Left + hPadding, pictureBox1.Top + vPadding, pictureBox1.BackgroundImage.Width, pictureBox1.BackgroundImage.Height);
e.Graphics.DrawImage(pictureBox1.BackgroundImage, imgRect);
}
Related
This question already has answers here:
How to draw rectangle on MouseDown/Move c#
(4 answers)
Closed 7 years ago.
I'm trying to create a windows forms application in which, when the user clicks anywhere on a picture box, a rectangle appears at the position where the image was clicked.
However, if I click anywhere on the image, the rectangle will appear at some random position regardless of where I clicked. It can appear either near or far away from the mouse click, and in some cases it never goes beyond the left half of the picture box.
May I have some guidance on how to resolve this issue? Specifically, I want the position where I clicked to be the center of the rectangle.
Thank you!
This is my code for reference:
private void pbImage_Click(object sender, EventArgs e)
{
//Note: pbImage is the name of the picture box used here.
var mouseEventArgs = e as MouseEventArgs;
int x = mouseEventArgs.Location.X;
int y = mouseEventArgs.Location.Y;
// We first cast the "Image" property of the pbImage picture box control
// into a Bitmap object.
Bitmap pbImageBitmap = (Bitmap)(pbImage.Image);
// Obtain a Graphics object from the Bitmap object.
Graphics graphics = Graphics.FromImage((Image)pbImageBitmap);
Pen whitePen = new Pen(Color.White, 1);
// Show the coordinates of the mouse click on the label, label1.
label1.Text = "X: " + x + " Y: " + y;
Rectangle rect = new Rectangle(x, y, 200, 200);
// Draw the rectangle, starting with the given coordinates, on the picture box.
graphics.DrawRectangle(whitePen, rect);
// Refresh the picture box control in order that
// our graphics operation can be rendered.
pbImage.Refresh();
// Calling Dispose() is like calling the destructor of the respective object.
// Dispose() clears all resources associated with the object, but the object still remains in memory
// until the system garbage-collects it.
graphics.Dispose();
}
UPDATE 12.55am, 16/8/2015 - I know why! The SizeMode property of the pictureBox was set to StretchImage. Changed it back to Normal mode and it worked fine. Not exactly sure why this is so, I'll definitely look into it.
To those who have replied, thank you so much for your help! :)
The first two arguments to the Rectangle constructor are the top-left (not center) coordinates.
And handle the mouse and paint events separately:
int mouseX, mouseY;
private void pbImage_MouseDown(object sender, MouseEventArgs e)
{
mouseX = e.X;
mouseY = e.Y;
pbImage.Refresh();
}
private void pbImage_Paint(object sender, PaintEventArgs e)
{
//... your other stuff
Rectangle rect = new Rectangle(mouseX - 100, mouseY - 100, 200, 200);
e.Graphics.DrawRectangle(whitePen, rect);
}
You are casting EventArgs to MouseEventArgs, I think that is incorrect. Are you tried with MouseDown or MouseUp events of the picture control? Those events provides you the information you need.
How do I resize button backgroundImage in c#?
I could only find properties which gets button backgroundImage size.
Nothing sets size.
I use WinForms
BackgroundImageLayout would help...If Not then,
1)Take a Panel (panel1).
2)Bind you Button Event to panel(panel1)
3)Add another panel (panel2) to Panel1 in above with background image that you want to set and BackgroundImageLayout property as ImageLayout.Stretch
4)Then Resize the panel2
this would resize your image
Hope this helps
I will not get any simpler than that in WinForms:
private void yourbutton_Paint(object sender, PaintEventArgs e)
{
// base.OnPaint(e); optional
Rectangle rc = yourButton.ClientRectangle;
Rectangle ri = new Rectangle(Point.Empty, yourButton.BackgroundImage.Size);
// e.Graphics.FillRectangle(SystemBrushes.Control, rc); optional
e.Graphics.DrawImage(yourButton.BackgroundImage, rc, ri, GraphicsUnit.Pixel);
e.Graphics.DrawString(yourButton.Text, yourButton.Font,
SystemBrushes.ControlText, Point.Empty); // if needed
}
If you look at the code you'll see that it effectively really is just one line, or two if you have text on the button..
Using a standard Label I aligned my image to the right side.
However there is a small indent (marked in red) that I cannot remove.
So my question: Is there an easy way to correctly align/snap an image to the right edge of a label? Or do I need to edit the label paint method so I can manually draw the image?
The label in question sits inside a "Panel", the following is my code:
label1.BackColor = System.Drawing.Color.Red;
label1.Image = global::TestProject.Properties.Resources.Header;
label1.ImageAlign = System.Drawing.ContentAlignment.MiddleRight;
label1.Size = new System.Drawing.Size(200, 40);
The simple answer appears to be: No there is no easy way to correctly align the image.
The "PictureBox" seems like the preferred component for working with images, however the image can be correctly aligned by editing the paint method of the label:
label1.Paint += new System.Windows.Forms.PaintEventHandler(this.label1_Paint);
And the paint method:
private void label1_Paint(object sender, PaintEventArgs e)
{
Image image = global::TestProject.Properties.Resources.Header;
Graphics g = e.Graphics;
//Align to far right: label width - image width
g.DrawImage(image, this.label1.Width - image.Width, 0);
}
Drawing a polygon according to the input coordinates
i got some code from here, i just take..
void pictureBox1_Paint(object sender, PaintEventArgs e) {
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
List<Point> polyPoints = new List<Point>();
polyPoints.Add(new Point(30, 30));
polyPoints.Add(new Point(36, 105));
polyPoints.Add(new Point(66, 105));
polyPoints.Add(new Point(72, 66));
using (SolidBrush br = new SolidBrush(Color.FromArgb(100, Color.Yellow)))
{
e.Graphics.FillPolygon(br, polyPoints.ToArray());
}
e.Graphics.DrawPolygon(Pens.DarkBlue, polyPoints.ToArray());
}
note : SmoothingMode use header using System.Drawing.Drawing2D
then i got problem about click area, i just want the click area at the visible area, in this case the picturebox1 have size 1366 x 768
this is example of picturebox, i want the red area be clickable and the gray is not clickable area
by default all area in the box is clickable
Have you looked at the Documentation on PictureBox?
I'm looking at it and it seems there's many ways of resizing aspects of the PixtureBox object. Take a look at using the DefaultSize Property or setting the Size property. In either case, you have to wrap the size in a Size object and set the according PictureBox size property.
Such as:
pictureBox1.Size = new Size(xSize, ySize);
or
pictureBox1.DefaultSize = new Size(xSize, ySize);
I'm developing a program to get all the pixels inside a rectangle. There is an image control and the user can click on a part inside it. When the user clicks on a particular location, a rectangle is drawn. I would like to get all the pixels inside that rectangle. I'm getting to draw the rectangle now. But i'm not able to get all the pixel values. Please find the code snippet for drawing the rectangle below.
private void panel1_Paint(object sender, PaintEventArgs e)
{
foreach (var rectKey in rectangles.Keys)
{
using (var pen = new Pen(rectKey)) //Create the pen used to draw the rectangle (using statement makes sure the pen is disposed)
{
//Draws all rectangles for the current color
//Note that we're using the Graphics object that is passed into the event handler.
e.Graphics.DrawRectangles(pen, rectangles[rectKey].ToArray());
}
}
}
private void panel1_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
Color c = System.Drawing.Color.GreenYellow ; //Gets a color for which to draw the rectangle
//Adds the rectangle using the color as the key for the dictionary
if (!rectangles.ContainsKey(c))
{
rectangles.Add(c, new List<Rectangle>());
}
rectangles[c].Add(new Rectangle(e.Location.X - 12, e.Location.Y - 12, 25, 25)); //Adds the rectangle to the collection
}
//Make the panel repaint itself.
panel1.Refresh();// Directs to panel1_Paint() event
rectangles.Clear();
}
You would have to work with the Bitmap not the graphics object in this case.
Bitmap has a method to get pixels at a position
Bitmap bmp = Bitmap.FromFile("");
// Get the color of a pixel within myBitmap.
Color pixelColor = bmp.GetPixel(50, 50);
To read all pixels within a rectangle you could use the bmp.LockBits method.