I am loading multiple images into a pictureBox and is trying to centre it at the bottom. I am using the below function:
public void toogleImage(Boolean visible, Bitmap img)
{
if (visible)
{
pict_statusCenter.Show();
pict_statusCenter.Image = img;
}
else
{
pict_statusCenter.Hide();
}
}
After reading several Q&A such as here, I have updated the paint event as below:
private void pict_statusCenter_Paint(object sender, PaintEventArgs e)
{
var g = e.Graphics;
g.DrawImage(pict_statusCenter.Image,
(pict_statusCenter.Width - pict_statusCenter.Image.Width) / 2,
pict_statusCenter.Height - pict_statusCenter.Image.Height);
}
The image is now painted at the right location of the picture box. The problem is that a duplicate of the image is painted in the top left corner. I am a bit lost, any clue?
Second question: my image is actually a gif. During debugging, I noticed that each gif update fires a paint event. Is that normal? Is this the right way to do it?
Thanks for your kind assistance.
Ok, I finally did a simple padding:
pict_statusCenter.Padding = new Padding(
(pict_statusCenter.Width - pict_statusCenter.Image.Width)/2,
(pict_statusCenter.Height- pict_statusCenter.Image.Height),
(pict_statusCenter.Width - pict_statusCenter.Image.Width)/2,
0);
Related
I want display an image in my picture box but when I run the code everything else works except the image isn't displayed. Here is the relevant code:
Image[] deadWoman = new Image[5]; //this array will hold the images of bit and pieces of katie
deadWoman[0] = Image.FromFile("F:/Jers Hangman Game/Jers Hangman Game/Resources/katie-hopkins.jpeg");
private void MainPic_Paint(object sender, PaintEventArgs e)
{
Graphics katie = e.Graphics; // creates a graphics object for the picture box
if (numWrongGuesses > 0)
{
e.Graphics.DrawImage(deadWoman[0], 20, 20,60,60);
}
}
I guess the image is never repainted, that's why you don't see it when numWrongGuesses is updated. You should Invalidate() the PictureBox in order to see the update.
I would advise to set the image though, and simply use Visible = true and Visible = false for showing and hiding. You could even set the BackgroundImage if you need to create some overlay effect.
You don't override Paint in order to put an Image object into a PictureBox. Just use the property:
MainPic.Image = deadWoman[0];
You can also do this in the WinForms designer, as long as the Image is a resource.
Also, you can hide and show your image by the .Visible property:
MainPic.Visible = numWrongGuesses > 0;
In my program, I'm coding a basic image editor. Part of this allows the user to draw a rectangular region and I pop up a display that shows that region zoomed by 3x or so (which they can adjust further with the mouse wheel). If they right click and drag this image, it will move the zoom region around on the original image, basically acting as a magnifying glass.
The problem is, I'm seeing some serious performance issues even on relatively small bitmaps. If the bitmap showing the zoomed region is around 400x400 it's still updating as fast as mouse can move and is perfectly smooth, but if I mouse wheel the zoom up to around 450x450, it immediately starts chunking, only down to around 2 updates per second, if that. I don't understand why such a small increase incurs such an enormous performance problem... it's like I've hit some internal memory limit or something. It doesn't seem to matter the size of the source bitmap that is being zoomed, just the size of the zoomed bitmap.
The problem is that I'm using Graphics.DrawImage and a PictureBox. Reading around this site, I see that the performance for both of these is typically not very good, but I don't know enough about the inner workings of GDI to improve my speed. I was hoping some of you might know where my bottlenecks are, as I'm likely just using these tools in poor ways or don't know of a better tool to use in its place.
Here are some snippets of my mouse events and related functions.
private void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
else if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
// slide the zoomed part to look at a different area of the original image
if (zoomFactor > 1)
{
isMovingZoom = true;
// try saving the graphics object?? are these settings helping at all??
zoomingGraphics = Graphics.FromImage(displayImage);
zoomingGraphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
zoomingGraphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Low;
zoomingGraphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
zoomingGraphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;
}
}
}
private void pictureBox_MouseMove(object sender, MouseEventArgs e)
{
if (isMovingZoom)
{
// some computation on where they moved mouse ommitted here
zoomRegion.X = originalZoomRegion.X + delta.X;
zoomRegion.Y = originalZoomRegion.Y + delta.Y;
zoomRegionEnlarged = scaleToOriginal(zoomRegion);
// overwrite the existing displayImage to prevent more Bitmaps being allocated
createZoomedImage(image.Bitmap, zoomRegionEnlarged, zoomFactor, displayImage, zoomingGraphics);
}
}
private void createZoomedImage(Bitmap source, Rectangle srcRegion, float zoom, Bitmap output, Graphics outputGraphics)
{
Rectangle destRect = new Rectangle(0, 0, (int)(srcRegion.Width * zoom), (int)(srcRegion.Height * zoom));
outputGraphics.DrawImage(source, destRect, srcRegion, GraphicsUnit.Pixel);
if (displayImage != originalDisplayImage && displayImage != output)
displayImage.Dispose();
setImageInBox(output);
}
// sets the picture box image, as well as resizes the window to fit
void setImageInBox(Bitmap bmp)
{
pictureBox.Image = bmp;
displayImage = bmp;
this.Width = pictureBox.Width + okButton.Width + SystemInformation.FrameBorderSize.Width * 2 + 25;
this.Height = Math.Max(450, pictureBox.Height) + SystemInformation.CaptionHeight + SystemInformation.FrameBorderSize.Height * 2 + 20;
}
private void pictureBox_MouseUp(object sender, MouseEventArgs e)
{
else if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
if (isMovingZoom)
{
isMovingZoom = false;
zoomingGraphics.Dispose();
}
}
}
As you can see, I'm not declaring a new Bitmap every time I want to draw something, I'm reusing an old Bitmap (and the Bitmap's graphics object, though I don't know if there is much cost with calling Graphics.FromImage repeatedly). I tried adding Stopwatches around to benchmark my code, but I think DrawImage passes functionality to another thread so the function claims to be done relatively quickly. I'm trying to Dispose all my Bitmap and Graphics objects when I'm not using them, and avoid repeated calls to allocate/deallocate resources during the MouseMove event. I'm using a PictureBox but I don't think that's the problem here.
Any help to speed up this code or teach me what's happening in DrawImage is appreciated! I've trimmed some excess code to make it more presentable, but if I've accidentally trimmed something important, or don't show how I'm using something which may be causing problems, please let me know and I'll revise the post.
The way I handle issues like that is when receiving the Paint event, I draw the whole image to a memory bitmap, and then BLT it to the window.
That way, all visual flash is eliminated, and it looks fast, even if it actually is not.
To be more clear, I don't do any painting from within the mouse event handlers.
I just set up what's needed for the main Paint handler, and then do Invalidate.
So the painting happens after the mouse event completes.
ADDED: To answer Tom's question in a comment, here's how I do it. Remember, I don't claim it's fast, only that it looks fast, because the _e.Graphics.DrawImage(bmToDrawOn, new Point(0,0)); appears instantaneous. It just bips from one image to the next.
The user doesn't see the window being cleared and then repainted, thing by thing.
It gives the same effect as double-buffering.
Graphics grToDrawOn = null;
Bitmap bmToDrawOn = null;
private void DgmWin_Paint(object sender, PaintEventArgs _e){
int w = ClientRectangle.Width;
int h = ClientRectangle.Height;
Graphics gr = _e.Graphics;
// if the bitmap needs to be made, do so
if (bmToDrawOn == null) bmToDrawOn = new Bitmap(w, h, gr);
// if the bitmap needs to be changed in size, do so
if (bmToDrawOn.Width != w || bmToDrawOn.Height != h){
bmToDrawOn = new Bitmap(w, h, gr);
}
// hook the bitmap into the graphics object
grToDrawOn = Graphics.FromImage(bmToDrawOn);
// clear the graphics object before drawing
grToDrawOn.Clear(Color.White);
// paint everything
DoPainting();
// copy the bitmap onto the real screen
_e.Graphics.DrawImage(bmToDrawOn, new Point(0,0));
}
private void DoPainting(){
grToDrawOn.blahblah....
}
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);
}
i am trying to move a image in picture box. i added panel to my application and also added picture box in panel. i opened an image.if the image size is big.i want to see the particular portion of image. so how can i move the image up and down (without using scroll bars) to see the particular portion of image?
You can add controls like move left, move right, move up, move down with associated actions to move the image within your picturebox. An example of how to do this for moving the image to the right is shown below. You can implement these action with mouse down and mouse up events so that the user just presses the appropriate buttons to move the picture as he wants. Also note that once you reach the maximum dimensions of the image, you can change the rectangular region to that within image bounds.
int ff = 0; //number of positions to move
Bitmap b2;
private void button1_Click(object sender, EventArgs e)
{
if (ff == 0) { b2 = new Bitmap(pictureBox1.Image);} //original image as bitmap b2
Bitmap b1 = new Bitmap(pictureBox1 .Width ,pictureBox1.Height ); //new bitmap with rectangular region of original image
Rectangle r1 = new Rectangle(ff++, 0, pictureBox1.Width, pictureBox1.Height );
Graphics g = Graphics.FromImage(b1);
g.DrawImage(b2, 0, 0, r1, GraphicsUnit.Pixel);
g.Dispose();
pictureBox1.Image = null;
pictureBox1.Image = (Image)b1;
pictureBox1.Refresh();
}
Not sure if it really answers your question, but this seems like a fun reason to play with Reactive Extensions (Rx). This video demonstrates nicely how well this stuff works with asynchronous events like mouse-input.
I have a picturebox with a png in it. Yet even when I set the BackColor to Transparent, it is not transparent. Any ideas what might be wrong? :)
Thanks!
I have also faced the problem regarding transparent pictures.
you have to Draw it through code.
See my question A PictureBox Problem
EDIT:
In paint event (Control containing Background Image)
write this
//If added your image in project's resources get from there OR your Image location
Image img = yourNamespace.Properties.Resources.yourPicture;
e.Graphics.DrawImage(img,50,50,100,100);
Your PNG file should also have the transparent background. This is can be done while creating the image(png) files.
You really have to draw it through code. Place a pictureBox on your form, set sizeMode and docking as you like. Then you may fire the following function on the pictureBox's PAINT event:
public void LogoDrawTransparent(PaintEventArgs e)
{
// Create a Bitmap object from an image file.
Image myImg;
Bitmap myBitmap;
try
{
myImg = cls_convertImagesByte.GetImageFromByte(newImg);
myBitmap = new Bitmap(myImg); // #"C:\Temp\imgSwacaa.jpg");
// Get the color of a background pixel.
Color backColor = myBitmap.GetPixel(0, 0); // GetPixel(1, 1);
Color backColorGray = Color.Gray;
Color backColorGrayLight = Color.LightGray;
Color backColorWhiteSmoke = Color.WhiteSmoke;
Color backColorWhite = Color.White;
Color backColorWheat = Color.Wheat;
// Make backColor transparent for myBitmap.
myBitmap.MakeTransparent(backColor);
// OPTIONALLY, you may make any other "suspicious" back color transparent (usually gray, light gray or whitesmoke)
myBitmap.MakeTransparent(backColorGray);
myBitmap.MakeTransparent(backColorGrayLight);
myBitmap.MakeTransparent(backColorWhiteSmoke);
// Draw myBitmap to the screen.
e.Graphics.DrawImage(myBitmap, 0, 0, pictureBox1.Width, pictureBox1.Height); //myBitmap.Width, myBitmap.Height);
}
catch
{
try { pictureBox1.Image = cls_convertImagesByte.GetImageFromByte(newImg); }
catch { } //must do something
}
}
This is my class that is referenced in the above function:
class cls_convertImagesByte
{
public static Image GetImageFromByte(byte[] byteArrayIn)
{
MemoryStream ms = new MemoryStream(byteArrayIn);
Image returnImage = Image.FromStream(ms);
return returnImage;
}
public static byte[] GetByteArrayFromImage(System.Drawing.Image imageIn)
{
MemoryStream ms = new MemoryStream();
imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
return ms.ToArray();
}
}
Thanks. chagbert.
From what I learned I can't do it within a windows form, as it doesn't have layers for the images. So guess will have to make it as WPF. :)
How did you create the background? Is that set by setting the Form.BackgroundImage?
If that background (the paper like image) is a container control, the transparency should just work.
However, If you are placing two PictureBox objects on top of eachother this doesn't work. The transparent area takes on the color of its parent object. If you have two PictureBox objects they both will have the Form as their parent. If this is your situation, it can be solved by setting the transparent image's Parent property to be the background image.
private void Form1_Load(object sender, EventArgs e)
{
transparentPictureBox.Parent = backgroundPictureBox;
}
When changing the Parent property, the Location of the tranparentPictureBox will become relative to its new parent. You'd have to subtract the x and y coordinates of the background image from the transparent image. See my answer on A PictureBox Question for an example with a screen shot.
AFAIK, you can not set the Parent in the Designer, only in code. Therefore, the Designer will still not show a transparent image, but at runtime it should.
The same problem occurs if you place a transparent Label on top of a PictureBox object.