I need a solution how could i make a Print Screen of my WinForm on C# and export it as PNG.
Bests
I think this blog post will help.
using (Bitmap bitmap = new Bitmap(ParentForm.Size.Width, ParentForm.Size.Height))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.CopyFromScreen(new Point(ParentForm.DesktopLocation.X, ParentForm.DesktopLocation.Y), new Point(0, 0), ParentForm.Size);
}
bitmap.Save(#"C:\test.jpg", ImageFormat.Jpeg);
}
Never tried it, but i'd think you should be able to call OnPaint(args) with a PaintEventArgs you create, that includes a Graphics for the image you want to draw on, and the ClipRectangle encompassing the whole area of the form.
This would only work if your form properly processes paint messages (ie: if it stores enough info to be able to repaint the window fully at will), and it may only get the client area (ie: it might not get the title bar or menus).
Related
I have been using Bitmap to take a capture of my main form and saving it as jpeg. Unfortunately bitmap does not keep my text colour. Best way I can describe this is by images (see below). My mainform has an objectlistview which has a column coloured red. Bitmap however captures this as black text? why?
Is there any other alternative method I can use?
I have tried capturing screen and cutting out the the mainform as shown in the code below. This works great on a 1080p monitor, but not on my 4k monitor with 200% scaling, it results in the image being cut.
public void SaveControlImage(Form form)
{
string path_and_file = "C:\1.png";
Bitmap controlBitMap = new Bitmap(form.Width, form.Height);
Graphics g = Graphics.FromImage(controlBitMap);
g.CopyFromScreen(PointToScreen(form.Location), new Point(0, 0), form.Size);
// example of saving to the desktop
controlBitMap.Save(path_and_file, System.Drawing.Imaging.ImageFormat.Png);
}
I have a problem on creating bitmap image out of my winform application.
Situation:
I have a UserControl named as "CanvasControl" that accepts OnPaint method acting as canvas for my Draw Pad application. Inside this user control I have a function "PrintCanvas()" that will create a screenshot image of the UserControl into PNG file. Below is the PrintCanvas() function:
public void PrintCanvas(string filename = "sample.png")
{
Graphics g = this.CreateGraphics();
//new bitmap object to save the image
Bitmap bmp = new Bitmap(this.Width, this.Height);
//Drawing control to the bitmap
this.DrawToBitmap(bmp, new Rectangle(0, 0, this.Width, this.Height));
bmp.Save(Application.StartupPath +
#"\ExperimentFiles\Experiment1" + filename, ImageFormat.Png);
bmp.Dispose();
}
This user control (CanvasControl) is called out inside my main form where user will draw something and have an option to save afterwards using a save button. The save button will call out the "PrintCanvas()" function of the UserControl.
I get the output image file as expected, but the problem is it was a blank image.
What I have tried so far:
To test that it is not a syntax issue, I tried to transfer the PrintCanvas() function into my main form and surprisingly I get an image of the whole main form on file but the UserControl is not visible there.
Is there any other setup i missed out to make a winform UserControl printable?
UPDATE: (DRAWING ROUTINES)
User control acting as canvas - code here
The code in the question gave a first hint but the code in the link showed the source of the problem: You use a 'wrong' instance of the Graphics object for drawing:
protected override void OnPaint(PaintEventArgs e)
{
// If there is an image and it has a location,
// paint it when the Form is repainted.
Graphics graphics = this.CreateGraphics();
..
This is one of the most common mistakes with winforms graphics! Never use CreateGraphics ! You always should draw onto the control surface with the Graphics object in a Paint or DrawXXX event. These events have a parameter e.Graphics which is the only one that can draw persistent graphics.
Persistent means that it will always be refreshed when necessary, not just when you trigger it. This is a nasty error because everything seems to work until you come upon a situation when an outside event makes redrawing necessary:
Minimizing and then maximizing the form
Moving it off the screen and back again
Calling DrawToBitmap
...
Note that all will only really work if you use the valid and current Graphics object from the PaintEventArgs e parameter.
So, the solution is simple:
protected override void OnPaint(PaintEventArgs e)
{
// If there is an image and it has a location,
// paint it when the Form is repainted.
Graphics graphics = e.Graphics(); // << === !!
..
But what is the CreateGraphics good for? It is only good for luring newbies into that error??
Not quite; here are some uses for it:
Drawing non-persistent graphics like a rubber-band rectangle or a special mouse cursor
Measuring text sizes without actually drawing it with a TextRenderer or the MeasureString method
Querying the screen or Bitmap resolution with Graphics.DpiX/Y
and probably some others I can't think of at the moment..
So for normal drawing onto controls always use the e.Grapahics object! You can pass it on to subroutines to make the code more structured, but do not try to cache it; it needs to be current!
I am working with a fingerprint module and am able to capture and display the output in a picture box (C#). Now picture.Image is null even though picturebox displays an image. So I am trying to save the picturebox image as bmp and then assign that bmp to the same picturebox so that Picturebox.image is not null.
Here is the code :
Bitmap bmp = new Bitmap(picFP.width, picFP.height);
picFP.DrawToBitmap(bmp, picFP.ClientRectangle);
bmp.Save("path", Imageformat.bmp);
picFP.image = bmp;
Here bitmap image saved is blank. What can be the problem?
A PictureBox has three layers it can display and PictureBox.DrawToBitmap will put all three things into the Bitmap:
The BackgroundImage
The Image
Any graphics created in or from the Paint event
If your bitmap comes out black then you have none of the three, or the last you have is all black.
From your description it seems as if you can display the image in the PictureBox.
So I assume that you don't display it in the right way, probably you do it like this:
using (Graphics G = picFP.CreateGraphics())
G.DrawImage(yourCapturedImage, ..)
This will not work as it only creates non-persistent graphics. These go away with e.g. each minimize-restore cycle and are not called from the DrawToBitmap call
If you really want to draw it onto the PB's surface use the Paint event! But the more natural choice would be to set the PB's Image directly:
picFP.Image = yourCapturedImage;
Update 1 As you now reveal that you don't display it yourself but simply give the control handle to the external code objNitgen=picFP.Handle; the same applies: It is that Nitgen draws only onto the surface and the result is non-persistent.
In this case the remedy is either
Taking a screenshot of the result and then work from that. Here is a post that shows you how to capture a control via screenshot..
Or you may want to check if Nitgen will draw into a bitmap directly..
For this you should be to pass it not a handle to the PictureBox but to a Bitmap instead:
private void button_Click(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap(picFP.ClientSize.Width, picFP.ClientSize.Height);
Graphics G = Graphics.FromImage(bmp);
IntPtr dc= G.GetHdc();
objNitgen = dc;
objNitgen.capture();
G.ReleaseHdc(dc);
pictureBox1.Image = bmp; // now display..
bmp.Save(yourfilename); // .. and/or save
}
Update 2
You noted in a comment that doing a manual screenshot also does not capture the image; so it seems the control handle is only used to overlay it with the image much like video overlays do; if this is the case I doubt you can get at the image without using other, more fitting Nitgen SDK methods.
I have C# app, but the painting job is done within C++ project (this is how it has to be).
So I added to my window PictureBox, and passed the handle to the drawing function. It works fine.
However when the control is invalidated (I move the window outside the screen and then move it back), I get in result partially empty window. AFAIK there are two approaches for this -- repaint or cache the image.
Repainting could be costly process (the image does not change often, but processing is time consuming, think of 3d renderer), so I would like to simply cache the image.
If I remember correctly from old days of programming directly with Win32 API all it takes is to set some flags. Is it possible with WinForms? If yes, how?
This will help:
Bitmap getControlSurface(Control ctl)
{
bitmap = new Bitmap(ctl.Width, ctl.Height);
using (Graphics g = Graphics.FromImage(bitmap))
{
Point pScreen = PointToScreen(ctl.Location);
g.CopyFromScreen(pScreen, Point.Empty, ctl.Size);
}
return bitmap;
}
If you know when the surface has been refreshed you can use it like this:
if ( pictureBox1.Image != null) pictureBox1.Image.Dispose();
pictureBox1.Image = getControlSurface(pictureBox1);
The only catch is that the PictureBox actually must be completely visible on the screen!
I am looking for a solution\software that I can use in order to render buttons in real time.
That is, I have an image and text, and I want them to be an image altogether in realtime.
Thank you
You can dynamically create an image based on text using the System.Drawing namespace.
private Bitmap CreateBitmapImage(string imageText, string imageUrl)
{
Bitmap myBitmap = new Bitmap(imageUrl);
Graphics g = Graphics.FromImage(myBitmap);
g.DrawString(imageText, new Font("Tahoma", 40), Brushes.White, new PointF(0, 0));
return (objBmpImage);
}
Once you have the Bitmap object in memory you can save it to the disk and call it's location from the web.
Bitmap bmp = CreateBitmapImage("my picture", #"C:\myBasePic.bmp");
bmp.Save(#"C:\bla.png", System.Drawing.Imaging.ImageFormat.png);
It would be good if you can specify why such requirement is there. One of such scenario that I had encountered was need of image buttons with different text (round corners with shaded background) - this can easily be achieved using CSS. If you really want to combine an image and text together then you can do that at server side (using say System.Drawing types) and serve the combined image over a handler/web-service.