i have some images..if these images are selected then it should generate another image which is the combination of all the selected images..
can anyone suggest as how to start with?
thanks
Use someting like that:
public void MergeImages(string FirstFileName, string SecondFileName)
{
Image firstImg = Image.FromFile(#"C:\temp\pic1.jpg");
Image secondImg = Image.FromFile(#"C:\temp\pic2.jpg");
Bitmap im1 = new Bitmap(firstImg);
Bitmap im2 = new Bitmap(secondImg);
Bitmap result = new Bitmap(im1.Width + im2.Width, (im1.Height > im2.Height) ? im1.Height : im2.Height);
Graphics gr = Graphics.FromImage(result);
gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
gr.DrawImage(firstImg, 0, 0);
gr.DrawImage(secondImg, im1.Width + 1, 0);
gr.Save();
result.Save(#"C:\test.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
}
this code merges two images in one, systeming them into line.
i used ImageMagick to do these kind of things (http://www.imagemagick.org/Usage/layers/)
It is however a little bit different then using gdi to create images, but it is a very fast (and when you get used to the imagemagick syntax) and powerful way to edit images.
Normally you use gdi to edit images in memory; imagemagick uses a commandline utility to create images.
So for example you want to layer two images on top, you start a new process in your code in which you fire up a imagemagick proces with the right parameters and then the image is created ON DISK.
Then you can server the created image with a response.writebinary.
Related
I need to show the preview thumbnails of high resolution images in a control for user selection. I currently use ImageListView to load images.
This works fine for low to medium resolution images.But when it comes to showing thumbnails of very high resolution images there is a noticeable delay.Sample image can be downloaded from https://drive.google.com/open?id=1Qgu_aVXBiMlbHluJFU4fBvmFC45-E81C
The image size is around 5000x3000 pixels and size is around 12 MB.The issue can be replicated by using 1000 copies of this image.
The issue screen capture is uploaded here
https://giphy.com/gifs/ZEH3T3JTfN42OL3J1A
The images are loaded using a background worker
foreach (var f in filepaths)
{
imageListView1.Items.Add(f);
}
1. In order to solve this issue I tried resizing large resolution images and adding the resized image to ImageListView ... but for resizing there is a heavy time consumption and thumbnail generation is slow.
Bitmap x = UpdatedResizeImage2(new Bitmap(f), new Size(1000, 1000));
string q = Path.GetTempPath() + Path.GetFileName(f);
x.Save(Path.GetTempPath() + Path.GetFileName(f));
x.Dispose();
imageListView1.Items.Add(Path.GetTempPath() + Path.GetFileName(f));
2. I have also tried Image.CreateThumbnail Method but this is also quite slow.
Is there a better way to solve this issue?
I would suggest using image processing library such ImageMagick.
ImageMagick has optimized this feature and you have Magick.NET a nuget package for .NET.
It is simple and straight forward:
var file = new FileInfo(#"c:\temp\input.jpg");
using (MagickImage image = new MagickImage(file))
{
{
image.Thumbnail(new MagickGeometry(100, 100));
image.Write(#"C:\temp\thumbnail.jpg");
}
}
example I made:
Here is some documentation and references that might be useful:
https://imagemagick.org/Usage/thumbnails/#creation
http://www.imagemagick.org/Usage/thumbnails/
https://github.com/dlemstra/Magick.NET
https://www.smashingmagazine.com/2015/06/efficient-image-resizing-with-imagemagick/
https://devblogs.microsoft.com/dotnet/net-core-image-processing/
https://weblogs.asp.net/bleroy/resizing-images-from-the-server-using-wpf-wic-instead-of-gdi
Alternatives to System.Drawing for use with ASP.NET?
You could use WPF interop and use the DecodePixelWidth/Height properties. They use underlying Windows imaging layer technology ("Windows Imaging Component") to create an optimized thumbnail, saving lots of memory (and possibly CPU): How to: Use a BitmapImage (XAML)
You can also use WPF/WIC by code, with a code like this (adapted from this article The fastest way to resize images from ASP.NET. And it’s (more) supported-ish.. You just need to add a reference to PresentationCore and WindowsBase which shouldn't be an issue for a desktop app.
// needs System.Windows.Media & System.Windows.Media.Imaging (PresentationCore & WindowsBase)
public static void SaveThumbnail(string absoluteFilePath, int thumbnailSize)
{
if (absoluteFilePath == null)
throw new ArgumentNullException(absoluteFilePath);
var bitmap = BitmapDecoder.Create(new Uri(absoluteFilePath), BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.None).Frames[0];
int width;
int height;
if (bitmap.Width > bitmap.Height)
{
width = thumbnailSize;
height = (int)(bitmap.Height * thumbnailSize / bitmap.Width);
}
else
{
width = (int)(bitmap.Width * thumbnailSize / bitmap.Height);
height = thumbnailSize;
}
var resized = BitmapFrame.Create(new TransformedBitmap(bitmap, new ScaleTransform(width / bitmap.Width * 96 / bitmap.DpiX, height / bitmap.Height * 96 / bitmap.DpiY, 0, 0)));
var encoder = new PngBitmapEncoder();
encoder.Frames.Add(resized);
var thumbnailFilePath = Path.ChangeExtension(absoluteFilePath, thumbnailSize + Path.GetExtension(absoluteFilePath));
using (var stream = File.OpenWrite(thumbnailFilePath))
{
encoder.Save(stream);
}
}
Otherwise there are lots of tools out there like MagicScaler, FreeImage ImageSharp, ImageMagick, Imazen, etc. Most were written for ASP.NET/Web server scenarios (for which WPF is officially not supported but works, read the article) and are also cross-platform which you don't seem to need. I'm not sure they're generally faster or use less memory than builtin Windows technology, but you should test all this in your context.
PS: otherwise there's no magic bullet, bigger images take more time.
There's also NetVips, the C# binding for libvips.
It's quite a bit quicker than Magick.NET: between 3x and 10x faster, depending on the benchmark.
Thumbnailing is straightforward:
using NetVips;
var image = Image.Thumbnail("some-image.jpg", 128);
image.WriteToFile("x.jpg");
There's an introduction in the documentation.
Most of answers approach is to resize bitmap and then save it. Its a bit offcourse slow, specially if you say very high resolution.
Why not use existing thumbnail created by windows explorer ? This is fastest way of all (specially if you use smaller thumbnails).
//https://stackoverflow.com/a/1751610
using Microsoft.WindowsAPICodePack.Shell;
var shellFile = ShellFile.FromFilePath(pathToYourFile); Bitmap
Image image = shellFile.Thumbnail.LargeBitmap;
Nuget : https://www.nuget.org/packages/WindowsAPICodePack-Shell (around 600KB)
Note: Its same as others, if thumbnail arent cached already.
We have a system that provides images in 8-bit grayscale either tiff or jpg formats. However, the component we have to process the images expects image to be in 8-bit jpg format.
When I use .Net to save the tiff images as jpg it convets it to 24-bit image.
Is there a way, hopefully simple and fast, to convert 8-bit grayscale tiff images to equivalent jpg?
I tried and tried just to conclude that I'm sorry: .Net library's Bitmap class DOES NOT save JPEG as 8bpp even when explicitly stated and data is in grayscale.
(note: although stated in some places, JPEG format DOES support 8bpp).
At Convert an image to grayscale you may find code snipet to convert to grayscale any Image.
Using that code, I was able to save a 8bpp grayscale Image instance with '.jpeg' extension, but stating ImageFormat.Gif... that's a cheat...
My findings show as solution an entirely different approach.
The FreeImage library offers powerful APIs, including the feature needed to solve your problem.
It's home page is at http://freeimage.sourceforge.net/faq.html
But, I could not easily compile it in my Win2008 + VS 2010 machine.
One ought to sweat a lot to make it run on modern environments.
Some hints on how to accomplish that are found at http://www.sambeauvois.be/blog/2010/05/freeimage-and-x64-projects-yes-you-can/
Good luck!
Image img = Image.FromFile(filePathOriginal);
Bitmap bmp = ConvertTo8bpp(img);
EncoderParameters parameters = new EncoderParameters();
parameters.Param[0] = new EncoderParameter(Encoder.ColorDepth, 8);
bmp.Save(filePathNew, jpgCodec, parameters);
bmp.Dispose();
img.Dispose();
...
private static Bitmap ConvertTo8bpp(Image img) {
var bmp = new Bitmap(img.Width, img.Height, System.Drawing.Imaging.PixelFormat.Format8bppIndexed);
using (var gr = Graphics.FromImage(bmp))
{
gr.DrawImage(img, new Rectangle(0, 0, img.Width, img.Height));
}
return bmp;
}
How can I convert a System.Drawing.Bitmap to GDK# Image so that I can set to the image widget.
I have tried this...
System.Drawing.Bitmap b = new Bitmap (1, 1);
Gdk.Image bmp = new Gdk.Image (b);
UPDATE:
Bitmap bmp=new Bitmap(50,50);
Graphics g=Graphics.FromImage(bmp);
System.Drawing.Font ff= new System.Drawing.Font (System.Drawing.FontFamily.GenericMonospace, 12.0F, FontStyle.Italic, GraphicsUnit.Pixel);
g.DrawString("hello world",ff,Brushes.Red,new PointF(0,0));
MemoryStream ms = new MemoryStream ();
bmp.Save (ms, ImageFormat.Png);
Gdk.Pixbuf pb= new Gdk.Pixbuf (ms);
image1.Pixbuf=pb;
Exception:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> GLib.GException: Unrecognized image file format
at Gdk.PixbufLoader.Close()
at Gdk.PixbufLoader.InitFromStream(Stream stream)
at Gdk.PixbufLoader..ctor(Stream stream)
at Gdk.Pixbuf..ctor(Stream stream)
One ugly, but working, way is to store the bitmap as a PNG in a MemoryStream.
To save the Bitmap, you can use the Save method:
b.Save(myMemoryStream, ImageFormat.Png);
That was easy enough. Loading the PNG data into the Gdk# Pixbuf is also rather easy; you can use the appropriate constructor:
Pixbuf pb = new Gdk.Pixbuf(myMemoryStream);
You may need to reset the memory stream so the reading position is at the start of the stream before creating the Pixbuf.
A word of caution: I do not consider this the best, or even a "good" solution. Transferring data between two object-oriented data structures by serializing and deserializing the data has a certain code smell to it. I genuinely hope someone else can come up with a better solution.
EDIT: As for the used libraries: This answer uses only plain GDI+ (System.Drawing.Bitmap) and Gdk# (Gdk.Pixbuf). Note that a Gtk.Image is a widget that displays a Gdk.Pixbuf. As such, Gtk.Image is the equivalent of Windows Forms' PictureBox, whereas Gdk.Pixbuf is roughly equivalent to Windows Forms' System.Drawing.Bitmap.
EDIT2: After testing your code, I have found that there are three additional preconditions to ensure before you can run your minimum example:
As suspected above, you must reset the stream position to the beginning of the after saving your Bitmap and before loading your Pixbuf: ms.Position = 0;
You must compile the application for x86 CPUs.
You must invoke Gtk.Application.Init(); before you do anything with Pixbuf.
You may draw in Gtk# like in Winforms. For this you must obtain System.Drawing.Graphics object and then you may draw lines, images and text on it. You may do it like this: 1. Create new Widget. 2. Subscribe on ExposeEvent. 3. On event handler write some code:
protected void OnExposeEvent(object o, ExposeEventArgs e)
{
Gdk.Window window = e.Event.Window;
using (System.Drawing.Graphics graphics =
Gtk.DotNet.Graphics.FromDrawable(window))
{
// draw your stuff here...
graphics.DrawLine(new System.Drawing.Pen(System.Drawing.Brushes.Black), 0, 0, 30, 40);
}
}
Also you need to add reference on gtk-dotnet.dll.
try this ....
Gdk.Pixbuf pixbufImage = mew Gdk.Pixbuf(#"images/test.png");
Gtk.Image gtkImage = new Gtk.Image(pixbufImage);
Gdk.Image gdkImage = gtkImage.ImageProp;
This is a .net web site. I have a list of 100 x,y coordinates.
I need to display 100 octagonal shapes the centre point of which sits at the respective co-ordinate.
I toyed with doing this by passing an array to javascript and dynamically creating and positioning the images. But it looks awful and resizing the browser window causes problems etc.
So, can I create a graphic myself? I saw this code answering a similar question:
using (Bitmap bmp = new Bitmap(10, 10))
{
using (Graphics g = Graphics.FromImage(bmp))
{
g.Clear(Color.White);
g.DrawLine(Pens.Black, new PointF(9.56f, 4.1f),
new PointF(3.456789f, 2.12345f));
}
bmp.Save(#"c:\myimage.jpg", ImageFormat.Jpeg);
}
Can you draw octagons easily enough using this?
However, when I try to run the code above, I am getting this error.
A generic error occurred in GDI+
I don't want to spend a long time working out out to draw octagons etc. if I can't get it to run.
One last thing, I don't need to save the graphic, I just want to display it as though it were an image I'm getting from the images folder.
Edit: Further to suggestion below I have modified the code like this:
using (MemoryStream ms = new MemoryStream())
{
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] buffer = ms.GetBuffer();
HttpContext.Current.Response.OutputStream.Write(buffer, 0, buffer.Length);
}
This is putting my drawing on the screen. Is there anything that should be tweaked?
You probably don't have write access to C:\.
Instead of saving to disk, you should save to a MemoryStream, then render it to the HTTP response. (inside of an ASHX or MVC action)
this is how my code look now:
System.Drawing.Image objImage = System.Drawing.Image.FromFile(Server.MapPath("aaa.jpg"));
int height = objImage.Height;
int width = objImage.Width;
System.Drawing.Bitmap bitmapimage = new System.Drawing.Bitmap(objImage, width, height);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmapimage);
System.Drawing.Image bitmap2 = (System.Drawing.Image)Bitmap.FromFile(Server.MapPath("sem.png"));
g.DrawImage(bitmap2, (objImage.Width - bitmap2.Width) / 2, (objImage.Height - bitmap2.Height) / 2);
MemoryStream stream = new MemoryStream();
bitmapimage.Save(stream, ImageFormat.Jpeg);
String saveImagePath = Server.MapPath("ImagesMerge/") + "aaa.jpg";
bitmapimage.Save(saveImagePath);
imgBig.ImageUrl = saveImagePath;
The problem I have now is that the image is not displayed in browser, I don't understand why .
like jmaglasang said, I would suggest to you to use an ashx file and if you don't need to keep the image, just send the image stream directly to the http without saving it on the disk
so you only need to do something like
<img src="Handler.ashx?action=merge&image1=blah.jpg&image2=bloh.jpg">
look at this code for an example of how to send an image made in memory that does not exist on the drive
Bitmap is a subclass of Image, so there no need to convert Bitmap to Image. It already is...
Probably because saveImagePath will be a local path (such as c:\somepath\aaa.jpg) that is not reachable from the browser. You probably want to set the ImageUrl = "ImagesMerge/aaa.jpg" instead.
You can also try:
imgBig.ImageUrl = ResolveUrl(saveImagePath);
EDIT:
If saveImagePath is under the WebApplication Directory, doing some modifications on the directory structure i.e. modifying files, deleting and creating can cause the application pool to recycle, and once it reaches the maximum recycle count the application pool will be stopped causing "Server unavailable" error.
I would suggests to add/save/modify images on a separate directory (not under the Apps Directory) then create a Handler(ASHX) that will read the images, just an advice though.
MapPath will give you a physycal address, not a virtual address which is what the browser needs to get to the image.
You might be forgetting to set the Response.Headers. Check out the following example that shows how to create bar chart images and then display it on the screen:
http://www.highoncoding.com/Articles/399_Creating_Bar_Chart_Using__NET_Graphics_API.aspx