Develop Reference

how to have my rectangle always on the middle of the image without knowing the size of the incomming image

Trying to add a watermark image to a png image, i´ve been able to do it, but i want to take out the hardCoded size regulation for the rectangle of the waterMark, and make it always stay in the center of the image. How can i achieve this.
public Form1()
{
InitializeComponent();
picBox.Parent = this;
picBox.Dock = DockStyle.Fill;
picBox.SizeMode = PictureBoxSizeMode.Zoom;
Bitmap Jpg = new Bitmap(#"C:\Users\tferreira\Desktop\213123.PNG");
using (Bitmap Bmp = new Bitmap(#"C:\Users\tferreira\Desktop\logo.png"))
{
using (Bitmap WatermarkBmp = new Bitmap(Bmp, Bmp.Width / 1, Bmp.Height / 1))
{
picBox.Image = WatermarkImage(Jpg, WatermarkBmp, new Point(400, 100), 0.40F);
}
}
}
public Bitmap WatermarkImage(Bitmap ImageToWatermark, Bitmap Watermark, Point WatermarkPosition, float Opacity)
{
using (Graphics G = Graphics.FromImage(ImageToWatermark))
{
using (ImageAttributes IA = new ImageAttributes())
{
ColorMatrix CM = new ColorMatrix();
CM.Matrix33 = Opacity;
IA.SetColorMatrix(CM);
G.DrawImage(Watermark, new Rectangle(WatermarkPosition, Watermark.Size), 0, 0, Watermark.Width, Watermark.Height, GraphicsUnit.Pixel, IA);
}
}
return ImageToWatermark;
}
Right now the images are hardCoded but that will be taken out. If anyone can help me make this watermark allways stay centered i thank you.

I fixed this problem with this nice peace of code.
System.Drawing.Image img = System.Drawing.Image.FromFile(JpgFilePath);
Bitmap jpg = new Bitmap(img);
filePath = JpgFilePath;
int Width = jpg.Width;
int Height = jpg.Height;
jpg.SetResolution(300, 300);
WaterMarked = WatermarkImage(jpg, WaterMarkBit, new Point((Width - WaterMarkBit.Width) / 2, (Height - WaterMarkBit.Height) / 2), 0.4F);
WaterMarked.Save(filePath.Replace(".jpg", "") + ".tif", ImageFormat.Tiff);
filesJpgForTif.Add(JpgFilePath.Replace("jpg", "tif"));
Using the the sizes of the image and sizes of the watermark and divide it by 2 it makes the image always stay centered.

How to save bmp (image) to file

I want to Video File thumbnail. Get Video path and convert to Image. Then convert to bmp, and save the bmp as an image file. If this is possible, please show me a way.
private void add_Video_Image(string sFullname_Path_of_Video)
{
//*create mediaplayer in memory and jump to position
MediaPlayer mediaPlayer = new MediaPlayer();
mediaPlayer.MediaOpened += new EventHandler(mediaplayer_OpenMedia);
mediaPlayer.ScrubbingEnabled = true;
mediaPlayer.Open(new Uri(sFullname_Path_of_Video));
mediaPlayer.Position = TimeSpan.FromSeconds(0);
}
private void mediaplayer_OpenMedia(object sender, EventArgs e)
{
MediaPlayer mediaPlayer = sender as MediaPlayer;
DrawingVisual drawingVisual = new DrawingVisual();
DrawingContext drawingContext = drawingVisual.RenderOpen();
drawingContext.DrawVideo(mediaPlayer, new Rect(0, 0, 160, 100));
drawingContext.Close();
double dpiX = 1 / 200;
double dpiY = 1 / 200;
RenderTargetBitmap bmp = new RenderTargetBitmap(160, 100, dpiX, dpiY, PixelFormats.Pbgra32);
bmp.Render(drawingVisual);
Image newImage = new Image();
newImage.Source = bmp;
newImage.Stretch = Stretch.Uniform;
newImage.Height = 100;
//save bmp to image
}

Please check this link. It holds the answer to your question: Easiest way of saving wpf Image control to a file
You can do the save prior to setting the 'RenderTargetBitmap' to the 'Image Control'.

Blur effect on image: different result before and after saving

I have a bug in my image editor with the blur tool.
When I select the rectangle to set the blur effect, and when I apply, result is a bit different see:
To create the "Before" I do:
var blurredImage = ExtractImageToBlur(); // extract the selected area from image
BlurredImageRectangle.Fill = new ImageBrush(blurredImage);
var effect = new BlurEffect();
effect.KernelType = KernelType.Gaussian;
effect.RenderingBias = RenderingBias.Quality;
effect.Radius = m_blurValue;
BlurredImageRectangle.Effect = effect;
To create the "After", I do:
var blurredImage = ExtractImageToBlur(); // extract the selected area from image
Rectangle rectangleToRender = new Rectangle();
rectangleToRender.Fill = new ImageBrush(blurredImage);
var effect = new BlurEffect();
effect.KernelType = KernelType.Gaussian;
effect.RenderingBias = RenderingBias.Quality;
effect.Radius = m_blurValue;
rectangleToRender.Effect = effect;
Size size = new Size(croppedImg.PixelWidth, croppedImg.PixelHeight);
rectangleToRender.Measure(size);
rectangleToRender.Arrange(new Rect(size));
var render = new RenderTargetBitmap(croppedImg.PixelWidth, croppedImg.PixelHeight, 96, 96, PixelFormats.Pbgra32);
render.Render(rectangleToRender);
// Merge the source with the blurred section
DrawingVisual drawingVisual = new DrawingVisual();
using (DrawingContext context = drawingVisual.RenderOpen())
{
int left = (int)(Canvas.GetLeft(BlurredImageRectangle) * WidthRatio);
int top = (int)(Canvas.GetTop(BlurredImageRectangle) * HeightRatio);
context.DrawImage(Source, new Rect(0, 0, Source.PixelWidth, Source.PixelHeight));
context.DrawImage(render, new Rect(left, top, croppedImg.PixelWidth, croppedImg.PixelHeight));
}
var bitmap = new RenderTargetBitmap(Source.PixelWidth, Source.PixelHeight, 96, 96, PixelFormats.Pbgra32);
bitmap.Render(drawingVisual);
And when I play with the blur radius, its sometimes a lot more different from both images.
Why its not the same?

Found the problem.
When I was drawing the rectangle on the screen, I applied the blur effect on the pixels on the screen.
When I hit save, the blur effect is applied on the pixel on the image on disk.
Huge difference.

Take a screenshot of a WPF window with the predefined image size without losing quality

When I take a screenshot of a current WPF window, the image resolution is that of my monitor (if the app is maximized), which is ok. However, if I was to print that image to a much bigger format, the image would look blurry. I found the way to capture the current window, and save it as a png file, but it's not doing the trick. The image is saved with the resolution I set, but the actual wpf window takes only a small portion of the saved image. Example is taken from:
http://blogs.msdn.com/b/saveenr/archive/2008/09/18/wpf-xaml-saving-a-window-or-canvas-as-a-png-bitmap.aspx
var screen = System.Windows.Application.Current.Windows.OfType<Window>().SingleOrDefault(x => x.IsActive);
var rtb = new RenderTargetBitmap(4000, 4000, 96, 96, PixelFormats.Pbgra32);
rtb.Render(screen);
var enc = new System.Windows.Media.Imaging.PngBitmapEncoder();
enc.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(rtb));
using (var stm = System.IO.File.Create("ScreenShot.png"))
{
enc.Save(stm);
using (Image img = Image.FromStream(stm))
{
Rectangle dest = new Rectangle(0, 0, 6000, 4000);
using (Graphics imgG = Graphics.FromImage(img))
{
imgG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
imgG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
imgG.DrawImage(img, dest);
}
img.Save("NewScreenShot.png");
}
}
So basically, I'd like to capture the screenshot with the resolution of 4000 x 4000, if that's possible, without losing quality.
The above code produces an image of 4000 x 4000, however the screenshot only takes a small portion of it, its original resolution.

To scale your image, you can use a DrawingVisual and a ScaleTransform :
var w = 4000;
var h = 4000;
var screen = System.Windows.Application.Current.Windows.OfType<Window>().SingleOrDefault(x => x.IsActive);
var visual = new DrawingVisual();
using (var context = visual.RenderOpen())
{
context.DrawRectangle(new VisualBrush(screen),
null,
new Rect(new Point(), new Size(screen.Width, screen.Height)));
}
visual.Transform = new ScaleTransform(w / screen.ActualWidth, h / screen.ActualHeight);
var rtb = new RenderTargetBitmap(w, h, 96, 96, PixelFormats.Pbgra32);
rtb.Render(visual);
var enc = new PngBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(rtb));
using (var stm = File.Create("ScreenShot.png"))
{
enc.Save(stm);
}

re-sizing image in c# doesn't work

I am trying to resize image to width=100 height=100
public ActionResult RegisterUser(userAuthModel user, HttpPostedFileBase userimage)
{
if (userimage.ContentLength > 0 && userimage != null)
{
string fname = userimage.FileName;
var path = Server.MapPath("~/Images/User_DP/" + userimage.FileName);
var image_100 = new System.Drawing.Bitmap(userimage, new Size(100, 100));
userimage.SaveAs(path);
}
.
.
.
.
.
}
Here I am using bitmap approach to resize imgae to some specific width and height.
But this shows me error in line-
var image_100 = new System.Drawing.Bitmap(userimage, new Size(100, 100));
of invalid arguments. How Do Ii resize image with using bitmap?

The System.Drawing.Bitmap class asks for two parameters in the constructor your are using:
System.Drawing.Image
System.Drawing.Size
In your code, you are passing the size correctly, but not the image. HttpPostedFileBase does not extend the Image class.
You will need to change that part of your code. If you are using the HttpPostedFileBase as a stream, then keep in mind that System.Drawing.Bitmap has no constructor asking for a Stream and a Size.
References:
System.Drawing.Image
System.Web.HttpPostedFileBase

you have to use mentioned method it may help you
private static BitmapFrame CreateResizedImage(ImageSource source, int width, int height, int margin)
{
var rect = new Rect(margin, margin, width - margin * 2, height - margin * 2);
var group = new DrawingGroup();
RenderOptions.SetBitmapScalingMode(group, BitmapScalingMode.HighQuality);
group.Children.Add(new ImageDrawing(source, rect));
var drawingVisual = new DrawingVisual();
using (var drawingContext = drawingVisual.RenderOpen())
drawingContext.DrawDrawing(group);
var resizedImage = new RenderTargetBitmap(
width, height, // Resized dimensions
96, 96, // Default DPI values
PixelFormats.Default); // Default pixel format
resizedImage.Render(drawingVisual);
return BitmapFrame.Create(resizedImage);
}