Develop Reference

Draw Images on Image/Canvas without showing

I want to create a collage (different images on an image). This works with a canvas which is defined and visible in my XAML. But how can I achieve this without showing the canvas?
System.Windows.Controls.Image img = new System.Windows.Controls.Image();
img.Source = new BitmapImage(new System.Uri(System.Environment.CurrentDirectory + "/" + b.Wert, System.UriKind.RelativeOrAbsolute));
TransformGroup tg = new TransformGroup();
double scaleX = (double)w / (double)img.Source.Width;
double scaleY = (double)h / (double)img.Source.Height;
tg.Children.Add(new ScaleTransform(scaleX, scaleY));
if (b.Rotation != null)
tg.Children.Add(new RotateTransform(b.Rotation, w/2, h/2));
tg.Children.Add(new TranslateTransform(x, y));
img.RenderTransform = tg;
canvas.Children.Add(img);
double dpi = 96d;
RenderTargetBitmap rtb = new RenderTargetBitmap(collage.Breite, collage.Hoehe, dpi, dpi, System.Windows.Media.PixelFormats.Default);
canvas.UpdateLayout();
rtb.Render(canvas);
// save as png
BitmapEncoder pngEncoder = new PngBitmapEncoder();
pngEncoder.Frames.Add(BitmapFrame.Create(rtb));
using (var fs = System.IO.File.OpenWrite("test.png"))
{
pngEncoder.Save(fs);
}

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.

How to Create High-Resolution Image from a FrameworkElement?

I have a FrameworkElement and I want to save it as a Height-Resolution Image (Jpeg). I tried the following code, but the results are not what I had hoped. I got an image with bad resolution when I print it with A4 as the paper size.
// ...
FrameworkElement element = this.Content;
element.Measure(new System.Windows.Size(double.PositiveInfinity, double.PositiveInfinity));
element.Arrange(new Rect(element.DesiredSize));
element.UpdateLayout();
// i used element.ActulaHeight and ActualWidth but not works.
RenderTargetBitmap bitmap = new RenderTargetBitmap((int)element.Width, (int)element.Height, GPFReporstPageSizeExtension.DPI, GPFReporstPageSizeExtension.DPI, System.Windows.Media.PixelFormats.Pbgra32);
bitmap.Render(element);
// ....

Finally i solved my problem, i posted the full solution in my blog "gamadev web site":
Saving FrameworkElement as Image
FrameworkElement element = myControl.Content;
// you can set the size as you need.
Size theTargetSize = new Size(1500,2000)
element.Measure(new System.Windows.Size(double.PositiveInfinity, double.PositiveInfinity));
element.Arrange(new Rect(theTargetSize ));
// to affect the changes in the UI, you must call this method at the end to apply the new changes
element.UpdateLayout();
double dpiScale = 300.0 / 96;
double dpiX = 300.0;
double dpiY = 300.0;
RenderTargetBitmap bmp = new RenderTargetBitmap(Convert.ToInt32(
(theTargetSize .Width) * dpiScale),
Convert.ToInt32((theTargetSize .Height) * dpiScale),
dpiX, dpiY, PixelFormats.Pbgra32);
bmp.Render(element);
element.Measure(new System.Windows.Size());
element.Arrange(new Rect());
element.UpdateLayout();
System.Windows.Media.Imaging.BitmapEncoder encoder = new System.Windows.Media.Imaging.PngBitmapEncoder();
MemoryStream myStream = new MemoryStream();
encoder.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(this.CreateRenderTargetBitmap()));
encoder.Save(myStream);
var img = System.Drawing.Bitmap.FromStream(myStream);
Bitmap bmp = new Bitmap((int)theTargetSize .Width, (int)theTargetSize .Height);
var g = Graphics.FromImage(bmp);
g.Clear(System.Drawing.Color.White);
g.DrawImage(this.GetPageAsImage(), (int)this.Margin.Left, (int)this.Margin.Top);
fileName = #”D:\myImage.png”;
bmp.Save(fileName);

How can add shape to BitmapImage in wpf and c#

I want to add path to image because I want to make curves on image. I don't know how can add curves to images. I want to draw shape on image and don't want to use canvas. because I want to convert line to Raster image this is my code:
Ellipse circle = new Ellipse();
circle.BeginInit();
circle.Height = 100;
circle.Width = 100;
circle.Stroke = System.Windows.Media.Brushes.Black;
circle.StrokeThickness = 1.0;
circle.Margin = new Thickness(0, 0, 0, 0);
circle.EndInit();
circle.Measure(new Size(200, 200));
circle.Arrange(
new Rect(new Size(200, 200)));
circle.UpdateLayout();
Line line = new Line();
line.BeginInit();
line.X1 = 0;
line.Y1 = 0;
line.X2 = 300;
line.Y2 = 300;
line.Stroke = System.Windows.Media.Brushes.Magenta;
line.StrokeThickness = 1;
line.EndInit();
line.Measure(new Size(300, 300));
line.Arrange(new
Rect(new Size(300, 300)));
SolidColorBrush blueBrush = new SolidColorBrush();
blueBrush.Color = Colors.Blue;
SolidColorBrush blackBrush = new SolidColorBrush();
blackBrush.Color = Colors.Black;
// Create a Path with black brush and blue fill
Path bluePath = new Path();
bluePath.BeginInit();
bluePath.Stroke = blackBrush;
bluePath.StrokeThickness = 3;
bluePath.Fill = blueBrush;
// Create a line geometry
LineGeometry blackLineGeometry = new LineGeometry();
blackLineGeometry.StartPoint = new Point(20, 200);
blackLineGeometry.EndPoint = new Point(300, 200);
// Create an ellipse geometry
EllipseGeometry blackEllipseGeometry = new EllipseGeometry();
blackEllipseGeometry.Center = new Point(80, 150);
blackEllipseGeometry.RadiusX = 50;
blackEllipseGeometry.RadiusY = 50;
// Create a rectangle geometry
RectangleGeometry blackRectGeometry = new RectangleGeometry();
Rect rct = new Rect();
rct.X = 80;
rct.Y = 167;
rct.Width = 150;
rct.Height = 30;
blackRectGeometry.Rect = rct;
// Add all the geometries to a GeometryGroup.
GeometryGroup blueGeometryGroup = new GeometryGroup();
blueGeometryGroup.Children.Add(blackLineGeometry);
blueGeometryGroup.Children.Add(blackEllipseGeometry);
blueGeometryGroup.Children.Add(blackRectGeometry);
// Set Path.Data
bluePath.Data = blueGeometryGroup;
bluePath.EndInit();
bluePath.Measure(new Size(300, 300));
bluePath.Arrange(new Rect(new Size(300, 300)));
RenderTargetBitmap RTbmap = new
RenderTargetBitmap(200, 200, 96, 96,
PixelFormats.Default);
RTbmap.Render(bluePath);
var renderTargetBitmap = RTbmap;
var bitmapImage = new BitmapImage();
var bitmapEncoder = new BmpBitmapEncoder();
bitmapEncoder.Frames.Add(BitmapFrame.Create(renderTargetBitmap));
using (var stream = new System.IO.MemoryStream())
{
bitmapEncoder.Save(stream);
stream.Seek(0, System.IO.SeekOrigin.Begin);
bitmapImage.BeginInit();
bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
bitmapImage.UriSource = new Uri("C:\\Users\\ErnaGroup.Com\\Pictures\\Pictures\\cartoon-ice-cream-3 - Copy.jpg"); // I want to add line to this image.
bitmapImage.StreamSource = stream;
bitmapImage.EndInit();
}
image1.Source = bitmapImage;
}
How can I do this?

Image is not a container control. You definitely need a container control like Canvas to hold your shapes.
Alternatively you can set your BitmapImage as Background of Canvas using ImageBrush and draw Path/Line/Ellipse on Canvas and later you can save your drawing on Canvas as a JPG image.
<Canvas>
<Canvas.Background>
<ImageBrush ImageSource="Your BitmapImage Path"></ImageBrush>
</Canvas.Background>
</Canvas>
Then you can save your modified data as a JPG image
public static void CreateBitmapFromVisual(Visual target, string filename)
{
// target will be your Canvas
// filename is the path where you want to save the image
if (target == null)
return;
Rect bounds = VisualTreeHelper.GetDescendantBounds(target);
RenderTargetBitmap rtb = new RenderTargetBitmap((Int32)bounds.Width, (Int32)bounds.Height, 96, 96, PixelFormats.Default);
rtb.Render(target);
JpegBitmapEncoder jpg = new JpegBitmapEncoder();
jpg.Frames.Add(BitmapFrame.Create(rtb));
using (Stream stm = File.Create(filename))
{
jpg.Save(stm);
}
}

RenderTargetBitmap problem

I am trying to add the image of a usercontrol to viewbox.
I am creating the usercontrol dynamically. I am using the code below.
private static RenderTargetBitmap CaptureScreen(Visual target, double dpiX, double dpiY)
{
if (target == null)
{
return null;
}
Rect bounds = VisualTreeHelper.GetDescendantBounds(target);
//RenderTargetBitmap rtb = new RenderTargetBitmap((int)(bounds.Width * dpiX / 96.0),
// (int)(bounds.Height * dpiY / 96.0),
// dpiX,
// dpiY,
// PixelFormats.Pbgra32);
RenderTargetBitmap rtb = new RenderTargetBitmap(596,596,dpiX,
dpiY,
PixelFormats.Pbgra32);
DrawingVisual dv = new DrawingVisual();
using (DrawingContext ctx = dv.RenderOpen())
{
VisualBrush vb = new VisualBrush(target);
ctx.DrawRectangle(vb, null, new Rect(new Point(), bounds.Size));
}
rtb.Render(dv);
return rtb;
}
I am creating the user control dynamically and passing this to capture screen method.
UserControls.UserControl1 uc1 = new UserControls.UserControl1();
visualList.Add(uc1);
for(int i = 0;i<=6;i++)
{
Image img = new Image();
img.Source = CaptureScreen(visualList[i], 96, 96);
img.Margin = new Thickness { Top = 2 };
usingWorkaround.Children.Add(img);
}
the VisualTreeHelper.GetDescendantBounds(target) is returning empty bounds. Thats why the image of the screen can not be created. Is there any other method to capture screen of dynamically created user control?

you can call Measure and Arrange As follows
private void ForceUpdate(FrameworkElement element, double width, double height)
{
Size size = new Size(width, height);
element.Measure(size);
element.Arrange(new Rect(0, 0, width, height));
element.UpdateLayout();
}

At the time when you try to create the image the controls don't yet exist in the visual tree and the size has not been calculated.
You will need to call Measure and Arrange on your visual first.