Develop Reference

Resize transparent image with Magick.NET

I got some weird issues when resizing an image with transparency in Magick.NET. I am using Q16-AnyCPU.
I am resizing a 100px image to 400px.
MagickImage image = new MagickImage("test.png");
image.Resize(400, 400);
image.Write("test_resized.png");
I have tried many combinations of image.FilterType and image.Interpolate without any good results.
Only when I use image.AdaptiveResize(400, 400);, it looks somewhat better, but not as expected. The final image I want to resize is much bigger and AdaptiveResize is very slow.
When I disable Alpha via image.Alpha(AlphaOption.Off); I looks quice nice, but I want to keep the alpha.
Source image (the white area is transparent):
What I get:
What I want:

I had to set VirtuaPixelMethod, thanks for the hint:
MagickImage image = new MagickImage("test.png");
image.VirtualPixelMethod = VirtualPixelMethod.Transparent;
image.Resize(400, 400);
image.Write("test_resized.png");

WinRT Bing.Maps - how add a image with a lat/lon bounding box?

I am able to add an image to my map just fine via code.
However when I zoom in/out, the image stays the same. I would like it scale relative to the map.
In the WPF version of the Map, you could use an ImageBrush for a MapPolygon and it would be constrained to the bounding box.
I tried the solution from this SO question, but it seems to have no effect on the Image.
imageLayer.Children.Clear();
MapLayer.SetPosition(_vm.RadarImage, new Location(_vm.Overlay.LatN, _vm.Overlay.LonW));
imageLayer.Children.Add(_vm.RadarImage);
shapeLayer.Shapes.Clear();
var rect = new MapPolygon();
rect.Locations.Add(new Location(_vm.Overlay.LatN, _vm.Overlay.LonW));
rect.Locations.Add(new Location(_vm.Overlay.LatS, _vm.Overlay.LonW));
rect.Locations.Add(new Location(_vm.Overlay.LatS, _vm.Overlay.LonE));
rect.Locations.Add(new Location(_vm.Overlay.LatN, _vm.Overlay.LonE));
rect.FillColor = Colors.Green;
shapeLayer.Shapes.Add(rect);
mappy.SetView(new LocationRect(new Location(_vm.Overlay.LatN + 0.0001, _vm.Overlay.LonW + 0.0001), new Location(_vm.Overlay.LatS - 0.0001, _vm.Overlay.LonE - 0.0001)));
This is the correct scaling.
When you zoom once via the Navigation, you can see the image is now larger than the Polygon

There isn't a simple solution for this. I have put together a sample app that shows one approach to do this. You can find it here: http://code.msdn.microsoft.com/Binding-and-Image-to-a-01a56e48 What I did was add a Canvas to the map, and then use the map to calculate the pixel coordinates of the bounding box for the image. I then used these pixel coordinates to scale and position the image on the canvas overtop the map. I've done something similar to create custom polygons that support image brushes in the past but haven't uploaded that code sample yet.

Images Scaling Down in draw in C#

Alright guys last little bit of this project I'll ask for help on I promise.
So I go to load the images, works fine however I notice upon loading that the dimensions of the image have been scaled down in the y to 300 (all are a constant value of 433) and up or down from their original width to 600.
I'm using the following method to load them
foreach (string file in Directory.EnumerateFiles(imagePath, "*.JPG"))
{
Image contents = Image.FromFile(file);
treesImage[count] = contents;
count++;
}
and this is the resulting image when I have it loaded.
http://i.stack.imgur.com/Q40kK.png
As you can see the image below the red rectangle is quite small
Any help would be appreciated. If you require any more information please post below and I'll make sure to edit the original question with the relevant information as soon as humanly possible.
EDIT: I am using a simple windows form application and not another graphical framework for my own reasons.
Thanks in advance :)

I'll assume you are using a PictureBox control to display the image.
When someone chooses a tree from your map, you obviously set the PictureBox Image property to the image object referenced by the index in the array. Use the Image object to set the ClientSize of the PictureBox control.
...
Image img = treesImage[idx];
MyPictureBox.SizeMode = PictureBoxSizeMode.Normal;
MyPictureBox.ClientSize = new Size(img.Width,img.Height);
MyPictureBox.Image = img;
...
Alternately you can define one size for your PictureBox and force all the images to be scaled to that size by setting the control SizeMode property to StretchImage declaratively.
I would recommend that you create a simple class (MyImageInfo for example) that would store the Path, Width, and Height of the images found in your first function into a list and then just as before when a user clicks to view an image you set the width and height of the PictureBox and then call the LoadAsync(path) method to get the image. then you aren't storing all images in memory at once, just as you need them since it doesn't look like this requires a lot of quick jumping from image to image.

C# drawing in layers

I have an idea and maybe you guys can give me a good start or an idea in which path might be correct.
I have a picturebox right now loading a specific bmp file. What I want to do is load this bmp file into the picturebox and then load another picture on top of it. The kicker to this all is the 2nd picture must be drawn. The 2nd picture is just a fill in black box. This black box must also overlay on the first image exactly right, the black box has cordinates from paint on it (yes we have the # of the cordaints).
Still think the picturebox is the way to go, or is there a way to load paint into this, and then paint on top of the paint image?
1) Need to load an image
2) Need to read a specific file that has cords
3) Need to draw a black rectangle that matches those coords (Those cords were created in paint).
What do you think the best way to approach this is? A Picture box with code to draw in the cords of the redacted image

Here's a code sample that should do what you're after:
//Load in an image
pbTest.Image = Image.FromFile("c:\\Chrysanthemum.jpg");
//Create the graphics surface to draw on
using (Graphics g = Graphics.FromImage(pbTest.Image))
{
using (SolidBrush brush = new SolidBrush(Color.Black))
{
//Draw a black rectangle at some coordinates
g.FillRectangle(brush, new Rectangle(0, 0, 20, 10));
//Or alternatively, given some points
//I'm manually creating the array here to prove the point, you'll want to create your array from your datasource.
Point[] somePoints = new Point[] { new Point(1,1), new Point(20,25), new Point(35, 50), new Point(90, 100) };
g.FillPolygon(brush, somePoints);
}
}
The finished article:

This answer is written to apply to both web and non-web uses of C# (why I did not give specific examples.)
GDI and other graphics libs all have functions that will paint a filled rectangle on top of an image. This is the way to go. If you use two images there is a good chance for a standard user and a great chance for a hacker they will be able to view just the original image, exposing the information you are trying to hide.
If you only send an image with the areas redacted, you will never have to worry about them being seen.

C#: Retain size despite different resolution using Graphics.DrawImage

I am trying to draw two images side-by-side using the C# Drawing namespace.
Here is a very simple example that assumes we have two images of the same height:
Image[] oldImages = GetOldImages();
var newImage = new Bitmap(oldImages[0].Width + oldImages[1].Width, 800);
using (var newImageGraphics = Graphics.FromImage(newImage))
{
newImageGraphics.DrawImage(oldImages[0], 0, 0);
newImageGraphics.DrawImage(oldImages[1], oldImage[0].Width, 0);
newImageGraphics.Save();
}
This works OK if the resolution of the two old images are the same.
However, if the resolutions are different then the image is resized, causing problems. For example, if the first image has a different resolution, then the second image will be positioned incorrectly.
Does anyone know how I can fix this problem easily? Ideally I want the original image's height and width to remain the same when they are drawn on to the new image.

Try this trick:
Bitmap picture_1 = new Bitmap(picture_1_path);
Graphics graphics = Graphics.FromImage(picture_1);
Bitmap picture_2 = new Bitmap(picture_2_path);
picture_2.SetResolution(graphics.DpiX, graphics.DpiY);
//Then do with pictures anything

Basically you'll need to resize the second image before adding to the new image.
Though as you say you want to retain the original height and width you'll need to change the canvas size of the second image. This increases the size of the image by adding empty space around the actual image. If the second image is larger than the first you'll need to do this to the first image instead.