Update README.md

Author: DarthAffe

README.md

@@ -4,6 +4,14 @@
 [![GitHub](https://img.shields.io/github/license/DarthAffe/ScreenCapture.NET?style=for-the-badge)](https://github.com/DarthAffe/ScreenCapture.NET/blob/master/LICENSE)
 [![GitHub Repo stars](https://img.shields.io/github/stars/DarthAffe/ScreenCapture.NET?style=for-the-badge)](https://github.com/DarthAffe/ScreenCapture.NET/stargazers)
 
+## NuGet-Packages:
+| Package | Description |
+|---------|-------------|
+| [ScreenCapture.NET](https://www.nuget.org/packages/ScreenCapture.NET)| The core-package required to use ScreenCapture.NET captures or write your own. |
+| [ScreenCapture.NET.DX11](https://www.nuget.org/packages/ScreenCapture.NET.DX11) | DirectX 11 based capturing. Fast and supports the whole set of features. **This should always be used if possible!** |
+| [ScreenCapture.NET.DX9](https://www.nuget.org/packages/ScreenCapture.NET.DX9) | DirectX 9 based  capturing. Slower then DX 11 and does not support rotated screens and GPU-accelerated downscaling. Only useful if the DX11 package can't be used for some reason. |
+| [ScreenCapture.NET.X11](https://www.nuget.org/packages/ScreenCapture.NET.X11) | libX11 based capturing for the X-Window-System. Currently the only way to use ScreenCapture.NET on linux. Quite slow and can easily break depending on the X-Server config. Works on my machine, but it's not really a high proprity to support at the moment. Does not support rotated screens and GPU-accelerated downscaling. |
+
 ## Usage
 ```csharp
 // Create a screen-capture service
@@ -18,50 +26,81 @@ IEnumerable<Display> displays = screenCaptureService.GetDisplays(graphicsCards.F
 // Create a screen-capture for all screens you want to capture
 IScreenCapture screenCapture = screenCaptureService.GetScreenCapture(displays.First());
 
-// Register the regions you want to capture on the screen
+// Register the regions you want to capture om the screen
 // Capture the whole screen
-CaptureZone fullscreen = screenCapture.RegisterCaptureZone(0, 0, screenCapture.Display.Width, screenCapture.Display.Height);
+ICaptureZone fullscreen = screenCapture.RegisterCaptureZone(0, 0, screenCapture.Display.Width, screenCapture.Display.Height);
 // Capture a 100x100 region at the top left and scale it down to 50x50
-CaptureZone topLeft = screenCapture.RegisterCaptureZone(0, 0, 100, 100, downscaleLevel: 1);
+ICaptureZone topLeft = screenCapture.RegisterCaptureZone(0, 0, 100, 100, downscaleLevel: 1);
 
 // Capture the screen
 // This should be done in a loop on a seperate thread as CaptureScreen blocks if the screen is not updated (still image).
 screenCapture.CaptureScreen();
 
 // Do something with the captured image - e.g. access all pixels (same could be done with topLeft)
-// Locking is not neccessary in that case as we're capturing in the same thread,
-// but when using a threaded-approach (which is recommended) it prevents potential tearing of the data in the buffer.
-lock (fullscreen.Buffer)
+
+//Lock the zone to access the data. Remember to dispose the returned disposable to unlock again.
+using (fullscreen.Lock())
 {
-    // Stride is the width in bytes of a row in the buffer (width in pixel * bytes per pixel)
-    int stride = fullscreen.Stride;
-
-    Span<byte> data = new(fullscreen.Buffer);
-
-    // Iterate all rows of the image
-    for (int y = 0; y < fullscreen.Height; y++)
-    {
-        // Select the actual data of the row
-        Span<byte> row = data.Slice(y * stride, stride);
-
-        // Iterate all pixels
-        for (int x = 0; x < row.Length; x += fullscreen.BytesPerPixel)
-        {
-            // Data is in BGRA format for the DX11ScreenCapture
-            byte b = row[x];
-            byte g = row[x + 1];
-            byte r = row[x + 2];
-            byte a = row[x + 3];
-        }
-    }
+    // You have multiple options now:
+    // 1. Access the raw byte-data
+    ReadOnlySpan<byte> rawData = fullscreen.RawBuffer;
+
+    // 2. Use the provided abstraction to access pixels without having to care about low-level byte handling
+    // Get the image captured for the zone
+    IImage image = fullscreen.Image;
+
+    // Iterate all pixels of the image
+    foreach (IColor color in image)
+        Console.WriteLine($"A: {color.A}, R: {color.R}, G: {color.G}, B: {color.B}");
+
+    // Get the pixel at location (x = 10, y = 20)
+    IColor imageColorExample = image[10, 20];
+
+    // Get the first row
+    IImage.IImageRow row = image.Rows[0];
+    // Get the 10th pixel of the row
+    IColor rowColorExample = row[10];
+
+    // Get the first column
+    IImage.IImageColumn column = image.Columns[0];
+    // Get the 10th pixel of the column
+    IColor columnColorExample = column[10];
+
+    // Cuts a rectangle out of the original image (x = 100, y = 150, width = 400, height = 300)
+    IImage subImage = image[100, 150, 400, 300];
+
+    // All of the things above (rows, columns, sub-images) do NOT allocate new memory so they are fast and memory efficient, but for that reason don't provide raw byte access.
 }
+```
 
-// Move the top left zone more towards the center
-// Using the Update-method allows to move the zone without having to allocate 
-// new buffers and textures which yields a good performance gain if done at high framerates.
-screenCapture.UpdateCaptureZone(topLeft, x: 100, y: 200);
+IF you know which Capture-provider you're using it performs a bit better to not use the abstraction but a more low-level approach instead.   
+This is the same example as above but without using the interfaces:
+```csharp
+DX11ScreenCaptureService screenCaptureService = new DX11ScreenCaptureService();
+IEnumerable<GraphicsCard> graphicsCards = screenCaptureService.GetGraphicsCards();
+IEnumerable<Display> displays = screenCaptureService.GetDisplays(graphicsCards.First());
+DX11ScreenCapture screenCapture = screenCaptureService.GetScreenCapture(displays.First());
+
+CaptureZone<ColorBGRA> fullscreen = screenCapture.RegisterCaptureZone(0, 0, screenCapture.Display.Width, screenCapture.Display.Height);
+CaptureZone<ColorBGRA> topLeft = screenCapture.RegisterCaptureZone(0, 0, 100, 100, downscaleLevel: 1);
+
+screenCapture.CaptureScreen();
+
+using (fullscreen.Lock())
+{
+    RefImage<ColorBGRA> image = fullscreen.Image;
 
-// Note that resizing the zone is also possible but currently reinitializes the zone
-// -> no performance gain compared to removing and readding the zone.
-screenCapture.UpdateCaptureZone(topLeft, width: 20, height: 20);
+    foreach (ColorBGRA color in image)
+        Console.WriteLine($"A: {color.A}, R: {color.R}, G: {color.G}, B: {color.B}");
+
+    ColorBGRA imageColorExample = image[10, 20];
+
+    ReadOnlyRefEnumerable<ColorBGRA> row = image.Rows[0];
+    ColorBGRA rowColorExample = row[10];
+
+    ReadOnlyRefEnumerable<ColorBGRA> column = image.Columns[0];
+    ColorBGRA columnColorExample = column[10];
+
+    RefImage<ColorBGRA> subImage = image[100, 150, 400, 300];
+}
 ```