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DarthAffe authored Sep 11, 2023
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[![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
Expand All @@ -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];
}
```

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