XAppCaptureReadScreenshotStream

Article
06/22/2023

Reads a screenshot stream.

Syntax

HRESULT XAppCaptureReadScreenshotStream(  
         XAppCaptureScreenshotStreamHandle handle,  
         uint64_t startPosition,  
         uint32_t bytesToRead,  
         uint8_t* buffer,  
         uint32_t* bytesWritten  
)

Parameters

handle _In_
Type: XAppCaptureScreenshotStreamHandle

Screenshot stream handle returned by calling XAppCaptureOpenScreenshotStream.

startPosition _In_
Type: uint64_t

Position in the stream to start reading.

bytesToRead _In_
Type: uint32_t

Number of bytes in the stream to read.

buffer _Out_writes_to_(bytesToRead,bytesWritten)
Type: uint8_t

Buffer to contain the bytes read by XAppCaptureReadScreenshotStream.

bytesWritten _Out_
Type: uint32_t*

Number of bytes actually written to the buffer.

Return value

Type: HRESULT

Function result.

Remarks

Note

This function isn't safe to call on a time-sensitive thread. For more information, see Time-sensitive threads.

Before reading a screenshot you must open a screenshot stream with XAppCaptureOpenScreenShotStream. This will produce the XAppCaptureScreenshotStreamHandle needed for the handle parameter. You may then call this function to read the screenshot. The startPosition and bytesToRead parameters will allow you to read a section of the screenshot, this is useful for reading a large stream a section at a time. You can get the total size of the stream from the totalBytes output parameter in XAppCaptureOpenScreenShotStream. The output parameters buffer and bytesWritten will help you accurately read the data returned from this function. After reading the screenshot data close the screenshot stream with XAppCaptureCloseScreenshotStream in order to avoid a memory leak.

const int MAX_DATA = 1024;

XAppCaptureTakeScreenshotResult takeScreenshotResult = {0};
XAppCaptureScreenshotStreamHandle handle = nullptr;
XAppCaptureScreenshotFormatFlag screenshotFormat = XAppCaptureScreenshotFormatFlag::SDR;

BYTE buffer[MAX_DATA];
HANDLE file = INVALID_HANDLE_VALUE;
UINT64 totalBytesRead = 0;
UINT64 totalBytesToRead = 0;
bool hdrAvailable = false;

/* ... obtain takeScreenshotResult with XAppCaptureTakeScreenshot. Refer to corresponding documentation ... */

hdrAvailable = static_cast<bool>(takeScreenshotResult.availableScreenshotFormats & XAppCaptureScreenshotFormatFlag::HDR);

/* Note: It is optional to obtain the HDR screenshot, if HDR is available. You will need to call XAppCaptureOpenScreenshotStream twice to obtain both SDR and HDR screenshots */
if (hdrAvailable)
{
    screenshotFormat = XAppCaptureScreenshotFormatFlag::HDR;
}

if (FAILED_LOG(XAppCaptureOpenScreenshotStream(takeScreenshotResult.localId, screenshotFormat, &handle, &totalBytesToRead)))
{
    return;
}

/* T:\ is one example of a writeable local directory. Be aware that the T:\ drive can be invalidated on suspend or resume, and as such it's better to use Persistant Local Storage */
file = CreateFileA(hdrAvailable ? "T:\\MyScreenshot.jxr" : "T:\\MyScreenshot.png", GENERIC_READ | GENERIC_WRITE, 0, 0, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
if (file == INVALID_HANDLE_VALUE)
{
    /* You must always call XAppCaptureCloseScreenshotStream on an open XAppCaptureScreenshotStreamHandle to avoid a memory leak */
    FAILED_LOG(XAppCaptureCloseScreenshotStream(handle));
    return;
}

while (totalBytesRead < totalBytesToRead)
{
    uint32_t bytesRead = 0;
    uint32_t bytesWritten = 0;
    if (SUCCEEDED(XAppCaptureReadScreenshotStream(handle, totalBytesRead, sizeof(buffer), buffer, &bytesRead)))
    {
        WriteFile(file, buffer, bytesRead, &bytesWritten, NULL);

        totalBytesRead += bytesRead;
    }
    else
    {
        break;
    }
}

FAILED_LOG(XAppCaptureCloseScreenshotStream(handle));

CloseHandle(file);

Requirements

Header: XAppCapture.h

Library: xgameruntime.lib

Supported platforms: Windows, Xbox One family consoles and Xbox Series consoles

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