2003-2014 The Khronos Group Inc.
eglCreateWindowSurface 3G
eglCreateWindowSurface create a new EGL window surface

## C Specification

EGLSurface `eglCreateWindowSurface` EGLDisplay display EGLConfig config NativeWindowType native_window EGLint const * attrib_list

## Parameters

display

  Specifies the EGL display connection.

config

  Specifies the EGL frame buffer configuration that defines the frame buffer resource available to the surface.

native_window

  Specifies the native window.

attrib_list

  Specifies window surface attributes. May be `NULL` or empty (first attribute is `EGL_NONE`).

## Description

`eglCreateWindowSurface` creates an EGL window surface and returns its handle. If `eglCreateWindowSurface` fails to create a window surface, `EGL_NO_SURFACE` is returned.

Surface attributes are specified as a list of attribute-value pairs, terminated with `EGL_NONE`. Accepted attributes are:

`EGL_RENDER_BUFFER`

  Specifies which buffer should be used for client API rendering to the window. If its value is `EGL_SINGLE_BUFFER`, then client APIs should render directly into the visible window. If its value is `EGL_BACK_BUFFER`, then client APIs should render into the back buffer. The default value of `EGL_RENDER_BUFFER` is `EGL_BACK_BUFFER`.

  Client APIs may not be able to respect the requested rendering buffer. To determine the actual buffer being rendered to by a context, call eglQueryContext.

`EGL_VG_ALPHA_FORMAT`

  Specifies how alpha values are interpreted by OpenVG when rendering to the surface. If its value is `EGL_VG_ALPHA_FORMAT_NONPRE`, then alpha values are not premultipled. If its value is `EGL_VG_ALPHA_FORMAT_PRE`, then alpha values are premultiplied. The default value of `EGL_VG_ALPHA_FORMAT` is `EGL_VG_ALPHA_FORMAT_NONPRE`.

`EGL_VG_COLORSPACE`

  Specifies the color space used by OpenVG when rendering to the surface. If its value is `EGL_VG_COLORSPACE_sRGB`, then a non-linear, perceptually uniform color space is assumed, with a corresponding VGImageFormat of form `VG_s*`. If its value is `EGL_VG_COLORSPACE_LINEAR`, then a linear color space is assumed, with a corresponding VGImageFormat of form `VG_l*`. The default value of `EGL_VG_COLORSPACE` is `EGL_VG_COLORSPACE_sRGB`.

Any EGL rendering context that was created with respect to config can be used to render into the surface. Use eglMakeCurrent to attach an EGL rendering context to the surface.

Use eglQuerySurface to retrieve the ID of config.

Use eglDestroySurface to destroy the surface.

## Notes

Attributes `EGL_RENDER_BUFFER`, `EGL_VG_ALPHA_FORMAT`, and `EGL_VG_COLORSPACE`, and the corresponding attribute values, are supported only if the EGL version is 1.2 or greater.

The `EGL_VG_ALPHA_FORMAT` and `EGL_VG_COLORSPACE` attributes are used only by OpenVG. EGL itself, and other client APIs such as OpenGL and OpenGL ES , do not distinguish multiple colorspace models. Refer to section 11.2 of the OpenVG 1.0 specification for more information. The native window system's use and interpretation of alpha values is outside the scope of EGL, although the preferred behavior is for the window system to ignore the value of `EGL_VG_ALPHA_FORMAT` when compositing window surfaces.

## Errors

`EGL_NO_SURFACE` is returned if creation of the context fails.

`EGL_BAD_DISPLAY` is generated if display is not an EGL display connection.

`EGL_NOT_INITIALIZED` is generated if display has not been initialized.

`EGL_BAD_CONFIG` is generated if config is not an EGL frame buffer configuration.

`EGL_BAD_NATIVE_WINDOW` may be generated if native_window is not a valid native window.

`EGL_BAD_ATTRIBUTE` is generated if attrib_list contains an invalid window attribute or if an attribute value is not recognized or is out of range.

`EGL_BAD_ALLOC` is generated if there are not enough resources to allocate the new surface.

`EGL_BAD_MATCH` is generated if the attributes of native_window do not correspond to config or if config does not support rendering to windows (the `EGL_SURFACE_TYPE` attribute does not contain `EGL_WINDOW_BIT`).

`EGL_BAD_MATCH` is generated if config does not support the specified OpenVG alpha format attribute (the value of `EGL_VG_ALPHA_FORMAT` is `EGL_VG_ALPHA_FORMAT_PRE` and the `EGL_VG_ALPHA_FORMAT_PRE_BIT` is not set in the `EGL_SURFACE_TYPE` attribute of config) or colorspace attribute (the value of `EGL_VG_COLORSPACE` is `EGL_VG_COLORSPACE_LINEAR` and the `EGL_VG_COLORSPACE_LINEAR_IT` is not set in the `EGL_SURFACE_TYPE` attribute of config).

## See Also

eglDestroySurface, eglChooseConfig, eglGetConfigs, eglMakeCurrent, eglQuerySurface

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