| <?xml version="1.0" encoding="UTF-8" standalone="no"?> |
| <!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml"> |
| <head> |
| <title xmlns:xlink="http://www.w3.org/1999/xlink">eglQuerySurface - EGL Reference Pages</title> |
| <link rel="stylesheet" type="text/css" href="khronos-man.css"/> |
| <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"/> |
| </head> |
| <body> |
| <header/> |
| <div class="refentry" id="eglQuerySurface"> |
| <div class="titlepage"/> |
| <div class="refnamediv"> |
| <h2>Name</h2> |
| <p>eglQuerySurface — |
| return <abbr class="acronym">EGL</abbr> surface information |
| </p> |
| </div> |
| <div class="refsynopsisdiv"> |
| <h2>C Specification</h2> |
| <div class="funcsynopsis"> |
| <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table"> |
| <tr> |
| <td> |
| <code class="funcdef">EGLBoolean <strong class="fsfunc">eglQuerySurface</strong>(</code> |
| </td> |
| <td>EGLDisplay <var class="pdparam">display</var>, </td> |
| </tr> |
| <tr> |
| <td> </td> |
| <td>EGLSurface <var class="pdparam">surface</var>, </td> |
| </tr> |
| <tr> |
| <td> </td> |
| <td>EGLint <var class="pdparam">attribute</var>, </td> |
| </tr> |
| <tr> |
| <td> </td> |
| <td>EGLint * <var class="pdparam">value</var><code>)</code>;</td> |
| </tr> |
| </table> |
| <div class="funcprototype-spacer"> </div> |
| </div> |
| </div> |
| <div class="refsect1" id="parameters"> |
| <h2>Parameters</h2> |
| <div class="variablelist"> |
| <dl class="variablelist"> |
| <dt> |
| <span class="term"> |
| <em class="parameter"> |
| <code>display</code> |
| </em> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Specifies the EGL display connection. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <em class="parameter"> |
| <code>surface</code> |
| </em> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Specifies the EGL surface to query. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <em class="parameter"> |
| <code>attribute</code> |
| </em> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Specifies the EGL surface attribute to be returned. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <em class="parameter"> |
| <code>value</code> |
| </em> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the requested value. |
| </p> |
| </dd> |
| </dl> |
| </div> |
| </div> |
| <div class="refsect1" id="description"> |
| <h2>Description</h2> |
| <p> |
| <code class="function">eglQuerySurface</code> returns in |
| <em class="parameter"><code>value</code></em> the value of |
| <em class="parameter"><code>attribute</code></em> for <em class="parameter"><code>surface</code></em>. |
| <em class="parameter"><code>attribute</code></em> can be one of the following: |
| </p> |
| <div class="variablelist"> |
| <dl class="variablelist"> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_CONFIG_ID</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the ID of the EGL frame buffer configuration |
| with respect to which the surface was created. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_GL_COLORSPACE</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the color space used by OpenGL and OpenGL ES |
| when rendering to the surface, either |
| <code class="constant">EGL_GL_COLORSPACE_SRGB</code> or |
| <code class="constant">EGL_GL_COLORSPACE_LINEAR</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_HEIGHT</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the height of the surface in pixels. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_HORIZONTAL_RESOLUTION</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the horizontal dot pitch of the display on |
| which a window surface is visible. The value |
| returned is equal to the actual dot pitch, in |
| pixels/meter, multiplied by the constant value |
| <code class="constant">EGL_DISPLAY_SCALING</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_LARGEST_PBUFFER</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the same attribute value specified when the |
| surface was created with |
| <a class="citerefentry" href="eglCreatePbufferSurface.xhtml"><span class="citerefentry"><span class="refentrytitle">eglCreatePbufferSurface</span></span></a>. |
| For a window or pixmap surface, |
| <em class="parameter"><code>value</code></em> is not modified. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_MIPMAP_LEVEL</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns which level of the mipmap to render to, if |
| texture has mipmaps. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_MIPMAP_TEXTURE</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns <code class="constant">EGL_TRUE</code> if texture has |
| mipmaps, <code class="constant">EGL_FALSE</code> otherwise. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_MULTISAMPLE_RESOLVE</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the filter used when resolving the |
| multisample buffer. The filter may be either |
| <code class="constant">EGL_MULTISAMPLE_RESOLVE_DEFAULT</code> |
| or <code class="constant">EGL_MULTISAMPLE_RESOLVE_BOX</code>, |
| as described for |
| <a class="citerefentry" href="eglSurfaceAttrib.xhtml"><span class="citerefentry"><span class="refentrytitle">eglSurfaceAttrib</span></span></a>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_PIXEL_ASPECT_RATIO</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the aspect ratio of an individual pixel (the |
| ratio of a pixel's width to its height). The value |
| returned is equal to the actual aspect ratio |
| multiplied by the constant value |
| <code class="constant">EGL_DISPLAY_SCALING</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_RENDER_BUFFER</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the buffer which client API rendering is |
| requested to use. For a window surface, this is the |
| same attribute value specified when the surface was |
| created. For a pbuffer surface, it is always |
| <code class="constant">EGL_BACK_BUFFER</code>. For a pixmap |
| surface, it is always |
| <code class="constant">EGL_SINGLE_BUFFER</code>. To determine |
| the actual buffer being rendered to by a context, |
| call |
| <a class="citerefentry" href="eglQueryContext.xhtml"><span class="citerefentry"><span class="refentrytitle">eglQueryContext</span></span></a>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_SWAP_BEHAVIOR</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the effect on the color buffer when posting |
| a surface with |
| <a class="citerefentry" href="eglSwapBuffers.xhtml"><span class="citerefentry"><span class="refentrytitle">eglSwapBuffers</span></span></a>. |
| Swap behavior may be either |
| <code class="constant">EGL_BUFFER_PRESERVED</code> or |
| <code class="constant">EGL_BUFFER_DESTROYED</code>, as |
| described for |
| <a class="citerefentry" href="eglSurfaceAttrib.xhtml"><span class="citerefentry"><span class="refentrytitle">eglSurfaceAttrib</span></span></a>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_TEXTURE_FORMAT</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns format of texture. Possible values are |
| <code class="constant">EGL_NO_TEXTURE</code>, |
| <code class="constant">EGL_TEXTURE_RGB</code>, and |
| <code class="constant">EGL_TEXTURE_RGBA</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_TEXTURE_TARGET</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns type of texture. Possible values are |
| <code class="constant">EGL_NO_TEXTURE</code>, or |
| <code class="constant">EGL_TEXTURE_2D</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_VERTICAL_RESOLUTION</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the vertical dot pitch of the display on |
| which a window surface is visible. The value |
| returned is equal to the actual dot pitch, in |
| pixels/meter, multiplied by the constant value |
| <code class="constant">EGL_DISPLAY_SCALING</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_VG_ALPHA_FORMAT</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the interpretation of alpha values used by |
| OpenVG when rendering to the surface, either |
| <code class="constant">EGL_VG_ALPHA_FORMAT_NONPRE</code> or |
| <code class="constant">EGL_VG_ALPHA_FORMAT_PRE</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_VG_COLORSPACE</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the color space used by OpenVG when rendering to |
| the surface, either |
| <code class="constant">EGL_VG_COLORSPACE_sRGB</code> or |
| <code class="constant">EGL_VG_COLORSPACE_LINEAR</code>. |
| </p> |
| </dd> |
| <dt> |
| <span class="term"> |
| <code class="constant">EGL_WIDTH</code> |
| </span> |
| </dt> |
| <dd> |
| <p> |
| Returns the width of the surface in pixels. |
| </p> |
| </dd> |
| </dl> |
| </div> |
| </div> |
| <div class="refsect1" id="notes"> |
| <h2>Notes</h2> |
| <p> |
| Attribute <code class="constant">EGL_GL_COLORSPACE</code> is supported |
| only if the EGL version is 1.5 or greater. |
| </p> |
| <p> |
| Attribute <code class="constant">EGL_MULTISAMPLE_RESOLVE</code> is |
| supported only if the EGL version is 1.4 or greater. |
| </p> |
| <p> |
| Attributes <code class="constant">EGL_DISPLAY_SCALING</code>. |
| <code class="constant">EGL_HORIZONTAL_RESOLUTION</code>, |
| <code class="constant">EGL_PIXEL_ASPECT_RATIO</code>, |
| <code class="constant">EGL_RENDER_BUFFER</code>, |
| <code class="constant">EGL_SWAP_BEHAVIOR</code>, and |
| <code class="constant">EGL_VERTICAL_RESOLUTION</code> are supported |
| only if the EGL version is 1.2 or greater. |
| </p> |
| <p> |
| Querying attributes <code class="constant">EGL_TEXTURE_FORMAT</code>, |
| <code class="constant">EGL_TEXTURE_TARGET</code>, |
| <code class="constant">EGL_MIPMAP_TEXTURE</code>, or |
| <code class="constant">EGL_MIPMAP_LEVEL</code> for a non-pbuffer |
| surface is not an error, but <em class="parameter"><code>value</code></em> is |
| not modified. |
| </p> |
| <p> |
| <code class="constant">EGL_DISPLAY_SCALING</code> is the constant |
| value 10000. Floating-point values such as resolution and |
| pixel aspect ratio are scaled by this value before being |
| returned as integers so that sufficient precision to be |
| meaningful will be retained in the returned value. |
| </p> |
| <p> |
| For an offscreen (pbuffer or pixmap) surface, or a surface |
| whose pixel dot pitch or aspect ratio are unknown, querying |
| <code class="constant">EGL_HORIZONTAL_RESOLUTION</code>, |
| <code class="constant">EGL_PIXEL_ASPECT_RATIO</code>, or |
| <code class="constant">EGL_VERTICAL_RESOLUTION</code> will return the |
| constant value <code class="constant">EGL_UNKNOWN</code> (-1). |
| </p> |
| </div> |
| <div class="refsect1" id="errors"> |
| <h2>Errors</h2> |
| <p> |
| <code class="constant">EGL_FALSE</code> is returned on failure, |
| <code class="constant">EGL_TRUE</code> otherwise. |
| <em class="parameter"><code>value</code></em> is not modified when |
| <code class="constant">EGL_FALSE</code> is returned. |
| </p> |
| <p> |
| <code class="constant">EGL_BAD_DISPLAY</code> is generated if |
| <em class="parameter"><code>display</code></em> is not an EGL display connection. |
| </p> |
| <p> |
| <code class="constant">EGL_NOT_INITIALIZED</code> is generated if |
| <em class="parameter"><code>display</code></em> has not been initialized. |
| </p> |
| <p> |
| <code class="constant">EGL_BAD_SURFACE</code> is generated if |
| <em class="parameter"><code>surface</code></em> is not an EGL surface. |
| </p> |
| <p> |
| <code class="constant">EGL_BAD_ATTRIBUTE</code> is generated if |
| <em class="parameter"><code>attribute</code></em> is not a valid surface attribute. |
| </p> |
| </div> |
| <div class="refsect1" id="seealso"> |
| <h2>See Also</h2> |
| <p> |
| <a class="citerefentry" href="eglCreatePbufferSurface.xhtml"><span class="citerefentry"><span class="refentrytitle">eglCreatePbufferSurface</span></span></a>, |
| <a class="citerefentry" href="eglCreatePixmapSurface.xhtml"><span class="citerefentry"><span class="refentrytitle">eglCreatePixmapSurface</span></span></a>, |
| <a class="citerefentry" href="eglCreateWindowSurface.xhtml"><span class="citerefentry"><span class="refentrytitle">eglCreateWindowSurface</span></span></a>, |
| <a class="citerefentry" href="eglSurfaceAttrib.xhtml"><span class="citerefentry"><span class="refentrytitle">eglSurfaceAttrib</span></span></a>, |
| <a class="citerefentry" href="eglSwapBuffers.xhtml"><span class="citerefentry"><span class="refentrytitle">eglSwapBuffers</span></span></a> |
| </p> |
| </div> |
| <p> |
| </p> |
| <div class="refsect3" id="copyright"> |
| <img src="KhronosLogo.jpg"/> |
| <p> |
| Copyright © 2003-2014 The Khronos Group Inc. |
| Permission is hereby granted, free of charge, to any person obtaining a |
| copy of this software and/or associated documentation files (the |
| "Materials"), to deal in the Materials without restriction, including |
| without limitation the rights to use, copy, modify, merge, publish, |
| distribute, sublicense, and/or sell copies of the Materials, and to |
| permit persons to whom the Materials are furnished to do so, subject to |
| the condition that this copyright notice and permission notice shall be included |
| in all copies or substantial portions of the Materials. |
| </p> |
| </div> |
| <p> |
| </p> |
| </div> |
| <footer/> |
| </body> |
| </html> |
