xref: /third_party/EGL/sdk/docs/man/docbook4/eglGetConfigAttrib.xml (revision 02f4aeb0)

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<refentry xml:base="" id="eglGetConfigAttrib">
    <refentryinfo>
         <copyright>
             <year>2003-2014</year>
             <holder>The Khronos Group Inc.</holder>
         </copyright>
    </refentryinfo>
    <refmeta>
        <refentrytitle>eglGetConfigAttrib</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>eglGetConfigAttrib</refname>
        <refpurpose>
            return information about an <acronym>EGL</acronym> frame buffer
            configuration
        </refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>EGLBoolean <function>eglGetConfigAttrib</function></funcdef>
                <paramdef>EGLDisplay <parameter>display</parameter></paramdef>
                <paramdef>EGLConfig <parameter>config</parameter></paramdef>
                <paramdef>EGLint <parameter>attribute</parameter></paramdef>
                <paramdef>EGLint * <parameter>value</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
            <varlistentry>
                <term><parameter>display</parameter></term>
                <listitem><para>Specifies the EGL display connection.</para></listitem>
            </varlistentry>
            <varlistentry>
                <term><parameter>config</parameter></term>
                <listitem><para>Specifies the EGL frame buffer configuration to be
                    queried.
                </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><parameter>attribute</parameter></term>
                <listitem><para>Specifies the EGL rendering context attribute to be
                returned.</para></listitem>
            </varlistentry>
            <varlistentry>
                <term><parameter>value</parameter></term>
                <listitem><para>Returns the requested value.</para></listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>eglGetConfigAttrib</function> returns in
            <parameter>value</parameter> the value of
            <parameter>attribute</parameter> for
            <parameter>config</parameter>
            (config attributes are described in more detail in the
            <citerefentry><refentrytitle>eglChooseConfig</refentrytitle></citerefentry>
            reference page).
            <parameter>attribute</parameter> can be one of the following:
        </para>
        <variablelist>
            <varlistentry>
            <term><constant>EGL_ALPHA_SIZE</constant></term>
            <listitem><para>Returns the number of bits of alpha stored in the
            color buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_ALPHA_MASK_SIZE</constant></term>
                <listitem><para>
                    Returns the number of bits in the alpha mask buffer.
                </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_BIND_TO_TEXTURE_RGB</constant></term>
            <listitem><para>Returns <constant>EGL_TRUE</constant> if color buffers can be
            bound to an RGB texture,
            <constant>EGL_FALSE</constant> otherwise.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_BIND_TO_TEXTURE_RGBA</constant></term>
            <listitem><para>Returns <constant>EGL_TRUE</constant> if color buffers can be
            bound to an RGBA texture,
            <constant>EGL_FALSE</constant> otherwise.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_BLUE_SIZE</constant></term>
            <listitem><para>Returns the number of bits of blue stored in the
            color buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_BUFFER_SIZE</constant></term>
            <listitem><para>Returns the depth of the color buffer.
                It is the sum of
                <constant>EGL_RED_SIZE</constant>,
                <constant>EGL_GREEN_SIZE</constant>,
                <constant>EGL_BLUE_SIZE</constant>, and
                <constant>EGL_ALPHA_SIZE</constant>.
            </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_COLOR_BUFFER_TYPE</constant></term>
                <listitem><para>
                    Returns the color buffer type. Possible types are
                    <constant>EGL_RGB_BUFFER</constant> and
                    <constant>EGL_LUMINANCE_BUFFER</constant>.
                </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_CONFIG_CAVEAT</constant></term>
            <listitem><para>Returns the caveats for the frame buffer configuration.
                Possible caveat values are
                <constant>EGL_NONE</constant>,
                <constant>EGL_SLOW_CONFIG</constant>, and
                <constant>EGL_NON_CONFORMANT</constant>.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_CONFIG_ID</constant></term>
            <listitem><para>Returns the ID of the frame buffer configuration.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_CONFORMANT</constant></term>
            <listitem><para>
                Returns a bitmask indicating which client API contexts
                created with respect to this config are conformant.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_DEPTH_SIZE</constant></term>
            <listitem><para>Returns the number of bits in the depth buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_GREEN_SIZE</constant></term>
            <listitem><para>Returns the number of bits of green stored in the
            color buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_LEVEL</constant></term>
            <listitem><para>Returns the frame buffer level.
                Level zero is the default frame buffer.
                Positive levels correspond to frame buffers that overlay the default
                buffer and negative levels correspond to frame buffers that underlay
                the default buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_LUMINANCE_SIZE</constant></term>
                <listitem>
                <para>
                    Returns the number of bits of luminance stored in the luminance buffer.
                </para>
                </listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_MAX_PBUFFER_WIDTH</constant></term>
            <listitem><para>Returns the maximum width of a pixel buffer surface in pixels.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_MAX_PBUFFER_HEIGHT</constant></term>
            <listitem><para>Returns the maximum height of a pixel buffer surface in pixels.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_MAX_PBUFFER_PIXELS</constant></term>
            <listitem><para>Returns the maximum size of a pixel buffer surface in pixels.
            </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_MAX_SWAP_INTERVAL</constant></term>
                <listitem><para>Returns the maximum value that can be passed to eglSwapInterval.
                </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_MIN_SWAP_INTERVAL</constant></term>
                <listitem><para>Returns the minimum value that can be passed to eglSwapInterval.
                </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_NATIVE_RENDERABLE</constant></term>
            <listitem><para>Returns <constant>EGL_TRUE</constant> if native rendering
                APIs can render into the surface,
                <constant>EGL_FALSE</constant> otherwise.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_NATIVE_VISUAL_ID</constant></term>
            <listitem><para>Returns the ID of the associated native visual.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_NATIVE_VISUAL_TYPE</constant></term>
            <listitem><para>Returns the type of the associated native visual.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_RED_SIZE</constant></term>
            <listitem><para>Returns the number of bits of red stored in the
            color buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>EGL_RENDERABLE_TYPE</constant></term>
                <listitem>
                <para>
                    Returns a bitmask indicating the types of supported
                    client API contexts.
                </para>
                </listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_SAMPLE_BUFFERS</constant></term>
            <listitem><para>Returns the number of multisample buffers.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_SAMPLES</constant></term>
            <listitem><para>Returns the number of samples per pixel.</para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_STENCIL_SIZE</constant></term>
            <listitem><para>Returns the number of bits in the stencil buffer.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_SURFACE_TYPE</constant></term>
            <listitem><para>
                Returns a bitmask indicating the types of supported EGL
                surfaces.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_TRANSPARENT_TYPE</constant></term>
            <listitem><para>Returns the type of supported transparency.
                Possible transparency values are:
                <constant>EGL_NONE</constant>, and
                <constant>EGL_TRANSPARENT_RGB</constant>.
            </para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_TRANSPARENT_RED_VALUE</constant></term>
            <listitem><para>Returns the transparent red value.</para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_TRANSPARENT_GREEN_VALUE</constant></term>
            <listitem><para>Returns the transparent green value.</para></listitem>
            </varlistentry>
            <varlistentry>
            <term><constant>EGL_TRANSPARENT_BLUE_VALUE</constant></term>
            <listitem><para>Returns the transparent blue value.</para></listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <constant>EGL_CONFORMANT</constant> is supported only if the
            EGL version is 1.3 or greater.
        </para>
        <para>
            <constant>EGL_ALPHA_MASK_SIZE</constant>,
            <constant>EGL_COLOR_BUFFER_TYPE</constant>,
            <constant>EGL_LUMINANCE_SIZE</constant>, and
            <constant>EGL_RENDERABLE_TYPE</constant> are supported only
            if the EGL version is 1.2 or greater.
        </para>
        <para>
            While <constant>EGL_MATCH_NATIVE_PIXMAP</constant> can be
            specified in the attribute list passed to
            <citerefentry><refentrytitle>eglChooseConfig</refentrytitle></citerefentry>,
            it is not an attribute of the resulting config and cannot be
            queried using <function>eglGetConfigAttrib</function>.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>EGL_FALSE</constant> is returned on failure,
            <constant>EGL_TRUE</constant> otherwise.
            <parameter>value</parameter> is not modified when
            <constant>EGL_FALSE</constant> is returned.
        </para>
        <para>
            <constant>EGL_BAD_DISPLAY</constant> is generated if
            <parameter>display</parameter> is not an EGL display connection.
        </para>
        <para>
            <constant>EGL_NOT_INITIALIZED</constant> is generated if
            <parameter>display</parameter> has not been initialized.
        </para>
        <para>
            <constant>EGL_BAD_CONFIG</constant> is generated if
            <parameter>config</parameter> is not an EGL frame buffer configuration.
        </para>
        <para>
            <constant>EGL_BAD_ATTRIBUTE</constant> is generated if
            <parameter>attribute</parameter> is not a valid frame buffer
            configuration attribute.
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>eglChooseConfig</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>eglGetConfigs</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect3 id="Copyright"><title></title>
        <!-- Content included from copyright.inc.xsl -->
        <imageobject>
                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
        </imageobject>
        <para />
    </refsect3>
</refentry>