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https://github.com/openharmony/third_party_egl.git
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lizheng
311 lines
14 KiB
XML
Executable File
311 lines
14 KiB
XML
Executable File
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:base="" xml:id="eglQuerySurface">
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<info>
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<copyright>
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<year>2003-2018</year>
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<holder>The Khronos Group Inc.</holder>
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</copyright>
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</info>
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<refmeta>
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<refentrytitle>eglQuerySurface</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>eglQuerySurface</refname>
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<refpurpose>
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return <acronym>EGL</acronym> surface information
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</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>EGLBoolean <function>eglQuerySurface</function></funcdef>
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<paramdef>EGLDisplay <parameter>display</parameter></paramdef>
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<paramdef>EGLSurface <parameter>surface</parameter></paramdef>
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<paramdef>EGLint <parameter>attribute</parameter></paramdef>
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<paramdef>EGLint * <parameter>value</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1 xml:id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>display</parameter></term>
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<listitem>
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<para>
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Specifies the EGL display connection.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>surface</parameter></term>
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<listitem>
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<para>
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Specifies the EGL surface to query.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>attribute</parameter></term>
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<listitem>
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<para>
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Specifies the EGL surface attribute to be returned.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>value</parameter></term>
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<listitem>
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<para>
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Returns the requested value.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 xml:id="description"><title>Description</title>
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<para>
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<function>eglQuerySurface</function> returns in
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<parameter>value</parameter> the value of
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<parameter>attribute</parameter> for <parameter>surface</parameter>.
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<parameter>attribute</parameter> can be one of the following:
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</para>
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<variablelist>
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<varlistentry>
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<term><constant>EGL_CONFIG_ID</constant></term>
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<listitem><para>
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Returns the ID of the EGL frame buffer configuration
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with respect to which the surface was created.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_GL_COLORSPACE</constant></term>
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<listitem><para>
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Returns the color space used by OpenGL and OpenGL ES
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when rendering to the surface, either
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<constant>EGL_GL_COLORSPACE_SRGB</constant> or
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<constant>EGL_GL_COLORSPACE_LINEAR</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_HEIGHT</constant></term>
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<listitem><para>
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Returns the height of the surface in pixels.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_HORIZONTAL_RESOLUTION</constant></term>
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<listitem><para>
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Returns the horizontal dot pitch of the display on
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which a window surface is visible. The value
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returned is equal to the actual dot pitch, in
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pixels/meter, multiplied by the constant value
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<constant>EGL_DISPLAY_SCALING</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_LARGEST_PBUFFER</constant></term>
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<listitem><para>
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Returns the same attribute value specified when the
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surface was created with
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<citerefentry><refentrytitle>eglCreatePbufferSurface</refentrytitle></citerefentry>.
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For a window or pixmap surface,
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<parameter>value</parameter> is not modified.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_MIPMAP_LEVEL</constant></term>
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<listitem><para>
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Returns which level of the mipmap to render to, if
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texture has mipmaps.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_MIPMAP_TEXTURE</constant></term>
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<listitem><para>
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Returns <constant>EGL_TRUE</constant> if texture has
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mipmaps, <constant>EGL_FALSE</constant> otherwise.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_MULTISAMPLE_RESOLVE</constant></term>
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<listitem>
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<para>
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Returns the filter used when resolving the
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multisample buffer. The filter may be either
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<constant>EGL_MULTISAMPLE_RESOLVE_DEFAULT</constant>
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or <constant>EGL_MULTISAMPLE_RESOLVE_BOX</constant>,
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as described for
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<citerefentry><refentrytitle>eglSurfaceAttrib</refentrytitle></citerefentry>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_PIXEL_ASPECT_RATIO</constant></term>
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<listitem><para>
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Returns the aspect ratio of an individual pixel (the
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ratio of a pixel's width to its height). The value
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returned is equal to the actual aspect ratio
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multiplied by the constant value
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<constant>EGL_DISPLAY_SCALING</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_RENDER_BUFFER</constant></term>
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<listitem><para>
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Returns the buffer which client API rendering is
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requested to use. For a window surface, this is the
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same attribute value specified when the surface was
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created. For a pbuffer surface, it is always
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<constant>EGL_BACK_BUFFER</constant>. For a pixmap
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surface, it is always
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<constant>EGL_SINGLE_BUFFER</constant>. To determine
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the actual buffer being rendered to by a context,
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call
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<citerefentry><refentrytitle>eglQueryContext</refentrytitle></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_SWAP_BEHAVIOR</constant></term>
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<listitem><para>
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Returns the effect on the color buffer when posting
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a surface with
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<citerefentry><refentrytitle>eglSwapBuffers</refentrytitle></citerefentry>.
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Swap behavior may be either
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<constant>EGL_BUFFER_PRESERVED</constant> or
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<constant>EGL_BUFFER_DESTROYED</constant>, as
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described for
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<citerefentry><refentrytitle>eglSurfaceAttrib</refentrytitle></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_TEXTURE_FORMAT</constant></term>
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<listitem><para>
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Returns format of texture. Possible values are
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<constant>EGL_NO_TEXTURE</constant>,
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<constant>EGL_TEXTURE_RGB</constant>, and
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<constant>EGL_TEXTURE_RGBA</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_TEXTURE_TARGET</constant></term>
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<listitem><para>
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Returns type of texture. Possible values are
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<constant>EGL_NO_TEXTURE</constant>, or
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<constant>EGL_TEXTURE_2D</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_VERTICAL_RESOLUTION</constant></term>
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<listitem><para>
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Returns the vertical dot pitch of the display on
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which a window surface is visible. The value
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returned is equal to the actual dot pitch, in
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pixels/meter, multiplied by the constant value
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<constant>EGL_DISPLAY_SCALING</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_VG_ALPHA_FORMAT</constant></term>
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<listitem><para>
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Returns the interpretation of alpha values used by
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OpenVG when rendering to the surface, either
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<constant>EGL_VG_ALPHA_FORMAT_NONPRE</constant> or
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<constant>EGL_VG_ALPHA_FORMAT_PRE</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_VG_COLORSPACE</constant></term>
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<listitem><para>
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Returns the color space used by OpenVG when rendering to
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the surface, either
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<constant>EGL_VG_COLORSPACE_sRGB</constant> or
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<constant>EGL_VG_COLORSPACE_LINEAR</constant>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>EGL_WIDTH</constant></term>
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<listitem><para>
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Returns the width of the surface in pixels.
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</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 xml:id="notes"><title>Notes</title>
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<para>
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Attribute <constant>EGL_GL_COLORSPACE</constant> is supported
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only if the EGL version is 1.5 or greater.
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</para>
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<para>
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Attribute <constant>EGL_MULTISAMPLE_RESOLVE</constant> is
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supported only if the EGL version is 1.4 or greater.
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</para>
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<para>
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Attributes <constant>EGL_DISPLAY_SCALING</constant>.
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<constant>EGL_HORIZONTAL_RESOLUTION</constant>,
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<constant>EGL_PIXEL_ASPECT_RATIO</constant>,
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<constant>EGL_RENDER_BUFFER</constant>,
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<constant>EGL_SWAP_BEHAVIOR</constant>, and
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<constant>EGL_VERTICAL_RESOLUTION</constant> are supported
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only if the EGL version is 1.2 or greater.
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</para>
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<para>
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Querying attributes <constant>EGL_TEXTURE_FORMAT</constant>,
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<constant>EGL_TEXTURE_TARGET</constant>,
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<constant>EGL_MIPMAP_TEXTURE</constant>, or
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<constant>EGL_MIPMAP_LEVEL</constant> for a non-pbuffer
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surface is not an error, but <parameter>value</parameter> is
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not modified.
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</para>
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<para>
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<constant>EGL_DISPLAY_SCALING</constant> is the constant
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value 10000. Floating-point values such as resolution and
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pixel aspect ratio are scaled by this value before being
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returned as integers so that sufficient precision to be
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meaningful will be retained in the returned value.
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</para>
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<para>
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For an offscreen (pbuffer or pixmap) surface, or a surface
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whose pixel dot pitch or aspect ratio are unknown, querying
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<constant>EGL_HORIZONTAL_RESOLUTION</constant>,
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<constant>EGL_PIXEL_ASPECT_RATIO</constant>, or
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<constant>EGL_VERTICAL_RESOLUTION</constant> will return the
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constant value <constant>EGL_UNKNOWN</constant> (-1).
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</para>
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</refsect1>
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<refsect1 xml:id="errors"><title>Errors</title>
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<para>
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<constant>EGL_FALSE</constant> is returned on failure,
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<constant>EGL_TRUE</constant> otherwise.
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<parameter>value</parameter> is not modified when
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<constant>EGL_FALSE</constant> is returned.
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</para>
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<para>
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<constant>EGL_BAD_DISPLAY</constant> is generated if
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<parameter>display</parameter> is not an EGL display connection.
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</para>
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<para>
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<constant>EGL_NOT_INITIALIZED</constant> is generated if
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<parameter>display</parameter> has not been initialized.
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</para>
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<para>
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<constant>EGL_BAD_SURFACE</constant> is generated if
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<parameter>surface</parameter> is not an EGL surface.
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</para>
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<para>
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<constant>EGL_BAD_ATTRIBUTE</constant> is generated if
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<parameter>attribute</parameter> is not a valid surface attribute.
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</para>
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</refsect1>
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<refsect1 xml:id="seealso"><title>See Also</title>
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<para>
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<citerefentry><refentrytitle>eglCreatePbufferSurface</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>eglCreatePixmapSurface</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>eglCreateWindowSurface</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>eglSurfaceAttrib</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>eglSwapBuffers</refentrytitle></citerefentry>
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</para>
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</refsect1>
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<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="copyright.xml"/>
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</refentry>
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