kc3-lang/angle/extensions/EGL_ANGLE_window_fixed_size.txt

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• Author : John Bauman
  Date : 2014-01-28 15:30:35
  Hash : 3dc300a5
  Message : Allow creating fixed-size window surfaces. BUG=320021 Change-Id: I97cdd65ac17ee142700dbf0f363891500e967571 Reviewed-on: https://chromium-review.googlesource.com/184205 Reviewed-by: John Bauman <jbauman@chromium.org> Tested-by: John Bauman <jbauman@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/190563 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Nicolas Capens <nicolascapens@chromium.org> Tested-by: Shannon Woods <shannonwoods@chromium.org>

• extensions/EGL_ANGLE_window_fixed_size.txt

• Name
  
      ANGLE_window_fixed_size
  
  Name Strings
  
      EGL_ANGLE_window_fixed_size
  
  Contributors
  
      John Bauman
      Shannon Woods
  
  Contacts
  
      John Bauman, Google Inc. (jbauman 'at' google.com)
  
  Status
  
      Complete
  
  Version
  
      Version 4, February 24, 2014
  
  Number
  
      EGL Extension #??
  
  Dependencies
  
      This extension is written against the wording of the EGL 1.4
      Specification.
  
  Overview
  
      This extension allows creating a window surface with a fixed size that is
      specified when it is created.
  
  New Types
  
      None
  
  New Procedures and Functions
  
      None
  
  New Tokens
  
      Accepted by the <attribute> parameter of eglQuerySurface and by the
      <attrib_list> parameter of eglCreateWindowSurface:
  
      EGL_FIXED_SIZE_ANGLE        0x3201
  
  Additions to Chapter 3 of the EGL 1.4 Specification:
  
      Modify the third paragraph of Section 3.5.1 (Creating On-Screen Rendering Surfaces)
  
      "<attrib_list> specifies a list of attributes for the window. The list has
      the same structure as described for eglChooseConfig.  Attributes that can
      be specified in <attrib_list> include EGL_RENDER_BUFFER,
      EGL_VG_COLORSPACE, EGL_VG_ALPHA_FORMAT, EGL_FIXED_SIZE_ANGLE, EGL_WIDTH,
      and EGL_HEIGHT."
  
      Add before the last paragraph of Section 3.5.1
  
      "EGL_FIXED_SIZE_ANGLE specifies whether the surface must be resized by the
      implementation when the native window is resized.  The default value is
      EGL_FALSE.  Its value can be EGL_TRUE, in which case the size must be
      specified when the window is created, or EGL_FALSE, in which case the size
      is taken from the native window. Its default value is EGL_FALSE.
  
      If the value of EGL_FIXED_SIZE_ANGLE is EGL_TRUE, the window surface's
      size in pixels is specified by the EGL_WIDTH and EGL_HEIGHT attributes,
      and will not change throughout the lifetime of the surface. If its value
      is EGL_FALSE, then the values of EGL_WIDTH and EGL_HEIGHT are ignored and
      the window surface must be resized by the implementation subsequent to the
      native window being resized, and prior to copying its contents to the
      native window (e.g. in eglSwapBuffers, as described in section 3.9.1.1).
      The default values for EGL_WIDTH and EGL_HEIGHT are zero. If the value
      specified for either of EGL_WIDTH or EGL_HEIGHT is less than zero then an
      EGL_BAD_PARAMETER error is generated."
  
      Add the following entry to Table 3.5
      (Queryable surface attributes and types)
  
      Attribute            Type    Description
      -------------------- ------- ---------------------------------------------
      EGL_FIXED_SIZE_ANGLE boolean Surface will not be resized with a native
                                   window
  
      Replace the last paragraph on page 37 in Section 3.5.6 (Surface Attributes)
  
      "Querying EGL_WIDTH and EGL_HEIGHT returns respectively the width and
      height, in pixels, of the surface. For a pixmap surface or window surface
      with EGL_FIXED_SIZE_ANGLE set to EGL_FALSE, these values are initially
      equal to the width and height of the native window or pixmap with respect
      to which the surface was created. If the native window is resized and the
      corresponding window surface is not fixed size, the corresponding window
      surface will eventually be resized by the implementation to match (as
      discussed in section 3.9.1). If there is a discrepancy because EGL has not
      yet resized the window surface, the size returned by eglQuerySurface will
      always be that of the EGL surface, not the corresponding native window."
  
      Add the following paragraph to Section 3.5.6 (Surface Attributes)
  
      "Querying EGL_FIXED_SIZE_ANGLE returns EGL_FALSE if the surface will be
      resized to match a native window, and EGL_TRUE if the surface cannot be
      resized."
  
      Alter the beginning of the first paragraph of Section 3.9.1.1 (Native
      Window Resizing)
  
      "If <surface> does not have EGL_FIXED_SIZE_ANGLE set and the native window
      corresponding to <surface> has been resized prior to the swap, <surface>
      must be resized to match."
  
  Issues
  
      1. Should there be a way to resize a window surface that had its size
      specified initially.
  
      RESOLVED: No. Surfaces that have their sizes specified initially must have
      EGL_FIXED_SIZE_ANGLE set and can never be resized.
  
  Revision History
  
      Version 4, 2014/02/24 - formatting changes.
  
      Version 3, 2014/02/12 - ignore EGL_WIDTH and EGL_HEIGHT if
      EGL_FIXED_SIZE_ANGLE is EGL_FALSE
  
      Version 2, 2014/02/07 - rename to EGL_ANGLE_window_fixed_size, and add an
      EGL_FIXED_SIZE_ANGLE token.
  
      Version 1, 2014/02/05 - first draft.