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>

1 files changed, 136 insertions, 0 deletions

diff --git a/extensions/EGL_ANGLE_window_fixed_size.txt b/extensions/EGL_ANGLE_window_fixed_size.txt
new file mode 100644
index 00000000..e4c1ac32
--- /dev/null
+++ b/extensions/EGL_ANGLE_window_fixed_size.txt
@@ -0,0 +1,136 @@
+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.