3 ANGLE_window_fixed_size
7 EGL_ANGLE_window_fixed_size
16 John Bauman, Google Inc. (jbauman 'at' google.com)
24 Version 4, February 24, 2014
32 This extension is written against the wording of the EGL 1.4
37 This extension allows creating a window surface with a fixed size that is
38 specified when it is created.
44 New Procedures and Functions
50 Accepted by the <attribute> parameter of eglQuerySurface and by the
51 <attrib_list> parameter of eglCreateWindowSurface:
53 EGL_FIXED_SIZE_ANGLE 0x3201
55 Additions to Chapter 3 of the EGL 1.4 Specification:
57 Modify the third paragraph of Section 3.5.1 (Creating On-Screen Rendering Surfaces)
59 "<attrib_list> specifies a list of attributes for the window. The list has
60 the same structure as described for eglChooseConfig. Attributes that can
61 be specified in <attrib_list> include EGL_RENDER_BUFFER,
62 EGL_VG_COLORSPACE, EGL_VG_ALPHA_FORMAT, EGL_FIXED_SIZE_ANGLE, EGL_WIDTH,
65 Add before the last paragraph of Section 3.5.1
67 "EGL_FIXED_SIZE_ANGLE specifies whether the surface must be resized by the
68 implementation when the native window is resized. The default value is
69 EGL_FALSE. Its value can be EGL_TRUE, in which case the size must be
70 specified when the window is created, or EGL_FALSE, in which case the size
71 is taken from the native window. Its default value is EGL_FALSE.
73 If the value of EGL_FIXED_SIZE_ANGLE is EGL_TRUE, the window surface's
74 size in pixels is specified by the EGL_WIDTH and EGL_HEIGHT attributes,
75 and will not change throughout the lifetime of the surface. If its value
76 is EGL_FALSE, then the values of EGL_WIDTH and EGL_HEIGHT are ignored and
77 the window surface must be resized by the implementation subsequent to the
78 native window being resized, and prior to copying its contents to the
79 native window (e.g. in eglSwapBuffers, as described in section 3.9.1.1).
80 The default values for EGL_WIDTH and EGL_HEIGHT are zero. If the value
81 specified for either of EGL_WIDTH or EGL_HEIGHT is less than zero then an
82 EGL_BAD_PARAMETER error is generated."
84 Add the following entry to Table 3.5
85 (Queryable surface attributes and types)
87 Attribute Type Description
88 -------------------- ------- ---------------------------------------------
89 EGL_FIXED_SIZE_ANGLE boolean Surface will not be resized with a native
92 Replace the last paragraph on page 37 in Section 3.5.6 (Surface Attributes)
94 "Querying EGL_WIDTH and EGL_HEIGHT returns respectively the width and
95 height, in pixels, of the surface. For a pixmap surface or window surface
96 with EGL_FIXED_SIZE_ANGLE set to EGL_FALSE, these values are initially
97 equal to the width and height of the native window or pixmap with respect
98 to which the surface was created. If the native window is resized and the
99 corresponding window surface is not fixed size, the corresponding window
100 surface will eventually be resized by the implementation to match (as
101 discussed in section 3.9.1). If there is a discrepancy because EGL has not
102 yet resized the window surface, the size returned by eglQuerySurface will
103 always be that of the EGL surface, not the corresponding native window."
105 Add the following paragraph to Section 3.5.6 (Surface Attributes)
107 "Querying EGL_FIXED_SIZE_ANGLE returns EGL_FALSE if the surface will be
108 resized to match a native window, and EGL_TRUE if the surface cannot be
111 Alter the beginning of the first paragraph of Section 3.9.1.1 (Native
114 "If <surface> does not have EGL_FIXED_SIZE_ANGLE set and the native window
115 corresponding to <surface> has been resized prior to the swap, <surface>
116 must be resized to match."
120 1. Should there be a way to resize a window surface that had its size
123 RESOLVED: No. Surfaces that have their sizes specified initially must have
124 EGL_FIXED_SIZE_ANGLE set and can never be resized.
128 Version 4, 2014/02/24 - formatting changes.
130 Version 3, 2014/02/12 - ignore EGL_WIDTH and EGL_HEIGHT if
131 EGL_FIXED_SIZE_ANGLE is EGL_FALSE
133 Version 2, 2014/02/07 - rename to EGL_ANGLE_window_fixed_size, and add an
134 EGL_FIXED_SIZE_ANGLE token.
136 Version 1, 2014/02/05 - first draft.