include/SDL_shape.h
author David Ludwig <dludwig@pobox.com>
Sat, 29 Nov 2014 10:09:30 -0500
changeset 9247 eddb899239fe
parent 8149 681eb46b8ac4
child 9619 b94b6d0bff0f
permissions -rw-r--r--
WinRT: bug and data-integrity fixes for SDL_GetPrefPath()

This change does a few things, all with regards to the WinRT implementation of
SDL_GetPrefPath():

1. it fixes a bug whereby SDL_GetPrefPath() did not create the directory it
returned. On other SDL platforms, SDL_GetPrefPath() will create separate
directories for its 'org' and 'app' folders. Without this, attempts to create
files in the pref-path would fail, unless those directories were first created
by the app, or by some other library the app used. This change makes sure
that these directories get created, before SDL_GetPrefPath() returns to its
caller(s).


2. it defaults to having SDL_GetPrefPath() return a WinRT 'Local' folder
on all platforms. Previously, for Windows Store apps, it would have used a
different, 'Roaming' folder. Files in Roaming folders can be automatically,
and synchronized across multiple devices by Windows. This synchronization can
happen while the app runs, with new files being copied into a running app's
pref-path. Unless an app is specifically designed to handle this scenario,
there is a chance that save-data could be overwritten in unwanted or
unexpected ways.

The default is now to use a Local folder, which does not get synchronized, and
which is arguably a bit safer to use. Apps that wish to use Roaming folders
can do so by setting SDL_HINT_WINRT_PREF_PATH_ROOT to "roaming", however it
is recommended that one first read Microsoft's documentation for Roaming
files, a link to which is provided in README-winrt.md.

To preserve older pref-path selection behavior (found in SDL 2.0.3, as well as
many pre-2.0.4 versions of SDL from hg.libsdl.org), which uses a Roaming path
in Windows Store apps, and a Local path in Windows Phone, set
SDL_HINT_WINRT_PREF_PATH_ROOT to "old".

Please note that Roaming paths are not supported on Windows Phone 8.0, due to
limitations in the OS itself. Attempts to use this will fail.
(Windows Phone 8.1 does not have this limitation, however.)


3. It makes SDL_GetPrefPath(), when on Windows Phone 8.0, and when
SDL_HINT_WINRT_PREF_PATH_ROOT is set to "roaming", return NULL, rather than
silently defaulting to a Local path (then switching to a Roaming path if and
when the user upgraded to Windows Phone 8.1).
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 #ifndef _SDL_shape_h
    23 #define _SDL_shape_h
    24 
    25 #include "SDL_stdinc.h"
    26 #include "SDL_pixels.h"
    27 #include "SDL_rect.h"
    28 #include "SDL_surface.h"
    29 #include "SDL_video.h"
    30 
    31 #include "begin_code.h"
    32 /* Set up for C function definitions, even when using C++ */
    33 #ifdef __cplusplus
    34 extern "C" {
    35 #endif
    36 
    37 /** \file SDL_shape.h
    38  *
    39  * Header file for the shaped window API.
    40  */
    41 
    42 #define SDL_NONSHAPEABLE_WINDOW -1
    43 #define SDL_INVALID_SHAPE_ARGUMENT -2
    44 #define SDL_WINDOW_LACKS_SHAPE -3
    45 
    46 /**
    47  *  \brief Create a window that can be shaped with the specified position, dimensions, and flags.
    48  *
    49  *  \param title The title of the window, in UTF-8 encoding.
    50  *  \param x     The x position of the window, ::SDL_WINDOWPOS_CENTERED, or
    51  *               ::SDL_WINDOWPOS_UNDEFINED.
    52  *  \param y     The y position of the window, ::SDL_WINDOWPOS_CENTERED, or
    53  *               ::SDL_WINDOWPOS_UNDEFINED.
    54  *  \param w     The width of the window.
    55  *  \param h     The height of the window.
    56  *  \param flags The flags for the window, a mask of SDL_WINDOW_BORDERLESS with any of the following:
    57  *               ::SDL_WINDOW_OPENGL,     ::SDL_WINDOW_INPUT_GRABBED,
    58  *               ::SDL_WINDOW_HIDDEN,     ::SDL_WINDOW_RESIZABLE,
    59  *               ::SDL_WINDOW_MAXIMIZED,  ::SDL_WINDOW_MINIMIZED,
    60  *       ::SDL_WINDOW_BORDERLESS is always set, and ::SDL_WINDOW_FULLSCREEN is always unset.
    61  *
    62  *  \return The window created, or NULL if window creation failed.
    63  *
    64  *  \sa SDL_DestroyWindow()
    65  */
    66 extern DECLSPEC SDL_Window * SDLCALL SDL_CreateShapedWindow(const char *title,unsigned int x,unsigned int y,unsigned int w,unsigned int h,Uint32 flags);
    67 
    68 /**
    69  * \brief Return whether the given window is a shaped window.
    70  *
    71  * \param window The window to query for being shaped.
    72  *
    73  * \return SDL_TRUE if the window is a window that can be shaped, SDL_FALSE if the window is unshaped or NULL.
    74  * \sa SDL_CreateShapedWindow
    75  */
    76 extern DECLSPEC SDL_bool SDLCALL SDL_IsShapedWindow(const SDL_Window *window);
    77 
    78 /** \brief An enum denoting the specific type of contents present in an SDL_WindowShapeParams union. */
    79 typedef enum {
    80     /** \brief The default mode, a binarized alpha cutoff of 1. */
    81     ShapeModeDefault,
    82     /** \brief A binarized alpha cutoff with a given integer value. */
    83     ShapeModeBinarizeAlpha,
    84     /** \brief A binarized alpha cutoff with a given integer value, but with the opposite comparison. */
    85     ShapeModeReverseBinarizeAlpha,
    86     /** \brief A color key is applied. */
    87     ShapeModeColorKey
    88 } WindowShapeMode;
    89 
    90 #define SDL_SHAPEMODEALPHA(mode) (mode == ShapeModeDefault || mode == ShapeModeBinarizeAlpha || mode == ShapeModeReverseBinarizeAlpha)
    91 
    92 /** \brief A union containing parameters for shaped windows. */
    93 typedef union {
    94     /** \brief a cutoff alpha value for binarization of the window shape's alpha channel. */
    95     Uint8 binarizationCutoff;
    96     SDL_Color colorKey;
    97 } SDL_WindowShapeParams;
    98 
    99 /** \brief A struct that tags the SDL_WindowShapeParams union with an enum describing the type of its contents. */
   100 typedef struct SDL_WindowShapeMode {
   101     /** \brief The mode of these window-shape parameters. */
   102     WindowShapeMode mode;
   103     /** \brief Window-shape parameters. */
   104     SDL_WindowShapeParams parameters;
   105 } SDL_WindowShapeMode;
   106 
   107 /**
   108  * \brief Set the shape and parameters of a shaped window.
   109  *
   110  * \param window The shaped window whose parameters should be set.
   111  * \param shape A surface encoding the desired shape for the window.
   112  * \param shape_mode The parameters to set for the shaped window.
   113  *
   114  * \return 0 on success, SDL_INVALID_SHAPE_ARGUMENT on invalid an invalid shape argument, or SDL_NONSHAPEABLE_WINDOW
   115  *           if the SDL_Window* given does not reference a valid shaped window.
   116  *
   117  * \sa SDL_WindowShapeMode
   118  * \sa SDL_GetShapedWindowMode.
   119  */
   120 extern DECLSPEC int SDLCALL SDL_SetWindowShape(SDL_Window *window,SDL_Surface *shape,SDL_WindowShapeMode *shape_mode);
   121 
   122 /**
   123  * \brief Get the shape parameters of a shaped window.
   124  *
   125  * \param window The shaped window whose parameters should be retrieved.
   126  * \param shape_mode An empty shape-mode structure to fill, or NULL to check whether the window has a shape.
   127  *
   128  * \return 0 if the window has a shape and, provided shape_mode was not NULL, shape_mode has been filled with the mode
   129  *           data, SDL_NONSHAPEABLE_WINDOW if the SDL_Window given is not a shaped window, or SDL_WINDOW_LACKS_SHAPE if
   130  *           the SDL_Window* given is a shapeable window currently lacking a shape.
   131  *
   132  * \sa SDL_WindowShapeMode
   133  * \sa SDL_SetWindowShape
   134  */
   135 extern DECLSPEC int SDLCALL SDL_GetShapedWindowMode(SDL_Window *window,SDL_WindowShapeMode *shape_mode);
   136 
   137 /* Ends C function definitions when using C++ */
   138 #ifdef __cplusplus
   139 }
   140 #endif
   141 #include "close_code.h"
   142 
   143 #endif /* _SDL_shape_h */