- explicitly use UNICODE versions of DrawText, EnumDisplaySettings,
EnumDisplayDevices, and CreateDC: the underlying structures have
WCHAR strings.
- change WIN_UpdateDisplayMode and WIN_GetDisplayMode() to accept
LPCWSTR instead of LPCTSTR for the same reason.
- change WIN_StringToUTF8 and WIN_UTF8ToString to the explicit 'W'
versions where appropriate.
- SDL_video.c (SDL_ShowMessageBox): replace messageboxdata, set title
or message field to "" if either of them is NULL.
- SDL_video.c (SDL_ShowSimpleMessageBox): set title or message to ""
if either of them is NULL for EMSCRIPTEN builds.
- SDL_bmessagebox.cc: add empty string check along with NULL check for
title and message fields.
- SDL_windowsmessagebox.c (AddDialogString): remove NULL string check
- SDL_windowsmessagebox.c (AddDialogControl): add empty string check
along with the NULL check.
- SDL_x11messagebox.c: revert commit 677c4cd68069
- SDL_os2messagebox.c: revert commit 2c2a489d76e7
- test/testmessage.c: Add NULL title and NULL message tests.
Simon Hug
I just wanted to fix a simple compiler warning in SDL_ShowMessageBox on Windows (which Sam fixed recently) and ended up finding some issues.
Attached patch fixes these issues:
- Because Windows only reports the lower 16 bits of the control identifier that was pushed, the button IDs used by SDL (C type int, most likely 32 bits) can get cut off.
- The documentation states (somewhat ambiguously) that the button ID will be -1 if the dialog was closed, but the current code sets 0. For SDL 2.1, I think this should be a return code of SDL_ShowMessageBox itself. That will free up the button ID and it seems a more appropriate place for signaling this event.
- Ampersands in controls will create mnemonics on Windows (underlined letters that, if combined with the Alt key, will push the button). I was thinking of adding a hint or flag to let the users enable it, but that might have unexpected results.
- When the size of the text gets calculated, it doesn't use the same parameters as the static control. This can cut off text or wrap it weirdly.
- On Windows, the Tab key is used to switch between control groups and sometimes between buttons in dialogs. This didn't seem to work correctly.
Attached patch also adds:
- Icons. Just the system ones that can be loaded with the ordinals IDI_ERROR, IDI_WARNING and IDI_INFORMATION.
- A button limit of 2^16 - 101.
- Some more specific error messages, but they never reach the user because how SDL_ShowMessageBox handles them if an implementation returns with an error.
Ozkan Sezer 2018-03-02 20:02:37 UTC
http://hg.libsdl.org/SDL/rev/d702b0c54e52 resulted in an error and
two warnings when compiled with mingw.
1. Error from SDL_windowstaskdialog.h:
In file included from src/video/windows/SDL_windowsmessagebox.c:29:0:
src/video/windows/SDL_windowstaskdialog.h:23:54: error: expected ')' before 'HWND'
This is fixed by removing unnecessary annotations:
2. Warning from SDL_assert.c:
src/SDL_assert.c: In function 'SDL_ExitProcess':
src/SDL_assert.c:138:1: warning: 'noreturn' function does return
Indeed ExitProcess() is prototyped with DECLSPEC_NORETURN, but
TerminateProcess() is not. This can be rectified by adding an
exit() call in there. Do NOTE, however, that requires building
with a libc:
3. Warning from SDL_windowsmessagebox.c:
src/video/windows/SDL_windowsmessagebox.c: In function 'WIN_ShowMessageBox':
src/video/windows/SDL_windowsmessagebox.c:513:9: warning: 'nCancelButton' may be used uninitialized in this function
My lazy solution was manually initializing nCancelButton to 0.
This lets the message box have an icon. Unless the app has opted-in to using
the v6 common controls, though, this will fall back to the usual SDL message
boxes.
Pegasus Epsilon
With the system dialog font set to Arial or Tahoma or another variable-width font, everything works just as expected. When using a fixed-width font, like Courier or DejaVu Sans Mono, the text gets cut off. Example screenshots attached.
romain.lacroix
For the windows implementation of SDL_ShowMessageBox() : ./src/video/windows/SDL_windowsmessagebox.c:345 WIN_ShowMessageBox()
The implementation in 2.0.4 uses "button index" for parameter "id" of function AddDialogButton().
It then expects the value provided in param wParam of function MessageBoxDialogProc() to be a valid index of a button.
It uses this value to index in the array of buttons when DialogBoxIndirect() returns (line 474 : *buttonid = buttons[which].buttonid;)
However, when dismissing this box with Escape, the return value of DialogBoxIndirect will be SDL_MESSAGEBOX_BUTTON_ESCAPEKEY_DEFAULT (=2) which is not always a valid index of array buttons.
When the array buttons has a length less or equal than 2, the memory access is invalid; I can see that the value written to *buttonId is uninitialized memory (random value).
The fix I propose : use value "buttonid" (field of button) for parameter "id" of AddDialogButton(), then copy return value of DialogBoxIndirect() in *buttonid. This way, we will not use an out-of-bounds index in array buttons.
Jan Hellwig
On Windows, you are able to navigate between the buttons on a MessageBox that was created using SDL_ShowMessageBox using the arrow keys. However, if you press the left arrow key, the selection jumps to the button on the right of the currently selected one (and vice versa).
This can be fixed by reversing the order in which the buttons are added to the dialog.
The attached patch files fixes this problem. However the first press of an arrow key leads to the selection of the leftmost or rightmost button on the MessageBox, not to the selection of the button left/right of the one that is selected by default.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
