Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetVideoMode.3 @ 4384:6800e2560310 SDL-1.2
Fixed bugs #882 and 865, re-opening bug #634
Ronald Lamprecht to SDL
Hi,
Sam Lantinga wrote:
The problem with that fix is that it breaks IME events again. Maybe
we can handle keyboard events differently to prevent this issue?
Spending an hour reading MSDN, analysing SDL and another hour testing the reality on XP I am really wondering how patch r4990 could have ever worked in any situation. It's main effect is to break the unicode translation and causing spurious activation events!
Why does TranslateMessage(&msg) nothing useful? Simply because it does not affect "msg" at all! All keyboard events are dispatched without the slightest change (see MSDN). TranslateMessage() just appends additional WM_CHAR, WM_DEADCHAR, WM_SYSCHAR, WM_SYSDEADCHAR event messages to the queue. But I could not find any SDL event handling routine that catches these events and transforms them to proper SDL keyevents while eliminating the corresponding WM_KEYDOWN, etc. events. Thus any IME input like the '@' generated by "Alt + 6(Numpad) + 4(Numpad)" is simply lost.
But the situation is even worse! Up to r4990 the TranslateKey()/ToUnicode() calls did evaluate dead keys and did deliver proper key events for subsequent key strokes like '´' + 'e' resulting in 'é'. ToUnicode() needs proper key state informations to be able to handle these substitutions. But unfortunatly TranslateMessage() needs the same state information and eats it up while generating the WM_CHAR messages :-( Thus the current 1.2.14 breakes the partial IME support of previous releases, too.
The key state race condition between ToUnicode() and TranslateMessage() requires to avoid any ToUnicode() usage for receiving proper WM_CHAR, etc. messages generated by TranslateMessage(). (Yes - the '@' and 'é' appear as WM_CHAR messages when unicode is switched off).
The spurious SDL activation events are *not* caused by additional WM_ACTIVATE Windows messages! Besides DIB_HandleMessage() SDL_PrivateAppActive() is called by another source which I am not yet aware of - any hints?
Thus I do strongly recommend the deletion of the TranslateMessage(&msg) call as a quick fix.
A proper support of unicode and IME requires a clean SDL keyboard input concept first. Which SDL keyboards events should be transmitted to the app when the user presses '´' + 'e' ? Within the current unicode handling the first key stroke is hidden. Even though ToUnicode() delivers the proper key SDL does ignore it in TranslateKey(). Just the composed key event is transmitted to the app. That is what you expect for text input, but the app can no longer use keys like '^' as a key button because it will never receive a key event for it!
With a given concept it seems to be necessary to regenerate SDL key events out of the WM_CHAR, etc. events and to drop all related direct WM_KEYDOWN, etc. events while the remaining basic WM_KEYDOWN, etc. events would still have to result in SDL key events.
Anyway the source of the spurious WM_ACTIVATE should be located to avoid future trouble.
Greets,
Ronald
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Tue, 17 Nov 2009 04:59:13 +0000 |
parents | 1238da4a7112 |
children |
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.TH "SDL_SetVideoMode" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetVideoMode \- Set up a video mode with the specified width, height and bits-per-pixel\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBSDL_Surface *\fBSDL_SetVideoMode\fP\fR(\fBint width, int height, int bpp, Uint32 flags\fR); .SH "DESCRIPTION" .PP Set up a video mode with the specified width, height and bits-per-pixel\&. .PP If \fBbpp\fR is 0, it is treated as the current display bits per pixel\&. .PP The \fBflags\fR parameter is the same as the \fBflags\fR field of the \fI\fBSDL_Surface\fR\fR structure\&. OR\&'d combinations of the following values are valid\&. .TP 20 \fBSDL_SWSURFACE\fP Create the video surface in system memory .TP 20 \fBSDL_HWSURFACE\fP Create the video surface in video memory .TP 20 \fBSDL_ASYNCBLIT\fP Enables the use of asynchronous updates of the display surface\&. This will usually slow down blitting on single CPU machines, but may provide a speed increase on SMP systems\&. .TP 20 \fBSDL_ANYFORMAT\fP Normally, if a video surface of the requested bits-per-pixel (\fBbpp\fR) is not available, SDL will emulate one with a shadow surface\&. Passing \fBSDL_ANYFORMAT\fP prevents this and causes SDL to use the video surface, regardless of its pixel depth\&. .TP 20 \fBSDL_HWPALETTE\fP Give SDL exclusive palette access\&. Without this flag you may not always get the the colors you request with \fI\fBSDL_SetColors\fP\fR or \fI\fBSDL_SetPalette\fP\fR\&. .TP 20 \fBSDL_DOUBLEBUF\fP Enable hardware double buffering; only valid with SDL_HWSURFACE\&. Calling \fI\fBSDL_Flip\fP\fR will flip the buffers and update the screen\&. All drawing will take place on the surface that is not displayed at the moment\&. If double buffering could not be enabled then \fBSDL_Flip\fP will just perform a \fI\fBSDL_UpdateRect\fP\fR on the entire screen\&. .TP 20 \fBSDL_FULLSCREEN\fP SDL will attempt to use a fullscreen mode\&. If a hardware resolution change is not possible (for whatever reason), the next higher resolution will be used and the display window centered on a black background\&. .TP 20 \fBSDL_OPENGL\fP Create an OpenGL rendering context\&. You should have previously set OpenGL video attributes with \fI\fBSDL_GL_SetAttribute\fP\fR\&. .TP 20 \fBSDL_OPENGLBLIT\fP Create an OpenGL rendering context, like above, but allow normal blitting operations\&. The screen (2D) surface may have an alpha channel, and \fI\fBSDL_UpdateRects\fP\fR must be used for updating changes to the screen surface\&. .TP 20 \fBSDL_RESIZABLE\fP Create a resizable window\&. When the window is resized by the user a \fI\fBSDL_VIDEORESIZE\fP\fR event is generated and \fBSDL_SetVideoMode\fP can be called again with the new size\&. .TP 20 \fBSDL_NOFRAME\fP If possible, \fBSDL_NOFRAME\fP causes SDL to create a window with no title bar or frame decoration\&. Fullscreen modes automatically have this flag set\&. .PP .RS \fBNote: .PP Whatever \fBflags\fR \fBSDL_SetVideoMode\fP could satisfy are set in the \fBflags\fR member of the returned surface\&. .RE .PP .RS \fBNote: .PP The \fBbpp\fR parameter is the number of bits per pixel, so a \fBbpp\fR of 24 uses the packed representation of 3 bytes/pixel\&. For the more common 4 bytes/pixel mode, use a \fBbpp\fR of 32\&. Somewhat oddly, both 15 and 16 will request a 2 bytes/pixel mode, but different pixel formats\&. .RE .SH "RETURN VALUE" .PP The framebuffer surface, or \fBNULL\fR if it fails\&. The surface returned is freed by SDL_Quit() and should nt be freed by the caller\&. .SH "SEE ALSO" .PP \fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_SetColors\fP\fR, \fI\fBSDL_Flip\fP\fR, \fI\fBSDL_Surface\fR\fR .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01