Mercurial > sdl-ios-xcode
view docs/man3/SDL_MapRGBA.3 @ 1626:a80e1e0880b8
Fixed bug #176
[I'm fixing this for the public headers, but I'm not going to bother for the SDL library code (yet)]
To clarify: Normaly, GCC (or, to be precise, the preprocessor) will ignore
this, and compile the code happily. However, one can specify -Wundef to get a
warning about this.
One can probably argue whether to consider this a bug or not; but I think that
(a) from a semantic point of view, using "#if FOO" when FOO is not defined is
strange, and (b) since it is possible to trigger a warning about this, and a
trivial fix exists, it should be corrected.
I can think of two alternative patches, BTW:
1) Simply use #define HAVE_FOO 0, instead of not defining HAVE_FOO at all
2) Change
#if HAVE_FOO
to
#if HAVE_FOO+0
which always does the right thing.
But I think I still prefer the attached patch :-).
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 13 Apr 2006 13:38:40 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_MapRGBA" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_MapRGBA\- Map a RGBA color value to a pixel format\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBUint32 \fBSDL_MapRGBA\fP\fR(\fBSDL_PixelFormat *fmt, Uint8 r, Uint8 g, Uint8 b, Uint8 a\fR); .SH "DESCRIPTION" .PP Maps the RGBA color value to the specified pixel format and returns the pixel value as a 32-bit int\&. .PP If the format has a palette (8-bit) the index of the closest matching color in the palette will be returned\&. .PP If the specified pixel format has no alpha component the alpha value will be ignored (as it will be in formats with a palette)\&. .SH "RETURN VALUE" .PP A pixel value best approximating the given RGBA color value for a given pixel format\&. If the pixel format bpp (color depth) is less than 32-bpp then the unused upper bits of the return value can safely be ignored (e\&.g\&., with a 16-bpp format the return value can be assigned to a \fBUint16\fP, and similarly a \fBUint8\fP for an 8-bpp format)\&. .SH "SEE ALSO" .PP \fISDL_GetRGB\fR, \fISDL_GetRGBA\fR, \fISDL_MapRGB\fR, \fISDL_PixelFormat\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01