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annotate docs/man3/SDL_MapRGBA.3 @ 1626:a80e1e0880b8

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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
rev   line source
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e5bc29de3f0a Updated from the SDL Documentation Project
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1 .TH "SDL_MapRGBA" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_MapRGBA\- Map a RGBA color value to a pixel format\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBUint32 \fBSDL_MapRGBA\fP\fR(\fBSDL_PixelFormat *fmt, Uint8 r, Uint8 g, Uint8 b, Uint8 a\fR);
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9 .SH "DESCRIPTION"
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10 .PP
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11 Maps the RGBA color value to the specified pixel format and returns the pixel value as a 32-bit int\&.
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12 .PP
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13 If the format has a palette (8-bit) the index of the closest matching color in the palette will be returned\&.
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14 .PP
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15 If the specified pixel format has no alpha component the alpha value will be ignored (as it will be in formats with a palette)\&.
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16 .SH "RETURN VALUE"
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17 .PP
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18 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)\&.
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19 .SH "SEE ALSO"
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20 .PP
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21 \fISDL_GetRGB\fR, \fISDL_GetRGBA\fR, \fISDL_MapRGB\fR, \fISDL_PixelFormat\fR
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22 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01