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annotate docs/man3/SDL_BlitSurface.3 @ 211:0cc95f442f3a
If we're looking at the /dev/input event devices, and we found
at least one, then we don't want to look at the input joystick
devices, since they're built on top of devices that we've already
seen, so we're done.
| author | Sam Lantinga <slouken@libsdl.org> |
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| date | Mon, 22 Oct 2001 21:34:50 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
| rev | line source |
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1 .TH "SDL_BlitSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_BlitSurface\- This performs a fast blit from the source surface to the destination surface\&. | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 .sp | |
| 8 \fBint \fBSDL_BlitSurface\fP\fR(\fBSDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect\fR); | |
| 9 .SH "DESCRIPTION" | |
| 10 .PP | |
| 11 This performs a fast blit from the source surface to the destination surface\&. | |
| 12 .PP | |
| 13 Only the position is used in the \fBdstrect\fR (the width and height are ignored)\&. | |
| 14 .PP | |
| 15 If either \fBsrcrect\fR or \fBdstrect\fR are \fBNULL\fP, the entire surface (\fBsrc\fR or \fBdst\fR) is copied\&. | |
| 16 .PP | |
| 17 The final blit rectangle is saved in \fBdstrect\fR after all clipping is performed (\fBsrcrect\fR is not modified)\&. | |
| 18 .PP | |
| 19 The blit function should not be called on a locked surface\&. | |
| 20 .PP | |
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21 The results of blitting operations vary greatly depending on whether \fBSDL_SRCAPLHA\fP is set or not\&. See \fISDL_SetAlpha\fR for an explaination of how this affects your results\&. Colorkeying and alpha attributes also interact with surface blitting, as the following pseudo-code should hopefully explain\&. |
| 0 | 22 .PP |
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23 .nf |
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24 \f(CWif (source surface has SDL_SRCALPHA set) { |
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25 if (source surface has alpha channel (that is, format->Amask != 0)) |
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26 blit using per-pixel alpha, ignoring any colour key |
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27 else { |
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28 if (source surface has SDL_SRCCOLORKEY set) |
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29 blit using the colour key AND the per-surface alpha value |
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30 else |
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31 blit using the per-surface alpha value |
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32 } |
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33 } else { |
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34 if (source surface has SDL_SRCCOLORKEY set) |
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35 blit using the colour key |
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36 else |
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37 ordinary opaque rectangular blit |
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38 }\fR |
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39 .fi |
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40 .PP |
| 0 | 41 .SH "RETURN VALUE" |
| 42 .PP | |
| 43 If the blit is successful, it returns \fB0\fR, otherwise it returns \fB-1\fR\&. | |
| 44 .PP | |
| 45 If either of the surfaces were in video memory, and the blit returns \fB-2\fR, the video memory was lost, so it should be reloaded with artwork and re-blitted: | |
| 46 .PP | |
| 47 .nf | |
| 48 \f(CW while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) { | |
| 49 while ( SDL_LockSurface(image)) < 0 ) | |
| 50 Sleep(10); | |
| 51 -- Write image pixels to image->pixels -- | |
| 52 SDL_UnlockSurface(image); | |
| 53 }\fR | |
| 54 .fi | |
| 55 .PP | |
| 56 This happens under DirectX 5\&.0 when the system switches away from your fullscreen application\&. Locking the surface will also fail until you have access to the video memory again\&. | |
| 57 .SH "SEE ALSO" | |
| 58 .PP | |
| 59 \fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_FillRect\fP\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_Rect\fR\fR | |
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60 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |