Mercurial > sdl-ios-xcode
view docs/man3/SDL_DisplayFormatAlpha.3 @ 911:04a403e4ccf5
Date: Mon, 3 May 2004 03:15:01 +0100
From: David Symmonds
Subject: SDL Typedef Structs
Hi, Thanks for the SDL libraries, I have been using them for about a year
now and they are really brilliant. One thing that I have just found whilst
using them through C++ (and needing forward declarations) is that when you
typedef structs you sometimes use
typedef struct Name
{
...
}Name;
e.g. SDL_Surface
and other times use
typedef struct
{
...
}Name;
e.g. SDL_Rect
The first type works fine, when I define a header file I can just put
'struct Name;' at the top and use the Name throughout. However, the second
type is harder to use in a header, and I haven't found a way yet, other than
to include 'SDL.h' in the header file (undesirable). Would there be any harm
in changing the definition of SDL_Rect and such like to the second form?
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 18 Jul 2004 22:57:40 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_DisplayFormatAlpha\- Convert a surface to the display format .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR); .SH "DESCRIPTION" .PP This function takes a surface and copies it to a new surface of the pixel format and colors of the video framebuffer plus an alpha channel, suitable for fast blitting onto the display surface\&. It calls \fISDL_ConvertSurface\fR .PP If you want to take advantage of hardware colorkey or alpha blit acceleration, you should set the colorkey and alpha value before calling this function\&. .PP This function can be used to convert a colourkey to an alpha channel, if the \fBSDL_SRCCOLORKEY\fP flag is set on the surface\&. The generated surface will then be transparent (alpha=0) where the pixels match the colourkey, and opaque (alpha=255) elsewhere\&. .SH "RETURN VALUE" .PP If the conversion fails or runs out of memory, it returns \fBNULL\fR .SH "SEE ALSO" .PP \fISDL_ConvertSurface\fR, \fISDL_SetAlpha\fR, \fISDL_SetColorKey\fR, \fISDL_DisplayFormat\fR, \fISDL_Surface\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01