NAME
SDL_SetRowStretchCode, SDL_PutRowStretchCode, SDL_RunRowStretchCode,
SDL_StretchRow1, SDL_StretchRow2, SDL_StretchRow3, SDL_StretchRow4 -
(SDL_stretchcode.h)
SYNOPSIS
#include <SDL_stretch.h>
unsigned char* SDL_SetRowStretchCode(int src_w, int dst_w, int bpp);
unsigned char* SDL_PutRowStretchCode(unsigned char* buffer, int buflen,
int src_w, int dst_w, int bpp);
void SDL_RunRowStretchCode(unsigned char* buffer, unsigned char* src,
unsigned char* dst);
void SDL_StretchRow1(Uint8 *src, int src_w, Uint8 *dst, int dst_w);
void SDL_StretchRow2(Uint16 *src, int src_w, Uint16 *dst, int dst_w);
void SDL_StretchRow3(Uint8 *src, int src_w, Uint8 *dst, int dst_w);
void SDL_StretchRow4(Uint32 *src, int src_w, Uint32 *dst, int dst_w);
DESCRIPTION
The SetRowStretchCode is a wrapper around PutRowStretchCode that uses
the Adress and Size of the shared SDL_TheRowStretchCode buffer. The
PutRowStretchCode will fill the given buffer with an assembler stream
that should be called with SDL_RunRowStretchCode. The assembler stream
is usually faster as all the scale decisions are done in advance of the
execution. This helps when a RunCode is done multiple times with the
same src_w/dst_w/bpp pair. All the pixel-get and pixel-set calls are
unrolled in that buffer. Therefore, the buffer should be big enough -
as a rule of thumb use a buffer of size (src_w+dst_w)*5
If PutCode or SetCode fails, a NULL is returned and SDL_SetError.
Otherwise, the start adress of the machine code buffer is returned,
which is also the input argument of PutCode and RunCode.
If SDL_SetRowStretchCode fails, the SDL_StretchRow1 function must be
used instead. The SDL_StretchRow1 function and its cousins are
singular routines that work in a tight loop to scale a single row. The
number specifies the byte-width of each pixel (it is not a bit-width!).