#include <stdlib.h>
#include <string.h>
#include "SDL_rotozoom.h"

Data Structures
struct	tColorRGBA
	A 32 bit RGBA pixel. More...
struct	tColorY
	A 8bit Y/palette pixel. More...
Defines
#define	MAX(a, b) (((a) > (b)) ? (a) : (b))
	Returns maximum of two numbers a and b.
#define	GUARD_ROWS (2)
	Number of guard rows added to destination surfaces.
#define	VALUE_LIMIT 0.001
	Lower limit of absolute zoom factor or rotation degrees.
Typedefs
typedef struct tColorRGBA	tColorRGBA
	A 32 bit RGBA pixel.
typedef struct tColorY	tColorY
	A 8bit Y/palette pixel.
Functions
Uint32	_colorkey (SDL_Surface *src)
	Returns colorkey info for a surface.
int	_shrinkSurfaceRGBA (SDL_Surface src, SDL_Surface dst, int factorx, int factory)
	Internal 32 bit integer-factor averaging Shrinker.
int	_shrinkSurfaceY (SDL_Surface src, SDL_Surface dst, int factorx, int factory)
	Internal 8 bit integer-factor averaging shrinker.
int	_zoomSurfaceRGBA (SDL_Surface src, SDL_Surface dst, int flipx, int flipy, int smooth)
	Internal 32 bit Zoomer with optional anti-aliasing by bilinear interpolation.
int	_zoomSurfaceY (SDL_Surface src, SDL_Surface dst, int flipx, int flipy)
	Internal 8 bit Zoomer without smoothing.
void	_transformSurfaceRGBA (SDL_Surface src, SDL_Surface dst, int cx, int cy, int isin, int icos, int flipx, int flipy, int smooth)
	Internal 32 bit rotozoomer with optional anti-aliasing.
void	transformSurfaceY (SDL_Surface src, SDL_Surface dst, int cx, int cy, int isin, int icos, int flipx, int flipy)
	Rotates and zooms 8 bit palette/Y 'src' surface to 'dst' surface without smoothing.
SDL_Surface *	rotateSurface90Degrees (SDL_Surface *src, int numClockwiseTurns)
	Rotates a 32 bit surface in increments of 90 degrees.
void	_rotozoomSurfaceSizeTrig (int width, int height, double angle, double zoomx, double zoomy, int dstwidth, int dstheight, double canglezoom, double sanglezoom)
	Internal target surface sizing function for rotozooms with trig result return.
void	rotozoomSurfaceSizeXY (int width, int height, double angle, double zoomx, double zoomy, int dstwidth, int dstheight)
	Returns the size of the resulting target surface for a rotozoomSurfaceXY() call.
void	rotozoomSurfaceSize (int width, int height, double angle, double zoom, int dstwidth, int dstheight)
	Returns the size of the resulting target surface for a rotozoomSurface() call.
SDL_Surface *	rotozoomSurface (SDL_Surface *src, double angle, double zoom, int smooth)
	Rotates and zooms a surface and optional anti-aliasing.
SDL_Surface *	rotozoomSurfaceXY (SDL_Surface *src, double angle, double zoomx, double zoomy, int smooth)
	Rotates and zooms a surface with different horizontal and vertival scaling factors and optional anti-aliasing.
void	zoomSurfaceSize (int width, int height, double zoomx, double zoomy, int dstwidth, int dstheight)
	Calculates the size of the target surface for a zoomSurface() call.
SDL_Surface *	zoomSurface (SDL_Surface *src, double zoomx, double zoomy, int smooth)
	Zoom a surface by independent horizontal and vertical factors with optional smoothing.
SDL_Surface *	shrinkSurface (SDL_Surface *src, int factorx, int factory)
	Shrink a surface by an integer ratio using averaging.

Define Documentation

#define GUARD_ROWS (2)

Number of guard rows added to destination surfaces.

This is a simple but effective workaround for observed issues. These rows allocate extra memory and are then hidden from the surface. Rows are added to the end of destination surfaces when they are allocated. This catches any potential overflows which seem to happen with just the right src image dimensions and scale/rotation and can lead to a situation where the program can segfault.

Definition at line 73 of file SDL_rotozoom.c.

#define MAX	(	a,
		b
	)	(((a) > (b)) ? (a) : (b))

Returns maximum of two numbers a and b.

Definition at line 61 of file SDL_rotozoom.c.

#define VALUE_LIMIT 0.001

Lower limit of absolute zoom factor or rotation degrees.

Definition at line 78 of file SDL_rotozoom.c.

Typedef Documentation

typedef struct tColorRGBA tColorRGBA

A 32 bit RGBA pixel.

typedef struct tColorY tColorY

A 8bit Y/palette pixel.

Function Documentation

Uint32 _colorkey ( SDL_Surface * src )

Returns colorkey info for a surface.

Definition at line 83 of file SDL_rotozoom.c.

void _rotozoomSurfaceSizeTrig	(	int	width,
		int	height,
		double	angle,
		double	zoomx,
		double	zoomy,
		int *	dstwidth,
		int *	dstheight,
		double *	canglezoom,
		double *	sanglezoom
	)

Internal target surface sizing function for rotozooms with trig result return.

Parameters:

width	The source surface width.
height	The source surface height.
angle	The angle to rotate in degrees.
zoomx	The horizontal scaling factor.
zoomy	The vertical scaling factor.
dstwidth	The calculated width of the destination surface.
dstheight	The calculated height of the destination surface.
canglezoom	The sine of the angle adjusted by the zoom factor.
sanglezoom	The cosine of the angle adjusted by the zoom factor.

Definition at line 949 of file SDL_rotozoom.c.

int _shrinkSurfaceRGBA	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	factorx,
		int	factory
	)

Internal 32 bit integer-factor averaging Shrinker.

Shrinks 32 bit RGBA/ABGR 'src' surface to 'dst' surface. Averages color and alpha values values of src pixels to calculate dst pixels. Assumes src and dst surfaces are of 32 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	The surface to shrink (input).
dst	The shrunken surface (output).
factorx	The horizontal shrinking ratio.
factory	The vertical shrinking ratio.

Returns:: 0 for success or -1 for error.

Definition at line 113 of file SDL_rotozoom.c.

int _shrinkSurfaceY	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	factorx,
		int	factory
	)

Internal 8 bit integer-factor averaging shrinker.

Shrinks 8bit Y 'src' surface to 'dst' surface. Averages color (brightness) values values of src pixels to calculate dst pixels. Assumes src and dst surfaces are of 8 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	The surface to shrink (input).
dst	The shrunken surface (output).
factorx	The horizontal shrinking ratio.
factory	The vertical shrinking ratio.

Returns:: 0 for success or -1 for error.

Definition at line 202 of file SDL_rotozoom.c.

void _transformSurfaceRGBA	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	cx,
		int	cy,
		int	isin,
		int	icos,
		int	flipx,
		int	flipy,
		int	smooth
	)

Internal 32 bit rotozoomer with optional anti-aliasing.

Rotates and zooms 32 bit RGBA/ABGR 'src' surface to 'dst' surface based on the control parameters by scanning the destination surface and applying optionally anti-aliasing by bilinear interpolation. Assumes src and dst surfaces are of 32 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	Source surface.
dst	Destination surface.
cx	Horizontal center coordinate.
cy	Vertical center coordinate.
isin	Integer version of sine of angle.
icos	Integer version of cosine of angle.
flipx	Flag indicating horizontal mirroring should be applied.
flipy	Flag indicating vertical mirroring should be applied.
smooth	Flag indicating anti-aliasing should be used.

Definition at line 638 of file SDL_rotozoom.c.

int _zoomSurfaceRGBA	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	flipx,
		int	flipy,
		int	smooth
	)

Internal 32 bit Zoomer with optional anti-aliasing by bilinear interpolation.

Zooms 32 bit RGBA/ABGR 'src' surface to 'dst' surface. Assumes src and dst surfaces are of 32 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	The surface to zoom (input).
dst	The zoomed surface (output).
flipx	Flag indicating if the image should be horizontally flipped.
flipy	Flag indicating if the image should be vertically flipped.
smooth	Antialiasing flag; set to SMOOTHING_ON to enable.

Returns:: 0 for success or -1 for error.

Definition at line 286 of file SDL_rotozoom.c.

int _zoomSurfaceY	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	flipx,
		int	flipy
	)

Internal 8 bit Zoomer without smoothing.

Zooms 8bit palette/Y 'src' surface to 'dst' surface. Assumes src and dst surfaces are of 8 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	The surface to zoom (input).
dst	The zoomed surface (output).
flipx	Flag indicating if the image should be horizontally flipped.
flipy	Flag indicating if the image should be vertically flipped.

Returns:: 0 for success or -1 for error.

Definition at line 519 of file SDL_rotozoom.c.

SDL_Surface* rotateSurface90Degrees	(	SDL_Surface *	src,
		int	numClockwiseTurns
	)

Rotates a 32 bit surface in increments of 90 degrees.

Specialized 90 degree rotator which rotates a 'src' surface in 90 degree increments clockwise returning a new surface. Faster than rotozoomer since not scanning or interpolation takes place. Input surface must be 32 bit. (code contributed by J. Schiller, improved by C. Allport and A. Schiffler)

Parameters:

src	Source surface to rotate.
numClockwiseTurns	Number of clockwise 90 degree turns to apply to the source.

Returns:: The new, rotated surface; or NULL for surfaces with incorrect input format.

Definition at line 814 of file SDL_rotozoom.c.

SDL_Surface* rotozoomSurface	(	SDL_Surface *	src,
		double	angle,
		double	zoom,
		int	smooth
	)

Rotates and zooms a surface and optional anti-aliasing.

Rotates and zoomes a 32bit or 8bit 'src' surface to newly created 'dst' surface. 'angle' is the rotation in degrees and 'zoom' a scaling factor. If 'smooth' is set then the destination 32bit surface is anti-aliased. If the surface is not 8bit or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly.

Parameters:

src	The surface to rotozoom.
angle	The angle to rotate in degrees.
zoom	The scaling factor.
smooth	Antialiasing flag; set to SMOOTHING_ON to enable.

Returns:: The new rotozoomed surface.

Definition at line 1030 of file SDL_rotozoom.c.

void rotozoomSurfaceSize	(	int	width,
		int	height,
		double	angle,
		double	zoom,
		int *	dstwidth,
		int *	dstheight
	)

Returns the size of the resulting target surface for a rotozoomSurface() call.

Parameters:

width	The source surface width.
height	The source surface height.
angle	The angle to rotate in degrees.
zoom	The scaling factor.
dstwidth	The calculated width of the rotozoomed destination surface.
dstheight	The calculated height of the rotozoomed destination surface.

Definition at line 1008 of file SDL_rotozoom.c.

void rotozoomSurfaceSizeXY	(	int	width,
		int	height,
		double	angle,
		double	zoomx,
		double	zoomy,
		int *	dstwidth,
		int *	dstheight
	)

Returns the size of the resulting target surface for a rotozoomSurfaceXY() call.

Parameters:

width	The source surface width.
height	The source surface height.
angle	The angle to rotate in degrees.
zoomx	The horizontal scaling factor.
zoomy	The vertical scaling factor.
dstwidth	The calculated width of the rotozoomed destination surface.
dstheight	The calculated height of the rotozoomed destination surface.

Definition at line 991 of file SDL_rotozoom.c.

SDL_Surface* rotozoomSurfaceXY	(	SDL_Surface *	src,
		double	angle,
		double	zoomx,
		double	zoomy,
		int	smooth
	)

Rotates and zooms a surface with different horizontal and vertival scaling factors and optional anti-aliasing.

Rotates and zooms a 32bit or 8bit 'src' surface to newly created 'dst' surface. 'angle' is the rotation in degrees, 'zoomx and 'zoomy' scaling factors. If 'smooth' is set then the destination 32bit surface is anti-aliased. If the surface is not 8bit or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly.

Parameters:

src	The surface to rotozoom.
angle	The angle to rotate in degrees.
zoomx	The horizontal scaling factor.
zoomy	The vertical scaling factor.
smooth	Antialiasing flag; set to SMOOTHING_ON to enable.

Returns:: The new rotozoomed surface.

Definition at line 1051 of file SDL_rotozoom.c.

SDL_Surface* shrinkSurface	(	SDL_Surface *	src,
		int	factorx,
		int	factory
	)

Shrink a surface by an integer ratio using averaging.

Shrinks a 32bit or 8bit 'src' surface to a newly created 'dst' surface. 'factorx' and 'factory' are the shrinking ratios (i.e. 2=1/2 the size, 3=1/3 the size, etc.) The destination surface is antialiased by averaging the source box RGBA or Y information. If the surface is not 8bit or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly. The input surface is not modified. The output surface is newly allocated.

Parameters:

src	The surface to shrink.
factorx	The horizontal shrinking ratio.
factory	The vertical shrinking ratio.

Returns:: The new, shrunken surface.

Definition at line 1548 of file SDL_rotozoom.c.

void transformSurfaceY	(	SDL_Surface *	src,
		SDL_Surface *	dst,
		int	cx,
		int	cy,
		int	isin,
		int	icos,
		int	flipx,
		int	flipy
	)

Rotates and zooms 8 bit palette/Y 'src' surface to 'dst' surface without smoothing.

Rotates and zooms 8 bit RGBA/ABGR 'src' surface to 'dst' surface based on the control parameters by scanning the destination surface. Assumes src and dst surfaces are of 8 bit depth. Assumes dst surface was allocated with the correct dimensions.

Parameters:

src	Source surface.
dst	Destination surface.
cx	Horizontal center coordinate.
cy	Vertical center coordinate.
isin	Integer version of sine of angle.
icos	Integer version of cosine of angle.
flipx	Flag indicating horizontal mirroring should be applied.
flipy	Flag indicating vertical mirroring should be applied.

Definition at line 755 of file SDL_rotozoom.c.

SDL_Surface* zoomSurface	(	SDL_Surface *	src,
		double	zoomx,
		double	zoomy,
		int	smooth
	)

Zoom a surface by independent horizontal and vertical factors with optional smoothing.

Zooms a 32bit or 8bit 'src' surface to newly created 'dst' surface. 'zoomx' and 'zoomy' are scaling factors for width and height. If 'smooth' is on then the destination 32bit surface is anti-aliased. If the surface is not 8bit or 32bit RGBA/ABGR it will be converted into a 32bit RGBA format on the fly. If zoom factors are negative, the image is flipped on the axes.

Parameters:

src	The surface to zoom.
zoomx	The horizontal zoom factor.
zoomy	The vertical zoom factor.
smooth	Antialiasing flag; set to SMOOTHING_ON to enable.

Returns:: The new, zoomed surface.

Definition at line 1392 of file SDL_rotozoom.c.

void zoomSurfaceSize	(	int	width,
		int	height,
		double	zoomx,
		double	zoomy,
		int *	dstwidth,
		int *	dstheight
	)

Calculates the size of the target surface for a zoomSurface() call.

The minimum size of the target surface is 1. The input factors can be positive or negative.

Parameters:

width	The width of the source surface to zoom.
height	The height of the source surface to zoom.
zoomx	The horizontal zoom factor.
zoomy	The vertical zoom factor.
dstwidth	Pointer to an integer to store the calculated width of the zoomed target surface.
dstheight	Pointer to an integer to store the calculated height of the zoomed target surface.

Definition at line 1342 of file SDL_rotozoom.c.

Data Structures

Defines

Typedefs

Functions

Define Documentation

Typedef Documentation

Function Documentation