1 /*
2     SDL - Simple DirectMedia Layer
3     Copyright (C) 1997-2012 Sam Lantinga
4 
5     This library is free software; you can redistribute it and/or
6     modify it under the terms of the GNU Lesser General Public
7     License as published by the Free Software Foundation; either
8     version 2.1 of the License, or (at your option) any later version.
9 
10     This library is distributed in the hope that it will be useful,
11     but WITHOUT ANY WARRANTY; without even the implied warranty of
12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13     Lesser General Public License for more details.
14 
15     You should have received a copy of the GNU Lesser General Public
16     License along with this library; if not, write to the Free Software
17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18 
19     Sam Lantinga
20     slouken@libsdl.org
21 */
22 
23 /** @file SDL_video.h
24  *  Header file for access to the SDL raw framebuffer window
25  */
26 
27 #ifndef _LRSDL_video_h
28 #define _LRSDL_video_h
29 
30 #include "LRSDL_stdinc.h"
31 #include "LRSDL_error.h"
32 #include "LRSDL_rwops.h"
33 
34 #include "begin_code.h"
35 /* Set up for C function definitions, even when using C++ */
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39 
40 /** @name Transparency definitions
41  *  These define alpha as the opacity of a surface
42  */
43 /*@{*/
44 #define SDL_ALPHA_OPAQUE 255
45 #define SDL_ALPHA_TRANSPARENT 0
46 /*@}*/
47 
48 /** @name Useful data types */
49 /*@{*/
50 typedef struct SDL_Rect {
51 	Sint16 x, y;
52 	Uint16 w, h;
53 } SDL_Rect;
54 
55 typedef struct SDL_Color {
56 	Uint8 r;
57 	Uint8 g;
58 	Uint8 b;
59 	Uint8 unused;
60 } SDL_Color;
61 #define SDL_Colour SDL_Color
62 
63 typedef struct SDL_Palette {
64 	int       ncolors;
65 	SDL_Color *colors;
66 } SDL_Palette;
67 /*@}*/
68 
69 /** Everything in the pixel format structure is read-only */
70 typedef struct SDL_PixelFormat {
71 	SDL_Palette *palette;
72 	Uint8  BitsPerPixel;
73 	Uint8  BytesPerPixel;
74 	Uint8  Rloss;
75 	Uint8  Gloss;
76 	Uint8  Bloss;
77 	Uint8  Aloss;
78 	Uint8  Rshift;
79 	Uint8  Gshift;
80 	Uint8  Bshift;
81 	Uint8  Ashift;
82 	Uint32 Rmask;
83 	Uint32 Gmask;
84 	Uint32 Bmask;
85 	Uint32 Amask;
86 
87 	/** RGB color key information */
88 	Uint32 colorkey;
89 	/** Alpha value information (per-surface alpha) */
90 	Uint8  alpha;
91 } SDL_PixelFormat;
92 
93 /** This structure should be treated as read-only, except for 'pixels',
94  *  which, if not NULL, contains the raw pixel data for the surface.
95  */
96 typedef struct SDL_Surface {
97 	Uint32 flags;				/**< Read-only */
98 	SDL_PixelFormat *format;		/**< Read-only */
99 	int w, h;				/**< Read-only */
100 	Uint16 pitch;				/**< Read-only */
101 	void *pixels;				/**< Read-write */
102 	int offset;				/**< Private */
103 
104 	/** Hardware-specific surface info */
105 	struct private_hwdata *hwdata;
106 
107 	/** clipping information */
108 	SDL_Rect clip_rect;			/**< Read-only */
109 	Uint32 unused1;				/**< for binary compatibility */
110 
111 	/** Allow recursive locks */
112 	Uint32 locked;				/**< Private */
113 
114 	/** info for fast blit mapping to other surfaces */
115 	struct SDL_BlitMap *map;		/**< Private */
116 
117 	/** format version, bumped at every change to invalidate blit maps */
118 	unsigned int format_version;		/**< Private */
119 
120 	/** Reference count -- used when freeing surface */
121 	int refcount;				/**< Read-mostly */
122 } SDL_Surface;
123 
124 /** @name SDL_Surface Flags
125  *  These are the currently supported flags for the SDL_surface
126  */
127 /*@{*/
128 
129 /** Available for SDL_CreateRGBSurface() or SDL_SetVideoMode() */
130 /*@{*/
131 #define SDL_SWSURFACE	0x00000000	/**< Surface is in system memory */
132 #define SDL_HWSURFACE	0x00000001	/**< Surface is in video memory */
133 #define SDL_ASYNCBLIT	0x00000004	/**< Use asynchronous blits if possible */
134 /*@}*/
135 
136 /** Available for SDL_SetVideoMode() */
137 /*@{*/
138 #define SDL_ANYFORMAT	0x10000000	/**< Allow any video depth/pixel-format */
139 #define SDL_HWPALETTE	0x20000000	/**< Surface has exclusive palette */
140 #define SDL_DOUBLEBUF	0x40000000	/**< Set up double-buffered video mode */
141 #define SDL_FULLSCREEN	0x80000000	/**< Surface is a full screen display */
142 #define SDL_OPENGL      0x00000002      /**< Create an OpenGL rendering context */
143 #define SDL_OPENGLBLIT	0x0000000A	/**< Create an OpenGL rendering context and use it for blitting */
144 #define SDL_RESIZABLE	0x00000010	/**< This video mode may be resized */
145 #define SDL_NOFRAME	0x00000020	/**< No window caption or edge frame */
146 /*@}*/
147 
148 /** Used internally (read-only) */
149 /*@{*/
150 #define SDL_HWACCEL	0x00000100	/**< Blit uses hardware acceleration */
151 #define SDL_SRCCOLORKEY	0x00001000	/**< Blit uses a source color key */
152 #define SDL_RLEACCELOK	0x00002000	/**< Private flag */
153 #define SDL_RLEACCEL	0x00004000	/**< Surface is RLE encoded */
154 #define SDL_SRCALPHA	0x00010000	/**< Blit uses source alpha blending */
155 #define SDL_PREALLOC	0x01000000	/**< Surface uses preallocated memory */
156 /*@}*/
157 
158 /*@}*/
159 
160 /** Evaluates to true if the surface needs to be locked before access */
161 #define SDL_MUSTLOCK(surface)	\
162   (surface->offset ||		\
163   ((surface->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_RLEACCEL)) != 0))
164 
165 /** typedef for private surface blitting functions */
166 typedef int (*SDL_blit)(struct SDL_Surface *src, SDL_Rect *srcrect,
167 			struct SDL_Surface *dst, SDL_Rect *dstrect);
168 
169 
170 /** Useful for determining the video hardware capabilities */
171 typedef struct SDL_VideoInfo {
172 	Uint32 hw_available :1;	/**< Flag: Can you create hardware surfaces? */
173 	Uint32 wm_available :1;	/**< Flag: Can you talk to a window manager? */
174 	Uint32 UnusedBits1  :6;
175 	Uint32 UnusedBits2  :1;
176 	Uint32 blit_hw      :1;	/**< Flag: Accelerated blits HW --> HW */
177 	Uint32 blit_hw_CC   :1;	/**< Flag: Accelerated blits with Colorkey */
178 	Uint32 blit_hw_A    :1;	/**< Flag: Accelerated blits with Alpha */
179 	Uint32 blit_sw      :1;	/**< Flag: Accelerated blits SW --> HW */
180 	Uint32 blit_sw_CC   :1;	/**< Flag: Accelerated blits with Colorkey */
181 	Uint32 blit_sw_A    :1;	/**< Flag: Accelerated blits with Alpha */
182 	Uint32 blit_fill    :1;	/**< Flag: Accelerated color fill */
183 	Uint32 UnusedBits3  :16;
184 	Uint32 video_mem;	/**< The total amount of video memory (in K) */
185 	SDL_PixelFormat *vfmt;	/**< Value: The format of the video surface */
186 	int    current_w;	/**< Value: The current video mode width */
187 	int    current_h;	/**< Value: The current video mode height */
188 } SDL_VideoInfo;
189 
190 
191 /** @name Overlay Formats
192  *  The most common video overlay formats.
193  *  For an explanation of these pixel formats, see:
194  *	http://www.webartz.com/fourcc/indexyuv.htm
195  *
196  *  For information on the relationship between color spaces, see:
197  *  http://www.neuro.sfc.keio.ac.jp/~aly/polygon/info/color-space-faq.html
198  */
199 /*@{*/
200 #define SDL_YV12_OVERLAY  0x32315659	/**< Planar mode: Y + V + U  (3 planes) */
201 #define SDL_IYUV_OVERLAY  0x56555949	/**< Planar mode: Y + U + V  (3 planes) */
202 #define SDL_YUY2_OVERLAY  0x32595559	/**< Packed mode: Y0+U0+Y1+V0 (1 plane) */
203 #define SDL_UYVY_OVERLAY  0x59565955	/**< Packed mode: U0+Y0+V0+Y1 (1 plane) */
204 #define SDL_YVYU_OVERLAY  0x55595659	/**< Packed mode: Y0+V0+Y1+U0 (1 plane) */
205 /*@}*/
206 
207 /** The YUV hardware video overlay */
208 typedef struct SDL_Overlay {
209 	Uint32 format;				/**< Read-only */
210 	int w, h;				/**< Read-only */
211 	int planes;				/**< Read-only */
212 	Uint16 *pitches;			/**< Read-only */
213 	Uint8 **pixels;				/**< Read-write */
214 
215 	/** @name Hardware-specific surface info */
216         /*@{*/
217 	struct private_yuvhwfuncs *hwfuncs;
218 	struct private_yuvhwdata *hwdata;
219         /*@{*/
220 
221 	/** @name Special flags */
222         /*@{*/
223 	Uint32 hw_overlay :1;	/**< Flag: This overlay hardware accelerated? */
224 	Uint32 UnusedBits :31;
225         /*@}*/
226 } SDL_Overlay;
227 
228 
229 /** @name flags for SDL_SetPalette() */
230 /*@{*/
231 #define SDL_LOGPAL 0x01
232 #define SDL_PHYSPAL 0x02
233 /*@}*/
234 
235 /* Function prototypes */
236 
237 /** @name SDL_Update Functions
238  * These functions should not be called while 'screen' is locked.
239  */
240 /*@{*/
241 /**
242  * Makes sure the given list of rectangles is updated on the given screen.
243  */
244 extern DECLSPEC void SDLCALL LRSDL_UpdateRects
245 		(SDL_Surface *screen, int numrects, SDL_Rect *rects);
246 /**
247  * If 'x', 'y', 'w' and 'h' are all 0, SDL_UpdateRect will update the entire
248  * screen.
249  */
250 extern DECLSPEC void SDLCALL LRSDL_UpdateRect
251 		(SDL_Surface *screen, Sint32 x, Sint32 y, Uint32 w, Uint32 h);
252 /*@}*/
253 
254 /**
255  * On hardware that supports double-buffering, this function sets up a flip
256  * and returns.  The hardware will wait for vertical retrace, and then swap
257  * video buffers before the next video surface blit or lock will return.
258  * On hardware that doesn not support double-buffering, this is equivalent
259  * to calling SDL_UpdateRect(screen, 0, 0, 0, 0);
260  * The SDL_DOUBLEBUF flag must have been passed to SDL_SetVideoMode() when
261  * setting the video mode for this function to perform hardware flipping.
262  * This function returns 0 if successful, or -1 if there was an error.
263  */
264 extern DECLSPEC int SDLCALL LRSDL_Flip(SDL_Surface *screen);
265 
266 /**
267  * Set the gamma correction for each of the color channels.
268  * The gamma values range (approximately) between 0.1 and 10.0
269  *
270  * If this function isn't supported directly by the hardware, it will
271  * be emulated using gamma ramps, if available.  If successful, this
272  * function returns 0, otherwise it returns -1.
273  */
274 extern DECLSPEC int SDLCALL LRSDL_SetGamma(float red, float green, float blue);
275 
276 /**
277  * Sets a portion of the colormap for the given 8-bit surface.  If 'surface'
278  * is not a palettized surface, this function does nothing, returning 0.
279  * If all of the colors were set as passed to SDL_SetColors(), it will
280  * return 1.  If not all the color entries were set exactly as given,
281  * it will return 0, and you should look at the surface palette to
282  * determine the actual color palette.
283  *
284  * When 'surface' is the surface associated with the current display, the
285  * display colormap will be updated with the requested colors.  If
286  * SDL_HWPALETTE was set in SDL_SetVideoMode() flags, SDL_SetColors()
287  * will always return 1, and the palette is guaranteed to be set the way
288  * you desire, even if the window colormap has to be warped or run under
289  * emulation.
290  */
291 extern DECLSPEC int SDLCALL LRSDL_SetColors(SDL_Surface *surface,
292 			SDL_Color *colors, int firstcolor, int ncolors);
293 
294 /**
295  * Sets a portion of the colormap for a given 8-bit surface.
296  * 'flags' is one or both of:
297  * SDL_LOGPAL  -- set logical palette, which controls how blits are mapped
298  *                to/from the surface,
299  * SDL_PHYSPAL -- set physical palette, which controls how pixels look on
300  *                the screen
301  * Only screens have physical palettes. Separate change of physical/logical
302  * palettes is only possible if the screen has SDL_HWPALETTE set.
303  *
304  * The return value is 1 if all colours could be set as requested, and 0
305  * otherwise.
306  *
307  * SDL_SetColors() is equivalent to calling this function with
308  *     flags = (SDL_LOGPAL|SDL_PHYSPAL).
309  */
310 extern DECLSPEC int SDLCALL LRSDL_SetPalette(SDL_Surface *surface, int flags,
311 				   SDL_Color *colors, int firstcolor,
312 				   int ncolors);
313 
314 /**
315  * Maps an RGB triple to an opaque pixel value for a given pixel format
316  */
317 extern DECLSPEC Uint32 SDLCALL LRSDL_MapRGB
318 (const SDL_PixelFormat * const format,
319  const Uint8 r, const Uint8 g, const Uint8 b);
320 
321 /**
322  * Maps an RGBA quadruple to a pixel value for a given pixel format
323  */
324 extern DECLSPEC Uint32 SDLCALL LRSDL_MapRGBA
325 (const SDL_PixelFormat * const format,
326  const Uint8 r, const Uint8 g, const Uint8 b, const Uint8 a);
327 
328 /**
329  * Maps a pixel value into the RGB components for a given pixel format
330  */
331 extern DECLSPEC void SDLCALL LRSDL_GetRGB(Uint32 pixel,
332 				const SDL_PixelFormat * const fmt,
333 				Uint8 *r, Uint8 *g, Uint8 *b);
334 
335 /**
336  * Maps a pixel value into the RGBA components for a given pixel format
337  */
338 extern DECLSPEC void SDLCALL LRSDL_GetRGBA(Uint32 pixel,
339 				const SDL_PixelFormat * const fmt,
340 				Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);
341 
342 /** @sa SDL_CreateRGBSurface */
343 #define LRSDL_AllocSurface    LRSDL_CreateRGBSurface
344 /**
345  * Allocate and free an RGB surface (must be called after SDL_SetVideoMode)
346  * If the depth is 4 or 8 bits, an empty palette is allocated for the surface.
347  * If the depth is greater than 8 bits, the pixel format is set using the
348  * flags '[RGB]mask'.
349  * If the function runs out of memory, it will return NULL.
350  *
351  * The 'flags' tell what kind of surface to create.
352  * SDL_SWSURFACE means that the surface should be created in system memory.
353  * SDL_HWSURFACE means that the surface should be created in video memory,
354  * with the same format as the display surface.  This is useful for surfaces
355  * that will not change much, to take advantage of hardware acceleration
356  * when being blitted to the display surface.
357  * SDL_ASYNCBLIT means that SDL will try to perform asynchronous blits with
358  * this surface, but you must always lock it before accessing the pixels.
359  * SDL will wait for current blits to finish before returning from the lock.
360  * SDL_SRCCOLORKEY indicates that the surface will be used for colorkey blits.
361  * If the hardware supports acceleration of colorkey blits between
362  * two surfaces in video memory, SDL will try to place the surface in
363  * video memory. If this isn't possible or if there is no hardware
364  * acceleration available, the surface will be placed in system memory.
365  * SDL_SRCALPHA means that the surface will be used for alpha blits and
366  * if the hardware supports hardware acceleration of alpha blits between
367  * two surfaces in video memory, to place the surface in video memory
368  * if possible, otherwise it will be placed in system memory.
369  * If the surface is created in video memory, blits will be _much_ faster,
370  * but the surface format must be identical to the video surface format,
371  * and the only way to access the pixels member of the surface is to use
372  * the SDL_LockSurface() and SDL_UnlockSurface() calls.
373  * If the requested surface actually resides in video memory, SDL_HWSURFACE
374  * will be set in the flags member of the returned surface.  If for some
375  * reason the surface could not be placed in video memory, it will not have
376  * the SDL_HWSURFACE flag set, and will be created in system memory instead.
377  */
378 extern DECLSPEC SDL_Surface * SDLCALL LRSDL_CreateRGBSurface
379 			(Uint32 flags, int width, int height, int depth,
380 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
381 /** @sa SDL_CreateRGBSurface */
382 extern DECLSPEC SDL_Surface * SDLCALL LRSDL_CreateRGBSurfaceFrom(void *pixels,
383 			int width, int height, int depth, int pitch,
384 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
385 extern DECLSPEC void SDLCALL LRSDL_FreeSurface(SDL_Surface *surface);
386 
387 /**
388  * SDL_LockSurface() sets up a surface for directly accessing the pixels.
389  * Between calls to SDL_LockSurface()/SDL_UnlockSurface(), you can write
390  * to and read from 'surface->pixels', using the pixel format stored in
391  * 'surface->format'.  Once you are done accessing the surface, you should
392  * use SDL_UnlockSurface() to release it.
393  *
394  * Not all surfaces require locking.  If SDL_MUSTLOCK(surface) evaluates
395  * to 0, then you can read and write to the surface at any time, and the
396  * pixel format of the surface will not change.  In particular, if the
397  * SDL_HWSURFACE flag is not given when calling SDL_SetVideoMode(), you
398  * will not need to lock the display surface before accessing it.
399  *
400  * No operating system or library calls should be made between lock/unlock
401  * pairs, as critical system locks may be held during this time.
402  *
403  * SDL_LockSurface() returns 0, or -1 if the surface couldn't be locked.
404  */
405 extern DECLSPEC int SDLCALL LRSDL_LockSurface(SDL_Surface *surface);
406 extern DECLSPEC void SDLCALL LRSDL_UnlockSurface(SDL_Surface *surface);
407 
408 /*
409  * Convert a surface into the specified pixel format.
410  */
411 extern DECLSPEC SDL_Surface * LRSDL_ConvertSurface (SDL_Surface *surface,
412 					SDL_PixelFormat *format, Uint32 flags);
413 
414 
415 /**
416  * Load a surface from a seekable SDL data source (memory or file.)
417  * If 'freesrc' is non-zero, the source will be closed after being read.
418  * Returns the new surface, or NULL if there was an error.
419  * The new surface should be freed with SDL_FreeSurface().
420  */
421 extern DECLSPEC SDL_Surface * SDLCALL LRSDL_LoadBMP_RW(LRSDL_RWops *src, int freesrc);
422 
423 /** Convenience macro -- load a surface from a file */
424 #define LRSDL_LoadBMP(file)	LRSDL_LoadBMP_RW(LRSDL_RWFromFile(file, "rb"), 1)
425 
426 /**
427  * Save a surface to a seekable SDL data source (memory or file.)
428  * If 'freedst' is non-zero, the source will be closed after being written.
429  * Returns 0 if successful or -1 if there was an error.
430  */
431 extern DECLSPEC int SDLCALL LRSDL_SaveBMP_RW
432 		(SDL_Surface *surface, LRSDL_RWops *dst, int freedst);
433 
434 /** Convenience macro -- save a surface to a file */
435 #define LRSDL_SaveBMP(surface, file) \
436 		LRSDL_SaveBMP_RW(surface, LRSDL_RWFromFile(file, "wb"), 1)
437 
438 /**
439  * Sets the color key (transparent pixel) in a blittable surface.
440  * If 'flag' is SDL_SRCCOLORKEY (optionally OR'd with SDL_RLEACCEL),
441  * 'key' will be the transparent pixel in the source image of a blit.
442  * SDL_RLEACCEL requests RLE acceleration for the surface if present,
443  * and removes RLE acceleration if absent.
444  * If 'flag' is 0, this function clears any current color key.
445  * This function returns 0, or -1 if there was an error.
446  */
447 extern DECLSPEC int SDLCALL LRSDL_SetColorKey
448 			(SDL_Surface *surface, Uint32 flag, Uint32 key);
449 
450 /**
451  * This function sets the alpha value for the entire surface, as opposed to
452  * using the alpha component of each pixel. This value measures the range
453  * of transparency of the surface, 0 being completely transparent to 255
454  * being completely opaque. An 'alpha' value of 255 causes blits to be
455  * opaque, the source pixels copied to the destination (the default). Note
456  * that per-surface alpha can be combined with colorkey transparency.
457  *
458  * If 'flag' is 0, alpha blending is disabled for the surface.
459  * If 'flag' is SDL_SRCALPHA, alpha blending is enabled for the surface.
460  * OR:ing the flag with SDL_RLEACCEL requests RLE acceleration for the
461  * surface; if SDL_RLEACCEL is not specified, the RLE accel will be removed.
462  *
463  * The 'alpha' parameter is ignored for surfaces that have an alpha channel.
464  */
465 extern DECLSPEC int SDLCALL LRSDL_SetAlpha(SDL_Surface *surface, Uint32 flag, Uint8 alpha);
466 
467 /**
468  * Sets the clipping rectangle for the destination surface in a blit.
469  *
470  * If the clip rectangle is NULL, clipping will be disabled.
471  * If the clip rectangle doesn't intersect the surface, the function will
472  * return SDL_FALSE and blits will be completely clipped.  Otherwise the
473  * function returns SDL_TRUE and blits to the surface will be clipped to
474  * the intersection of the surface area and the clipping rectangle.
475  *
476  * Note that blits are automatically clipped to the edges of the source
477  * and destination surfaces.
478  */
479 extern DECLSPEC LRSDL_bool SDLCALL LRSDL_SetClipRect(SDL_Surface *surface, const SDL_Rect *rect);
480 
481 /**
482  * This performs a fast blit from the source surface to the destination
483  * surface.  It assumes that the source and destination rectangles are
484  * the same size.  If either 'srcrect' or 'dstrect' are NULL, the entire
485  * surface (src or dst) is copied.  The final blit rectangles are saved
486  * in 'srcrect' and 'dstrect' after all clipping is performed.
487  * If the blit is successful, it returns 0, otherwise it returns -1.
488  *
489  * The blit function should not be called on a locked surface.
490  *
491  * The blit semantics for surfaces with and without alpha and colorkey
492  * are defined as follows:
493  *
494  * RGBA->RGB:
495  *     SDL_SRCALPHA set:
496  * 	alpha-blend (using alpha-channel).
497  * 	SDL_SRCCOLORKEY ignored.
498  *     SDL_SRCALPHA not set:
499  * 	copy RGB.
500  * 	if SDL_SRCCOLORKEY set, only copy the pixels matching the
501  * 	RGB values of the source colour key, ignoring alpha in the
502  * 	comparison.
503  *
504  * RGB->RGBA:
505  *     SDL_SRCALPHA set:
506  * 	alpha-blend (using the source per-surface alpha value);
507  * 	set destination alpha to opaque.
508  *     SDL_SRCALPHA not set:
509  * 	copy RGB, set destination alpha to source per-surface alpha value.
510  *     both:
511  * 	if SDL_SRCCOLORKEY set, only copy the pixels matching the
512  * 	source colour key.
513  *
514  * RGBA->RGBA:
515  *     SDL_SRCALPHA set:
516  * 	alpha-blend (using the source alpha channel) the RGB values;
517  * 	leave destination alpha untouched. [Note: is this correct?]
518  * 	SDL_SRCCOLORKEY ignored.
519  *     SDL_SRCALPHA not set:
520  * 	copy all of RGBA to the destination.
521  * 	if SDL_SRCCOLORKEY set, only copy the pixels matching the
522  * 	RGB values of the source colour key, ignoring alpha in the
523  * 	comparison.
524  *
525  * RGB->RGB:
526  *     SDL_SRCALPHA set:
527  * 	alpha-blend (using the source per-surface alpha value).
528  *     SDL_SRCALPHA not set:
529  * 	copy RGB.
530  *     both:
531  * 	if SDL_SRCCOLORKEY set, only copy the pixels matching the
532  * 	source colour key.
533  *
534  * If either of the surfaces were in video memory, and the blit returns -2,
535  * the video memory was lost, so it should be reloaded with artwork and
536  * re-blitted:
537  * @code
538  *	while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
539  *		while ( SDL_LockSurface(image) < 0 )
540  *			Sleep(10);
541  *		-- Write image pixels to image->pixels --
542  *		SDL_UnlockSurface(image);
543  *	}
544  * @endcode
545  *
546  * This happens under DirectX 5.0 when the system switches away from your
547  * fullscreen application.  The lock will also fail until you have access
548  * to the video memory again.
549  *
550  * You should call SDL_BlitSurface() unless you know exactly how SDL
551  * blitting works internally and how to use the other blit functions.
552  */
553 
554 /** This is the public blit function, SDL_BlitSurface(), and it performs
555  *  rectangle validation and clipping before passing it to SDL_LowerBlit()
556  */
557 extern DECLSPEC int SDLCALL LRSDL_UpperBlit
558 			(SDL_Surface *src, SDL_Rect *srcrect,
559 			 SDL_Surface *dst, SDL_Rect *dstrect);
560 /** This is a semi-private blit function and it performs low-level surface
561  *  blitting only.
562  */
563 extern DECLSPEC int SDLCALL LRSDL_LowerBlit
564 			(SDL_Surface *src, SDL_Rect *srcrect,
565 			 SDL_Surface *dst, SDL_Rect *dstrect);
566 
567 /**
568  * This function performs a fast fill of the given rectangle with 'color'
569  * The given rectangle is clipped to the destination surface clip area
570  * and the final fill rectangle is saved in the passed in pointer.
571  * If 'dstrect' is NULL, the whole surface will be filled with 'color'
572  * The color should be a pixel of the format used by the surface, and
573  * can be generated by the SDL_MapRGB() function.
574  * This function returns 0 on success, or -1 on error.
575  */
576 extern DECLSPEC int SDLCALL LRSDL_FillRect
577 		(SDL_Surface *dst, SDL_Rect *dstrect, Uint32 color);
578 
579 /**
580  * This function takes a surface and copies it to a new surface of the
581  * pixel format and colors of the video framebuffer, suitable for fast
582  * blitting onto the display surface.  It calls SDL_ConvertSurface()
583  *
584  * If you want to take advantage of hardware colorkey or alpha blit
585  * acceleration, you should set the colorkey and alpha value before
586  * calling this function.
587  *
588  * If the conversion fails or runs out of memory, it returns NULL
589  */
590 extern DECLSPEC SDL_Surface * SDLCALL LRSDL_DisplayFormat(SDL_Surface *surface);
591 
592 /**
593  * This function takes a surface and copies it to a new surface of the
594  * pixel format and colors of the video framebuffer (if possible),
595  * suitable for fast alpha blitting onto the display surface.
596  * The new surface will always have an alpha channel.
597  *
598  * If you want to take advantage of hardware colorkey or alpha blit
599  * acceleration, you should set the colorkey and alpha value before
600  * calling this function.
601  *
602  * If the conversion fails or runs out of memory, it returns NULL
603  */
604 extern DECLSPEC SDL_Surface * SDLCALL LRSDL_DisplayFormatAlpha(SDL_Surface *surface);
605 
606 /* Ends C function definitions when using C++ */
607 #ifdef __cplusplus
608 }
609 #endif
610 #include "close_code.h"
611 
612 #endif /* _SDL_video_h */
613