include/SDL_surface.h

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/**
 *  \file SDL_surface.h
 *  
 *  Header file for ::SDL_surface definition and management functions.
 */

#ifndef _SDL_surface_h
#define _SDL_surface_h

#include "SDL_stdinc.h"
#include "SDL_pixels.h"
#include "SDL_rect.h"
#include "SDL_rwops.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif

/**
 *  \name Surface flags
 *  
 *  These are the currently supported flags for the ::SDL_surface.
 *  
 *  \internal
 *  Used internally (read-only).
 */
/*@{*/
#define SDL_PREALLOC        0x00000001  /**< Surface uses preallocated memory */
#define SDL_RLEACCEL        0x00000002  /**< Surface is RLE encoded */
/*@}*//*Surface flags*/

/**
 *  Evaluates to true if the surface needs to be locked before access.
 */
#define SDL_MUSTLOCK(S)	(((S)->flags & SDL_RLEACCEL) != 0)

/**
 * \brief A collection of pixels used in software blitting.
 *
 * \note  This structure should be treated as read-only, except for \c pixels,
 *        which, if not NULL, contains the raw pixel data for the surface.
 */
typedef struct SDL_Surface
{
    Uint32 flags;               /**< Read-only */
    SDL_PixelFormat *format;    /**< Read-only */
    int w, h;                   /**< Read-only */
    int pitch;                  /**< Read-only */
    void *pixels;               /**< Read-write */

    /** Application data associated with the surfade */
    void *userdata;             /**< Read-write */

    /** information needed for surfaces requiring locks */
    int locked;                 /**< Read-only */
    void *lock_data;            /**< Read-only */

    /** clipping information */
    SDL_Rect clip_rect;         /**< Read-only */

    /** info for fast blit mapping to other surfaces */
    struct SDL_BlitMap *map;    /**< Private */

    /** format version, bumped at every change to invalidate blit maps */
    unsigned int format_version;        /**< Private */

    /** Reference count -- used when freeing surface */
    int refcount;               /**< Read-mostly */
} SDL_Surface;

/**
 * \brief The type of function used for surface blitting functions.
 */
typedef int (*SDL_blit) (struct SDL_Surface * src, SDL_Rect * srcrect,
                         struct SDL_Surface * dst, SDL_Rect * dstrect);

/**
 *  Allocate and free an RGB surface (must be called after SDL_SetVideoMode).
 *  
 *  If the depth is 4 or 8 bits, an empty palette is allocated for the surface.
 *  If the depth is greater than 8 bits, the pixel format is set using the
 *  flags '[RGB]mask'.
 *  
 *  If the function runs out of memory, it will return NULL.
 *  
 *  \param flags The \c flags are obsolete and should be set to 0.
 */
extern DECLSPEC SDL_Surface *SDLCALL SDL_CreateRGBSurface
    (Uint32 flags, int width, int height, int depth,
     Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
extern DECLSPEC SDL_Surface *SDLCALL SDL_CreateRGBSurfaceFrom(void *pixels,
                                                              int width,
                                                              int height,
                                                              int depth,
                                                              int pitch,
                                                              Uint32 Rmask,
                                                              Uint32 Gmask,
                                                              Uint32 Bmask,
                                                              Uint32 Amask);
extern DECLSPEC void SDLCALL SDL_FreeSurface(SDL_Surface * surface);

/**
 *  \brief Set the palette used by a surface.
 *  
 *  \return 0, or -1 if the surface format doesn't use a palette.
 *  
 *  \note A single palette can be shared with many surfaces.
 */
extern DECLSPEC int SDLCALL SDL_SetSurfacePalette(SDL_Surface * surface,
                                                  SDL_Palette * palette);

/**
 *  \brief Sets up a surface for directly accessing the pixels.
 *  
 *  Between calls to SDL_LockSurface() / SDL_UnlockSurface(), you can write
 *  to and read from \c surface->pixels, using the pixel format stored in 
 *  \c surface->format.  Once you are done accessing the surface, you should 
 *  use SDL_UnlockSurface() to release it.
 *  
 *  Not all surfaces require locking.  If SDL_MUSTLOCK(surface) evaluates
 *  to 0, then you can read and write to the surface at any time, and the
 *  pixel format of the surface will not change.
 *  
 *  No operating system or library calls should be made between lock/unlock
 *  pairs, as critical system locks may be held during this time.
 *  
 *  SDL_LockSurface() returns 0, or -1 if the surface couldn't be locked.
 *  
 *  \sa SDL_UnlockSurface()
 */
extern DECLSPEC int SDLCALL SDL_LockSurface(SDL_Surface * surface);
/** \sa SDL_LockSurface() */
extern DECLSPEC void SDLCALL SDL_UnlockSurface(SDL_Surface * surface);

/**
 *  Load a surface from a seekable SDL data source (memory or file).
 *  
 *  If \c freesrc is non-zero, the source will be closed after being read.
 *  
 *  The new surface should be freed with SDL_FreeSurface().
 *  
 *  \return the new surface, or NULL if there was an error.
 */
extern DECLSPEC SDL_Surface *SDLCALL SDL_LoadBMP_RW(SDL_RWops * src,
                                                    int freesrc);

/**
 *  Load a surface from a file.
 *  
 *  Convenience macro.
 */
#define SDL_LoadBMP(file)	SDL_LoadBMP_RW(SDL_RWFromFile(file, "rb"), 1)

/**
 *  Save a surface to a seekable SDL data source (memory or file).
 *  
 *  If \c freedst is non-zero, the source will be closed after being written.
 *  
 *  \return 0 if successful or -1 if there was an error.
 */
extern DECLSPEC int SDLCALL SDL_SaveBMP_RW
    (SDL_Surface * surface, SDL_RWops * dst, int freedst);

/** 
 *  Save a surface to a file.
 *  
 *  Convenience macro.
 */
#define SDL_SaveBMP(surface, file) \
		SDL_SaveBMP_RW(surface, SDL_RWFromFile(file, "wb"), 1)

/**
 *  \brief Sets the RLE acceleration hint for a surface.
 *  
 *  \return 0 on success, or -1 if the surface is not valid
 *  
 *  \note If RLE is enabled, colorkey and alpha blending blits are much faster,
 *        but the surface must be locked before directly accessing the pixels.
 */
extern DECLSPEC int SDLCALL SDL_SetSurfaceRLE(SDL_Surface * surface,
                                              int flag);

/**
 *  \brief Sets the color key (transparent pixel) in a blittable surface.
 *  
 *  \param surface The surface to update
 *  \param flag Non-zero to enable colorkey and 0 to disable colorkey 
 *  \param key The transparent pixel in the native surface format
 *  
 *  \return 0 on success, or -1 if the surface is not valid
 */
extern DECLSPEC int SDLCALL SDL_SetColorKey(SDL_Surface * surface,
                                            Uint32 flag, Uint32 key);

/**
 *  \brief Sets the color key (transparent pixel) in a blittable surface.
 *  
 *  \param surface The surface to update
 *  \param key A pointer filled in with the transparent pixel in the native 
 *             surface format
 *  
 *  \return 0 on success, or -1 if the surface is not valid or colorkey is not 
 *          enabled.
 */
extern DECLSPEC int SDLCALL SDL_GetColorKey(SDL_Surface * surface,
                                            Uint32 * key);

/**
 *  \brief Set an additional color value used in blit operations.
 *  
 *  \param surface The surface to update.
 *  \param r The red source color value multiplied into blit operations.
 *  \param g The green source color value multiplied into blit operations.
 *  \param b The blue source color value multiplied into blit operations.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_GetSurfaceColorMod()
 */
extern DECLSPEC int SDLCALL SDL_SetSurfaceColorMod(SDL_Surface * surface,
                                                   Uint8 r, Uint8 g, Uint8 b);


/**
 *  \brief Get the additional color value used in blit operations.
 *  
 *  \param surface The surface to query.
 *  \param r A pointer filled in with the source red color value.
 *  \param g A pointer filled in with the source green color value.
 *  \param b A pointer filled in with the source blue color value.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_SetSurfaceColorMod()
 */
extern DECLSPEC int SDLCALL SDL_GetSurfaceColorMod(SDL_Surface * surface,
                                                   Uint8 * r, Uint8 * g,
                                                   Uint8 * b);

/**
 *  \brief Set an additional alpha value used in blit operations.
 *  
 *  \param surface The surface to update.
 *  \param alpha The source alpha value multiplied into blit operations.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_GetSurfaceAlphaMod()
 */
extern DECLSPEC int SDLCALL SDL_SetSurfaceAlphaMod(SDL_Surface * surface,
                                                   Uint8 alpha);

/**
 *  \brief Get the additional alpha value used in blit operations.
 *  
 *  \param surface The surface to query.
 *  \param alpha A pointer filled in with the source alpha value.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_SetSurfaceAlphaMod()
 */
extern DECLSPEC int SDLCALL SDL_GetSurfaceAlphaMod(SDL_Surface * surface,
                                                   Uint8 * alpha);

/**
 *  \brief Set the blend mode used for blit operations.
 *  
 *  \param surface The surface to update.
 *  \param blendMode ::SDL_BlendMode to use for blit blending.
 *  
 *  \return 0 on success, or -1 if the parameters are not valid.
 *  
 *  \sa SDL_GetSurfaceBlendMode()
 */
extern DECLSPEC int SDLCALL SDL_SetSurfaceBlendMode(SDL_Surface * surface,
                                                    int blendMode);

/**
 *  \brief Get the blend mode used for blit operations.
 *  
 *  \param surface   The surface to query.
 *  \param blendMode A pointer filled in with the current blend mode.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_SetSurfaceBlendMode()
 */
extern DECLSPEC int SDLCALL SDL_GetSurfaceBlendMode(SDL_Surface * surface,
                                                    int *blendMode);

/**
 *  \brief Set the scale mode used for blit operations.
 *  
 *  \param surface   The surface to update.
 *  \param scaleMode ::SDL_TextureScaleMode to use for blit scaling.
 *  
 *  \return 0 on success, or -1 if the surface is not valid or the scale mode is
 *          not supported.
 *  
 *  \note If the scale mode is not supported, the closest supported mode is 
 *        chosen.  Currently only ::SDL_TEXTURESCALEMODE_FAST is supported on 
 *        surfaces.
 *  
 *  \sa SDL_GetSurfaceScaleMode()
 */
extern DECLSPEC int SDLCALL SDL_SetSurfaceScaleMode(SDL_Surface * surface,
                                                    int scaleMode);

/**
 *  \brief Get the scale mode used for blit operations.
 *  
 *  \param surface   The surface to query.
 *  \param scaleMode A pointer filled in with the current scale mode.
 *  
 *  \return 0 on success, or -1 if the surface is not valid.
 *  
 *  \sa SDL_SetSurfaceScaleMode()
 */
extern DECLSPEC int SDLCALL SDL_GetSurfaceScaleMode(SDL_Surface * surface,
                                                    int *scaleMode);

/**
 *  Sets the clipping rectangle for the destination surface in a blit.
 *  
 *  If the clip rectangle is NULL, clipping will be disabled.
 *  
 *  If the clip rectangle doesn't intersect the surface, the function will
 *  return SDL_FALSE and blits will be completely clipped.  Otherwise the
 *  function returns SDL_TRUE and blits to the surface will be clipped to
 *  the intersection of the surface area and the clipping rectangle.
 *  
 *  Note that blits are automatically clipped to the edges of the source
 *  and destination surfaces.
 */
extern DECLSPEC SDL_bool SDLCALL SDL_SetClipRect(SDL_Surface * surface,
                                                 const SDL_Rect * rect);

/**
 *  Gets the clipping rectangle for the destination surface in a blit.
 *  
 *  \c rect must be a pointer to a valid rectangle which will be filled
 *  with the correct values.
 */
extern DECLSPEC void SDLCALL SDL_GetClipRect(SDL_Surface * surface,
                                             SDL_Rect * rect);

/**
 *  Creates a new surface of the specified format, and then copies and maps 
 *  the given surface to it so the blit of the converted surface will be as 
 *  fast as possible.  If this function fails, it returns NULL.
 *  
 *  The \c flags parameter is passed to SDL_CreateRGBSurface() and has those 
 *  semantics.  You can also pass ::SDL_RLEACCEL in the flags parameter and
 *  SDL will try to RLE accelerate colorkey and alpha blits in the resulting
 *  surface.
 *  
 *  This function is used internally by SDL_DisplayFormat().
 */
extern DECLSPEC SDL_Surface *SDLCALL SDL_ConvertSurface
    (SDL_Surface * src, SDL_PixelFormat * fmt, Uint32 flags);

/**
 *  Draws a point with \c color.
 *
 *  The color should be a pixel of the format used by the surface, and 
 *  can be generated by the SDL_MapRGB() function.
 *  
 *  \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_DrawPoint
    (SDL_Surface * dst, int x, int y, Uint32 color);

/**
 *  Blends a point with an RGBA value.
 *  
 *  The color should be a pixel of the format used by the surface, and 
 *  can be generated by the SDL_MapRGB() function.
 *  
 *  \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_BlendPoint
    (SDL_Surface * dst, int x, int y, int blendMode,
     Uint8 r, Uint8 g, Uint8 b, Uint8 a);

/**
 *  Draws a line with \c color.
 *  
 *  The color should be a pixel of the format used by the surface, and 
 *  can be generated by the SDL_MapRGB() function.
 *  
 *  \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_DrawLine
    (SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color);

/**
 *  Blends an RGBA value along a line.
 *  
 *  \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_BlendLine
    (SDL_Surface * dst, int x1, int y1, int x2, int y2, int blendMode,
     Uint8 r, Uint8 g, Uint8 b, Uint8 a);

/**
 *  Performs a fast fill of the given rectangle with \c color.
 *  
 *  The given rectangle is clipped to the destination surface clip area
 *  and the final fill rectangle is saved in the passed in pointer.
 *  
 *  If \c dstrect is NULL, the whole surface will be filled with \c color.
 *  
 *  The color should be a pixel of the format used by the surface, and 
 *  can be generated by the SDL_MapRGB() function.
 *  
 *  \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_FillRect
    (SDL_Surface * dst, SDL_Rect * dstrect, Uint32 color);

/**
 *  Blends an RGBA value into the given rectangle.
 *  
 *  The given rectangle is clipped to the destination surface clip area
 *  and the final fill rectangle is saved in the passed in pointer.
 *  
 *  If \c dstrect is NULL, the whole surface will be filled with \c color.
 *  
 *  \return This function returns 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_BlendRect
    (SDL_Surface * dst, SDL_Rect * dstrect, int blendMode, Uint8 r, Uint8 g,
     Uint8 b, Uint8 a);

/**
 *  Performs a fast blit from the source surface to the destination surface.
 *  
 *  This assumes that the source and destination rectangles are
 *  the same size.  If either \c srcrect or \c dstrect are NULL, the entire
 *  surface (\c src or \c dst) is copied.  The final blit rectangles are saved
 *  in \c srcrect and \c dstrect after all clipping is performed.
 *  
 *  \return If the blit is successful, it returns 0, otherwise it returns -1.
 *
 *  The blit function should not be called on a locked surface.
 *
 *  The blit semantics for surfaces with and without alpha and colorkey
 *  are defined as follows:
 *  \verbatim
    RGBA->RGB:
      SDL_SRCALPHA set:
        alpha-blend (using alpha-channel).
        SDL_SRCCOLORKEY ignored.
      SDL_SRCALPHA not set:
        copy RGB.
        if SDL_SRCCOLORKEY set, only copy the pixels matching the
        RGB values of the source colour key, ignoring alpha in the
        comparison.
   
    RGB->RGBA:
      SDL_SRCALPHA set:
        alpha-blend (using the source per-surface alpha value);
        set destination alpha to opaque.
      SDL_SRCALPHA not set:
        copy RGB, set destination alpha to source per-surface alpha value.
      both:
        if SDL_SRCCOLORKEY set, only copy the pixels matching the
        source colour key.
   
    RGBA->RGBA:
      SDL_SRCALPHA set:
        alpha-blend (using the source alpha channel) the RGB values;
        leave destination alpha untouched. [Note: is this correct?]
        SDL_SRCCOLORKEY ignored.
      SDL_SRCALPHA not set:
        copy all of RGBA to the destination.
        if SDL_SRCCOLORKEY set, only copy the pixels matching the
        RGB values of the source colour key, ignoring alpha in the
       comparison.
   
    RGB->RGB: 
      SDL_SRCALPHA set:
        alpha-blend (using the source per-surface alpha value).
      SDL_SRCALPHA not set:
        copy RGB.
      both:
        if SDL_SRCCOLORKEY set, only copy the pixels matching the
        source colour key.
    \endverbatim
 *  
 *  If either of the surfaces were in video memory, and the blit returns -2,
 *  the video memory was lost, so it should be reloaded with artwork and 
 *  re-blitted:
 *  @code
 *  while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
 *      while ( SDL_LockSurface(image) < 0 )
 *          Sleep(10);
 *      -- Write image pixels to image->pixels --
 *      SDL_UnlockSurface(image);
 *  }
 *  @endcode
 *  
 *  This happens under DirectX 5.0 when the system switches away from your
 *  fullscreen application.  The lock will also fail until you have access
 *  to the video memory again.
 *  
 *  You should call SDL_BlitSurface() unless you know exactly how SDL
 *  blitting works internally and how to use the other blit functions.
 */
#define SDL_BlitSurface SDL_UpperBlit

/**
 *  This is the public blit function, SDL_BlitSurface(), and it performs
 *  rectangle validation and clipping before passing it to SDL_LowerBlit()
 */
extern DECLSPEC int SDLCALL SDL_UpperBlit
    (SDL_Surface * src, SDL_Rect * srcrect,
     SDL_Surface * dst, SDL_Rect * dstrect);

/**
 *  This is a semi-private blit function and it performs low-level surface
 *  blitting only.
 */
extern DECLSPEC int SDLCALL SDL_LowerBlit
    (SDL_Surface * src, SDL_Rect * srcrect,
     SDL_Surface * dst, SDL_Rect * dstrect);

/**
 *  \brief Perform a fast, low quality, stretch blit between two surfaces of the
 *         same pixel format.
 *  
 *  \note This function uses a static buffer, and is not thread-safe.
 */
extern DECLSPEC int SDLCALL SDL_SoftStretch(SDL_Surface * src,
                                            const SDL_Rect * srcrect,
                                            SDL_Surface * dst,
                                            const SDL_Rect * dstrect);

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"

#endif /* _SDL_surface_h */

/* vi: set ts=4 sw=4 expandtab: */