osd_utils.h

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/*******************************************************************************
 * Copyright © 2014 The DTVKit Open Software Foundation Ltd (www.dtvkit.org)
 * Copyright © 2006 Ocean Blue Software Ltd
 *
 * This file is part of a DTVKit Software Component
 * You are permitted to copy, modify or distribute this file subject to the terms
 * of the DTVKit 1.0 Licence which can be found in licence.txt or at www.dtvkit.org
 * 
 * THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
 * EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * If you or your organisation is not a member of DTVKit then you have access
 * to this source code outside of the terms of the licence agreement
 * and you are expected to delete this and any associated files immediately.
 * Further information on DTVKit, membership and terms can be found at www.dtvkit.org
 *******************************************************************************/
#ifndef _OSD_UTILS_H
#define _OSD_UTILS_H

/*---includes for this file--------------------------------------------------*/

/* compiler library header files */

/* third party header files */

/* OBS header files */
#include <techtype.h>

/*---Constant and macro definitions for public use-----------------------------*/

/* Macros to extract red, green, blue, transparent and alpha values from an
 *  OSDColor value
 */
#define GetRValue(osdcolour)        (((osdcolour) >> 16) & 0xff)
#define GetGValue(osdcolour)        (((osdcolour) >> 8) & 0xff)
#define GetBValue(osdcolour)        ((osdcolour) & 0xff)
#define GetTValue(osdcolour)        (((osdcolour) >> 24) ^ 0xff)
#define GetAValue(osdcolour)        ((osdcolour) >> 24)


/* Macros to convert from discrete red, green, blue and transparent values to
 * OSDColor values
 */
#define RGB(r, g, b)        (0xff000000 | ((r) << 16) | ((g) << 8) | (b))
#define RGBT(r, g, b, t)    ((((t) ^ 0xff) << 24) | ((r) << 16) | ((g) << 8) | (b))
#define RGBA(r, g, b, a)    (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))

#define MakeHD2Color(osdcol)  (((osdcol >> 16) & 0xf000) | ((osdcol >> 12) & 0x0f00) \
                               | ((osdcol >> 8) & 0x00f0) | ((osdcol >> 4) & 0x000f))

/*
 * HD2Colour is two byte colour, again in the ARGB format:
 * Alpha bits     15..12
 * Red bits       11..8
 * Green bits     7.. 4
 * Blue bits      3.. 0
 *
 * Note:
 * For bits 15..12, the value of 0xf represents completely opaque,
 * and the value of 0x0 represents completely transparent.
 */
typedef U16BIT HD2Color;


#ifdef OSD_8_BIT

   #ifndef PALETTE_OFFSET
   #define PALETTE_OFFSET 0
   #endif
   #define OFFSET_TRANS            (PALETTE_OFFSET + 0)
   #define OFFSET_OPAQUE           (PALETTE_OFFSET + 49)
extern OSDColor *mg_palette;


/*---Enumerations for public use-----------------------------------------------*/

/*---Global type defs for public use-------------------------------------------*/

/*---Global Function prototypes for public use---------------------------------*/

/*!**************************************************************************
 * @fn       OSD_FindNearestColourIndex
 * @brief    Return nearest colour index.
 * @param    U8BIT       r                    Red component of colour
 *           U8BIT       g                    Green component of colour
 *           U8BIT       b                    Blue component of colour
 *           U8BIT       a                    Alpha component of colour
 * @return   U8BIT                            Index of nearest colour in the
 *                                            MHEG palette
 * @warning  This function depends on the order of the MHEG palette.
 * @bug
 ****************************************************************************/
extern U8BIT OSD_FindNearestColourIndex(OSDColor target);

/*!**************************************************************************
 * @fn       OSD_BlendPixels
 * @brief    Plots pixels into a buffer, comparing the new and old values to
 *           ensure that pixels with transparent components are correctly
 *           blended together.
 * @param    U8BIT*      pixel                Destination pointer for the pixel
 *                                            This contains the old pixel
 *           U8BIT       colour               Colour index of the new pixel
 * @return   None
 * @warning  None
 * @bug      None
 ****************************************************************************/
void OSD_BlendPixels(U8BIT *pixel, U8BIT colour);

/*!**************************************************************************
 * @fn       OSD_IsColourOpaque
 * @brief    Tell whether a colour is opaque or not
 * @param    U8BIT       colour               The colour
 * @return   TRUE if the colour is opaque, FALSE otherwise
 * @warning  This function depends on the order of the MHEG palette.
 * @bug      None.
 ****************************************************************************/
/* BOOLEAN OSD_IsColourOpaque(U8BIT colour); */
   #define OSD_IsColourOpaque(colour)  (colour >= OFFSET_OPAQUE)

#endif /*OSD_8_BIT*/

#endif /* _OSD_UTILS_H */