/*
*********************************************************************************************************
*                                                uC/GUI
*                        Universal graphic software for embedded applications
*
*                       (c) Copyright 2002, Micrium Inc., Weston, FL
*                       (c) Copyright 2002, SEGGER Microcontroller Systeme GmbH
*
*              µC/GUI is protected by international copyright laws. Knowledge of the
*              source code may not be used to write a similar product. This file may
*              only be used in accordance with a license and should not be redistributed
*              in any way. We appreciate your understanding and fairness.
*
----------------------------------------------------------------------
File        : GUIAALib.C
Purpose     : Antialiasing library
---------------------------END-OF-HEADER------------------------------
*/

#include "GUI_Private.h"
#include "LCD_ConfDefaults.h"            /* Required in order to know max. XSize so we do not waste memory */

#if GUI_SUPPORT_AA

#include <stdio.h>
#include <string.h>

/*********************************************************************
*
*       Defines, config defaults
*
**********************************************************************
*/

#ifndef GUI_AA_LINEBUFFER_SIZE
  #define GUI_AA_LINEBUFFER_SIZE LCD_XSIZE
#endif

/*********************************************************************
*
*       Static data
*
**********************************************************************
*/

static U8   abAABuffer[GUI_AA_LINEBUFFER_SIZE];   /* This could be changed to dynamic memory ... */
static U8*  pabAABuffer;
static int  _x0, _x1, _y, _x0_InUse, _x1_InUse;
static GUI_RECT ClipRect_HL;

static tLCD_HL_APIList           DrawAPICopy;    /* Copy of device function ptr list */
static const tLCD_HL_APIList*    pLCD_HLPrev;    /* Copy of device function ptr list */

/*********************************************************************
*
*       Static code
*
**********************************************************************
*/
/*********************************************************************
*
*       _CleanLine
*/
static void _CleanLine(void) {
  GUI_MEMSET(pabAABuffer,0, _x1 - _x0+1);
  _y = -16383;  /* Invalidate */  
  _x0_InUse =  16383;
  _x1_InUse = -16383;
}

/*********************************************************************
*
*       _FlushLine
*/
static void _FlushLine(void) {
  int i;
  int iEnd = _x1_InUse-_x0;
  int IMax = GUI_Context.AA_Factor * GUI_Context.AA_Factor;
  for (i =_x0_InUse-_x0; i<=iEnd; i++) {
    int Intens = *(pabAABuffer+i);
    if (Intens) {
      /* Check we can use line draw */
      if (Intens == IMax) {
        int j;
        for (j=i; j<iEnd; ) {
          if (*(pabAABuffer+j+1) != IMax) {
            break;
          }
          j++;
        }
        /* Draw the full pixel(s) */
        if (j!=i) {
          pLCD_HLPrev->pfDrawHLine(_x0+i, _y, _x0+j);
          i = j;  /*xxx*/
        } else {
          LCD_HL_DrawPixel (_x0+i,_y);
        }
      } else {
        LCD_SetPixelAA(_x0+i,_y, (15*Intens+IMax/2)/IMax);
      }
    }    
  }
  _CleanLine();
}

/*********************************************************************
*
*       _DrawHLine
*
* Purpose:
*   This is the redirected DrawHLine routine which is called
*   instead of the default output routine. Its job is to do
*   antialiasing and then perform the drawing operations.
*/
static void _DrawHLine  (int x0, int y,  int x1) {
  int x0Real, x1Real;
/* Make sure there is something to do */
  if (x1<x0)
    return;
/* Flush line if we are in an other pixel (real) line */
  if (y/GUI_Context.AA_Factor != _y) {
    _FlushLine();
    _y = y/GUI_Context.AA_Factor;
  }
  x0Real = x0/GUI_Context.AA_Factor;
  x1Real = x1/GUI_Context.AA_Factor;
/* Handle used area (speed optimization for drawing) */
  if (x0Real < _x0_InUse)
    _x0_InUse = x0Real;
  if (x1Real > _x1_InUse)
    _x1_InUse = x1Real;
/* Clip (should not be necessary ... Just to be on the safe side ! */
  if (x0Real < _x0) {
    x0 = _x0 * GUI_Context.AA_Factor;
  }
  if (x1Real > _x1) {
    x1 = (_x1+1)*GUI_Context.AA_Factor-1;
  }
/* Make sure there is still something to do (after clipping) */
  if (x1<x0)
    return;
/* Inc. hit counters in buffer */
  {
    int x0_Off = x0/GUI_Context.AA_Factor-_x0;
    int x1_Off = x1/GUI_Context.AA_Factor-_x0;
    int iRem = x1_Off-x0_Off+1;
    U8 *pDest = pabAABuffer+x0_Off;
    if (iRem ==1) {
      *(pDest) += x1-x0+1;
    } else {
      /* First Pixel */
      *pDest++ += ((x0_Off+_x0+1)*GUI_Context.AA_Factor-x0);
      /* Middle Pixels */
      for (;--iRem>1; ) {
        *pDest++ +=GUI_Context.AA_Factor;
      }
      /* Last Pixel */
      *pDest += (1+x1- (x1_Off+_x0) *GUI_Context.AA_Factor);
    }
  }
}

/*********************************************************************
*
*       CalcClipRectHL
*/
static void CalcClipRectHL(void) {
  ClipRect_HL.x0 =  GUI_Context.ClipRect.x0    * GUI_Context.AA_Factor;
  ClipRect_HL.y0 =  GUI_Context.ClipRect.y0    * GUI_Context.AA_Factor;
  ClipRect_HL.x1 = (GUI_Context.ClipRect.x1+1) * GUI_Context.AA_Factor -1;
  ClipRect_HL.y1 = (GUI_Context.ClipRect.y1+1) * GUI_Context.AA_Factor -1;
}

/*********************************************************************
*
*       Public code
*
**********************************************************************
*/
/*********************************************************************
*
*       GUI_AA_Init
*/
int GUI_AA_Init(int x0, int x1) {
  int r =0;
  /* Bounds checking:
     Make sure x0, x1 are in legal range ...
     (The important point is that they span no more than configured as
      buffer size)
  */
  if (x0<0)
    x0 =0;
  if (x1-x0 > GUI_AA_LINEBUFFER_SIZE-1)
    x1 = x0+GUI_AA_LINEBUFFER_SIZE-1;
  /* Is there anything to do at all ??? */
  if (x1 < x0) {
    x1 = x0;   /* Not really ... */
    r =1;
  }
  DrawAPICopy = *GUI_Context.pLCD_HL; /* Copy API table */
  pLCD_HLPrev = GUI_Context.pLCD_HL; /* Remember list ptr (for restore) */
  DrawAPICopy.pfDrawHLine = _DrawHLine;  /* modify function ptr. for hline */
  GUI_Context.pLCD_HL = &DrawAPICopy;      /* Use copy of fp-list */
  pabAABuffer = abAABuffer;
  _x0 = x0;
  _x1 = x1;
  _CleanLine();
  CalcClipRectHL();
  GUI_Context.pClipRect_HL = &ClipRect_HL;
  return r;
}

/*********************************************************************
*
*       GUI_AA_Init_HiRes
*/
int GUI_AA_Init_HiRes(int x0, int x1) {
  x0 /= GUI_Context.AA_Factor;
  x1 /= GUI_Context.AA_Factor;
  return GUI_AA_Init(x0, x1);
}

/*********************************************************************
*
*       GUI_AA_SetFactor
*/
void GUI_AA_SetFactor(int Factor) {
  GUI_Context.AA_Factor = Factor;
  CalcClipRectHL();      /* High level clipping depends on quality factor */
}

/*********************************************************************
*
*       GUI_AA_GetFactor
*/
int GUI_AA_GetFactor(void) {
  return GUI_Context.AA_Factor;
}

/*********************************************************************
*
*       GUI_AA_DisableHiRes
*/
void GUI_AA_DisableHiRes(void) {
  GUI_Context.AA_HiResEnable = 0;
}

/*********************************************************************
*
*       GUI_AA_EnableHiRes
*/
void GUI_AA_EnableHiRes(void) {
  GUI_Context.AA_HiResEnable =1;
}

/*********************************************************************
*
*       GUI_AA_HiRes2Pixel
*/
I16 GUI_AA_HiRes2Pixel(int HiRes) {
  return GUI_Context.AA_Factor ? (HiRes / GUI_Context.AA_Factor) : HiRes;
}

/*********************************************************************
*
*       GUI_AA_Exit
*/
void GUI_AA_Exit(void) {
  _FlushLine();
  /* restore previous settings */
  GUI_Context.pLCD_HL = pLCD_HLPrev;
  GUI_Context.pClipRect_HL = &GUI_Context.ClipRect;
}

#else                            /* Avoid problems with empty object modules */
  void GUIAALib_C(void);
  void GUIAALib_C(void) {}
#endif /* GUI_SUPPORT_AA */

/*************************** End of file ****************************/