libmng_pixels.c

这个是Linux的qt源代码

/* ************************************************************************** */
/* *             For conditions of distribution and use,                    * */
/* *                see copyright notice in libmng.h                        * */
/* ************************************************************************** */
/* *                                                                        * */
/* * project   : libmng                                                     * */
/* * file      : libmng_pixels.c           copyright (c) 2000 G.Juyn        * */
/* * version   : 1.0.4                                                      * */
/* *                                                                        * */
/* * purpose   : Pixel-row management routines (implementation)             * */
/* *                                                                        * */
/* * author    : G.Juyn                                                     * */
/* * web       : http://www.3-t.com                                         * */
/* * email     : mailto:[e-mail]                                        * */
/* *                                                                        * */
/* * comment   : implementation of the pixel-row management routines        * */
/* *                                                                        * */
/* *             the dual alpha-composing for RGBA/BGRA/etc output-canvas'  * */
/* *             is based on the Note on Compositing chapter of the         * */
/* *             DOH-3 draft, noted to me by Adam M. Costello               * */
/* *                                                                        * */
/* * changes   : 0.5.1 - 05/08/2000 - G.Juyn                                * */
/* *             - changed strict-ANSI stuff                                * */
/* *             0.5.1 - 05/11/2000 - G.Juyn                                * */
/* *             - added callback error-reporting support                   * */
/* *             0.5.1 - 05/12/2000 - G.Juyn                                * */
/* *             - changed trace to macro for callback error-reporting      * */
/* *                                                                        * */
/* *             0.5.2 - 05/22/2000 - G.Juyn                                * */
/* *             - added JNG support                                        * */
/* *             0.5.2 - 05/30/2000 - G.Juyn                                * */
/* *             - fixed minor bugs 16-bit pixel-handling                   * */
/* *             - added delta-image row-processing routines                * */
/* *             0.5.2 - 06/02/2000 - G.Juyn                                * */
/* *             - fixed endian support (hopefully)                         * */
/* *             0.5.2 - 06/03/2000 - G.Juyn                                * */
/* *             - fixed makeup for Linux gcc compile                       * */
/* *             0.5.2 - 06/05/2000 - G.Juyn                                * */
/* *             - implemented app bkgd restore routines                    * */
/* *             - implemented RGBA8, ARGB8, BGRA8 & ABGR8 display routines * */
/* *             - added support for RGB8_A8 canvasstyle                    * */
/* *             0.5.2 - 06/09/2000 - G.Juyn                                * */
/* *             - fixed alpha-handling for alpha canvasstyles              * */
/* *                                                                        * */
/* *             0.5.3 - 06/16/2000 - G.Juyn                                * */
/* *             - changed progressive-display processing                   * */
/* *             0.5.3 - 06/17/2000 - G.Juyn                                * */
/* *             - changed to support delta-images                          * */
/* *             - optimized some store_xxx routines                        * */
/* *             0.5.3 - 06/20/2000 - G.Juyn                                * */
/* *             - fixed nasty bug with embedded PNG after delta-image      * */
/* *             0.5.3 - 06/24/2000 - G.Juyn                                * */
/* *             - fixed problem with 16-bit GA format                      * */
/* *             0.5.3 - 06/25/2000 - G.Juyn                                * */
/* *             - fixed problem with cheap transparency for 4-bit gray     * */
/* *             - fixed display_xxxx routines for interlaced images        * */
/* *             0.5.3 - 06/28/2000 - G.Juyn                                * */
/* *             - fixed compiler-warning for non-initialized iB variable   * */
/* *                                                                        * */
/* *             0.9.1 - 07/05/2000 - G.Juyn                                * */
/* *             - fixed mandatory BACK color to be opaque                  * */
/* *                                                                        * */
/* *             0.9.2 - 07/31/2000 - G.Juyn                                * */
/* *             - B110547 - fixed bug in interlace code                    * */
/* *             0.9.2 - 08/05/2000 - G.Juyn                                * */
/* *             - changed file-prefixes                                    * */
/* *                                                                        * */
/* *             0.9.3 - 08/20/2000 - G.Juyn                                * */
/* *             - fixed app-supplied background restore                    * */
/* *             0.9.3 - 08/26/2000 - G.Juyn                                * */
/* *             - added MAGN chunk                                         * */
/* *             0.9.3 - 09/07/2000 - G.Juyn                                * */
/* *             - added support for new filter_types                       * */
/* *             0.9.3 - 09/30/2000 - G.Juyn                                * */
/* *             - fixed MAGN rounding errors (thanks Matthias!)            * */
/* *             0.9.3 - 10/10/2000 - G.Juyn                                * */
/* *             - fixed alpha-blending for RGBA canvasstyle                * */
/* *             0.9.3 - 10/11/2000 - G.Juyn                                * */
/* *             - fixed alpha-blending for other alpha-canvasstyles        * */
/* *             0.9.3 - 10/16/2000 - G.Juyn                                * */
/* *             - added optional support for bKGD for PNG images           * */
/* *             - added support for JDAA                                   * */
/* *             0.9.3 - 10/17/2000 - G.Juyn                                * */
/* *             - fixed support for bKGD                                   * */
/* *             0.9.3 - 10/19/2000 - G.Juyn                                * */
/* *             - implemented delayed delta-processing                     * */
/* *             0.9.3 - 10/28/2000 - G.Juyn                                * */
/* *             - fixed tRNS processing for gray-image < 8-bits            * */
/* *                                                                        * */
/* *             0.9.4 - 12/16/2000 - G.Juyn                                * */
/* *             - fixed mixup of data- & function-pointers (thanks Dimitri)* */
/* *             0.9.4 -  1/18/2001 - G.Juyn                                * */
/* *             - removed "old" MAGN methods 3 & 4                         * */
/* *             - added "new" MAGN methods 3, 4 & 5                        * */
/* *             - removed test filter-methods 1 & 65                       * */
/* *                                                                        * */
/* *             1.0.1 - 04/21/2001 - G.Juyn (code by G.Kelly)              * */
/* *             - added BGRA8 canvas with premultiplied alpha              * */
/* *             1.0.1 - 04/25/2001 - G.Juyn                                * */
/* *             - moved mng_clear_cms to libmng_cms                        * */
/* *                                                                        * */
/* *             1.0.2 - 06/25/2001 - G.Juyn                                * */
/* *             - added option to turn off progressive refresh             * */
/* *                                                                        * */
/* *             1.0.4 - 11/04/2001 - G.Juyn                                * */
/* *             - fixed possible compile-problem in cleanup_rowproc        * */
/* *             1.0.4 - 06/22/2002 - G.Juyn                                * */
/* *             - B558212 - off by one error                               * */
/* *             - MNG subimage alpha composite wrong for rgba8 images      * */
/* *                                                                        * */
/* ************************************************************************** */

#include "libmng.h"
#include "libmng_data.h"
#include "libmng_error.h"
#include "libmng_trace.h"
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#include "libmng_objects.h"
#include "libmng_memory.h"
#include "libmng_cms.h"
#include "libmng_filter.h"
#include "libmng_pixels.h"

#if defined(__BORLANDC__) && defined(MNG_STRICT_ANSI)
#pragma option -A                      /* force ANSI-C */
#endif

/* ************************************************************************** */

#ifdef MNG_INCLUDE_DISPLAY_PROCS

/* TODO: magnification & canvas-positioning/-clipping */

/* TODO: major optimization of pixel-loops by using assembler (?) */

/* ************************************************************************** */
/* *                                                                        * */
/* * Interlace tables                                                       * */
/* *                                                                        * */
/* ************************************************************************** */

mng_uint32 const interlace_row      [7] = { 0, 0, 4, 0, 2, 0, 1 };
mng_uint32 const interlace_rowskip  [7] = { 8, 8, 8, 4, 4, 2, 2 };
mng_uint32 const interlace_col      [7] = { 0, 4, 0, 2, 0, 1, 0 };
mng_uint32 const interlace_colskip  [7] = { 8, 8, 4, 4, 2, 2, 1 };
mng_uint32 const interlace_roundoff [7] = { 7, 7, 3, 3, 1, 1, 0 };
mng_uint32 const interlace_divider  [7] = { 3, 3, 2, 2, 1, 1, 0 };

/* ************************************************************************** */
/* *                                                                        * */
/* * Alpha composing macros                                                 * */
/* * the code below is slightly modified from the libpng package            * */
/* * the original was last optimized by Greg Roelofs & Mark Adler           * */
/* *                                                                        * */
/* ************************************************************************** */

#define MNG_COMPOSE8(RET,FG,ALPHA,BG) {                                    \
       mng_uint16 iH = (mng_uint16)((mng_uint16)(FG) * (mng_uint16)(ALPHA) \
                        + (mng_uint16)(BG)*(mng_uint16)(255 -              \
                          (mng_uint16)(ALPHA)) + (mng_uint16)128);         \
       (RET) = (mng_uint8)((iH + (iH >> 8)) >> 8); }

#define MNG_COMPOSE16(RET,FG,ALPHA,BG) {                                   \
       mng_uint32 iH = (mng_uint32)((mng_uint32)(FG) * (mng_uint32)(ALPHA) \
                        + (mng_uint32)(BG)*(mng_uint32)(65535L -           \
                          (mng_uint32)(ALPHA)) + (mng_uint32)32768L);      \
       (RET) = (mng_uint16)((iH + (iH >> 16)) >> 16); }

/* ************************************************************************** */
/* *                                                                        * */
/* * Alpha blending macros                                                  * */
/* * this code is based on Adam Costello's "Note on Compositing" from the   * */
/* * mng-list which gives the following formula:                            * */
/* *                                                                        * */
/* * top pixel       = (Rt, Gt, Bt, At)                                     * */
/* * bottom pixel    = (Rb, Gb, Bb, Ab)                                     * */
/* * composite pixel = (Rc, Gc, Bc, Ac)                                     * */
/* *                                                                        * */
/* * all values in the range 0..1                                           * */
/* *                                                                        * */
/* * Ac = 1 - (1 - At)(1 - Ab)                                              * */
/* * s = At / Ac                                                            * */
/* * t = (1 - At) Ab / Ac                                                   * */
/* * Rc = s Rt + t Rb                                                       * */
/* * Gc = s Gt + t Gb                                                       * */
/* * Bc = s Bt + t Bb                                                       * */
/* *                                                                        * */
/* * (I just hope I coded it correctly in integer arithmetic...)            * */
/* *                                                                        * */
/* ************************************************************************** */

#define MNG_BLEND8(RT, GT, BT, AT, RB, GB, BB, AB, RC, GC, BC, AC) {         \
       mng_uint32 S, T;                                                      \
       (AC) = (mng_uint8)((mng_uint32)255 -                                  \
                          ((((mng_uint32)255 - (mng_uint32)(AT)) *           \
                            ((mng_uint32)255 - (mng_uint32)(AB))   ) >> 8)); \
       S    = (mng_uint32)(((mng_uint32)(AT) << 8) /                         \
                           (mng_uint32)(AC));                                \
       T    = (mng_uint32)(((mng_uint32)255 - (mng_uint32)(AT)) *            \
                            (mng_uint32)(AB) / (mng_uint32)(AC));            \
       (RC) = (mng_uint8)((S * (mng_uint32)(RT) +                            \
                           T * (mng_uint32)(RB) + (mng_uint32)127) >> 8);    \
       (GC) = (mng_uint8)((S * (mng_uint32)(GT) +                            \
                           T * (mng_uint32)(GB) + (mng_uint32)127) >> 8);    \
       (BC) = (mng_uint8)((S * (mng_uint32)(BT) +                            \
                           T * (mng_uint32)(BB) + (mng_uint32)127) >> 8); }

#define MNG_BLEND16(RT, GT, BT, AT, RB, GB, BB, AB, RC, GC, BC, AC) {            \
       mng_uint32 S, T;                                                          \
       (AC) = (mng_uint16)((mng_uint32)65525 -                                   \
                           ((((mng_uint32)65535 - (mng_uint32)(AT)) *            \
                             ((mng_uint32)65535 - (mng_uint32)(AB))   ) >> 16)); \
       S    = (mng_uint32)(((mng_uint32)(AT) << 16) /                            \
                            (mng_uint32)(AC));                                   \
       T    = (mng_uint32)(((mng_uint32)65535 - (mng_uint32)(AT)) *              \
                            (mng_uint32)(AB) / (mng_uint32)(AC));                \
       (RC) = (mng_uint16)((S * (mng_uint32)(RT) +                               \
                            T * (mng_uint32)(RB) + (mng_uint32)32767) >> 16);    \
       (GC) = (mng_uint16)((S * (mng_uint32)(GT) +                               \
                            T * (mng_uint32)(GB) + (mng_uint32)32767) >> 16);    \
       (BC) = (mng_uint16)((S * (mng_uint32)(BT) +                               \
                            T * (mng_uint32)(BB) + (mng_uint32)32767) >> 16); }

/* ************************************************************************** */

/* note a good optimizing compiler will optimize this */
#define DIV255B8(x) (mng_uint8)(((x) + 127) / 255)
#define DIV255B16(x) (mng_uint16)(((x) + 32767) / 65535)

/* ************************************************************************** */
/* *                                                                        * */
/* * Progressive display check - checks to see if progressive display is    * */
/* * in order & indicates so                                                * */
/* *                                                                        * */
/* * The routine is called after a call to one of the display_xxx routines  * */
/* * if appropriate                                                         * */
/* *                                                                        * */
/* * The refresh is warrented in the read_chunk routine (mng_read.c)        * */
/* * and only during read&display processing, since there's not much point  * */
/* * doing it from memory!                                                  * */
/* *                                                                        * */
/* ************************************************************************** */

mng_retcode display_progressive_check (mng_datap pData)
{
  if ((pData->bDoProgressive) &&       /* need progressive display? */
      ((pData->eImagetype != mng_it_mng) || (pData->iDataheight > 300)) &&
      (pData->iDestb - pData->iDestt > 50) && (!pData->pCurraniobj))
  {
    mng_int32 iC = pData->iRow + pData->iDestt - pData->iSourcet;

    if (iC % 20 == 0)                  /* every 20th line */
      pData->bNeedrefresh = MNG_TRUE;

  }

  return MNG_NOERROR;
}

/* ************************************************************************** */
/* *                                                                        * */
/* * Display routines - convert rowdata (which is already color-corrected)  * */
/* * to the output canvas, respecting the opacity information               * */
/* *                                                                        * */
/* ************************************************************************** */

void check_update_region (mng_datap pData)
{                                      /* determine actual canvas row */
  mng_int32 iRow = pData->iRow + pData->iDestt - pData->iSourcet;
                                       /* check for change in update-region */
  if ((pData->iDestl < (mng_int32)pData->iUpdateleft) || (pData->iUpdateright == 0))
    pData->iUpdateleft   = pData->iDestl;

  if (pData->iDestr > (mng_int32)pData->iUpdateright)
    pData->iUpdateright  = pData->iDestr;

  if ((iRow < (mng_int32)pData->iUpdatetop) || (pData->iUpdatebottom == 0))
    pData->iUpdatetop    = iRow;

  if (iRow+1 > (mng_int32)pData->iUpdatebottom)
    pData->iUpdatebottom = iRow+1;

  return;
}