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gd.c

/* $Id: gd.c,v 1.33 2004/01/19 19:10:19 airwin Exp $

         PNG and JPEG device driver based on libgd

   Copyright (C) 2004  Joao Cardoso

   This file is part of PLplot.

   PLplot is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Library Public License as published
   by the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   PLplot 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 Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with PLplot; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

/*
 *  The GD drivers, PNG and JPEG, support a number of different options
 *  depending on the version of GD installed.
 *
 *  If you have installed GD Ver 2.+ you gain support for truecolour (24
 *  bit, 16 millionish) modes as well as different line widths. These
 *  capibilities are part of GD more so than the GD driver, so they aren't
 *  available in any 1.? versions of the driver.
 *
 *  24 bit support is, by default, set to "auto" if you have V2.+ of GD.
 *  What this means is the *driver* decides when to use 24 bit or 8 bit
 *  modes for PNG files. The logic is rather simple - if you have less than
 *  257 colours, it is set to 8 bit mode, if more then it's in 24 bit mode.
 *  This should work fine for most people, most of the time, in most
 *  situations; however, it can be overridden in case it has to via the
 *  "-drvopt" command line switch. The png driver has two related settings:
 *              8bit    and
 *              24bit
 *
 *  If either of these command line toggles are set, that mode becomes the
 *  standard used regardless of the number of colours used. It can be envoked
 *  as follows:
 *                 x08c -dev png -drvopt 8bit -fam -o 8bitpng
 *                                      or
 *                 x08c -dev png -drvopt 24bit -fam -o 24bitpng
 *
 *  NOTE:
 *  The 24 bit PNG file is an RGBA file, not RGB - it includes alpha channel
 *  (transparency). Transparency is set to opaque, but the fact it is an
 *  RGBA and not an RGB might cause some problems with some viewers.
 *  Sadly, I can't do anything about it... sorry.
 *
 *
 *  Stuff for GD V1.? as well as V2.+
 *
 *  optimise
 *
 *  From version 1.17 of the GD driver, a command line option has been
 *  added to try and optimise the PNG files. If successful, the optimise
 *  command will create 4 bit (16 colour) PNGs instead of 8 bit (256 colour)
 *  ones. This results in slightly smaller files with no loss in any colour
 *  information. The function has no real memory overhead, but does have a
 *  slight speed hit in exchange for the optimisation. For example:
 *         x08c -dev png -drvopt 8bit,optimise -fam -o 8bitpng
 *  forces the png driver to make 8bit pngs, and will then optimise any PNG
 *  images with 16 or less colours into a 4 bit PNG. Note, this DOESN'T WORK
 *  WITH 24bit PNGs yet, and will never work with JPEGs.
 *
 *
 *  Also as of version 1.17 of the GD driver, the options for palette
 *  modification previously set with the command line option "-hack" have
 *  now been moved to two options settable from the -drvopt switch.
 *
 *  def_black15
 *
 *  -drvopt def_black15 sets index 15, usually white, to black if index 0,
 *  the background colour and usually black, has been set to white from the
 *  command line option -bg
 *
 *  swp_red15
 *
 *  -drvopt swp_red15 swaps index 15, usually white, with index 1, which is
 *  usually red. This might be desirable occasionally, but it is principally
 *  included for cases when the background has been set on the command line
 *  to white, and the "def_black15" option has been issued to redefine index
 *  15 as black. By issuing a command like:
 *                 x08c -dev png -bg ffffff -drvopt def_black15,swp_red15
 *  the driver will set the background to white, then redefine index 15 of
 *  cmap0, which is usually white to black, then swap index 2 (red) to 15
 *  (white originally, now black), so at the end of the day, the "default"
 *  plotting colour is now black. Why do all of this ? It is a very quick
 *  way of making a nice web-friendly png without having to redefine the
 *  cmaps within your program.
 *
 */


#include "plDevs.h"

#if defined(PLD_png) || defined(PLD_jpeg)

#include "plplotP.h"
#include "drivers.h"

#include <gd.h>

/* Device info */
char* plD_DEVICE_INFO_gd = "jpeg:JPEG file:0:gd:40:jpeg\n"
                       "png:PNG file:0:gd:39:png";


#ifdef HAVE_FREETYPE

/*
 *  Freetype support has been added to the GD family of drivers using the
 *  plfreetype.c module, and implemented as a driver-specific optional extra
 *  invoked via the -drvopt command line toggle. It uses the
 *  "PLESC_HAS_TEXT" command for rendering within the driver.
 *
 *  Freetype support is turned on/off at compile time by defining
 *  "HAVE_FREETYPE".
 *
 *  To give the user some level of control over the fonts that are used,
 *  environmental variables can be set to over-ride the definitions used by
 *  the five default plplot fonts.
 *
 *  Freetype rendering is used with the command line "-drvopt text".
 *  Anti-aliased fonts can be used by issuing "-drvopt text,smooth"
 */

#include "plfreetype.h"

#endif

/* Prototypes for functions in this file. */

static void fill_polygon      (PLStream *pls);
static void setcmap           (PLStream *pls);
static void     plD_init_png_Dev(PLStream *pls);
static void     plD_gd_optimise (PLStream *pls);
static void     plD_black15_gd  (PLStream *pls);
static void     plD_red15_gd    (PLStream *pls);

#ifdef HAVE_FREETYPE

static void plD_pixel_gd (PLStream *pls, short x, short y);
static void init_freetype_lv1 (PLStream *pls);
static void init_freetype_lv2 (PLStream *pls);

extern void plD_FreeType_init(PLStream *pls);
extern void plD_render_freetype_text (PLStream *pls, EscText *args);
extern void plD_FreeType_Destroy(PLStream *pls);
extern void pl_set_extended_cmap0(PLStream *pls, int ncol0_width, int ncol0_org);

#endif

/* top level declarations */

static int NCOLOURS=gdMaxColors;

/* In an attempt to fix a problem with the hidden line removal functions
 * that results in hidden lines *not* being removed from "small" plot
 * pages (ie, like a normal video screen), a "virtual" page of much
 * greater size is used to trick the algorithm into working correctly.
 * If, in future, this gets fixed on its own, then don't define
 * "use_experimental_hidden_line_hack"
 */

#define use_experimental_hidden_line_hack

/* I think the current version of Freetype supports up to a maximum of
 * 128 grey levels for text smoothing. You can get quite acceptable
 * results with as few as 4 grey-levels. Uusually only about 5 get used
 * anyway, but the question is where, in the "grey spectrum" will they be ?
 * Who knows ? The following define lets you set a maximum limit on the
 * number of grey-levels used. It is really only here for the 24bit mode
 * and could be set to 255, but that would slow things down and use more
 * memory. 64 seems to be a nice compromise, but if you want to change it,
 * then change it here.
 */

#ifndef max_number_of_grey_levels_used_in_text_smoothing
#define max_number_of_grey_levels_used_in_text_smoothing 64
#endif

/* Not present in versions before 2.0 */

#ifndef gdImagePalettePixel
#define gdImagePalettePixel(  im, x, y )   (im)->pixels[(y)][(x)]
#endif

/* Struct to hold device-specific info. */

typedef struct {

      gdImagePtr im_out;                      /* Graphics pointer */
        PLINT pngx;
        PLINT pngy;

        int colour;                             /* Current Colour               */
        int totcol;                             /* Total number of colours      */
        int ncol1;                              /* Actual size of ncol1 we got  */

      int scale;                              /* scaling factor to "blow up" to */
                                                /* the "virtual" page in removing hidden lines*/

      int optimise;                           /* Flag used for 4bit pngs */
        int black15;                            /* Flag used for forcing a black colour */
        int red15;                              /* Flag for swapping red and 15 */

#if GD2_VERS >= 2
        int truecolour;                         /* Flag to ALWAYS force 24 bit mode */
        int palette;                            /* Flag to ALWAYS force  8 bit mode */
#endif

} png_Dev;

void plD_init_png       (PLStream *);
void plD_line_png       (PLStream *, short, short, short, short);
void plD_polyline_png         (PLStream *, short *, short *, PLINT);
void plD_eop_png        (PLStream *);
void plD_eop_jpeg       (PLStream *);
void plD_bop_png        (PLStream *);
void plD_tidy_png       (PLStream *);
void plD_state_png            (PLStream *, PLINT);
void plD_esc_png        (PLStream *, PLINT, void *);

#ifdef PLD_png

void plD_dispatch_init_png( PLDispatchTable *pdt )
{
#ifndef ENABLE_DYNDRIVERS
    pdt->pl_MenuStr  = "PNG file";
    pdt->pl_DevName  = "png";
#endif
    pdt->pl_type     = plDevType_FileOriented;
    pdt->pl_seq      = 39;
    pdt->pl_init     = (plD_init_fp)     plD_init_png;
    pdt->pl_line     = (plD_line_fp)     plD_line_png;
    pdt->pl_polyline = (plD_polyline_fp) plD_polyline_png;
    pdt->pl_eop      = (plD_eop_fp)      plD_eop_png;
    pdt->pl_bop      = (plD_bop_fp)      plD_bop_png;
    pdt->pl_tidy     = (plD_tidy_fp)     plD_tidy_png;
    pdt->pl_state    = (plD_state_fp)    plD_state_png;
    pdt->pl_esc      = (plD_esc_fp)      plD_esc_png;
}

#endif

#ifdef PLD_jpeg

void plD_dispatch_init_jpeg( PLDispatchTable *pdt )
{
#ifndef ENABLE_DYNDRIVERS
    pdt->pl_MenuStr  = "JPEG File";
    pdt->pl_DevName  = "jpeg";
#endif
    pdt->pl_type     = plDevType_FileOriented;
    pdt->pl_seq      = 40;
    pdt->pl_init     = (plD_init_fp)     plD_init_png;
    pdt->pl_line     = (plD_line_fp)     plD_line_png;
    pdt->pl_polyline = (plD_polyline_fp) plD_polyline_png;
    pdt->pl_eop      = (plD_eop_fp)      plD_eop_jpeg;
    pdt->pl_bop      = (plD_bop_fp)      plD_bop_png;
    pdt->pl_tidy     = (plD_tidy_fp)     plD_tidy_png;
    pdt->pl_state    = (plD_state_fp)    plD_state_png;
    pdt->pl_esc      = (plD_esc_fp)      plD_esc_png;
}
#endif

/*--------------------------------------------------------------------------*\
 * plD_init_png_Dev()
 *
\*--------------------------------------------------------------------------*/

static void
plD_init_png_Dev(PLStream *pls)
{
    png_Dev *dev;

/*  Stuff for the driver options, these vars are copied into the driver
 *  structure so that everything is thread safe and reenterant.
 */

    int optimise=0;
    int black15=0;
    int red15=0;
#if GD2_VERS >= 2
    int truecolour=0;
    int palette=0;
#endif
#ifdef HAVE_FREETYPE
    int freetype=0;
    int smooth_text=0;
    FT_Data *FT;
#endif

    DrvOpt gd_options[] = {{"optimise", DRV_INT, &optimise, "Optimise PNG palette when possible"},
                              {"def_black15", DRV_INT, &black15, "Define idx 15 as black. If the background is \"whiteish\" (from \"-bg\" option), force index 15 (traditionally white) to be \"black\""},
                              {"swp_red15", DRV_INT, &red15, "Swap index 1 (usually red) and 1 (usually white); always done after \"black15\"; quite useful for quick changes to web pages"},
#if GD2_VERS >= 2
                              {"8bit", DRV_INT, &palette, "Palette (8 bit) mode"},
                              {"24bit", DRV_INT, &truecolour, "Truecolor (24 bit) mode"},
#endif
#ifdef HAVE_FREETYPE
                              {"text", DRV_INT, &freetype, "Use driver text (FreeType)"},
                              {"smooth", DRV_INT, &smooth_text, "Turn text smoothing on (1) or off (0)"},
#endif
                        {NULL, DRV_INT, NULL, NULL}};


/* Allocate and initialize device-specific data */

    if (pls->dev != NULL)
      free((void *) pls->dev);

    pls->dev = calloc(1, (size_t) sizeof(png_Dev));
    if (pls->dev == NULL)
      plexit("plD_init_png_Dev: Out of memory.");

    dev = (png_Dev *) pls->dev;

    dev->colour=1;  /* Set a fall back pen colour in case user doesn't */

/*
 *  Set the compression/quality level for JPEG files
 *  The higher the value, the bigger/better the image is
 */
    if ( (pls->dev_compression<=0)||(pls->dev_compression>99) )
       pls->dev_compression=90;

/* Check for and set up driver options */

    plParseDrvOpts(gd_options);

    dev->black15=black15;
    dev->red15=red15;
    dev->optimise=optimise;

#if GD2_VERS >= 2

    dev->palette=palette;
    dev->truecolour=truecolour;

    if ((dev->truecolour>0) && (dev->palette>0))
       plwarn("Selecting both \"truecolor\" AND \"palette\" driver options is contradictory, so\nI will just use my best judgment.\n");
    else if (dev->truecolour>0)
       NCOLOURS=16777216;
    else if ((dev->truecolour==0)&&(dev->palette==0)&&((pls->ncol1+pls->ncol0)>NCOLOURS))
       {
        NCOLOURS=16777216;
       }

#endif

#ifdef HAVE_FREETYPE
if (freetype)
   {
    pls->dev_text = 1; /* want to draw text */
    init_freetype_lv1(pls);
    FT=(FT_Data *)pls->FT;
    FT->want_smooth_text=smooth_text;
   }

#endif
}

/*----------------------------------------------------------------------*\
 * plD_init_png()
 *
 * Initialize device.
\*----------------------------------------------------------------------*/

void plD_init_png(PLStream *pls)
{
    png_Dev *dev=NULL;

    pls->termin = 0;            /* Not an interactive device */
    pls->icol0 = 1;
    pls->bytecnt = 0;
    pls->page = 0;
    pls->dev_fill0 = 1;         /* Can do solid fills */

    if (!pls->colorset)
      pls->color = 1;         /* Is a color device */

/* Initialize family file info */
    plFamInit(pls);

/* Prompt for a file name if not already set */
    plOpenFile(pls);

/* Allocate and initialize device-specific data */
    plD_init_png_Dev(pls);
    dev=(png_Dev *)pls->dev;

      if (pls->xlength <= 0 || pls->ylength <=0)
      {
/* use default width, height of 800x600 if not specifed by -geometry option
 * or plspage */
       plspage(0., 0., 800, 600, 0, 0);
      }

     pls->graphx = GRAPHICS_MODE;

     dev->pngx = pls->xlength - 1;  /* should I use -1 or not??? */
     dev->pngy = pls->ylength - 1;

#ifdef use_experimental_hidden_line_hack

     if (dev->pngx>dev->pngy)    /* Work out the scaling factor for the  */
        {                        /* "virtual" (oversized) page           */
        dev->scale=PIXELS_X/dev->pngx;
        }
     else
        {
        dev->scale=PIXELS_Y/dev->pngy;
        }
#else

     dev->scale=1;

#endif


     if (pls->xdpi<=0)
     {
/* This corresponds to a typical monitor resolution of 4 pixels/mm. */
        plspage(4.*25.4, 4.*25.4, 0, 0, 0, 0);
     }
     else
     {
        pls->ydpi=pls->xdpi;        /* Set X and Y dpi's to the same value */
     }
/* Convert DPI to pixels/mm */
     plP_setpxl(dev->scale*pls->xdpi/25.4,dev->scale*pls->ydpi/25.4);

     plP_setphy(0, dev->scale*dev->pngx, 0, dev->scale*dev->pngy);

#ifdef HAVE_FREETYPE
if (pls->dev_text)
   {
    init_freetype_lv2(pls);
   }
#endif

}

/*----------------------------------------------------------------------*\
 * plD_line_png()
 *
 * Draw a line in the current color from (x1,y1) to (x2,y2).
\*----------------------------------------------------------------------*/

void
plD_line_png(PLStream *pls, short x1a, short y1a, short x2a, short y2a)
{
    png_Dev *dev=(png_Dev *)pls->dev;
    int x1 = x1a/dev->scale, y1 = y1a/dev->scale, x2 = x2a/dev->scale, y2 = y2a/dev->scale;
    y1 = dev->pngy - y1;
    y2 = dev->pngy - y2;

    gdImageLine(dev->im_out, x1, y1, x2, y2, dev->colour);

}

/*----------------------------------------------------------------------*\
 * plD_polyline_png()
 *
 * Draw a polyline in the current color.
\*----------------------------------------------------------------------*/

void
plD_polyline_png(PLStream *pls, short *xa, short *ya, PLINT npts)
{
    PLINT i;

    for (i = 0; i < npts - 1; i++)
      plD_line_png(pls, xa[i], ya[i], xa[i + 1], ya[i + 1]);
}


/*----------------------------------------------------------------------*\
 * fill_polygon()
 *
 * Fill polygon described in points pls->dev_x[] and pls->dev_y[].
\*----------------------------------------------------------------------*/

static void
fill_polygon(PLStream *pls)
{
png_Dev *dev=(png_Dev *)pls->dev;

    int i;
    gdPoint *points=NULL;

    if (pls->dev_npts < 1)
      return;

     points = malloc((size_t)pls->dev_npts * sizeof(gdPoint));

     for (i = 0; i < pls->dev_npts; i++)
         {
         points[i].x = pls->dev_x[i]/dev->scale;
         points[i].y = dev->pngy - (pls->dev_y[i]/dev->scale);
         }

   gdImageFilledPolygon(dev->im_out, points, pls->dev_npts, dev->colour);
   free(points);

}

/*----------------------------------------------------------------------*\
 * setcmap()
 *
 * Sets up color palette.
\*----------------------------------------------------------------------*/

static void
setcmap(PLStream *pls)
{
    int i, ncol1=pls->ncol1;
    int ncol0=pls->ncol0, total_colours;
    PLColor cmap1col;
    png_Dev *dev=(png_Dev *)pls->dev;
    PLFLT tmp_colour_pos;

/*
 * Yuckky fix to get rid of the previosuly allocated palette from the
 * GD image
 */

    for (i=0;i<256;i++)
      {
       gdImageColorDeallocate(dev->im_out,i);
      }

    if (ncol0>NCOLOURS/2)     /* Check for ridiculous number of colours */
       {                      /* in ncol0, and appropriately adjust the */
        plwarn("Too many colours in cmap0.");     /* number, issuing a  */
        ncol0=NCOLOURS/2;                         /* warning if it does */
        pls->ncol0=ncol0;
       }

    dev->totcol=0;       /* Reset the number of colours counter to zero */

    total_colours=ncol0+ncol1;  /* Work out how many colours are wanted */

    if (total_colours>NCOLOURS)     /* Do some rather modest error      */
       {                            /* checking to make sure that       */
        total_colours=NCOLOURS;     /* we are not defining more colours */
        ncol1=total_colours-ncol0;  /* than we have room for.           */

        if (ncol1<=0)
           {
            plexit("Problem setting colourmap in PNG or JPEG driver.");
           }
       }

 dev->ncol1=ncol1;  /* The actual size of ncol1, regardless of what was asked.
                     * This is dependent on colour slots available.
                     * It might well be the same as ncol1.
                     */

/* Initialize cmap 0 colors */

if (ncol0>0)  /* make sure the program actually asked for cmap0 first */
   {
    for (i = 0; i < ncol0; i++)
        {
        gdImageColorAllocate(dev->im_out,
                             pls->cmap0[i].r, pls->cmap0[i].g, pls->cmap0[i].b);
        ++dev->totcol; /* count the number of colours we use as we use them */
        }


  }

/* Initialize any remaining slots for cmap1 */


if (ncol1>0)    /* make sure that we want to define cmap1 first */
   {
    for (i = 0; i < ncol1; i++)
        {

         if (ncol1<pls->ncol1)       /* Check the dynamic range of colours */
            {

             /*
              * Ok, now if we have less colour slots available than are being
              * defined by pls->ncol1, then we still want to use the full
              * dynamic range of cmap1 as best we can, so what we do is work
              * out an approximation to the index in the full dynamic range
              * in cases when pls->ncol1 exceeds the number of free colours.
              */

             tmp_colour_pos= i>0 ? pls->ncol1*((PLFLT)i/ncol1) : 0;
             plcol_interp(pls, &cmap1col, (int) tmp_colour_pos, pls->ncol1);

            }
         else
            {
             plcol_interp(pls, &cmap1col, i, ncol1);
            }


         gdImageColorAllocate(dev->im_out,
                                   cmap1col.r, cmap1col.g, cmap1col.b);

         ++dev->totcol; /* count the number of colours we use as we go */
        }
   }
}


/*----------------------------------------------------------------------*\
 * plD_state_png()
 *
 * Handle change in PLStream state (color, pen width, fill attribute, etc).
\*----------------------------------------------------------------------*/

void
plD_state_png(PLStream *pls, PLINT op)
{
png_Dev *dev=(png_Dev *)pls->dev;
PLFLT tmp_colour_pos;
#if GD2_VERS >= 2
long temp_col;
#endif


    switch (op) {

#if GD2_VERS >= 2
    case PLSTATE_WIDTH:
        gdImageSetThickness(dev->im_out, pls->width);
      break;
#endif

    case PLSTATE_COLOR0:
#if GD2_VERS >= 2

      if ( (pls->icol0 == PL_RGB_COLOR)||     /*  Should never happen since PL_RGB_COLOR is depreciated, but here for backwards compatibility */
             (gdImageTrueColor(dev->im_out)) )  /*  We will do this if we are in "TrueColour" mode */
           {
          if ( (dev->totcol < NCOLOURS)||         /* See if there are slots left, if so we will allocate a new colour */
                 (gdImageTrueColor(dev->im_out)) )  /* In TrueColour mode we allocate each colour as we come to it */
             {
              /* Next allocate a new colour to a temporary slot since what we do with it will varay depending on if its a pallter index or truecolour */
                temp_col=gdImageColorAllocate(dev->im_out,pls->curcolor.r,
                                             pls->curcolor.g, pls->curcolor.b);

                if (gdImageTrueColor(dev->im_out))
                    dev->colour = temp_col;     /* If it's truecolour, then we will directly set dev->colour to our "new" colour */
                else
                    {
                     dev->colour = dev->totcol;  /* or else, we will just set it to the last colour */
                     dev->totcol++;              /* Bump the total colours for next time round */
                    }
             }

           }
         else  /* just a normal colour allocate, so don't worry about the above stuff, just grab the index */
           {
            dev->colour = pls->icol0;
           }

#else
      dev->colour = pls->icol0;
      if (dev->colour == PL_RGB_COLOR)
           {
          if (dev->totcol < NCOLOURS)
             {
                gdImageColorAllocate(dev->im_out,pls->curcolor.r, pls->curcolor.g,  pls->curcolor.b);
            dev->colour = dev->totcol;
             }

           }
#endif
      break;

    case PLSTATE_COLOR1:

#if GD2_VERS >= 2
       if (!gdImageTrueColor(dev->im_out))
          {
#endif
           /*
            * Start by checking to see if we have to compensate for cases where
            * we don't have the full dynamic range of cmap1 at our disposal
            */
           if (dev->ncol1<pls->ncol1)
              {
               tmp_colour_pos=dev->ncol1*((PLFLT)pls->icol1/(pls->ncol1>0 ? pls->ncol1 : 1));
               dev->colour = pls->ncol0 + (int)tmp_colour_pos;
              }
           else
              dev->colour = pls->ncol0 + pls->icol1;
#if GD2_VERS >= 2
           }
        else    /* it is a truecolour image */
           {
             dev->colour = gdTrueColor(pls->curcolor.r, pls->curcolor.g, pls->curcolor.b);
           }
#endif
      break;


    case PLSTATE_CMAP0:
    case PLSTATE_CMAP1:

#if GD2_VERS >= 2
       if (!gdImageTrueColor(dev->im_out))
          {
#endif

    /*
     *  Code to redefine the entire palette
     */


      if (pls->color)
          setcmap(pls);

#if GD2_VERS >= 2
}
#endif

      break;
    }
}


/*----------------------------------------------------------------------*\
 * plD_esc_png()
 *
 * Escape function.
\*----------------------------------------------------------------------*/

void plD_esc_png(PLStream *pls, PLINT op, void *ptr)
{
    switch (op) {

      case PLESC_FILL:  /* fill */
      fill_polygon(pls);
      break;

#ifdef HAVE_FREETYPE
     case PLESC_HAS_TEXT:
        plD_render_freetype_text(pls, (EscText *)ptr);
        break;
#endif

    }
}

/*----------------------------------------------------------------------*\
 * plD_bop_png()
 *
 * Set up for the next page.
 * Advance to next family file if necessary (file output).
\*----------------------------------------------------------------------*/

void plD_bop_png(PLStream *pls)
{
    png_Dev *dev;

    plGetFam(pls);
/* force new file if pls->family set for all subsequent calls to plGetFam
 * n.b. putting this after plGetFam call is important since plinit calls
 * bop, and you don't want the familying sequence started until after
 * that first call to bop.*/

/* n.b. pls->dev can change because of an indirect call to plD_init_png
 * from plGetFam if familying is enabled.  Thus, wait to define dev until
 * now. */

    dev = (png_Dev *) pls->dev;

    pls->famadv = 1;

    pls->page++;

if (dev->black15) plD_black15_gd(pls);
if (dev->red15) plD_red15_gd(pls);

#if GD2_VERS >= 2
  if ( ( (((dev->truecolour>0) && (dev->palette>0)) ||     /* In an EXTREMELY convaluted */
         ((dev->truecolour==0) && (dev->palette==0))) &&   /* manner, all this is just   */
          ((pls->ncol1+pls->ncol0) <= 256) ) ||             /* asking the question, do we */
       (((dev->palette>0) && (dev->truecolour==0)))  )   /* want truecolour or not ?   */
        {
#endif

           dev->im_out = gdImageCreate(pls->xlength, pls->ylength);

           setcmap(pls);

#if GD2_VERS >= 2
         }
       else
         {
         dev->im_out = gdImageCreateTrueColor(pls->xlength, pls->ylength);

/*
 * In truecolour mode, the background colour GD makes is ALWAYS black, so to
 * "simulate" (stimulate?) a background colour other than black, we will just
 * draw a dirty big rectange covering the whole image and colour it in
 * whatever colour cmap0[0] happens to be.
 *
 * Question to C gurus: while it is slightly illogical and ugly, would:
 *   if ((pls->cmap0[0].r+pls->cmap0[0].g+pls->cmap0[0].b)!=0)
 * be more computationally efficient than:
 *   if ((pls->cmap0[0].r!=0)||(pls->cmap0[0].g!=0)||(pls->cmap0[0].b!=0))
 *  ???
 */

         if ( (pls->cmap0[0].r!=0)||(pls->cmap0[0].g!=0)||
              (pls->cmap0[0].b!=0) )
            {
             gdImageFilledRectangle(dev->im_out,0,0, pls->xlength-1, pls->ylength-1,
                                    gdTrueColor(pls->cmap0[0].r,pls->cmap0[0].g,
                                                pls->cmap0[0].b));
            }

         }


/* This ensures the line width is set correctly at the beginning of
 *    each page */

   plD_state_png(pls, PLSTATE_WIDTH);

#endif


}

/*----------------------------------------------------------------------*\
 * plD_tidy_png()
 *
 * Close graphics file or otherwise clean up.
\*----------------------------------------------------------------------*/

void plD_tidy_png(PLStream *pls)
{

#ifdef HAVE_FREETYPE
   if (pls->dev_text)
     {
      FT_Data *FT=(FT_Data *)pls->FT;
      plscmap0n(FT->ncol0_org);
      plD_FreeType_Destroy(pls);
     }
#endif

   fclose(pls->OutFile);
   free_mem(pls->dev);
}

/*----------------------------------------------------------------------*\
 * plD_black15_gd()
 *
 *  This small function simply redefines index 15 of cmap0, which is
 *  usually set to white, to black, but only if index 0, which is usually
 *  black, has been redefined to white (for example, through -bg).
 *
\*----------------------------------------------------------------------*/

void plD_black15_gd(PLStream *pls)
{

if (pls->ncol0>15)
   {
    if ((pls->cmap0[0].r>227)&&(pls->cmap0[0].g>227)&&(pls->cmap0[0].b>227))
       {
        pls->cmap0[15].r=0;
        pls->cmap0[15].g=0;
        pls->cmap0[15].b=0;
      }
   }
}


/*----------------------------------------------------------------------*\
 * plD_red15_gd()
 *
 *
 *  This function swaps index 1, often the default plotting colour, with
 *  index 15, the last defined colour.
 *
 *  Colour 15 is usually white, and 1 is usually red, so swapping the two
 *  might be desirable occasionally, but it is principally here for cases
 *  when the background has been set on the command line to white, and the
 *  "def_black15" option has been issued to redefine index 15 as black. By
 *  issuing a command like
 *
 *      ... -bg ffffff -drvopt def_black15,swp_red15
 *
 *  the driver will set the background to white, then redefine index 15 of
 *  cmap0, which is usually white to black, then swap index 2 (red) to 15
 *  (white originally, now black), so at the end of the day, the "default"
 *  plotting colour is now black. Why do all of this ? It is a very quick
 *  way of making a nice web-friendly png without having to redefine the
 *  cmaps within your program.
 *
 *  If you don't like it, don't use it !
 *
\*----------------------------------------------------------------------*/

void plD_red15_gd(PLStream *pls)
{
char r=pls->cmap0[1].r;
char g=pls->cmap0[1].g;
char b=pls->cmap0[1].b;

if (pls->ncol0>15)
   {
    pls->cmap0[1].r=pls->cmap0[15].r;
    pls->cmap0[1].g=pls->cmap0[15].r;
    pls->cmap0[1].b=pls->cmap0[15].r;

    pls->cmap0[15].r=r;
    pls->cmap0[15].g=g;
    pls->cmap0[15].b=b;
   }
}


/*----------------------------------------------------------------------*\
 * plD_gd_optimise()
 *
 *
 *  This function pretty much does exactly what it says - it optimises the
 *  PNG file. It does this by checking to see if all the allocated colours
 *  were actually used. If they were not, then it deallocates them. This
 *  function often results in the PNG file being saved as a 4 bit (16
 *  colour) PNG rather than an 8 bit (256 colour) PNG. The file size
 *  difference is not huge, not as great as for GIFs for example (I think
 *  most of the saving comes from removing redundant entries from the
 *  palette entry in the header); however some modest size savings occur.
 *
 *  The function isn't always successful - the optimiser will always
 *  deallocate unused colours as it finds them, but GD will only deallocate
 *  them "for real" until 16 colours are used up, and then stop since it
 *  doesn't make a difference if you have 17 colours or 255 colours. The
 *  result of this is you may end up with an image using say, 130 colours,
 *  but you will have 240 colour entries, some of which aren't used, and
 *  aren't blanked out.
 *
 *  Another side-effect of this function is the relative position of the
 *  colour indices MAY shift as colours are deallocated. I really don't
 *  think this should worry anyone, but if it does, don't optimise the
 *  image !
 *
\*----------------------------------------------------------------------*/

void plD_gd_optimise(PLStream *pls)
{
png_Dev *dev=(png_Dev *)pls->dev;
int i,j;
char *bbuf;

bbuf=calloc(256,(size_t) 1);    /* Allocate a buffer to "check off" colours as they are used */
if (bbuf==NULL) plexit("plD_gd_optimise: Out of memory.");

    for(i=0;i<(pls->xlength-1);i++)        /* Walk through the image pixel by pixel */
       {                                   /* checking to see what colour it is */
        for(j=0;j<(pls->ylength-1);j++)    /* and adding it to the list of used colours */
           {
            bbuf[gdImagePalettePixel(dev->im_out, i, j)]=1;
           }
       }

for (i=0;i<256;i++)     /* next walk over the colours and deallocate */
    {                   /* unused ones */
    if (bbuf[i]==0) gdImageColorDeallocate(dev->im_out,i);
    }

free(bbuf);
}


#ifdef PLD_png

/*----------------------------------------------------------------------*\
 * plD_eop_png()
 *
 * End of page.
\*----------------------------------------------------------------------*/

void plD_eop_png(PLStream *pls)
{
png_Dev *dev=(png_Dev *)pls->dev;

    if (pls->family || pls->page == 1) {

   if (dev->optimise)
     {
#if GD2_VERS >= 2
      if ( ( (((dev->truecolour>0) && (dev->palette>0)) ||     /* In an EXTREMELY convaluted */
             ((dev->truecolour==0) && (dev->palette==0))) &&   /* manner, all this is just   */
              ((pls->ncol1+pls->ncol0)<=256) ) ||             /* asking the question, do we */
           ( ((dev->palette>0)&&(dev->truecolour==0)) )  )   /* want truecolour or not ?   */
            {
#endif
             plD_gd_optimise(pls);

#if GD2_VERS >= 2
            }
#endif
        }

       gdImagePng(dev->im_out, pls->OutFile);

       gdImageDestroy(dev->im_out);
    }
}

#endif

#ifdef HAVE_FREETYPE

/*----------------------------------------------------------------------*\
 *  void plD_pixel_gd (PLStream *pls, short x, short y)
 *
 *  callback function, of type "plD_pixel_fp", which specifies how a single
 *  pixel is set in the current colour.
\*----------------------------------------------------------------------*/

void plD_pixel_gd (PLStream *pls, short x, short y)
{
png_Dev *dev=(png_Dev *)pls->dev;

   gdImageSetPixel(dev->im_out, x, y,dev->colour);

}

/*----------------------------------------------------------------------*\
 *  void init_freetype_lv1 (PLStream *pls)
 *
 *  "level 1" initialisation of the freetype library.
 *  "Level 1" initialisation calls plD_FreeType_init(pls) which allocates
 *  memory to the pls->FT structure, then sets up the pixel callback
 *  function.
\*----------------------------------------------------------------------*/

static void init_freetype_lv1 (PLStream *pls)
{
FT_Data *FT;

plD_FreeType_init(pls);

FT=(FT_Data *)pls->FT;
FT->pixel= (plD_pixel_fp)plD_pixel_gd;


}

/*----------------------------------------------------------------------*\
 *  void init_freetype_lv2 (PLStream *pls)
 *
 *  "Level 2" initialisation of the freetype library.
 *  "Level 2" fills in a few setting that aren't public until after the
 *  graphics sub-syetm has been initialised.
 *  The "level 2" initialisation fills in a few things that are defined
 *  later in the initialisation process for the GD driver.
 *
 *  FT->scale is a scaling factor to convert co-ordinates. This is used by
 *  the GD and other drivers to scale back a larger virtual page and this
 *  eliminate the "hidden line removal bug". Set it to 1 if your device
 *  doesn't have scaling.
 *
 *  Some coordinate systems have zero on the bottom, others have zero on
 *  the top. Freetype does it one way, and most everything else does it the
 *  other. To make sure everything is working ok, we have to "flip" the
 *  coordinates, and to do this we need to know how big in the Y dimension
 *  the page is, and whether we have to invert the page or leave it alone.
 *
 *  FT->ymax specifies the size of the page FT->invert_y=1 tells us to
 *  invert the y-coordinates, FT->invert_y=0 will not invert the
 *  coordinates.
\*----------------------------------------------------------------------*/

static void init_freetype_lv2 (PLStream *pls)
{
png_Dev *dev=(png_Dev *)pls->dev;
FT_Data *FT=(FT_Data *)pls->FT;

FT->scale=dev->scale;
FT->ymax=dev->pngy;
FT->invert_y=1;
FT->smooth_text=0;

if (FT->want_smooth_text==1)    /* do we want to at least *try* for smoothing ? */
   {
    FT->ncol0_org=pls->ncol0;                                   /* save a copy of the original size of ncol0 */
    FT->ncol0_xtra=NCOLOURS-(pls->ncol1+pls->ncol0);            /* work out how many free slots we have */
    FT->ncol0_width=FT->ncol0_xtra/(pls->ncol0-1);              /* find out how many different shades of anti-aliasing we can do */
    if (FT->ncol0_width>4)     /* are there enough colour slots free for text smoothing ? */
       {
        if (FT->ncol0_width>max_number_of_grey_levels_used_in_text_smoothing)
           FT->ncol0_width=max_number_of_grey_levels_used_in_text_smoothing;                 /* set a maximum number of shades */
        plscmap0n(FT->ncol0_org+(FT->ncol0_width*pls->ncol0));      /* redefine the size of cmap0 */
/* the level manipulations are to turn off the plP_state(PLSTATE_CMAP0)
 * call in plscmap0 which (a) leads to segfaults since the GD image is
 * not defined at this point and (b) would be inefficient in any case since
 * setcmap is always called later (see plD_bop_png) to update the driver
 * color palette to be consistent with cmap0. */
         {
          PLINT level_save;
          level_save = pls->level;
          pls->level = 0;
          pl_set_extended_cmap0(pls, FT->ncol0_width, FT->ncol0_org); /* call the function to add the extra cmap0 entries and calculate stuff */
          pls->level = level_save;
         }
        FT->smooth_text=1;      /* Yippee ! We had success setting up the extended cmap0 */
      }
    else
      plwarn("Insufficient colour slots available in CMAP0 to do text smoothing.");
   }
}

#endif


#ifdef PLD_jpeg

/*----------------------------------------------------------------------*\
 * plD_eop_jpeg()
 *
 * End of page.
\*----------------------------------------------------------------------*/

void plD_eop_jpeg(PLStream *pls)
{
png_Dev *dev=(png_Dev *)pls->dev;

    if (pls->family || pls->page == 1) {
       gdImageJpeg(dev->im_out, pls->OutFile, pls->dev_compression);

       gdImageDestroy(dev->im_out);
    }
}

#endif

/*#endif*/


#else
int
pldummy_png()
{
    return 0;
}

#endif                        /* PNG */

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