/src/MapServer/src/mapscale.c

Source
/******************************************************************************
 * $Id$
 *
 * Project:  MapServer
 * Purpose:  Scale object rendering.
 * Author:   Steve Lime and the MapServer team.
 *
 ******************************************************************************
 * Copyright (c) 1996-2005 Regents of the University of Minnesota.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies of this Software or works derived from this Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "mapserver.h"

#define VMARGIN 3 /* buffer around the scalebar */
#define HMARGIN 3
#define VSPACING .8 /* spacing (% of font height) between scalebar and text */
#define VSLOP 5     /* makes things fit a bit better vertically */

/*
** Match this with with unit enumerations is mapserver.h
*/
static char *unitText[9] = {
    "in", "ft", "mi", "m", "km",
    "dd", "??", "??", "NM"}; /* MS_PIXEL and MS_PERCENTAGE not used */
double inchesPerUnit[9] = {1,       12, 63360.0, 39.3701,   39370.1,
                           4374754, 1,  1,       72913.3858};

static double roundInterval(double d) {
  if (d < .001)
    return (MS_NINT(d * 10000) / 10000.0);
  if (d < .01)
    return (MS_NINT(d * 1000) / 1000.0);
  if (d < .1)
    return (MS_NINT(d * 100) / 100.0);
  if (d < 1)
    return (MS_NINT(d * 10) / 10.0);
  if (d < 100)
    return (MS_NINT(d));
  if (d < 1000)
    return (MS_NINT(d / 10) * 10);
  if (d < 10000)
    return (MS_NINT(d / 100) * 100);
  if (d < 100000)
    return (MS_NINT(d / 1000) * 1000);
  if (d < 1000000)
    return (MS_NINT(d / 10000) * 10000);
  if (d < 10000000)
    return (MS_NINT(d / 100000) * 100000);
  if (d < 100000000)
    return (MS_NINT(d / 1000000) * 1000000);

  return (-1);
}

/*
** Calculate the approximate scale based on a few parameters. Note that this
*assumes the scale is
** the same in the x direction as in the y direction, so run msAdjustExtent(...)
*first.
*/
int msCalculateScale(rectObj extent, int units, int width, int height,
                     double resolution, double *scale) {
  double md, gd, center_y;

  /* if((extent.maxx == extent.minx) || (extent.maxy == extent.miny))   */
  if (!MS_VALID_EXTENT(extent)) {
    msSetError(MS_MISCERR,
               "Invalid image extent, minx=%lf, miny=%lf, maxx=%lf, maxy=%lf.",
               "msCalculateScale()", extent.minx, extent.miny, extent.maxx,
               extent.maxy);
    return (MS_FAILURE);
  }

  if ((width <= 0) || (height <= 0)) {
    msSetError(MS_MISCERR, "Invalid image width or height.",
               "msCalculateScale()");
    return (MS_FAILURE);
  }

  switch (units) {
  case (MS_DD):
  case (MS_METERS):
  case (MS_KILOMETERS):
  case (MS_MILES):
  case (MS_NAUTICALMILES):
  case (MS_INCHES):
  case (MS_FEET):
    center_y = (extent.miny + extent.maxy) / 2.0;
    md = (width - 1) /
         (resolution *
          msInchesPerUnit(
              units, center_y)); /* remember, we use a pixel-center to
                                    pixel-center extent, hence the width-1 */
    gd = extent.maxx - extent.minx;
    *scale = gd / md;
    break;
  default:
    *scale = -1; /* this is not an error */
    break;
  }

  return (MS_SUCCESS);
}

double msInchesPerUnit(int units, double center_lat) {
  (void)center_lat;
  double lat_adj = 1.0, ipu = 1.0;

  switch (units) {
  case (MS_METERS):
  case (MS_KILOMETERS):
  case (MS_MILES):
  case (MS_NAUTICALMILES):
  case (MS_INCHES):
  case (MS_FEET):
    ipu = inchesPerUnit[units];
    break;
  case (MS_DD):
    /* With geographical (DD) coordinates, we adjust the inchesPerUnit
     * based on the latitude of the center of the view. For this we assume
     * we have a perfect sphere and just use cos(lat) in our calculation.
     */
#ifdef ENABLE_VARIABLE_INCHES_PER_DEGREE
    if (center_lat != 0.0) {
      double cos_lat;
      cos_lat = cos(MS_PI * center_lat / 180.0);
      lat_adj = sqrt(1 + cos_lat * cos_lat) / sqrt(2.0);
    }
#endif
    ipu = inchesPerUnit[units] * lat_adj;
    break;
  default:
    break;
  }

  return ipu;
}

#define X_STEP_SIZE 5

imageObj *msDrawScalebar(mapObj *map) {
  int status;
  char label[32];
  double i, msx;
  int j;
  int isx, sx, sy, ox, oy, state, dsx;
  pointObj p;
  rectObj r;
  imageObj *image = NULL;
  double fontWidth, fontHeight;
  outputFormatObj *format = NULL;
  strokeStyleObj strokeStyle = {0};
  shapeObj shape;
  lineObj line;
  pointObj points[5];
  textSymbolObj ts;
  rendererVTableObj *renderer;

  strokeStyle.patternlength = 0;
  initTextSymbol(&ts);

  if ((int)map->units == -1) {
    msSetError(MS_MISCERR, "Map units not set.", "msDrawScalebar()");
    return (NULL);
  }

  renderer = MS_MAP_RENDERER(map);
  if (!renderer || !MS_MAP_RENDERER(map)->supports_pixel_buffer) {
    msSetError(MS_MISCERR, "Outputformat not supported for scalebar",
               "msDrawScalebar()");
    return (NULL);
  }

  msPopulateTextSymbolForLabelAndString(
      &ts, &map->scalebar.label, msStrdup("0123456789"), 1.0,
      map->resolution / map->defresolution, 0);

  /*
   *  A string containing the ten decimal digits is rendered to compute an
   * average cell size for each number, which is used later to place labels on
   * the scalebar.
   */

  if (msGetTextSymbolSize(map, &ts, &r) != MS_SUCCESS) {
    return NULL;
  }
  fontWidth = (r.maxx - r.minx) / 10.0;
  fontHeight = r.maxy - r.miny;

  map->cellsize = msAdjustExtent(&(map->extent), map->width, map->height);
  status = msCalculateScale(map->extent, map->units, map->width, map->height,
                            map->resolution, &map->scaledenom);
  if (status != MS_SUCCESS) {
    return (NULL);
  }
  dsx = map->scalebar.width - 2 * HMARGIN;
  do {
    msx = (map->cellsize * dsx) / (msInchesPerUnit(map->scalebar.units, 0) /
                                   msInchesPerUnit(map->units, 0));
    i = roundInterval(msx / map->scalebar.intervals);
    snprintf(label, sizeof(label), "%g",
             map->scalebar.intervals * i); /* last label */
    isx = MS_NINT((i / (msInchesPerUnit(map->units, 0) /
                        msInchesPerUnit(map->scalebar.units, 0))) /
                  map->cellsize);
    sx = (map->scalebar.intervals * isx) +
         MS_NINT((1.5 + strlen(label) / 2.0 +
                  strlen(unitText[map->scalebar.units])) *
                 fontWidth);

    if (sx <= (map->scalebar.width - 2 * HMARGIN))
      break; /* it will fit */

    dsx -= X_STEP_SIZE; /* change the desired size in hopes that it will fit in
                           user supplied width */
  } while (1);

  sy = (2 * VMARGIN) + MS_NINT(VSPACING * fontHeight) + fontHeight +
       map->scalebar.height - VSLOP;

  /*Ensure we have an image format representing the options for the scalebar.*/
  msApplyOutputFormat(&format, map->outputformat, map->scalebar.transparent);

  if (map->scalebar.transparent == MS_OFF) {
    if (!MS_VALID_COLOR(map->scalebar.imagecolor))
      MS_INIT_COLOR(map->scalebar.imagecolor, 255, 255, 255, 255);
  }
  image = msImageCreate(map->scalebar.width, sy, format, map->web.imagepath,
                        map->web.imageurl, map->resolution, map->defresolution,
                        &map->scalebar.imagecolor);

  /* did we succeed in creating the image? */
  if (!image) {
    msSetError(MS_MISCERR, "Unable to initialize image.", "msDrawScalebar()");
    return NULL;
  }
  image->map = map;

  /* drop this reference to output format */
  msApplyOutputFormat(&format, NULL, MS_NOOVERRIDE);

  switch (map->scalebar.align) {
  case (MS_ALIGN_LEFT):
    ox = HMARGIN;
    break;
  case (MS_ALIGN_RIGHT):
    ox = MS_NINT((map->scalebar.width - sx) + fontWidth);
    break;
  default:
    ox = MS_NINT((map->scalebar.width - sx) / 2.0 +
                 fontWidth / 2.0); /* center the computed scalebar */
  }
  oy = VMARGIN;

  switch (map->scalebar.style) {
  case (0): {

    line.numpoints = 5;
    line.point = points;
    shape.line = &line;
    shape.numlines = 1;
    if (MS_VALID_COLOR(map->scalebar.color)) {
      INIT_STROKE_STYLE(strokeStyle);
      strokeStyle.color = &map->scalebar.outlinecolor;
      strokeStyle.color->alpha = 255;
      strokeStyle.width = 1;
    }
    map->scalebar.backgroundcolor.alpha = 255;
    map->scalebar.color.alpha = 255;
    state = 1; /* 1 means filled */
    for (j = 0; j < map->scalebar.intervals; j++) {
      points[0].x = points[4].x = points[3].x = ox + j * isx + 0.5;
      points[0].y = points[4].y = points[1].y = oy + 0.5;
      points[1].x = points[2].x = ox + (j + 1) * isx + 0.5;
      points[2].y = points[3].y = oy + map->scalebar.height + 0.5;
      if (state == 1 && MS_VALID_COLOR(map->scalebar.color))
        status = renderer->renderPolygon(image, &shape, &map->scalebar.color);
      else if (MS_VALID_COLOR(map->scalebar.backgroundcolor))
        status = renderer->renderPolygon(image, &shape,
                                         &map->scalebar.backgroundcolor);

      if (MS_UNLIKELY(status == MS_FAILURE)) {
        goto scale_cleanup;
      }

      if (strokeStyle.color) {
        status = renderer->renderLine(image, &shape, &strokeStyle);

        if (MS_UNLIKELY(status == MS_FAILURE)) {
          goto scale_cleanup;
        }
      }

      snprintf(label, sizeof(label), "%g", j * i);
      map->scalebar.label.position = MS_CC;
      p.x = ox + j * isx; /* + MS_NINT(fontPtr->w/2); */
      p.y = oy + map->scalebar.height + MS_NINT(VSPACING * fontHeight);
      status = msDrawLabel(map, image, p, msStrdup(label), &map->scalebar.label,
                           1.0);
      if (MS_UNLIKELY(status == MS_FAILURE)) {
        goto scale_cleanup;
      }
      state = -state;
    }
    snprintf(label, sizeof(label), "%g", j * i);
    ox = ox + j * isx - MS_NINT((strlen(label) * fontWidth) / 2.0);
    snprintf(label, sizeof(label), "%g %s", j * i,
             unitText[map->scalebar.units]);
    map->scalebar.label.position = MS_CR;
    p.x = ox; /* + MS_NINT(fontPtr->w/2); */
    p.y = oy + map->scalebar.height + MS_NINT(VSPACING * fontHeight);
    status =
        msDrawLabel(map, image, p, msStrdup(label), &map->scalebar.label, 1.0);
    if (MS_UNLIKELY(status == MS_FAILURE)) {
      goto scale_cleanup;
    }
    break;
  }
  case (1): {
    line.numpoints = 2;
    line.point = points;
    shape.line = &line;
    shape.numlines = 1;
    if (MS_VALID_COLOR(map->scalebar.color)) {
      strokeStyle.width = 1;
      strokeStyle.color = &map->scalebar.color;
    }

    points[0].y = points[1].y = oy;
    points[0].x = ox;
    points[1].x = ox + isx * map->scalebar.intervals;
    status = renderer->renderLine(image, &shape, &strokeStyle);
    if (MS_UNLIKELY(status == MS_FAILURE)) {
      goto scale_cleanup;
    }

    points[0].y = oy;
    points[1].y = oy + map->scalebar.height;
    p.y = oy + map->scalebar.height + MS_NINT(VSPACING * fontHeight);
    for (j = 0; j <= map->scalebar.intervals; j++) {
      points[0].x = points[1].x = ox + j * isx;
      status = renderer->renderLine(image, &shape, &strokeStyle);
      if (MS_UNLIKELY(status == MS_FAILURE)) {
        goto scale_cleanup;
      }

      snprintf(label, sizeof(label), "%g", j * i);
      if (j != map->scalebar.intervals) {
        map->scalebar.label.position = MS_CC;
        p.x = ox + j * isx; /* + MS_NINT(fontPtr->w/2); */
      } else {
        snprintf(label, sizeof(label), "%g %s", j * i,
                 unitText[map->scalebar.units]);
        map->scalebar.label.position = MS_CR;
        p.x = ox + j * isx - MS_NINT((strlen(label) * fontWidth) / 2.0);
      }
      status = msDrawLabel(map, image, p, msStrdup(label), &map->scalebar.label,
                           1.0);
      if (MS_UNLIKELY(status == MS_FAILURE)) {
        goto scale_cleanup;
      }
    }
    break;
  }
  default:
    msSetError(MS_MISCERR, "Unsupported scalebar style.", "msDrawScalebar()");
    return (NULL);
  }

scale_cleanup:
  freeTextSymbol(&ts);
  if (MS_UNLIKELY(status == MS_FAILURE)) {
    msFreeImage(image);
    return NULL;
  }
  return (image);
}

int msEmbedScalebar(mapObj *map, imageObj *img) {
  int l, index, s, status = MS_SUCCESS;
  pointObj point;
  imageObj *image = NULL;
  rendererVTableObj *renderer;
  symbolObj *embeddedSymbol;
  char *imageType = NULL;

  index = msGetSymbolIndex(&(map->symbolset), "scalebar", MS_FALSE);
  if (index != -1)
    msRemoveSymbol(&(map->symbolset),
                   index); /* remove cached symbol in case the function is
   called multiple times with different zoom levels */

  if ((embeddedSymbol = msGrowSymbolSet(&map->symbolset)) == NULL)
    return MS_FAILURE;

  s = map->symbolset.numsymbols;
  map->symbolset.numsymbols++;

  if (!MS_RENDERER_PLUGIN(map->outputformat) ||
      !MS_MAP_RENDERER(map)->supports_pixel_buffer) {
    imageType = msStrdup(map->imagetype); /* save format */
    if MS_DRIVER_CAIRO (map->outputformat)
      map->outputformat = msSelectOutputFormat(map, "cairopng");
    else
      map->outputformat = msSelectOutputFormat(map, "png");

    msInitializeRendererVTable(map->outputformat);
  }
  renderer = MS_MAP_RENDERER(map);

  image = msDrawScalebar(map);

  if (imageType) {
    map->outputformat =
        msSelectOutputFormat(map, imageType); /* restore format */
    msFree(imageType);
  }

  if (!image) {
    return MS_FAILURE;
  }
  embeddedSymbol->pixmap_buffer = calloc(1, sizeof(rasterBufferObj));
  MS_CHECK_ALLOC(embeddedSymbol->pixmap_buffer, sizeof(rasterBufferObj),
                 MS_FAILURE);

  if (MS_SUCCESS !=
      renderer->getRasterBufferCopy(image, embeddedSymbol->pixmap_buffer)) {
    return MS_FAILURE;
  }

  embeddedSymbol->type = MS_SYMBOL_PIXMAP; /* initialize a few things */
  embeddedSymbol->name = msStrdup("scalebar");
  embeddedSymbol->sizex = embeddedSymbol->pixmap_buffer->width;
  embeddedSymbol->sizey = embeddedSymbol->pixmap_buffer->height;
  if (map->scalebar.transparent) {
    embeddedSymbol->transparent = MS_TRUE;
    embeddedSymbol->transparentcolor = 0;
  }

  switch (map->scalebar.position) {
  case (MS_LL):
    point.x = MS_NINT(embeddedSymbol->pixmap_buffer->width / 2.0) +
              map->scalebar.offsetx;
    point.y = map->height -
              MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) -
              map->scalebar.offsety;
    break;
  case (MS_LR):
    point.x = map->width - MS_NINT(embeddedSymbol->pixmap_buffer->width / 2.0) -
              map->scalebar.offsetx;
    point.y = map->height -
              MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) -
              map->scalebar.offsety;
    break;
  case (MS_LC):
    point.x = MS_NINT(map->width / 2.0) + map->scalebar.offsetx;
    point.y = map->height -
              MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) -
              map->scalebar.offsety;
    break;
  case (MS_UR):
    point.x = map->width - MS_NINT(embeddedSymbol->pixmap_buffer->width / 2.0) -
              map->scalebar.offsetx;
    point.y = MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) +
              map->scalebar.offsety;
    break;
  case (MS_UL):
    point.x = MS_NINT(embeddedSymbol->pixmap_buffer->width / 2.0) +
              map->scalebar.offsetx;
    point.y = MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) +
              map->scalebar.offsety;
    break;
  case (MS_UC):
    point.x = MS_NINT(map->width / 2.0) + map->scalebar.offsetx;
    point.y = MS_NINT(embeddedSymbol->pixmap_buffer->height / 2.0) +
              map->scalebar.offsety;
    break;
  }

  l = msGetLayerIndex(map, "__embed__scalebar");
  if (l == -1) {
    if (msGrowMapLayers(map) == NULL)
      return (-1);
    l = map->numlayers;
    map->numlayers++;
    if (initLayer((GET_LAYER(map, l)), map) == -1)
      return (-1);
    GET_LAYER(map, l)->name = msStrdup("__embed__scalebar");
    GET_LAYER(map, l)->type = MS_LAYER_POINT;

    if (msGrowLayerClasses(GET_LAYER(map, l)) == NULL)
      return (-1);

    if (initClass(GET_LAYER(map, l)->class[0]) == -1)
      return (-1);
    GET_LAYER(map, l)->numclasses = 1; /* so we make sure to free it */

    /* update the layer order list with the layer's index. */
    map->layerorder[l] = l;
  }

  GET_LAYER(map, l)->status = MS_ON;
  if (map->scalebar.postlabelcache) { /* add it directly to the image */
    if (msMaybeAllocateClassStyle(GET_LAYER(map, l)->class[0], 0) == MS_FAILURE)
      return MS_FAILURE;
    GET_LAYER(map, l)->class[0]->styles[0]->symbol = s;
    status = msDrawMarkerSymbol(map, img, &point,
                                GET_LAYER(map, l)->class[0] -> styles[0], 1.0);
    if (MS_UNLIKELY(status == MS_FAILURE)) {
      goto embed_cleanup;
    }
  } else {
    if (!GET_LAYER(map, l)->class[0] -> labels) {
      if (msGrowClassLabels(GET_LAYER(map, l)->class[0]) == NULL)
        return MS_FAILURE;
      initLabel(GET_LAYER(map, l)->class[0] -> labels[0]);
      GET_LAYER(map, l)->class[0]->numlabels = 1;
      GET_LAYER(map, l)->class[0]->labels[0]->force = MS_TRUE;
      GET_LAYER(map, l)->class[0]->labels[0]->size =
          MS_MEDIUM; /* must set a size to have a valid label definition */
      GET_LAYER(map, l)->class[0]->labels[0]->priority = MS_MAX_LABEL_PRIORITY;
    }
    if (GET_LAYER(map, l)->class[0] -> labels[0] -> numstyles == 0) {
      if (msGrowLabelStyles(GET_LAYER(map, l)->class[0] -> labels[0]) == NULL)
        return (MS_FAILURE);
      GET_LAYER(map, l)->class[0]->labels[0]->numstyles = 1;
      initStyle(GET_LAYER(map, l)->class[0] -> labels[0] -> styles[0]);
      GET_LAYER(map, l)->class[0]->labels[0]->styles[0]->_geomtransform.type =
          MS_GEOMTRANSFORM_LABELPOINT;
    }
    GET_LAYER(map, l)->class[0]->labels[0]->styles[0]->symbol = s;
    status = msAddLabel(map, img, GET_LAYER(map, l)->class[0] -> labels[0], l,
                        0, NULL, &point, -1, NULL);
    if (MS_UNLIKELY(status == MS_FAILURE)) {
      goto embed_cleanup;
    }
  }

embed_cleanup:
  /* Mark layer as deleted so that it doesn't interfere with html legends or
   * with saving maps */
  GET_LAYER(map, l)->status = MS_DELETE;

  msFreeImage(image);
  return status;
}

/************************************************************************/
/* These two functions are used in PHP/Mapscript and Swig/Mapscript     */
/************************************************************************/

/************************************************************************/
/*  double GetDeltaExtentsUsingScale(double scale, int units,           */
/*                                   double centerLat, int width,       */
/*                                   double resolution)                 */
/*                                                                      */
/*      Utility function to return the maximum extent using the         */
/*      scale and the width of the image.                               */
/*                                                                      */
/*      Base on the function msCalculateScale (mapscale.c)              */
/************************************************************************/
double GetDeltaExtentsUsingScale(double scale, int units, double centerLat,
                                 int width, double resolution) {
  double md = 0.0;
  double dfDelta = -1.0;

  if (scale <= 0 || width <= 0)
    return -1;

  switch (units) {
  case (MS_DD):
  case (MS_METERS):
  case (MS_KILOMETERS):
  case (MS_MILES):
  case (MS_NAUTICALMILES):
  case (MS_INCHES):
  case (MS_FEET):
    /* remember, we use a pixel-center to pixel-center extent, hence the width-1
     */
    md = (width - 1) / (resolution * msInchesPerUnit(units, centerLat));
    dfDelta = md * scale;
    break;

  default:
    break;
  }

  return dfDelta;
}

/************************************************************************/
/*    static double Pix2Georef(int nPixPos, int nPixMin, double nPixMax,*/
/*                              double dfGeoMin, double dfGeoMax,       */
/*                              bool bULisYOrig)                        */
/*                                                                      */
/*      Utility function to convert a pixel pos to georef pos. If       */
/*      bULisYOrig parameter is set to true then the upper left is      */
/*      considered to be the Y origin.                                  */
/*                                                                      */
/************************************************************************/
double Pix2Georef(int nPixPos, int nPixMin, int nPixMax, double dfGeoMin,
                  double dfGeoMax, int bULisYOrig) {
  double dfPosGeo = 0.0;

  const double dfWidthGeo = dfGeoMax - dfGeoMin;
  const int nWidthPix = nPixMax - nPixMin;

  if (dfWidthGeo > 0.0 && nWidthPix > 0) {
    const double dfPixToGeo = dfWidthGeo / (double)nWidthPix;

    int nDeltaPix;
    if (!bULisYOrig)
      nDeltaPix = nPixPos - nPixMin;
    else
      nDeltaPix = nPixMax - nPixPos;

    const double dfDeltaGeo = nDeltaPix * dfPixToGeo;

    dfPosGeo = dfGeoMin + dfDeltaGeo;
  }
  return (dfPosGeo);
}

/* This function converts a pixel value in geo ref. The return value is in
 * layer units. This function has been added for the purpose of the ticket #1340
 */

double Pix2LayerGeoref(mapObj *map, layerObj *layer, int value) {
  double cellsize =
      MS_MAX(MS_CELLSIZE(map->extent.minx, map->extent.maxx, map->width),
             MS_CELLSIZE(map->extent.miny, map->extent.maxy, map->height));

  double resolutionFactor = map->resolution / map->defresolution;
  double unitsFactor = 1;

  if (layer->sizeunits != MS_PIXELS)
    unitsFactor =
        msInchesPerUnit(map->units, 0) / msInchesPerUnit(layer->sizeunits, 0);

  return value * cellsize * resolutionFactor * unitsFactor;
}

Coverage Report

Created: 2026-07-25 06:50