Reduce UTF grid size by removing unused entries (#5002)

Author: Francois Blackburn

maputfgrid.cpp

@@ -50,7 +50,7 @@ static utfpix32 UTF_WATER = utfpix32(32);
 
 #define utfitem(c) utfpix32(c)
 
-struct shapeData 
+struct shapeData
 {
   char *datavalues;
   char *itemvalue;
@@ -71,7 +71,7 @@ class lookupTable {
     counter = 0;
   }
 
-  ~lookupTable() 
+  ~lookupTable()
   {
     int i;
 
@@ -82,7 +82,7 @@ class lookupTable {
       if(table[i].itemvalue)
         msFree(table[i].itemvalue);
     }
-    msFree(table); 
+    msFree(table);
   }
 
   shapeData  *table;
@@ -96,12 +96,12 @@ class lookupTable {
 class polygon_adaptor_utf:public polygon_adaptor
 {
 public:
-  polygon_adaptor_utf(shapeObj *shape,int utfres_in):polygon_adaptor(shape) 
+  polygon_adaptor_utf(shapeObj *shape,int utfres_in):polygon_adaptor(shape)
   {
     utfresolution = utfres_in;
   }
 
-  virtual unsigned vertex(double* x, double* y) 
+  virtual unsigned vertex(double* x, double* y)
   {
     if(m_point < m_pend) {
       bool first = m_point == m_line->point;
@@ -125,7 +125,7 @@ class polygon_adaptor_utf:public polygon_adaptor
     }
     return mapserver::path_cmd_stop;
   }
-  
+
 private:
   int utfresolution;
 };
@@ -136,7 +136,7 @@ class polygon_adaptor_utf:public polygon_adaptor
 class line_adaptor_utf:public line_adaptor
 {
 public:
-  line_adaptor_utf(shapeObj *shape,int utfres_in):line_adaptor(shape) 
+  line_adaptor_utf(shapeObj *shape,int utfres_in):line_adaptor(shape)
   {
     utfresolution = utfres_in;
   }
@@ -152,8 +152,8 @@ class line_adaptor_utf:public line_adaptor
     }
     m_line++;
     *x = *y = 0.0;
-    if(m_line>=m_lend) 
-      return mapserver::path_cmd_stop; 
+    if(m_line>=m_lend)
+      return mapserver::path_cmd_stop;
 
     m_point=m_line->point;
     m_pend=&(m_line->point[m_line->numpoints]);
@@ -217,6 +217,24 @@ unsigned int encodeForRendering(unsigned int toencode)
   return encoded;
 }
 
+/*
+ * Decode value to have the initial one
+ */
+unsigned int decodeRendered(unsigned int todecode)
+{
+  unsigned int decoded;
+  
+  if(todecode >= 92)
+    todecode --;
+
+  if(todecode >= 34)
+    todecode --;
+
+  decoded = todecode-32;
+
+  return decoded;
+}
+
 /*
  * Allocate more memory to the table if necessary.
  */
@@ -285,8 +303,8 @@ band_type addToTable(UTFGridRenderer *r, shapeObj *p)
 /*
  * Use AGG to render any path.
  */
-template<class vertex_source> 
-int utfgridRenderPath(imageObj *img, vertex_source &path) 
+template<class vertex_source>
+int utfgridRenderPath(imageObj *img, vertex_source &path)
 {
   UTFGridRenderer *r = UTFGRID_RENDERER(img);
   r->m_rasterizer.reset();
@@ -359,6 +377,91 @@ int utfgridFreeImage(imageObj *img)
   return MS_SUCCESS;
 }
 
+/*
+ * Update a character in the utfgrid.
+*/
+
+int utfgridUpdateChar(imageObj *img, band_type oldChar, band_type newChar)
+{
+  UTFGridRenderer *r = UTFGRID_RENDERER(img);
+  int i,bufferLength;
+
+  bufferLength = (img->height/r->utfresolution) * (img->width/r->utfresolution);
+
+  for(i=0;i<bufferLength;i++){
+    if(r->buffer[i] == oldChar)
+      r->buffer[i] = newChar;
+  }
+
+  return MS_SUCCESS;
+}
+
+/*
+ * Remove unnecessary data that didn't made it to the final grid.
+ */
+
+int utfgridCleanData(imageObj *img)
+{
+  UTFGridRenderer *r = UTFGRID_RENDERER(img);
+  unsigned char* usedChar;
+  int i,bufferLength,itemFound,dataCounter;
+  shapeData* updatedData;
+  band_type utfvalue;
+
+  bufferLength = (img->height/r->utfresolution) * (img->width/r->utfresolution);
+
+  usedChar =(unsigned char*) msSmallMalloc(r->data->counter*sizeof(unsigned char));
+
+  for(i=0;i<r->data->counter;i++){
+    usedChar[i]=0;
+  }
+
+  itemFound=0;
+
+  for(i=0;i<bufferLength;i++)
+  {
+    if(decodeRendered(r->buffer[i]) != 0 && usedChar[decodeRendered(r->buffer[i])-1]==0)
+    {
+      itemFound++;
+      usedChar[decodeRendered(r->buffer[i])-1] = 1;
+    }
+  }
+
+  updatedData = (shapeData*) msSmallMalloc(itemFound * sizeof(shapeData));
+  dataCounter = 0;
+
+  for(i=0; i< r->data->counter; i++){
+    if(usedChar[decodeRendered(r->data->table[i].utfvalue)-1]==1){
+        updatedData[dataCounter] = r->data->table[i];
+
+        updatedData[dataCounter].serialid=dataCounter+1;
+
+        utfvalue=encodeForRendering(dataCounter+1);
+
+        utfgridUpdateChar(img,updatedData[dataCounter].utfvalue,utfvalue);
+        updatedData[dataCounter].utfvalue = utfvalue;
+
+      dataCounter++;
+    }
+    else {
+      if(r->data->table[i].datavalues)
+        msFree(r->data->table[i].datavalues);
+      if(r->data->table[i].itemvalue)
+        msFree(r->data->table[i].itemvalue);
+    }
+  }
+
+  msFree(usedChar);
+
+  msFree(r->data->table);
+
+  r->data->table = updatedData;
+  r->data->counter = dataCounter;
+  r->data->size = dataCounter;
+
+  return MS_SUCCESS;
+}
+
 /*
  * Print the renderer datas as a JSON.
  */
@@ -367,20 +470,22 @@ int utfgridSaveImage(imageObj *img, mapObj *map, FILE *fp, outputFormatObj *form
   int row, col, i, imgheight, imgwidth;
   band_type pixelid;
   char* pszEscaped;
- 
+
+  utfgridCleanData(img);
+
   UTFGridRenderer *renderer = UTFGRID_RENDERER(img);
 
   if(renderer->layerwatch>1)
-    return MS_FAILURE; 
+    return MS_FAILURE;
 
   imgheight = img->height/renderer->utfresolution;
   imgwidth = img->width/renderer->utfresolution;
 
   fprintf(fp,"{\"grid\":[");
 
-  /* Print the buffer, also */  
+  /* Print the buffer, also */
   for(row=0; row<imgheight; row++) {
-    
+
     wchar_t *string = (wchar_t*) msSmallMalloc ((imgwidth + 1) * sizeof(wchar_t));
     wchar_t *stringptr;
     stringptr = string;
@@ -393,11 +498,11 @@ int utfgridSaveImage(imageObj *img, mapObj *map, FILE *fp, outputFormatObj *form
       pixelid = renderer->buffer[(row*imgwidth)+col];
 
       *stringptr = pixelid;
-      stringptr++;      
+      stringptr++;
     }
 
     /* Convertion to UTF-8 encoding */
-    *stringptr = '\0';  
+    *stringptr = '\0';
     char * utf8;
     utf8 = msConvertWideStringToUTF8 (string, "UCS-4LE");
     fprintf(fp,"%s", utf8);
@@ -409,7 +514,7 @@ int utfgridSaveImage(imageObj *img, mapObj *map, FILE *fp, outputFormatObj *form
   fprintf(fp,"],\"keys\":[\"\"");
 
   /* Prints the key specified */
-  for(i=0;i<renderer->data->counter;i++) {  
+  for(i=0;i<renderer->data->counter;i++) {
       fprintf(fp,",");
 
     if(renderer->useutfitem)
@@ -504,11 +609,11 @@ int utfgridEndLayer(imageObj *img, mapObj *map, layerObj *layer)
  * Do the table operations on the shapes. Allow multiple type of data to be rendered.
  */
 int utfgridStartShape(imageObj *img, shapeObj *shape)
-{  
+{
   UTFGridRenderer *r = UTFGRID_RENDERER(img);
 
   if(!r->renderlayer)
-    return MS_FAILURE;  
+    return MS_FAILURE;
 
   /* Table operations */
   r->utfvalue = addToTable(r, shape);
@@ -521,7 +626,7 @@ int utfgridStartShape(imageObj *img, shapeObj *shape)
  */
 int utfgridEndShape(imageObj *img, shapeObj *shape)
 {
-  UTFGridRenderer *r = UTFGRID_RENDERER(img);  
+  UTFGridRenderer *r = UTFGRID_RENDERER(img);
 
   r->utfvalue = 0;
   return MS_SUCCESS;
@@ -547,7 +652,7 @@ int utfgridRenderPolygon(imageObj *img, shapeObj *polygonshape, colorObj *color)
 }
 
 /*
- * Function that render lines into UTFGrid. Starts by looking if the line is a polygon  
+ * Function that render lines into UTFGrid. Starts by looking if the line is a polygon
  * outline. Then draw it if it's not.
  */
 int utfgridRenderLine(imageObj *img, shapeObj *lineshape, strokeStyleObj *linestyle)
@@ -567,7 +672,7 @@ int utfgridRenderLine(imageObj *img, shapeObj *lineshape, strokeStyleObj *linest
   } else {
     r->stroke->attach(lines);
   }
-  r->stroke->width(linestyle->width/r->utfresolution);  
+  r->stroke->width(linestyle->width/r->utfresolution);
   utfgridRenderPath(img, *r->stroke);
 
   return MS_SUCCESS;
@@ -585,7 +690,7 @@ int utfgridRenderVectorSymbol(imageObj *img, double x, double y, symbolObj *symb
   /* utfvalue is set to 0 if the shape isn't in the table. */
   if(r->utfvalue == 0) {
     return MS_FAILURE;
-  }  
+  }
 
   /* Pathing the symbol */
   mapserver::path_storage path = imageVectorSymbol(symbol);
@@ -615,12 +720,12 @@ int utfgridRenderPixmapSymbol(imageObj *img, double x, double y, symbolObj *symb
   /* utfvalue is set to 0 if the shape isn't in the table. */
   if(r->utfvalue == 0) {
     return MS_FAILURE;
-  }  
+  }
 
   /* Pathing the symbol BBox */
   mapserver::path_storage pixmap_bbox;
   double w, h;
-  w = pixmap->width*style->scale/(2.0); 
+  w = pixmap->width*style->scale/(2.0);
   h= pixmap->height*style->scale/(2.0);
   pixmap_bbox.move_to((x-w)/r->utfresolution,(y-h)/r->utfresolution);
   pixmap_bbox.line_to((x+w)/r->utfresolution,(y-h)/r->utfresolution);
@@ -643,13 +748,13 @@ int utfgridRenderEllipseSymbol(imageObj *img, double x, double y, symbolObj *sym
   /* utfvalue is set to 0 if the shape isn't in the table. */
   if(r->utfvalue == 0) {
     return MS_FAILURE;
-  }  
+  }
 
   /* Pathing the symbol. */
   mapserver::path_storage path;
   mapserver::ellipse ellipse(x/r->utfresolution,y/r->utfresolution,symbol->sizex*style->scale/2/r->utfresolution,symbol->sizey*style->scale/2/r->utfresolution);
   path.concat_path(ellipse);
- 
+
   /* Rotation if necessary. */
   if( style->rotation != 0) {
     mapserver::trans_affine mtx;
@@ -686,7 +791,7 @@ int msPopulateRendererVTableUTFGrid( rendererVTableObj *renderer )
   renderer->saveImage = &utfgridSaveImage;
 
   renderer->startLayer = &utfgridStartLayer;
-  renderer->endLayer = &utfgridEndLayer;  
+  renderer->endLayer = &utfgridEndLayer;
 
   renderer->startShape = &utfgridStartShape;
   renderer->endShape = &utfgridEndShape;