src/livarot/AlphaLigne.cpp

   1 /*
   2  *  AlphaLigne.cpp
   3  *  nlivarot
   4  *
   5  *  Created by fred on Fri Jul 25 2003.
   6  *  public domain
   7  *
   8  */
   9
  10 #include "AlphaLigne.h"
  11 //#include "Buffer.h"
  12
  13 #include <math.h>
  14 #include <glib/gmem.h>
  15
  16 AlphaLigne::AlphaLigne(int iMin,int iMax)
  17 {
  18         min=iMin;
  19         max=iMax;
  20         if ( max < min+1 ) max=min+1;
  21         steps=NULL;
  22         nbStep=maxStep=0;
  23         before.x=min-1;
  24         before.delta=0;
  25         after.x=max+1;
  26         after.delta=0;
  27 }
  28 AlphaLigne::~AlphaLigne(void)
  29 {
  30         g_free(steps);
  31         steps=NULL;
  32         nbStep=maxStep=0;
  33 }
  34 void                                             AlphaLigne::Affiche(void)
  35 {
  36         printf("%i steps\n",nbStep);
  37         for (int i=0;i<nbStep;i++) {
  38                 printf("(%i %f) ",steps[i].x,steps[i].delta); // localization ok
  39         }
  40         printf("\n");
  41 }
  42
  43
  44 void             AlphaLigne::Reset(void)
  45 {
  46   // reset to empty line
  47   // doesn't deallocate the steps array, to minimize memory operations
  48         curMin=max;
  49         curMax=min;
  50         nbStep=0;
  51         before.x=min-1;
  52         before.delta=0;
  53         after.x=max+1;
  54         after.delta=0;
  55 }
  56 int              AlphaLigne::AddBord(float spos,float sval,float epos,float eval,float tPente)
  57 {
  58 //      printf("%f %f -> %f %f / %f\n",spos,sval,epos,eval,tPente);
  59         if ( sval == eval ) return 0;
  60   // compute the footprint of [spos,epos] on the line of pixels
  61         float  curStF=floor(spos);
  62         float  curEnF=floor(epos);
  63         int   curSt=(int)curStF;
  64         int   curEn=(int)curEnF;
  65
  66   // update curMin and curMax
  67         if ( curSt > max ) {
  68     // we're on the right of the visible portion of the line: bail out!
  69     if ( eval < sval ) curMax=max;
  70     return 0;
  71   }
  72         if ( curSt < curMin ) curMin=curSt;
  73         if ( ceil(epos) > curMax ) curMax=(int)ceil(epos);
  74
  75   // clamp the changed portion to [min,max], no need for bigger
  76         if ( curMax > max ) curMax=max;
  77         if ( curMin < min ) curMin=min;
  78
  79   // total amount of change in pixel coverage from before the right to after the run
  80         float    needed=eval-sval;
  81         float    needC=/*(int)ldexpf(*/needed/*,24)*/;
  82
  83         if ( curEn < min ) {
  84     // the added portion is entirely on the left, so we only have to change the initial coverage for the line
  85     before.delta+=needC;
  86     return 0;
  87         }
  88
  89   // add the steps
  90   // the pixels from [curSt..curEn] (included) intersect with [spos;epos]
  91   // since we're dealing with delta in the coverage, there is also a curEn+1 delta, since the curEn pixel intersect
  92   // with [spos;epos] and thus has some delta with respect to its next pixel
  93   // lots of different cases... ugly
  94         if ( curSt == curEn ) {
  95                 if ( curSt+1 < min ) {
  96                         before.delta+=needC;
  97                 } else {
  98                         if ( nbStep+2 >= maxStep ) {
  99                                 maxStep=2*nbStep+2;
 100                                 steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 101                         }
 102                         float  stC=/*(int)ldexpf(*/(eval-sval)*(0.5*(epos-spos)+curStF+1-epos)/*,24)*/;
 103                         steps[nbStep].x=curSt;
 104                         steps[nbStep].delta=stC;
 105                         nbStep++;
 106                         steps[nbStep].x=curSt+1;
 107                         steps[nbStep].delta=needC-stC; //  au final, on a toujours le bon delta, meme avec une arete completement verticale
 108                         nbStep++;
 109                 }
 110         } else if ( curEn == curSt+1 ) {
 111                 if ( curSt+2 < min ) {
 112                         before.delta+=needC;
 113                 } else {
 114                         if ( nbStep+3 >= maxStep ) {
 115                                 maxStep=2*nbStep+3;
 116                                 steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 117                         }
 118                         float  stC=/*(int)ldexpf(*/0.5*tPente*(curEnF-spos)*(curEnF-spos)/*,24)*/;
 119                         float  enC=/*(int)ldexpf(*/tPente-0.5*tPente*((spos-curStF)*(spos-curStF)+(curEnF+1.0-epos)*(curEnF+1.0-epos))/*,24)*/;
 120                         steps[nbStep].x=curSt;
 121                         steps[nbStep].delta=stC;
 122                         nbStep++;
 123                         steps[nbStep].x=curEn;
 124                         steps[nbStep].delta=enC;
 125                         nbStep++;
 126                         steps[nbStep].x=curEn+1;
 127                         steps[nbStep].delta=needC-stC-enC;
 128                         nbStep++;
 129                 }
 130         } else {
 131                 float  stC=/*(int)ldexpf(*/0.5*tPente*(curStF+1-spos)*(curStF+1-spos)/*,24)*/;
 132                 float  stFC=/*(int)ldexpf(*/tPente-0.5*tPente*(spos-curStF)*(spos-curStF)/*,24)*/;
 133                 float  enC=/*(int)ldexpf(*/tPente-0.5*tPente*(curEnF+1.0-epos)*(curEnF+1.0-epos)/*,24)*/;
 134                 float  miC=/*(int)ldexpf(*/tPente/*,24)*/;
 135                 if ( curSt < min ) {
 136                         if ( curEn > max ) {
 137                                 if ( nbStep+(max-min) >= maxStep ) {
 138                                         maxStep=2*nbStep+(max-min);
 139                                         steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 140                                 }
 141                                 float  bfd=min-curSt-1;
 142                                 bfd*=miC;
 143                                 before.delta+=stC+bfd;
 144                                 for (int i=min;i<max;i++) {
 145                                         steps[nbStep].x=i;
 146                                         steps[nbStep].delta=miC;
 147                                         nbStep++;
 148                                 }
 149                         } else {
 150                                 if ( nbStep+(curEn-min)+2 >= maxStep ) {
 151                                         maxStep=2*nbStep+(curEn-min)+2;
 152                                         steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 153                                 }
 154                                 float  bfd=min-curSt-1;
 155                                 bfd*=miC;
 156                                 before.delta+=stC+bfd;
 157                                 for (int i=min;i<curEn;i++) {
 158                                         steps[nbStep].x=i;
 159                                         steps[nbStep].delta=miC;
 160                                         nbStep++;
 161                                 }
 162                                 steps[nbStep].x=curEn;
 163                                 steps[nbStep].delta=enC;
 164                                 nbStep++;
 165                                 steps[nbStep].x=curEn+1;
 166                                 steps[nbStep].delta=needC-stC-stFC-enC-(curEn-curSt-2)*miC;
 167                                 nbStep++;
 168                         }
 169                 } else {
 170                         if ( curEn > max ) {
 171                                 if ( nbStep+3+(max-curSt) >= maxStep ) {
 172                                         maxStep=2*nbStep+3+(curEn-curSt);
 173                                         steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 174                                 }
 175                                 steps[nbStep].x=curSt;
 176                                 steps[nbStep].delta=stC;
 177                                 nbStep++;
 178                                 steps[nbStep].x=curSt+1;
 179                                 steps[nbStep].delta=stFC;
 180                                 nbStep++;
 181                                 for (int i=curSt+2;i<max;i++) {
 182                                         steps[nbStep].x=i;
 183                                         steps[nbStep].delta=miC;
 184                                         nbStep++;
 185                                 }
 186                         } else {
 187                                 if ( nbStep+3+(curEn-curSt) >= maxStep ) {
 188                                         maxStep=2*nbStep+3+(curEn-curSt);
 189                                         steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 190                                 }
 191                                 steps[nbStep].x=curSt;
 192                                 steps[nbStep].delta=stC;
 193                                 nbStep++;
 194                                 steps[nbStep].x=curSt+1;
 195                                 steps[nbStep].delta=stFC;
 196                                 nbStep++;
 197                                 for (int i=curSt+2;i<curEn;i++) {
 198                                         steps[nbStep].x=i;
 199                                         steps[nbStep].delta=miC;
 200                                         nbStep++;
 201                                 }
 202                                 steps[nbStep].x=curEn;
 203                                 steps[nbStep].delta=enC;
 204                                 nbStep++;
 205                                 steps[nbStep].x=curEn+1;
 206                                 steps[nbStep].delta=needC-stC-stFC-enC-(curEn-curSt-2)*miC;
 207                                 nbStep++;
 208                         }
 209                 }
 210         }
 211
 212         return 0;
 213 }
 214 int              AlphaLigne::AddBord(float spos,float sval,float epos,float eval)
 215 {
 216         // pas de pente dans ce cas; on ajoute le delta au premier pixel
 217         float   tPente=(eval-sval);
 218
 219         float curStF=floor(spos);
 220         float curEnF=floor(epos);
 221         int   curSt=(int)curStF;
 222         int   curEn=(int)curEnF;
 223
 224         if ( curSt > max ) {
 225     if ( eval < sval ) curMax=max;
 226     return 0; // en dehors des limites (attention a ne pas faire ca avec curEn)
 227   }
 228         if ( curEn < min ) {
 229     before.delta+=eval-sval;
 230     return 0; // en dehors des limites (attention a ne pas faire ca avec curEn)
 231         }
 232
 233         if ( curSt < curMin ) curMin=curSt;
 234 //      int   curEn=(int)curEnF;
 235         if ( ceil(epos) > curMax-1 ) curMax=1+(int)ceil(epos);
 236         if ( curSt < min ) {
 237                 before.delta+=eval-sval;
 238         } else {
 239                 AddRun(curSt,/*(int)ldexpf(*/(((float)(curSt+1))-spos)*tPente/*,24)*/);
 240                 AddRun(curSt+1,/*(int)ldexpf(*/(spos-((float)(curSt)))*tPente/*,24)*/);
 241         }
 242         return 0;
 243 }
 244
 245 void             AlphaLigne::Flatten(void)
 246 {
 247   // just sort
 248         if ( nbStep > 0 ) qsort(steps,nbStep,sizeof(alpha_step),CmpStep);
 249 }
 250 void             AlphaLigne::AddRun(int st,float pente)
 251 {
 252         if ( nbStep >= maxStep ) {
 253                 maxStep=2*nbStep+1;
 254                 steps=(alpha_step*)g_realloc(steps,maxStep*sizeof(alpha_step));
 255         }
 256         int nStep=nbStep++;
 257         steps[nStep].x=st;
 258         steps[nStep].delta=pente;
 259 }
 260
 261 void             AlphaLigne::Raster(raster_info &dest,void* color,RasterInRunFunc worker)
 262 {
 263   // start by checking if there are actually pixels in need of rasterization
 264         if ( curMax <= curMin ) return;
 265         if ( dest.endPix <= curMin || dest.startPix >= curMax ) return;
 266
 267         int    nMin=curMin,nMax=curMax;
 268         float  alpSum=before.delta; // alpSum will be the pixel coverage value, so we start at before.delta
 269         int    curStep=0;
 270
 271   // first add all the deltas up to the first pixel in need of rasterization
 272   while ( curStep < nbStep && steps[curStep].x < nMin ) {
 273     alpSum+=steps[curStep].delta;
 274     curStep++;
 275   }
 276   // just in case, if the line bounds are greater than the buffer bounds.
 277         if ( nMin < dest.startPix ) {
 278                 for (;( curStep < nbStep && steps[curStep].x < dest.startPix) ;curStep++) alpSum+=steps[curStep].delta;
 279                 nMin=dest.startPix;
 280         }
 281         if ( nMax > dest.endPix ) nMax=dest.endPix;
 282
 283   // raster!
 284         int       curPos=dest.startPix;
 285         for (;curStep<nbStep;curStep++) {
 286                 if ( alpSum > 0 && steps[curStep].x > curPos ) {
 287       // we're going to change the pixel position curPos, and alpSum is > 0: rasterization needed from
 288       // the last position (curPos) up to the pixel we're moving to (steps[curStep].x)
 289                         int  nst=curPos,nen=steps[curStep].x;
 290 //Buffer::RasterRun(dest,color,nst,alpSum,nen,alpSum);
 291       (worker)(dest,color,nst,alpSum,nen,alpSum);
 292                 }
 293     // add coverage deltas
 294                 alpSum+=steps[curStep].delta;
 295                 curPos=steps[curStep].x;
 296                 if ( curPos >= nMax ) break;
 297         }
 298   // if we ended the line with alpSum > 0, we need to raster from curPos to the right edge
 299         if ( alpSum > 0 && curPos < nMax ) {
 300                 int  nst=curPos,nen=max;
 301     (worker)(dest,color,nst,alpSum,nen,alpSum);
 302 //Buffer::RasterRun(dest,color,nst,alpSum,nen,alpSum);
 303         }
 304 }