Fix image resampling bug when outside grid limits (#85)

Author: tbonfort

include/mapcache.h

@@ -889,7 +889,7 @@ mapcache_image* mapcache_image_create_with_data(mapcache_context *ctx, int width
 void mapcache_image_copy_resampled_nearest(mapcache_context *ctx, mapcache_image *src, mapcache_image *dst,
     double off_x, double off_y, double scale_x, double scale_y);
 void mapcache_image_copy_resampled_bilinear(mapcache_context *ctx, mapcache_image *src, mapcache_image *dst,
-    double off_x, double off_y, double scale_x, double scale_y);
+    double off_x, double off_y, double scale_x, double scale_y, int reflect_edges);
 
 
 /**

lib/image.c

@@ -233,7 +233,7 @@ void mapcache_image_copy_resampled_nearest(mapcache_context *ctx, mapcache_image
 }
 
 void mapcache_image_copy_resampled_bilinear(mapcache_context *ctx, mapcache_image *src, mapcache_image *dst,
-    double off_x, double off_y, double scale_x, double scale_y)
+    double off_x, double off_y, double scale_x, double scale_y, int reflect_edges)
 {
 #ifdef USE_PIXMAN
   pixman_image_t *si = pixman_image_create_bits(PIXMAN_a8r8g8b8,src->w,src->h,
@@ -244,7 +244,9 @@ void mapcache_image_copy_resampled_bilinear(mapcache_context *ctx, mapcache_imag
   pixman_transform_init_translate(&transform,pixman_double_to_fixed(-off_x),pixman_double_to_fixed(-off_y));
   pixman_transform_scale(&transform,NULL,pixman_double_to_fixed(1.0/scale_x),pixman_double_to_fixed(1.0/scale_y));
   pixman_image_set_transform (si, &transform);
-  pixman_image_set_repeat (si, PIXMAN_REPEAT_REFLECT);
+  if(reflect_edges) {
+    pixman_image_set_repeat (si, PIXMAN_REPEAT_REFLECT);
+  }
   pixman_image_set_filter(si,PIXMAN_FILTER_BILINEAR, NULL, 0);
   pixman_image_composite (PIXMAN_OP_OVER, si, NULL, bi,
                           0, 0, 0, 0, 0, 0, dst->w,dst->h);

lib/tileset.c

@@ -340,7 +340,7 @@ mapcache_image* mapcache_tileset_assemble_map_tiles(mapcache_context *ctx, mapca
   } else {
     switch(mode) {
       case MAPCACHE_RESAMPLE_BILINEAR:
-        mapcache_image_copy_resampled_bilinear(ctx,srcimage,image,dstminx,dstminy,hf,vf);
+        mapcache_image_copy_resampled_bilinear(ctx,srcimage,image,dstminx,dstminy,hf,vf,0);
         break;
       default:
         mapcache_image_copy_resampled_nearest(ctx,srcimage,image,dstminx,dstminy,hf,vf);
@@ -691,7 +691,7 @@ void mapcache_tileset_assemble_out_of_zoom_tile(mapcache_context *ctx, mapcache_
      * ctx->log(ctx, MAPCACHE_DEBUG, "factor: %g. start: %g,%g (im size: %g)",scalefactor,dstminx,dstminy,scalefactor*256);
      */
     if(scalefactor <= tile->grid_link->grid->tile_sx/2) /*FIXME: might fail for non-square tiles, also check tile_sy */
-      mapcache_image_copy_resampled_bilinear(ctx,childtile->raw_image,tile->raw_image,dstminx,dstminy,scalefactor,scalefactor);
+      mapcache_image_copy_resampled_bilinear(ctx,childtile->raw_image,tile->raw_image,dstminx,dstminy,scalefactor,scalefactor,1);
     else {
       /* no use going through bilinear resampling if the requested scalefactor maps less than 4 pixels onto the
       * resulting tile, plus pixman has some rounding bugs in this case, see