Add an option to produce only a single tile

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.27.7
+
+* Add an option to produce only a single tile
+
 ## 1.27.6
 
 * Fix opportunities for integer overflow and out-of-bounds references

README.md

@@ -162,6 +162,8 @@ Parallel processing will also be automatic if the input file is in Geobuf format
  * `-ae` or `--extend-zooms-if-still-dropping`: Increase the maxzoom if features are still being dropped at that zoom level.
    The detail and simplification options that ordinarily apply only to the maximum zoom level will apply both to the originally
    specified maximum zoom and to any levels added beyond that.
+ * `-R` _zoom_`/`_x_`/`_y_ or `--one-tile=`_zoom_`/`_x_`/`_y_: Set the minzoom and maxzoom to _zoom_ and produce only
+   the single specified tile at that zoom level.
 
 ### Tile resolution
 

main.cpp

@@ -71,6 +71,7 @@ double simplification = 1;
 size_t max_tile_size = 500000;
 size_t max_tile_features = 200000;
 int cluster_distance = 0;
+long justx = -1, justy = -1;
 
 int prevent[256];
 int additional[256];
@@ -1774,6 +1775,12 @@ int read_input(std::vector<source> &sources, char *fname, int maxzoom, int minzo
 	unsigned iz = 0, ix = 0, iy = 0;
 	choose_first_zoom(file_bbox, readers, &iz, &ix, &iy, minzoom, buffer);
 
+	if (justx >= 0) {
+		iz = minzoom;
+		ix = justx;
+		iy = justy;
+	}
+
 	long long geompos = 0;
 
 	/* initial tile is 0/0/0 */
@@ -2312,6 +2319,7 @@ int main(int argc, char **argv) {
 		{"maximum-zoom", required_argument, 0, 'z'},
 		{"minimum-zoom", required_argument, 0, 'Z'},
 		{"extend-zooms-if-still-dropping", no_argument, &additional[A_EXTEND_ZOOMS], 1},
+		{"one-tile", required_argument, 0, 'R'},
 
 		{"Tile resolution", 0, 0, 0},
 		{"full-detail", required_argument, 0, 'd'},
@@ -2489,6 +2497,19 @@ int main(int argc, char **argv) {
 			minzoom = atoi(optarg);
 			break;
 
+		case 'R': {
+			unsigned z, x, y;
+			if (sscanf(optarg, "%u/%u/%u", &z, &x, &y) == 3) {
+				minzoom = z;
+				maxzoom = z;
+				justx = x;
+				justy = y;
+			} else {
+				fprintf(stderr, "--one-tile argument must be z/x/y\n");
+				exit(EXIT_FAILURE);
+			}
+		}
+
 		case 'B':
 			if (strcmp(optarg, "g") == 0) {
 				basezoom = -2;

man/tippecanoe.1

@@ -176,6 +176,9 @@ Parallel processing will also be automatic if the input file is in Geobuf format
 \fB\fC\-ae\fR or \fB\fC\-\-extend\-zooms\-if\-still\-dropping\fR: Increase the maxzoom if features are still being dropped at that zoom level.
 The detail and simplification options that ordinarily apply only to the maximum zoom level will apply both to the originally
 specified maximum zoom and to any levels added beyond that.
+.IP \(bu 2
+\fB\fC\-R\fR \fIzoom\fP\fB\fC/\fR\fIx\fP\fB\fC/\fR\fIy\fP or \fB\fC\-\-one\-tile=\fR\fIzoom\fP\fB\fC/\fR\fIx\fP\fB\fC/\fR\fIy\fP: Set the minzoom and maxzoom to \fIzoom\fP and produce only
+the single specified tile at that zoom level.
 .RE
 .SS Tile resolution
 .RS

version.hpp

@@ -1,6 +1,6 @@
 #ifndef VERSION_HPP
 #define VERSION_HPP
 
-#define VERSION "tippecanoe v1.27.6\n"
+#define VERSION "tippecanoe v1.27.7\n"
 
 #endif