Add tilecache before smartcrop to avoid over-computation

docs/changelog.md

@@ -22,6 +22,10 @@ Requires libvips v8.6.0.
   [#977](https://github.com/lovell/sharp/pull/977)
   [@jardakotesovec](https://github.com/jardakotesovec)
 
+* Add tilecache before smartcrop to avoid over-computation of previous operations.
+  [#1028](https://github.com/lovell/sharp/issues/1028)
+  [@coffeebite](https://github.com/coffeebite)
+
 * TIFF output: switch default predictor from 'none' to 'horizontal' to match libvips' behaviour.
 
 ### v0.18 - "*ridge*"

src/operations.cc

@@ -267,23 +267,6 @@ namespace sharp {
     }
   }
 
-  /*
-    Insert a tile cache to prevent over-computation of any previous operations in the pipeline
-  */
-  VImage TileCache(VImage image, double const factor) {
-    int tile_width;
-    int tile_height;
-    int scanline_count;
-    vips_get_tile_size(image.get_image(), &tile_width, &tile_height, &scanline_count);
-    double const need_lines = 1.2 * scanline_count / factor;
-    return image.tilecache(VImage::option()
-      ->set("tile_width", image.width())
-      ->set("tile_height", 10)
-      ->set("max_tiles", static_cast<int>(round(1.0 + need_lines / 10.0)))
-      ->set("access", VIPS_ACCESS_SEQUENTIAL)
-      ->set("threaded", TRUE));
-  }
-
   VImage Threshold(VImage image, double const threshold, bool const thresholdGrayscale) {
     if (!thresholdGrayscale) {
       return image >= threshold;

src/operations.h

@@ -72,11 +72,6 @@ namespace sharp {
    */
   VImage Sharpen(VImage image, double const sigma, double const flat, double const jagged);
 
-  /*
-    Insert a tile cache to prevent over-computation of any previous operations in the pipeline
-  */
-  VImage TileCache(VImage image, double const factor);
-
   /*
     Threshold an image
   */

src/pipeline.cc

@@ -466,6 +466,9 @@ class PipelineWorker : public Nan::AsyncWorker {
             image = image.extract_area(left, top, width, height);
           } else {
             // Attention-based or Entropy-based crop
+            image = image.tilecache(VImage::option()
+              ->set("access", baton->accessMethod)
+              ->set("threaded", TRUE));
             image = image.smartcrop(baton->width, baton->height, VImage::option()
               ->set("interesting", baton->crop == 16 ? VIPS_INTERESTING_ENTROPY : VIPS_INTERESTING_ATTENTION));
             baton->hasCropOffset = true;