Try libvips/pyvips#148

0001-Partially-fix-for-issue-703.patch

@@ -169,12 +169,9 @@ index 1111111..2222222 100644
 
  	VipsRect s;
 
-@@ -317,10 +332,8 @@ vips_reduceh_gen( VipsRegion *out_region, void *seq,
-
- 	s.left = r->left * reduceh->hshrink;
+@@ -319,8 +334,6 @@ vips_reduceh_gen( VipsRegion *out_region, void *seq,
  	s.top = r->top;
--	s.width = r->width * reduceh->hshrink + reduceh->n_point;
-+	s.width = r->width * reduceh->hshrink + reduceh->n_point - 1;
+ 	s.width = r->width * reduceh->hshrink + reduceh->n_point;
  	s.height = r->height;
 -	if( reduceh->centre )
 -		s.width += 1;
@@ -267,14 +264,12 @@ index 1111111..2222222 100644
 
  	VipsRect s;
 
-@@ -533,20 +538,19 @@ vips_reducev_gen( VipsRegion *out_region, void *vseq,
- 	s.left = r->left;
+@@ -534,19 +539,18 @@ vips_reducev_gen( VipsRegion *out_region, void *vseq,
  	s.top = r->top * reducev->vshrink;
  	s.width = r->width;
--	s.height = r->height * reducev->vshrink + reducev->n_point;
+ 	s.height = r->height * reducev->vshrink + reducev->n_point;
 -	if( reducev->centre )
 -		s.height += 1;
-+	s.height = r->height * reducev->vshrink + reducev->n_point - 1;
  	if( vips_region_prepare( ir, &s ) )
  		return( -1 );
 
@@ -320,14 +315,12 @@ index 1111111..2222222 100644
 
  	VipsExecutor executor[MAX_PASS];
  	VipsRect s;
-@@ -646,9 +654,7 @@ vips_reducev_vector_gen( VipsRegion *out_region, void *vseq,
- 	s.left = r->left;
+@@ -647,8 +655,6 @@ vips_reducev_vector_gen( VipsRegion *out_region, void *vseq,
  	s.top = r->top * reducev->vshrink;
  	s.width = r->width;
--	s.height = r->height * reducev->vshrink + reducev->n_point;
+ 	s.height = r->height * reducev->vshrink + reducev->n_point;
 -	if( reducev->centre )
 -		s.height += 1;
-+	s.height = r->height * reducev->vshrink + reducev->n_point - 1;
  	if( vips_region_prepare( ir, &s ) )
  		return( -1 );
 

README.md

@@ -29,6 +29,9 @@ G_MESSAGES_DEBUG=all ./test-single
 
 # Generate an animated WebP image from the output of `./test-single`
 ./test-anim
+
+# https://github.com/libvips/pyvips/issues/148
+VIPS_CONCURRENCY=1 python3 test-resize.py input/radial.rgb.png
 ```
 
 See [output/](output) directory.

test-resize.py

@@ -0,0 +1,49 @@
+# https://github.com/libvips/pyvips/issues/148
+import sys
+import timeit
+import pyvips
+from PIL import Image
+
+image = sys.argv[1]
+number, repeat = 10, 3
+
+pyvips.cache_set_max_mem(0)
+im = pyvips.Image.new_from_file(image)
+print(f'\nSize: {im.width}x{im.height}')
+for scale in [8, 9.4, 16]:
+    for method, call in [
+        ('shrink', lambda im, scale: im.shrink(scale, scale)),
+        ('reduce', lambda im, scale: im.reduce(scale, scale, centre=True)),
+        ('resize', lambda im, scale: im.resize(1/scale, vscale=1/scale)),
+    ]:
+        fname = f'output/{scale}x_vips_{method}.png'
+        call(im, scale).write_to_file(fname)
+
+        time = min(timeit.repeat(
+            lambda: call(im, scale).write_to_memory(),
+            repeat=repeat, number=number)) / number
+        print(f'{fname}: {time:2.6f}s')
+
+
+im = Image.open(image)
+print(f'\nSize: {im.width}x{im.height}')
+for scale in [8, 9.4, 16]:
+    for method, call in [
+        ('reduce', lambda im, scale: im.reduce((scale, scale))),
+        ('resize', lambda im, scale:
+        im.resize((round(im.width / scale), round(im.height / scale)), Image.LANCZOS)),
+        ('resize_gap', lambda im, scale:
+        im.resize((round(im.width / scale), round(im.height / scale)),
+                  Image.LANCZOS, reducing_gap=2.0)),
+    ]:
+        try:
+            fname = f'output/{scale}x_pillow_{method}.png'
+            call(im, scale).save(fname)
+
+            time = min(timeit.repeat(
+                lambda: call(im, scale),
+                repeat=repeat, number=number)) / number
+            print(f'{fname}: {time:2.6f}s')
+        except TypeError:
+            # reduce doesn't work with float scales
+            pass

test-single-pillow.py

@@ -22,7 +22,7 @@
     elif i == 7: im = im.rotate(90, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
     elif i == 4: im = im.rotate(180, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
 
-    im.save('output-patch/Landscape_{}.jpg'.format(i))
+    im.save('output-patch/lanczos3/Landscape_{}.jpg'.format(i))
 
 for i in range(1, 9):
     im = Image.open('input/Portrait_{}.jpg'.format(i))
@@ -44,4 +44,4 @@
     elif i == 7: im = im.rotate(90, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
     elif i == 4: im = im.rotate(180, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
 
-    im.save('output-patch/Portrait_{}.jpg'.format(i))
+    im.save('output-patch/lanczos3/Portrait_{}.jpg'.format(i))