warn against thumbnail_image

jcupitt · jcupitt · commit 54bfa2302539 · 2020-05-03T12:31:17.000+01:00
see #1637 (comment)
diff --git a/libvips/resample/thumbnail.c b/libvips/resample/thumbnail.c
@@ -1520,7 +1520,12 @@ vips_thumbnail_image_init( VipsThumbnailImage *image )
  * * @export_profile: %gchararray, export ICC profile
  * * @intent: #VipsIntent, rendering intent
  *
- * Exacty as vips_thumbnail(), but read from an existing image.
+ * Exacty as vips_thumbnail(), but read from an existing image. 
+ *
+ * This operation
+ * is not able to exploit shrink-on-load features of image load libraries, so
+ * it can be much slower than `vips_thumbnail()` and produce poorer quality
+ * output. Only use it if you really have to.
  *
  * See also: vips_thumbnail().
  *

Original file line number	Diff line number	Diff line change
`@@ -1520,7 +1520,12 @@ vips_thumbnail_image_init( VipsThumbnailImage *image )`
`1520`	`1520`	`* * @export_profile: %gchararray, export ICC profile`
`1521`	`1521`	`* * @intent: #VipsIntent, rendering intent`
`1522`	`1522`	`*`
`1523`		`- * Exacty as vips_thumbnail(), but read from an existing image.`
	`1523`	`+ * Exacty as vips_thumbnail(), but read from an existing image.`
	`1524`	`+ *`
	`1525`	`+ * This operation`
	`1526`	`+ * is not able to exploit shrink-on-load features of image load libraries, so`
	`1527`	+ * it can be much slower than `vips_thumbnail()` and produce poorer quality
	`1528`	`+ * output. Only use it if you really have to.`
`1524`	`1529`	`*`
`1525`	`1530`	`* See also: vips_thumbnail().`
`1526`	`1531`	`*`