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fix thumbnail shrink-on-load

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we had the alignment check in the wrong place
This commit is contained in:
John Cupitt 2019-04-27 22:33:20 +01:00
parent 120c3b62d9
commit efadb5dc42
2 changed files with 15 additions and 14 deletions
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5
libvips/iofuncs/header.c
View File

@ -782,7 +782,8 @@ vips_image_get_offset( const VipsImage *image )
* vips_image_get_page_height: (method)
* @image: image to get from
*
* Multi-page images can have a page height. Fetch it, and sanity check it.
* Multi-page images can have a page height. Fetch it, and sanity check it. If
* page-height is not set, it defaults to the image height.
*
* Returns: the page height.
*/
@ -791,7 +792,7 @@ vips_image_get_page_height( VipsImage *image )
{
int page_height;
page_height = 0;
page_height = image->Ysize;
if( vips_image_get_typeof( image, VIPS_META_PAGE_HEIGHT ) &&
vips_image_get_int( image, VIPS_META_PAGE_HEIGHT,
&page_height ) )

24
libvips/resample/thumbnail.c
View File

@ -355,18 +355,6 @@ vips_thumbnail_calculate_shrink( VipsThumbnail *thumbnail,
*hshrink = VIPS_MAX( 1, *hshrink );
*vshrink = VIPS_MAX( 1, *vshrink );
}
/* In toilet-roll mode, we must adjust vshrink so that we exactly hit
* page_height or we'll have pixels straddling pixel boundaries.
*/
if( thumbnail->input_height > thumbnail->page_height ) {
int target_page_height = VIPS_RINT( input_height / *vshrink );
int target_image_height = target_page_height *
thumbnail->n_pages;
*vshrink = (double) input_height * thumbnail->n_pages /
target_image_height;
}
}
/* Just the common part of the shrink: the bit by which both axes must be
@ -670,6 +658,18 @@ vips_thumbnail_build( VipsObject *object )
vips_thumbnail_calculate_shrink( thumbnail,
in->Xsize, thumbnail->page_height, &hshrink, &vshrink );
/* In toilet-roll mode, we must adjust vshrink so that we exactly hit
* page_height or we'll have pixels straddling pixel boundaries.
*/
if( in->Ysize > thumbnail->page_height ) {
int target_page_height = VIPS_RINT(
thumbnail->page_height / vshrink );
int target_image_height = target_page_height *
thumbnail->n_pages;
vshrink = (double) in->Ysize / target_image_height;
}
if( vips_resize( in, &t[4], 1.0 / hshrink,
"vscale", 1.0 / vshrink,
NULL ) )