Media: Prevent image_get_intermediate_size() from returning cropped images.

When `$size` is passed to `image_get_intermediate_size()` as an array of width
and height values and an exact image size matching those values isn't available,
the function loops through the available attachment sizes and returns the
smallest image larger than the requested dimensions with the same aspect ratio.

The aspect ratio check is skipped for the 'thumbnail' size to provide a fallback
for small sizes when no other image option is available. This resulted in a poor
selection when the size requested was smaller than the 'thumbnail' dimensions
but a larger size matching the requested ratio existed.

This refactors the internals of `image_get_intermediate_size()` to ensure the
'thumbnail' size is only returned as a fallback to small sizes once all other
options have been considered, and makes the control flow easier to follow.

This also introduces a new helper function, `wp_image_matches_ratio()` for
testing whether the aspect ratios of two sets of dimensions match. This function
is also now used in `wp_calculate_image_srcset()` during the selection process.

Props flixos, joemcgill.
Fixes #34384, #34980.
Built from https://develop.svn.wordpress.org/trunk@38086


git-svn-id: http://core.svn.wordpress.org/trunk@38027 1a063a9b-81f0-0310-95a4-ce76da25c4cd
This commit is contained in:
Joe McGill 2016-07-18 02:14:29 +00:00
parent eca1a22719
commit 28a132dfee
2 changed files with 77 additions and 51 deletions

View File

@ -591,6 +591,36 @@ function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
return false;
}
/**
* Helper function to test if aspect ratios for two images match.
*
* @since 4.6.0
*
* @param int $source_width Width of the first image in pixels.
* @param int $source_height Height of the first image in pixels.
* @param int $target_width Width of the second image in pixels.
* @param int $target_height Height of the second image in pixels.
* @return bool True if aspect ratios match within 1px. False if not.
*/
function wp_image_matches_ratio( $source_width, $source_height, $target_width, $target_height ) {
/*
* To test for varying crops, we constrain the dimensions of the larger image
* to the dimensions of the smaller image and see if they match.
*/
if ( $source_width > $target_width ) {
$constrained_size = wp_constrain_dimensions( $source_width, $source_height, $target_width );
$expected_size = array( $target_width, $target_height );
} else {
$constrained_size = wp_constrain_dimensions( $target_width, $target_height, $source_width );
$expected_size = array( $source_width, $source_height );
}
// If the image dimensions are within 1px of the expected size, we consider it a match.
$matched = ( abs( $constrained_size[0] - $expected_size[0] ) <= 1 && abs( $constrained_size[1] - $expected_size[1] ) <= 1 );
return $matched;
}
/**
* Retrieves the image's intermediate size (resized) path, width, and height.
*
@ -623,64 +653,73 @@ function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
* @type string $file Image's path relative to uploads directory
* @type int $width Width of image
* @type int $height Height of image
* @type string $path Optional. Image's absolute filesystem path. Only returned if registered
* size is passed to `$size` parameter.
* @type string $url Optional. Image's URL. Only returned if registered size is passed to `$size`
* parameter.
* @type string $path Image's absolute filesystem path.
* @type string $url Image's URL.
* }
*/
function image_get_intermediate_size( $post_id, $size = 'thumbnail' ) {
if ( !is_array( $imagedata = wp_get_attachment_metadata( $post_id ) ) )
if ( ! $size || ! is_array( $imagedata = wp_get_attachment_metadata( $post_id ) ) || empty( $imagedata['sizes'] ) ) {
return false;
}
// get the best one for a specified set of dimensions
if ( is_array($size) && !empty($imagedata['sizes']) ) {
$data = array();
// Find the best match when '$size' is an array.
if ( is_array( $size ) ) {
$candidates = array();
foreach ( $imagedata['sizes'] as $_size => $data ) {
// If there's an exact match to an existing image size, short circuit.
if ( $data['width'] == $size[0] && $data['height'] == $size[1] ) {
list( $data['width'], $data['height'] ) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );
/** This filter is documented in wp-includes/media.php */
return apply_filters( 'image_get_intermediate_size', $data, $post_id, $size );
$candidates[ $data['width'] * $data['height'] ] = $data;
break;
}
// If it's not an exact match but it's at least the dimensions requested.
// If it's not an exact match, consider larger sizes with the same aspect ratio.
if ( $data['width'] >= $size[0] && $data['height'] >= $size[1] ) {
$candidates[ $data['width'] * $data['height'] ] = $_size;
// If '0' is passed to either size, we test ratios against the original file.
if ( 0 === $size[0] || 0 === $size[1] ) {
$same_ratio = wp_image_matches_ratio( $data['width'], $data['height'], $imagedata['width'], $imagedata['height'] );
} else {
$same_ratio = wp_image_matches_ratio( $data['width'], $data['height'], $size[0], $size[1] );
}
if ( $same_ratio ) {
$candidates[ $data['width'] * $data['height'] ] = $data;
}
}
}
if ( ! empty( $candidates ) ) {
// find for the smallest image not smaller than the desired size
ksort( $candidates );
foreach ( $candidates as $_size ) {
$data = $imagedata['sizes'][$_size];
// Skip images with unexpectedly divergent aspect ratios (crops)
// First, we calculate what size the original image would be if constrained to a box the size of the current image in the loop
$maybe_cropped = image_resize_dimensions($imagedata['width'], $imagedata['height'], $data['width'], $data['height'], false );
// If the size doesn't match within one pixel, then it is of a different aspect ratio, so we skip it, unless it's the thumbnail size
if ( 'thumbnail' != $_size &&
( ! $maybe_cropped
|| ( $maybe_cropped[4] != $data['width'] && $maybe_cropped[4] + 1 != $data['width'] )
|| ( $maybe_cropped[5] != $data['height'] && $maybe_cropped[5] + 1 != $data['height'] )
) ) {
continue;
}
// If we're still here, then we're going to use this size.
list( $data['width'], $data['height'] ) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );
/** This filter is documented in wp-includes/media.php */
return apply_filters( 'image_get_intermediate_size', $data, $post_id, $size );
// Sort the array by size if we have more than one candidate.
if ( 1 < count( $candidates ) ) {
ksort( $candidates );
}
$data = array_shift( $candidates );
/*
* When the size requested is smaller than the thumbnail dimensions, we
* fall back to the thumbnail size to maintain backwards compatibility with
* pre 4.6 versions of WordPress.
*/
} elseif ( ! empty( $imagedata['sizes']['thumbnail'] ) && $imagedata['sizes']['thumbnail']['width'] >= $size[0] && $imagedata['sizes']['thumbnail']['width'] >= $size[1] ) {
$data = $imagedata['sizes']['thumbnail'];
} else {
return false;
}
// Constrain the width and height attributes to the requested values.
list( $data['width'], $data['height'] ) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );
} elseif ( ! empty( $imagedata['sizes'][ $size ] ) ) {
$data = $imagedata['sizes'][ $size ];
}
if ( is_array($size) || empty($size) || empty($imagedata['sizes'][$size]) )
// If we still don't have a match at this point, return false.
if ( empty( $data ) ) {
return false;
}
$data = $imagedata['sizes'][$size];
// include the full filesystem path of the intermediate file
if ( empty($data['path']) && !empty($data['file']) ) {
$file_url = wp_get_attachment_url($post_id);
@ -1092,21 +1131,8 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
continue;
}
/**
* To check for varying crops, we calculate the expected size of the smaller
* image if the larger were constrained by the width of the smaller and then
* see if it matches what we're expecting.
*/
if ( $image_width > $image['width'] ) {
$constrained_size = wp_constrain_dimensions( $image_width, $image_height, $image['width'] );
$expected_size = array( $image['width'], $image['height'] );
} else {
$constrained_size = wp_constrain_dimensions( $image['width'], $image['height'], $image_width );
$expected_size = array( $image_width, $image_height );
}
// If the image dimensions are within 1px of the expected size, use it.
if ( abs( $constrained_size[0] - $expected_size[0] ) <= 1 && abs( $constrained_size[1] - $expected_size[1] ) <= 1 ) {
if ( wp_image_matches_ratio( $image_width, $image_height, $image['width'], $image['height'] ) ) {
// Add the URL, descriptor, and value to the sources array to be returned.
$source = array(
'url' => $image_baseurl . $image['file'],

View File

@ -4,7 +4,7 @@
*
* @global string $wp_version
*/
$wp_version = '4.6-beta3-38085';
$wp_version = '4.6-beta3-38086';
/**
* Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.