class Features {
public $has_primary_item = false; // True if "pitm" was parsed.
public $has_alpha = false; // True if an alpha "auxC" was parsed.
public $primary_item_id;
public $primary_item_features = array( // Deduced from the data below.
'width' => UNDEFINED, // In number of pixels.
'height' => UNDEFINED, // Ignores mirror and rotation.
'bit_depth' => UNDEFINED, // Likely 8, 10 or 12 bits per channel per pixel.
'num_channels' => UNDEFINED // Likely 1, 2, 3 or 4 channels:
// (1 monochrome or 3 colors) + (0 or 1 alpha)
);
public $tiles = array(); // Tile[]
public $props = array(); // Prop[]
public $dim_props = array(); // Dim_Prop[]
public $chan_props = array(); // Chan_Prop[]
/**
* Binds the width, height, bit depth and number of channels from stored internal features.
*
* @param int $target_item_id Id of the item whose features will be bound.
* @param int $tile_depth Maximum recursion to search within tile-parent relations.
* @return Status FOUND on success or NOT_FOUND on failure.
*/
private function get_item_features( $target_item_id, $tile_depth ) {
foreach ( $this->props as $prop ) {
if ( $prop->item_id != $target_item_id ) {
continue;
}
// Retrieve the width and height of the primary item if not already done.
if ( $target_item_id == $this->primary_item_id &&
( $this->primary_item_features['width'] == UNDEFINED ||
$this->primary_item_features['height'] == UNDEFINED ) ) {
foreach ( $this->dim_props as $dim_prop ) {
if ( $dim_prop->property_index != $prop->property_index ) {
continue;
}
$this->primary_item_features['width'] = $dim_prop->width;
$this->primary_item_features['height'] = $dim_prop->height;
if ( $this->primary_item_features['bit_depth'] != UNDEFINED &&
$this->primary_item_features['num_channels'] != UNDEFINED ) {
return FOUND;
}
break;
}
}
// Retrieve the bit depth and number of channels of the target item if not
// already done.
if ( $this->primary_item_features['bit_depth'] == UNDEFINED ||
$this->primary_item_features['num_channels'] == UNDEFINED ) {
foreach ( $this->chan_props as $chan_prop ) {
if ( $chan_prop->property_index != $prop->property_index ) {
continue;
}
$this->primary_item_features['bit_depth'] = $chan_prop->bit_depth;
$this->primary_item_features['num_channels'] = $chan_prop->num_channels;
if ( $this->primary_item_features['width'] != UNDEFINED &&
$this->primary_item_features['height'] != UNDEFINED ) {
return FOUND;
}
break;
}
}
}
// Check for the bit_depth and num_channels in a tile if not yet found.
if ( $tile_depth < 3 ) {
foreach ( $this->tiles as $tile ) {
if ( $tile->parent_item_id != $target_item_id ) {
continue;
}
$status = $this->get_item_features( $tile->tile_item_id, $tile_depth + 1 );
if ( $status != NOT_FOUND ) {
return $status;
}
}
}
return NOT_FOUND;
}
/**
* Finds the width, height, bit depth and number of channels of the primary item.
*
* @return Status FOUND on success or NOT_FOUND on failure.
*/
public function get_primary_item_features() {
// Nothing to do without the primary item ID.
if ( !$this->has_primary_item ) {
return NOT_FOUND;
}
// Early exit.
if ( empty( $this->dim_props ) || empty( $this->chan_props ) ) {
return NOT_FOUND;
}
$status = $this->get_item_features( $this->primary_item_id, /*tile_depth=*/ 0 );
if ( $status != FOUND ) {
return $status;
}
// "auxC" is parsed before the "ipma" properties so it is known now, if any.
if ( $this->has_alpha ) {
++$this->primary_item_features['num_channels'];
}
return FOUND;
}
}
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