Knowledge Base

iiif_get_canvases()

Description

Get an array of all the canvases for the identifier ready for JSON encoding

Parameters

Column	Type	Default	Description
$identifier	integer		IIIF identifier (this associates resources via the metadata field set as $iiif_identifier_field
$iiif_results	array		Array of ResourceSpace search results that match the $identifier, sorted
$sequencekeys	boolean	false	Get the array with each key matching the value set in the metadata field $iiif_sequence_field. By default the array will be sorted but have a 0 based index

Return

array

Location

include/api_functions.php lines 209 to 265

Definition

 
function iiif_get_canvases($identifier, $iiif_results,$sequencekeys=false)
    {
    global $rooturl,$rootimageurl;    
            
    $canvases = array();
    foreach ($iiif_results as $iiif_result)
        {
        $size = (strtolower($iiif_result["file_extension"]) != "jpg") ? "hpr" : "";
        $img_path = get_resource_path($iiif_result["ref"],true,$size,false);

        if(!file_exists($img_path))
            {
            continue;
            }
            
        $position = $iiif_result["iiif_position"];
        $canvases[$position]["@id"] = $rooturl . $identifier . "/canvas/" . $position;
        $canvases[$position]["@type"] = "sc:Canvas";
        $canvases[$position]["label"] = ($GLOBALS['position_prefix'] ?? '') . $position;
        
        // Get the size of the images
        $image_size = get_original_imagesize($iiif_result["ref"],$img_path);
        $canvases[$position]["height"] = intval($image_size[2]);
        $canvases[$position]["width"] = intval($image_size[1]);
                
        // "If the largest image�s dimensions are less than 1200 pixels on either edge, then the canvas�s dimensions should be double those of the image." - From http://iiif.io/api/presentation/2.1/#canvas
        if($image_size[1] < 1200 || $image_size[2] < 1200)
            {
            $image_size[1] = $image_size[1] * 2;
            $image_size[2] = $image_size[2] * 2;
            }
        
        $canvases[$position]["thumbnail"] = iiif_get_thumbnail($iiif_result["ref"]);
        
        // Add image (only 1 per canvas currently supported)
        $canvases[$position]["images"] = array();
        $size_info = array(
            'identifier' => $size,
            'return_height_width' => false,
        );
        $canvases[$position]["images"][] = iiif_get_image($identifier, $iiif_result["ref"], $position, $size_info);
        }
    
    if($sequencekeys)
        {
        // keep the sequence identifiers as keys so a required canvas can be accessed by sequence id
        return $canvases;
        }
    
    ksort($canvases);    
    $return=array();
    foreach($canvases as $canvas)
        {
        $return[] = $canvas;
        }
    return $return;
    }


This article was last updated 21st November 2023 21:35 Europe/London time based on the source file dated 17th November 2023 18:27 Europe/London time.