image_example.pages.inc

<?php


/**
 * @file
 * Page/form showing image styles in use.
 */

/**
 * Form for uploading and displaying an image using selected style.
 *
 * This page provides a form that allows the user to upload an image and choose
 * a style from the list of defined image styles to use when displaying the
 * the image. This serves as an example of integrating image styles with your
 * module and as a way to demonstrate that the styles and effects defined by
 * this module are available via Drupal's image handling system.
 *
 * @see theme_image_style()
 *
 * @ingroup image_example
 */
function image_example_style_form($form, &$form_state) {
    // If there is already an uploaded image display the image here.
    if ($image_fid = variable_get('image_example_image_fid', FALSE)) {
        $image = file_load($image_fid);
        $style = variable_get('image_example_style_name', 'thumbnail');
        $form['image'] = array(
            '#markup' => theme('image_example_image', array(
                'image' => $image,
                'style' => $style,
            )),
        );
    }
    // Use the #managed_file FAPI element to upload an image file.
    $form['image_example_image_fid'] = array(
        '#title' => t('Image'),
        '#type' => 'managed_file',
        '#description' => t('The uploaded image will be displayed on this page using the image style chosen below.'),
        '#default_value' => variable_get('image_example_image_fid', ''),
        '#upload_location' => 'public://image_example_images/',
    );
    // Provide a select field for choosing an image style to use when displaying
    // the image.
    $form['image_example_style_name'] = array(
        '#title' => t('Image style'),
        '#type' => 'select',
        '#description' => t('Choose an image style to use when displaying this image.'),
        // The image_style_options() function returns an array of all available
        // image styles both the key and the value of the array are the image
        // style's name. The function takes on paramater, a boolean flag
        // signifying whether or not the array should include a <none> option.
'#options' => image_style_options(TRUE),
        '#default_value' => variable_get('image_example_style_name', ''),
    );
    // Submit Button.
    $form['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Save'),
    );
    return $form;
}

/**
 * Verifies that the user supplied an image with the form..
 *
 * @ingroup image_example
 */
function image_example_style_form_validate($form, &$form_state) {
    if (!isset($form_state['values']['image_example_image_fid']) || !is_numeric($form_state['values']['image_example_image_fid'])) {
        form_set_error('image_example_image_fid', t('Please select an image to upload.'));
    }
}

/**
 * Form Builder; Display a form for uploading an image.
 *
 * @ingroup image_example
 */
function image_example_style_form_submit($form, &$form_state) {
    // When using the #managed_file form element the file is automatically
    // uploaded an saved to the {file} table. The value of the corresponding
    // form element is set to the {file}.fid of the new file.
    //
    // If fid is not 0 we have a valid file.
    if ($form_state['values']['image_example_image_fid'] != 0) {
        // The new file's status is set to 0 or temporary and in order to ensure
        // that the file is not removed after 6 hours we need to change it's status
        // to 1. Save the ID of the uploaded image for later use.
        $file = file_load($form_state['values']['image_example_image_fid']);
        $file->status = FILE_STATUS_PERMANENT;
        file_save($file);
        // When a module is managing a file, it must manage the usage count.
        // Here we increment the usage count with file_usage_add().
        file_usage_add($file, 'image_example', 'sample_image', 1);
        // Save the fid of the file so that the module can reference it later.
        variable_set('image_example_image_fid', $file->fid);
        drupal_set_message(t('The image @image_name was uploaded and saved with an ID of @fid and will be displayed using the style @style.', array(
            '@image_name' => $file->filename,
            '@fid' => $file->fid,
            '@style' => $form_state['values']['image_example_style_name'],
        )));
    }
    elseif ($form_state['values']['image_example_image_fid'] == 0) {
        // Retrieve the old file's id.
        $fid = variable_get('image_example_image_fid', FALSE);
        $file = $fid ? file_load($fid) : FALSE;
        if ($file) {
            // When a module is managing a file, it must manage the usage count.
            // Here we decrement the usage count with file_usage_delete().
            file_usage_delete($file, 'image_example', 'sample_image', 1);
            // The file_delete() function takes a file object and checks to see if
            // the file is being used by any other modules. If it is the delete
            // operation is cancelled, otherwise the file is deleted.
            file_delete($file);
        }
        // Either way the module needs to update it's reference since even if the
        // file is in use by another module and not deleted we no longer want to
        // use it.
        variable_set('image_example_image_fid', FALSE);
        drupal_set_message(t('The image @image_name was removed.', array(
            '@image_name' => $file->filename,
        )));
    }
    // Save the name of the image style chosen by the user.
    variable_set('image_example_style_name', $form_state['values']['image_example_style_name']);
}

/**
 * Theme function displays an image rendered using the specified style.
 *
 * @ingroup image_example
 */
function theme_image_example_image($variables) {
    $image = $variables['image'];
    $style = $variables['style'];
    // theme_image_style() is the primary method for displaying images using
    // one of the defined styles. The $variables array passed to the theme
    // contains the following two important values:
    // - 'style_name': the name of the image style to use when displaying the
    //   image.
    // - 'path': the $file->uri of the image to display.
    //
    // When given a style and an image path the function will first determine
    // if a derivative image already exists, in which case the existing image
    // will be displayed. If the derivative image does not already exist the
    // function returns an <img> tag with a specially crafted callback URL
    // as the src attribute for the tag. When accessed, the callback URL will
    // generate the derivative image and serve it to the browser.
    $output = theme('image_style', array(
        'style_name' => $style,
        'path' => $image->uri,
        'getsize' => FALSE,
    ));
    $output .= '<p>' . t('This image is being displayed using the image style %style_name.', array(
        '%style_name' => $style,
    )) . '</p>';
    return $output;
}