<?php
if ( ! defined( 'ABSPATH' ) ) {
	die( 'You are not allowed to call this page directly.' );
}

/**
 *  Signature to Image: A supplemental script for Signature Pad that
 *  generates an image of the signature’s JSON output server-side using PHP.
 *
 *  @project    ca.thomasjbradley.applications.signaturetoimage
 *  @author     Thomas J Bradley <hey@thomasjbradley.ca>
 *  @link       http://thomasjbradley.ca/lab/signature-to-image
 *  @link       http://github.com/thomasjbradley/signature-to-image
 *  @copyright  Copyright MMXI–, Thomas J Bradley
 *  @license    New BSD License
 *  @version    1.0.1
 */

/**
 *  Accepts a signature created by signature pad in Json format
 *  Converts it to an image resource
 *  The image resource can then be changed into png, jpg whatever PHP GD supports
 *
 *  To create a nicely anti-aliased graphic the signature is drawn 12 times it's original size then shrunken
 *
 *  @param  string|array $json
 *  @param  array        $options    OPTIONAL; the options for image creation
 *           imageSize => array(width, height)
 *           bgColour => array(red, green, blue)
 *           penWidth => int
 *           penColour => array(red, green, blue)
 *
 *  @deprecated 3.0
 *
 *  @return object
 */
function sigJsonToImage( $json, $options = array() ) {
	_deprecated_function( __FUNCTION__, '3.0' );

	$defaultOptions = array(
		'imageSize'      => array( 400, 150 ),
		'bgColour'       => array( 0xff, 0xff, 0xff ),
		'penWidth'       => 2,
		'penColour'      => array( 0x14, 0x53, 0x94 ),
		'drawMultiplier' => 12,
	);

	$options = array_merge( $defaultOptions, $options );

	$img = imagecreatetruecolor( $options['imageSize'][0] * $options['drawMultiplier'], $options['imageSize'][1] * $options['drawMultiplier'] );

	if ( $options['bgColour'] == 'transparent' ) {
		imagesavealpha( $img, true );
		$bg = imagecolorallocatealpha( $img, 0, 0, 0, 127 );
	} else {
		$bg = imagecolorallocate( $img, $options['bgColour'][0], $options['bgColour'][1], $options['bgColour'][2] );
	}

	$pen = imagecolorallocate( $img, $options['penColour'][0], $options['penColour'][1], $options['penColour'][2] );
	imagefill( $img, 0, 0, $bg );

	if ( is_string( $json ) ) {
		$json = json_decode( stripslashes( $json ) );
	}

	foreach ( $json as $v ) {
		drawThickLine( $img, $v->lx * $options['drawMultiplier'], $v->ly * $options['drawMultiplier'], $v->mx * $options['drawMultiplier'], $v->my * $options['drawMultiplier'], $pen, $options['penWidth'] * ( $options['drawMultiplier'] / 2 ) );
	}

	$imgDest = imagecreatetruecolor( $options['imageSize'][0], $options['imageSize'][1] );

	if ( $options['bgColour'] == 'transparent' ) {
		imagealphablending( $imgDest, false );
		imagesavealpha( $imgDest, true );
	}

	imagecopyresampled( $imgDest, $img, 0, 0, 0, 0, $options['imageSize'][0], $options['imageSize'][0], $options['imageSize'][0] * $options['drawMultiplier'], $options['imageSize'][0] * $options['drawMultiplier'] );
	imagedestroy( $img );

	return $imgDest;
}

/**
 *  Draws a thick line
 *  Changing the thickness of a line using imagesetthickness doesn't produce as nice of result
 *
 *  @param  object $img
 *  @param  int    $startX
 *  @param  int    $startY
 *  @param  int    $endX
 *  @param  int    $endY
 *  @param  object $colour
 *  @param  int    $thickness
 *
 *  @deprecated 3.0
 *
 *  @return void
 */
function drawThickLine( $img, $startX, $startY, $endX, $endY, $colour, $thickness ) {
	_deprecated_function( __FUNCTION__, '3.0' );

	$angle = ( atan2( ( $startY - $endY ), ( $endX - $startX ) ) );

	$dist_x = $thickness * ( sin( $angle ) );
	$dist_y = $thickness * ( cos( $angle ) );

	$p1x = ceil( ( $startX + $dist_x ) );
	$p1y = ceil( ( $startY + $dist_y ) );
	$p2x = ceil( ( $endX + $dist_x ) );
	$p2y = ceil( ( $endY + $dist_y ) );
	$p3x = ceil( ( $endX - $dist_x ) );
	$p3y = ceil( ( $endY - $dist_y ) );
	$p4x = ceil( ( $startX - $dist_x ) );
	$p4y = ceil( ( $startY - $dist_y ) );

	$array = array(
		0 => $p1x,
		$p1y,
		$p2x,
		$p2y,
		$p3x,
		$p3y,
		$p4x,
		$p4y,
	);
	imagefilledpolygon( $img, $array, ( count( $array ) / 2 ), $colour );
}