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<?php

/**
 * MvcCore
 *
 * This source file is subject to the BSD 3 License
 * For the full copyright and license information, please view
 * the LICENSE.md file that are distributed with this source code.
 *
 * @copyright   Copyright (c) 2016 Tom Flidr (https://github.com/mvccore)
 * @license     https://mvccore.github.io/docs/mvccore/5.0.0/LICENCE.md
 */

namespace MvcCore\Ext\Tools\Images\Gds;

class RoundCorners {

    /**
     * @param  resource $img
     * @param  float    $x
     * @param  float    $y
     * @return void
     */
    public static function Process ($img, $x, $y) {
        $x *= 2;
        $y *= 2;

        // Get sizes and set up new picture
        $w = imagesx($img);
        $h = imagesy($img);

        // create mask image
        $maskImg = imagecreatetruecolor($w, $h);
        $maskWhite = imagecolorallocate($maskImg, 255, 255, 255);

        // mask corners
        $xHalf = $x / 2;
        $yHalf = $y / 2;
        $fix = 1;
        // mask - top left corner
        imagefilledellipse($maskImg, $xHalf, $yHalf, $x, $y, $maskWhite);
        // mask - top right corner
        imagefilledellipse($maskImg, $w - $xHalf - $fix, $yHalf, $x, $y, $maskWhite);
        // mask - bottom left corner
        imagefilledellipse($maskImg, $xHalf, $h - $yHalf - $fix, $x, $y, $maskWhite);
        // mask - bottom right corner
        imagefilledellipse($maskImg, $w - $xHalf - $fix, $h - $yHalf - $fix, $x, $y, $maskWhite);
        // mask - center fills
        $points = [
            $xHalf, 0,
            $w - $xHalf - $fix, 0,
            $w, $yHalf,
            $w, $h - $yHalf - $fix,
            $w - $xHalf - $fix, $h,
            $xHalf, $h,
            0, $h - $yHalf - $fix,
            0, $yHalf
        ];
        imagefilledpolygon($maskImg, $points, 8, $maskWhite);

        // create new result image
        $newImg = imagecreatetruecolor($w, $h);
        imagesavealpha($newImg, TRUE);
        imagefill(
            $newImg, 0, 0,
            imagecolorallocatealpha($newImg, 0, 0, 0, 127)
        );

        // copy flat places into new image
        imagecopy($newImg, $img, $xHalf, 0, $xHalf, 0, $w - $x, $yHalf);
        imagecopy($newImg, $img, 0, $yHalf, 0, $yHalf, $w, $h - $y);
        imagecopy($newImg, $img, $xHalf, $h - $yHalf, $xHalf, $h - $yHalf, $w - $x, $yHalf);

        // top left corner
        self::copyCornerWithMask($img, $maskImg, $newImg, 0, 0, $xHalf, $yHalf);
        self::copyCornerWithMask($img, $maskImg, $newImg, $w - $xHalf, 0, $w, $yHalf);
        self::copyCornerWithMask($img, $maskImg, $newImg, 0, $h - $yHalf, $xHalf, $h);
        self::copyCornerWithMask($img, $maskImg, $newImg, $w - $xHalf, $h - $yHalf, $w, $h);

        imagedestroy($img);
        $img = $newImg;

        imagedestroy($maskImg);
    }

    protected static function copyCornerWithMask (
        $img, $maskImg, $newImg,
        $x, $y, $w, $h
    ) {
        for ($i = $x; $i < $w; $i += 1) {
            for ($j = $y; $j < $h; $j += 1) {
                $rgba = imagecolorsforindex(
                    $maskImg, imagecolorat($maskImg, $i, $j)
                );
                $whiteRatio = (
                    $rgba['red'] + $rgba['green'] + $rgba['blue']
                ) / 765;
                $alpha = 127 - round(127 * $whiteRatio);
                $color = imagecolorsforindex(
                    $img, imagecolorat($img, $i, $j)
                );
                imagesetpixel(
                    $newImg,
                    $i, $j,
                    imagecolorallocatealpha(
                        $newImg,
                        $color['red'],
                        $color['green'],
                        $color['blue'],
                        $alpha
                    )
                );
            }
        }
    }
}