1 files changed, 292 insertions, 0 deletions
diff --git a/lib/private/Avatar/Avatar.php b/lib/private/Avatar/Avatar.php
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+++ b/lib/private/Avatar/Avatar.php
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+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2018 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OC\Avatar;
+
+use Imagick;
+use OC\User\User;
+use OCP\Color;
+use OCP\Files\NotFoundException;
+use OCP\IAvatar;
+use OCP\IConfig;
+use Psr\Log\LoggerInterface;
+
+/**
+ * This class gets and sets users avatars.
+ */
+abstract class Avatar implements IAvatar {
+	/**
+	 * https://github.com/sebdesign/cap-height -- for 500px height
+	 * Automated check: https://codepen.io/skjnldsv/pen/PydLBK/
+	 * Noto Sans cap-height is 0.715 and we want a 200px caps height size
+	 * (0.4 letter-to-total-height ratio, 500*0.4=200), so: 200/0.715 = 280px.
+	 * Since we start from the baseline (text-anchor) we need to
+	 * shift the y axis by 100px (half the caps height): 500/2+100=350
+	 */
+	private string $svgTemplate = '<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+		<svg width="{size}" height="{size}" version="1.1" viewBox="0 0 500 500" xmlns="http://www.w3.org/2000/svg">
+			<rect width="100%" height="100%" fill="#{fill}"></rect>
+			<text x="50%" y="350" style="font-weight:normal;font-size:280px;font-family:\'Noto Sans\';text-anchor:middle;fill:#{fgFill}">{letter}</text>
+		</svg>';
+
+	public function __construct(
+		protected IConfig $config,
+		protected LoggerInterface $logger,
+	) {
+	}
+
+	/**
+	 * Returns the user display name.
+	 */
+	abstract public function getDisplayName(): string;
+
+	/**
+	 * Returns the first letter of the display name, or "?" if no name given.
+	 */
+	private function getAvatarText(): string {
+		$displayName = $this->getDisplayName();
+		if (empty($displayName) === true) {
+			return '?';
+		}
+		$firstTwoLetters = array_map(function ($namePart) {
+			return mb_strtoupper(mb_substr($namePart, 0, 1), 'UTF-8');
+		}, explode(' ', $displayName, 2));
+		return implode('', $firstTwoLetters);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function get(int $size = 64, bool $darkTheme = false) {
+		try {
+			$file = $this->getFile($size, $darkTheme);
+		} catch (NotFoundException $e) {
+			return false;
+		}
+
+		$avatar = new \OCP\Image();
+		$avatar->loadFromData($file->getContent());
+		return $avatar;
+	}
+
+	/**
+	 * {size} = 500
+	 * {fill} = hex color to fill
+	 * {letter} = Letter to display
+	 *
+	 * Generate SVG avatar
+	 *
+	 * @param int $size The requested image size in pixel
+	 * @return string
+	 *
+	 */
+	protected function getAvatarVector(string $userDisplayName, int $size, bool $darkTheme): string {
+		$fgRGB = $this->avatarBackgroundColor($userDisplayName);
+		$bgRGB = $fgRGB->alphaBlending(0.1, $darkTheme ? new Color(0, 0, 0) : new Color(255, 255, 255));
+		$fill = sprintf('%02x%02x%02x', $bgRGB->red(), $bgRGB->green(), $bgRGB->blue());
+		$fgFill = sprintf('%02x%02x%02x', $fgRGB->red(), $fgRGB->green(), $fgRGB->blue());
+		$text = $this->getAvatarText();
+		$toReplace = ['{size}', '{fill}', '{fgFill}', '{letter}'];
+		return str_replace($toReplace, [$size, $fill, $fgFill, $text], $this->svgTemplate);
+	}
+
+	/**
+	 * Select the rendering font based on the user's display name and language
+	 */
+	private function getFont(string $userDisplayName): string {
+		if (preg_match('/\p{Han}/u', $userDisplayName) === 1) {
+			switch ($this->getAvatarLanguage()) {
+				case 'zh_TW':
+					return __DIR__ . '/../../../core/fonts/NotoSansTC-Regular.ttf';
+				case 'zh_HK':
+					return __DIR__ . '/../../../core/fonts/NotoSansHK-Regular.ttf';
+				case 'ja':
+					return __DIR__ . '/../../../core/fonts/NotoSansJP-Regular.ttf';
+				case 'ko':
+					return __DIR__ . '/../../../core/fonts/NotoSansKR-Regular.ttf';
+				default:
+					return __DIR__ . '/../../../core/fonts/NotoSansSC-Regular.ttf';
+			}
+		}
+		return __DIR__ . '/../../../core/fonts/NotoSans-Regular.ttf';
+	}
+
+	/**
+	 * Generate png avatar from svg with Imagick
+	 */
+	protected function generateAvatarFromSvg(string $userDisplayName, int $size, bool $darkTheme): ?string {
+		if (!extension_loaded('imagick')) {
+			return null;
+		}
+		$formats = Imagick::queryFormats();
+		// Avatar generation breaks if RSVG format is enabled. Fall back to gd in that case
+		if (in_array('RSVG', $formats, true)) {
+			return null;
+		}
+		$text = $this->getAvatarText();
+		try {
+			$font = $this->getFont($text);
+			$svg = $this->getAvatarVector($userDisplayName, $size, $darkTheme);
+			$avatar = new Imagick();
+			$avatar->setFont($font);
+			$avatar->readImageBlob($svg);
+			$avatar->setImageFormat('png');
+			$image = new \OCP\Image();
+			$image->loadFromData((string)$avatar);
+			return $image->data();
+		} catch (\Exception $e) {
+			return null;
+		}
+	}
+
+	/**
+	 * Generate png avatar with GD
+	 * @throws \Exception when an error occurs in gd calls
+	 */
+	protected function generateAvatar(string $userDisplayName, int $size, bool $darkTheme): string {
+		$text = $this->getAvatarText();
+		$textColor = $this->avatarBackgroundColor($userDisplayName);
+		$backgroundColor = $textColor->alphaBlending(0.1, $darkTheme ? new Color(0, 0, 0) : new Color(255, 255, 255));
+
+		$im = imagecreatetruecolor($size, $size);
+		if ($im === false) {
+			throw new \Exception('Failed to create avatar image');
+		}
+		$background = imagecolorallocate(
+			$im,
+			$backgroundColor->red(),
+			$backgroundColor->green(),
+			$backgroundColor->blue()
+		);
+		$textColor = imagecolorallocate($im,
+			$textColor->red(),
+			$textColor->green(),
+			$textColor->blue()
+		);
+		if ($background === false || $textColor === false) {
+			throw new \Exception('Failed to create avatar image color');
+		}
+		imagefilledrectangle($im, 0, 0, $size, $size, $background);
+
+		$font = $this->getFont($text);
+
+		$fontSize = $size * 0.4;
+		[$x, $y] = $this->imageTTFCenter(
+			$im, $text, $font, (int)$fontSize
+		);
+
+		imagettftext($im, $fontSize, 0, $x, $y, $textColor, $font, $text);
+
+		ob_start();
+		imagepng($im);
+		$data = ob_get_contents();
+		ob_end_clean();
+
+		return $data;
+	}
+
+	/**
+	 * Calculate real image ttf center
+	 *
+	 * @param \GdImage $image
+	 * @param string $text text string
+	 * @param string $font font path
+	 * @param int $size font size
+	 * @param int $angle
+	 * @return array
+	 */
+	protected function imageTTFCenter(
+		$image,
+		string $text,
+		string $font,
+		int $size,
+		int $angle = 0,
+	): array {
+		// Image width & height
+		$xi = imagesx($image);
+		$yi = imagesy($image);
+
+		// bounding box
+		$box = imagettfbbox($size, $angle, $font, $text);
+
+		// imagettfbbox can return negative int
+		$xr = abs(max($box[2], $box[4]));
+		$yr = abs(max($box[5], $box[7]));
+
+		// calculate bottom left placement
+		$x = intval(($xi - $xr) / 2);
+		$y = intval(($yi + $yr) / 2);
+
+		return [$x, $y];
+	}
+
+
+	/**
+	 * Convert a string to an integer evenly
+	 * @param string $hash the text to parse
+	 * @param int $maximum the maximum range
+	 * @return int between 0 and $maximum
+	 */
+	private function hashToInt(string $hash, int $maximum): int {
+		$final = 0;
+		$result = [];
+
+		// Splitting evenly the string
+		for ($i = 0; $i < strlen($hash); $i++) {
+			// chars in md5 goes up to f, hex:16
+			$result[] = intval(substr($hash, $i, 1), 16) % 16;
+		}
+		// Adds up all results
+		foreach ($result as $value) {
+			$final += $value;
+		}
+		// chars in md5 goes up to f, hex:16
+		return intval($final % $maximum);
+	}
+
+	/**
+	 * @return Color Object containing r g b int in the range [0, 255]
+	 */
+	public function avatarBackgroundColor(string $hash): Color {
+		// Normalize hash
+		$hash = strtolower($hash);
+
+		// Already a md5 hash?
+		if (preg_match('/^([0-9a-f]{4}-?){8}$/', $hash, $matches) !== 1) {
+			$hash = md5($hash);
+		}
+
+		// Remove unwanted char
+		$hash = preg_replace('/[^0-9a-f]+/', '', $hash);
+
+		$red = new Color(182, 70, 157);
+		$yellow = new Color(221, 203, 85);
+		$blue = new Color(0, 130, 201); // Nextcloud blue
+
+		// Number of steps to go from a color to another
+		// 3 colors * 6 will result in 18 generated colors
+		$steps = 6;
+
+		$palette1 = Color::mixPalette($steps, $red, $yellow);
+		$palette2 = Color::mixPalette($steps, $yellow, $blue);
+		$palette3 = Color::mixPalette($steps, $blue, $red);
+
+		$finalPalette = array_merge($palette1, $palette2, $palette3);
+
+		return $finalPalette[$this->hashToInt($hash, $steps * 3)];
+	}
+
+	/**
+	 * Get the language to be used for avatar generation.
+	 * This is used to determine the font to use for the avatar text (e.g. CJK characters).
+	 */
+	protected function getAvatarLanguage(): string {
+		return $this->config->getSystemValueString('default_language', 'en');
+	}
+}