Move thumbnail code to dedicated class

This also moves the code from mfile->image_dimension() to the only
place where it was called.

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 169 insertions, 0 deletions

diff --git a/application/libraries/Imglib.php b/application/libraries/Imglib.php
new file mode 100644
index 000000000..4d6de21d3
--- /dev/null
+++ b/application/libraries/Imglib.php
@@ -0,0 +1,169 @@
+<?php
+/*
+ * Copyright 2014 Florian "Bluewind" Pritz <bluewind@server-speed.net>
+ *
+ * Licensed under AGPLv3
+ * (see COPYING for full license text)
+ *
+ */
+
+class Imglib {
+	/*
+	 * This returns a square thumbnail for the input image
+	 * Source: http://salman-w.blogspot.co.at/2009/04/crop-to-fit-image-using-aspphp.html
+	 */
+	public function makeThumb($file, $size = 150, $target_type = null)
+	{
+		$source_gdim = imagecreatefromstring(file_get_contents($file));
+		if ($source_gdim === false) {
+			show_error("Unsupported image type");
+		}
+		imagealphablending($source_gdim,false);
+		imagesavealpha($source_gdim,true);
+
+		list($source_width, $source_height, $source_type) = getimagesize($file);
+
+		if ($target_type === null) {
+			$target_type = $source_type;
+		}
+
+		$target_width = $size;
+		$target_height = $size;
+
+		$source_aspect_ratio = $source_width / $source_height;
+		$desired_aspect_ratio = $target_width / $target_height;
+
+		if ($source_aspect_ratio > $desired_aspect_ratio) {
+			// Triggered when source image is wider
+			$temp_height = $target_height;
+			$temp_width = round(($target_height * $source_aspect_ratio));
+		} else {
+			// Triggered otherwise (i.e. source image is similar or taller)
+			$temp_width = $target_width;
+			$temp_height = round(($target_width / $source_aspect_ratio));
+		}
+
+		/*
+		 * Resize the image into a temporary GD image
+		 */
+
+		$temp_gdim = imagecreatetruecolor($temp_width, $temp_height);
+		imagealphablending($temp_gdim,false);
+		imagesavealpha($temp_gdim,true);
+		imagecopyresampled(
+			$temp_gdim,
+			$source_gdim,
+			0, 0,
+			0, 0,
+			$temp_width, $temp_height,
+			$source_width, $source_height
+		);
+
+		/*
+		 * Copy cropped region from temporary image into the desired GD image
+		 */
+
+		$x0 = ($temp_width - $target_width) / 2;
+		$y0 = ($temp_height - $target_height) / 2;
+		$thumb = imagecreatetruecolor($target_width, $target_height);
+		imagealphablending($thumb,false);
+		imagesavealpha($thumb,true);
+		imagecopy(
+			$thumb,
+			$temp_gdim,
+			0, 0,
+			$x0, $y0,
+			$target_width, $target_height
+		);
+
+		/*
+		 * Fix orientation according to exif tag
+		 */
+		try {
+			$exif = exif_read_data($file);
+		} catch (ErrorException $e) {
+		}
+
+		if (isset($exif['Orientation'])) {
+			$mirror = false;
+			$deg    = 0;
+
+			switch ($exif['Orientation']) {
+			case 2:
+				$mirror = true;
+				break;
+			case 3:
+				$deg = 180;
+				break;
+			case 4:
+				$deg = 180;
+				$mirror = true;
+				break;
+			case 5:
+				$deg = 270;
+				$mirror = true;
+				break;
+			case 6:
+				$deg = 270;
+				break;
+			case 7:
+				$deg = 90;
+				$mirror = true;
+				break;
+			case 8:
+				$deg = 90;
+				break;
+			}
+			if ($deg) $thumb = imagerotate($thumb, $deg, 0);
+			if ($mirror) $thumb = $this->_mirrorImage($thumb);
+		}
+
+		ob_start();
+		switch ($target_type) {
+			case IMAGETYPE_GIF:
+				$ret = imagegif($thumb);
+				break;
+			case IMAGETYPE_JPEG:
+				$ret = imagejpeg($thumb);
+				break;
+			case IMAGETYPE_PNG:
+				$ret = imagepng($thumb);
+				break;
+			default:
+				assert(0);
+		}
+		$result = ob_get_clean();
+
+		if (!$ret) {
+			show_error("Failed to create thumbnail");
+		}
+
+		imagedestroy($thumb);
+		imagedestroy($temp_gdim);
+		imagedestroy($source_gdim);
+
+		return $result;
+	}
+
+	private function _mirrorImage($imgsrc)
+	{
+		$width = imagesx($imgsrc);
+		$height = imagesy($imgsrc);
+
+		$src_x = $width -1;
+		$src_y = 0;
+		$src_width = -$width;
+		$src_height = $height;
+
+		$imgdest = imagecreatetruecolor($width, $height);
+		imagealphablending($imgdest,false);
+		imagesavealpha($imgdest,true);
+
+		if (imagecopyresampled($imgdest, $imgsrc, 0, 0, $src_x, $src_y, $width, $height, $src_width, $src_height)) {
+			return $imgdest;
+		}
+
+		return $imgsrc;
+	}
+
+}