Added getWaveformData() method and $soxCommand configuration

Author: maximal

Waveform.php

@@ -3,6 +3,7 @@
  *
  *
  * @author MaximAL
+ * @since 2018-10-22 Added `getWaveformData()` method and `$soxCommand` configuration
  * @since 2016-11-21
  * @date 2016-11-21
  * @time 19:08
@@ -31,6 +32,9 @@ class Waveform
 	public static $backgroundColor = [245, 245, 245, 1];
 	public static $axisColor = [0, 0, 0, 0.1];
 
+	// SoX command: 'sox', '/usr/local/bin/sox' etc
+	public static $soxCommand = 'sox';
+
 
 	public function __construct($filename)
 	{
@@ -41,7 +45,7 @@ public function getInfo()
 	{
 		$out = null;
 		$ret = null;
-		exec('sox --i ' . escapeshellarg($this->filename) . ' 2>&1', $out, $ret);
+		exec(self::$soxCommand . ' --i ' . escapeshellarg($this->filename) . ' 2>&1', $out, $ret);
 		$str = implode('|', $out);
 
 		$match = null;
@@ -100,8 +104,58 @@ public function getDuration()
 		return $this->duration;
 	}
 
-
 	public function getWaveform($filename, $width, $height)
+	{
+		// Calculating parameters
+		$needChannels = $this->getChannels() > 1 ? 2 : 1;
+		$data = $this->getWaveformData($width);
+		$lines1 = $data['lines1'];
+		$lines2 = $data['lines2'];
+
+		// Creating image
+		$img = imagecreatetruecolor($width, $height);
+		imagesavealpha($img, true);
+		//if (function_exists('imageantialias')) {
+		//	imageantialias($img, true);
+		//}
+
+		// Colors
+		$back = self::rgbaToColor($img, self::$backgroundColor);
+		$color = self::rgbaToColor($img, self::$color);
+		$axis = self::rgbaToColor($img, self::$axisColor);
+		imagefill($img, 0, 0, $back);
+
+		// Center Ys
+		$center1 = $needChannels === 2 ? ($height / 2 - 1) / 2 : $height / 2;
+		$center2 = $needChannels === 2 ? $height - $center1 : null;
+
+		// Drawing channel 1
+		for ($i = 0; $i < count($lines1); $i += 2) {
+			$min = $lines1[$i];
+			$max = $lines1[$i+1];
+			$x = $i / 2 / self::$linesPerPixel;
+
+			imageline($img, $x, $center1 - $min * $center1, $x, $center1 - $max * $center1, $color);
+		}
+		// Drawing channel 2
+		for ($i = 0; $i < count($lines2); $i += 2) {
+			$min = $lines2[$i];
+			$max = $lines2[$i + 1];
+			$x = $i / 2 / self::$linesPerPixel;
+
+			imageline($img, $x, $center2 - $min * $center1, $x, $center2 - $max * $center1, $color);
+		}
+
+		// Axis
+		imageline($img, 0, $center1, $width - 1, $center1, $axis);
+		if ($center2 !== null) {
+			imageline($img, 0, $center2, $width - 1, $center2, $axis);
+		}
+
+		return imagepng($img, $filename);
+	}
+
+	public function getWaveformData($width)
 	{
 		// Calculating parameters
 		$needChannels = $this->getChannels() > 1 ? 2 : 1;
@@ -113,7 +167,7 @@ public function getWaveform($filename, $width, $height)
 		//}
 
 		// Command text
-		$command = 'sox ' . escapeshellarg($this->filename) .
+		$command = self::$soxCommand . ' ' . escapeshellarg($this->filename) .
 			' -c ' . $needChannels .
 			' -r ' . $needRate . ' -e floating-point -t raw -';
 
@@ -126,7 +180,7 @@ public function getWaveform($filename, $width, $height)
 		$pipes = null;
 		$proc = proc_open($command, $outputs, $pipes);
 		if (!$proc) {
-			throw new \Exception('Failed to run sox command');
+			throw new \Exception('Failed to run `sox` command');
 		}
 
 		$lines1 = [];
@@ -157,47 +211,7 @@ public function getWaveform($filename, $width, $height)
 			throw new \Exception('Failed to run `sox` command. Error:' . PHP_EOL . $err);
 		}
 
-		// Creating image
-		$img = imagecreatetruecolor($width, $height);
-		imagesavealpha($img, true);
-		//if (function_exists('imageantialias')) {
-		//	imageantialias($img, true);
-		//}
-
-		// Colors
-		$back = self::rgbaToColor($img, self::$backgroundColor);
-		$color = self::rgbaToColor($img, self::$color);
-		$axis = self::rgbaToColor($img, self::$axisColor);
-		imagefill($img, 0, 0, $back);
-
-		// Center Ys
-		$center1 = $needChannels === 2 ? ($height / 2 - 1) / 2 : $height / 2;
-		$center2 = $needChannels === 2 ? $height - $center1 : null;
-
-		// Drawing channel 1
-		for ($i = 0; $i < count($lines1); $i += 2) {
-			$min = $lines1[$i];
-			$max = $lines1[$i+1];
-			$x = $i / 2 / self::$linesPerPixel;
-
-			imageline($img, $x, $center1 - $min * $center1, $x, $center1 - $max * $center1, $color);
-		}
-		// Drawing channel 2
-		for ($i = 0; $i < count($lines2); $i += 2) {
-			$min = $lines2[$i];
-			$max = $lines2[$i + 1];
-			$x = $i / 2 / self::$linesPerPixel;
-
-			imageline($img, $x, $center2 - $min * $center1, $x, $center2 - $max * $center1, $color);
-		}
-
-		// Axis
-		imageline($img, 0, $center1, $width - 1, $center1, $axis);
-		if ($center2 !== null) {
-			imageline($img, 0, $center2, $width - 1, $center2, $axis);
-		}
-
-		return imagepng($img, $filename);
+		return ['lines1' => $lines1, 'lines2' => $lines2];
 	}
 
 	public static function rgbaToColor($img, $rgba)

readme.md

@@ -103,6 +103,20 @@ $success = $waveform->getWaveform('thumbnail.png', 1024, 512);
    By default they are WAV, MP3 and OGG files.
 
 
+## Integration with other libraries (e.g. wavesurfer.js)
+
+`Waveform` class has `getWaveformData()` method for retrieving the waveform data without generating the image.
+You can use it to integrate with different libraries, for instance, with the great
+[wavesurfer.js](https://wavesurfer-js.org/).
+
+```php
+$waveform = new Waveform('track.mp3');
+$width = 1024;
+$data = $waveform->getWaveformData($width);
+// $data['lines1'] and $data['lines2'] now have the waveform data for channels 1 and 2
+```
+
+
 ## Contact the author
 
  * Website: https://maximals.ru (Russian)