try to improve color guessing algorithm a bit

include/colors.php

@@ -1,5 +1,7 @@
 <?php
 
+require_once "lib/floIcon.php";
+
 function _resolve_htmlcolor($color) {
 	$htmlcolors = array ("aliceblue" => "#f0f8ff",
 		"antiquewhite" => "#faebd7",
@@ -278,4 +280,62 @@ function hsl2rgb($arr) {
     return array($r, $g, $B);
 }
 
+	function colorPalette($imageFile, $numColors, $granularity = 5) {
+	   $granularity = max(1, abs((int)$granularity));
+	   $colors = array();
+
+		$size = @getimagesize($imageFile);
+
+		if (strtolower($size['mime']) == 'image/vnd.microsoft.icon') {
+			$ico = new floIcon();
+			@$ico->readICO($imageFile);
+
+			if(count($ico->images)==0)
+				return null;
+			else
+				$img = @$ico->images[count($ico->images)-1]->getImageResource();
+
+		} else {
+		   $img = @imagecreatefromstring(file_get_contents($imageFile));
+		}
+
+		if (!$img) return false;
+
+	   for($x = 0; $x < $size[0]; $x += $granularity) {
+	      for($y = 0; $y < $size[1]; $y += $granularity) {
+	         $thisColor = imagecolorat($img, $x, $y);
+	         $rgb = imagecolorsforindex($img, $thisColor);
+	         $red = round(round(($rgb['red'] / 0x33)) * 0x33);
+	         $green = round(round(($rgb['green'] / 0x33)) * 0x33);
+	         $blue = round(round(($rgb['blue'] / 0x33)) * 0x33);
+	         $thisRGB = sprintf('%02X%02X%02X', $red, $green, $blue);
+	         if(array_key_exists($thisRGB, $colors)) {
+	            $colors[$thisRGB]++;
+	         } else{
+	            $colors[$thisRGB] = 1;
+	         }
+	      }
+		}
+
+	   arsort($colors);
+	   return array_slice(array_keys($colors), 0, $numColors);
+	}
+
+	function calculate_avg_color($iconFile) {
+		$palette = colorPalette($iconFile, 4, 4);
+
+		if (is_array($palette)) {
+			foreach ($palette as $p) {
+				$hsl = rgb2hsl(_color_unpack("#$p"));
+
+				if ($hsl[1] > 0.25 && $hsl[2] > 0.25 &&
+					!($hsl[0] >= 0 && $hsl[0] < 0.01 && $hsl[1] < 0.01) &&
+					!($hsl[0] >= 0 && $hsl[0] < 0.01 && $hsl[2] > 0.99)) {
+
+					return _color_pack(hsl2rgb($hsl));
+				}
+			}
+		}
+		return false;
+	}
 ?>

include/functions.php

@@ -512,47 +512,6 @@
 		}
 	}
 
-	function calculate_avg_color($iconFile) {
-
-		require_once "lib/floIcon.php";
-
-		$imgInfo = @getimagesize($iconFile);
-
-		if(strtolower($imgInfo['mime'])=='image/vnd.microsoft.icon') {
-			$ico = new floIcon();
-			@$ico->readICO($iconFile);
-			//TODO: error logging
-			if(count($ico->images)==0)
-				return null;
-			else {
-				$image = @$ico->images[count($ico->images)-1]->getImageResource();
-			}
-			$type = "ico";
-			}
-		elseif(strtolower($imgInfo['mime'])=='image/png') {
-            $image = imagecreatefrompng($iconFile);
-			$type = 'png';
-		}
-		elseif(strtolower($imgInfo['mime'])=='image/jpeg') {
-			$image = imagecreatefromjpeg($iconFile);
-			$type = 'jpg';
-		}
-		elseif(strtolower($imgInfo['mime'])=='image/gif') {
-			$image = imagecreatefromgif($iconFile);
-			$type = 'gif';
-		}
-		//TODO: error logging
-		if (is_null($image))
-			return null;
-		$width = imagesx($image);
-		$height = imagesy($image);
-		$pixel = imagecreatetruecolor(1, 1);
-		imagecopyresampled($pixel, $image, 0, 0, 0, 0, 1, 1, $width, $height);
-		$rgb = imagecolorat($pixel, 0, 0);
-		$color = imagecolorsforindex($pixel, $rgb);
-		return $color;
-	}
-
 	function print_select($id, $default, $values, $attributes = "") {
 		print "<select name=\"$id\" id=\"$id\" $attributes>";
 		foreach ($values as $v) {

include/rssfuncs.php

@@ -412,17 +412,12 @@
 				$favicon_file = ICONS_DIR . "/$feed.ico";
 
 				if (file_exists($favicon_file)) {
-					    $favicon_color = calculate_avg_color($favicon_file);
-
 						 require_once "colors.php";
 
-						 if (is_array($favicon_color))
-								$tmp = array($favicon_color['red'],
-									$favicon_color['green'],
-									$favicon_color['blue']);
+						 $favicon_color = db_escape_string($link,
+							 calculate_avg_color($favicon_file));
 
-								 $favicon_colorstring = ",favicon_avg_color = '" .
-								_color_pack($tmp) . "'";
+						 $favicon_colorstring = ",favicon_avg_color = '".$favicon_color."'";
 				}
 
 				db_query($link, "UPDATE ttrss_feeds SET favicon_last_checked = NOW() $favicon_colorstring