From 2d91824d0ca83d0a5f6cf03cc10c51c41cef19f4 Mon Sep 17 00:00:00 2001
From: Luke Page <luke.a.page@gmail.com>
Date: Sat, 1 Aug 2015 22:53:29 +0100
Subject: [PATCH] Support for 16 bit

---
 lib/bitmapper.js | 31 +++++++++++++++++++++----------
 lib/filter.js    |  2 +-
 lib/parser.js    | 10 ++--------
 test/test.js     |  3 +--
 4 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/lib/bitmapper.js b/lib/bitmapper.js
index 924dada..af6dc98 100644
--- a/lib/bitmapper.js
+++ b/lib/bitmapper.js
@@ -9,9 +9,12 @@ function bitRetriever(data, depth) {
       default:
         throw new Error("unrecognised depth");
         break;
-/*      case 8:
+      case 16:
+        var byte2 = data[i];
+        i++;
+        byte = Math.floor((((byte << 8) + byte2) * 255) / (Math.pow(2, 16) - 1) + 0.5);
         leftOver.push(byte);
-        break;*/
+        break;
       case 4:
         var byte2 = byte & 0x0f;
         var byte1 = byte >> 4;
@@ -39,32 +42,32 @@ function bitRetriever(data, depth) {
   }
   return {
     get: function(count) {
-      var returner;
-      if (depth === 8) {
-        returner = data.slice(i, i + count);
-        i += count;
-        return returner;
-      }
       while(leftOver.length < count) {
         split();
       }
-      returner = leftOver.slice(0, count);
+      var returner = leftOver.slice(0, count);
       leftOver = leftOver.slice(count);
       return returner;
     },
     resetAfterLine: function() {
       leftOver.length = 0;
+    },
+    end: function() {
+      if (i !== data.length) {
+        throw new Error("extra data found");
+      }
     }
   };
 }
 
 exports.dataToBitMap = function(data, width, height, bpp, depth) {
+
   if (depth !== 8) {
     var bits = bitRetriever(data, depth);
   }
   var pxData = new Buffer(width * height * 4);
   var pxPos = 0;
-  var maxBit = Math.pow(2, depth) - 1;
+  var maxBit = depth >= 8 ? 255 : (Math.pow(2, depth) - 1);
   var rawPos = 0;
   var pixelData;
 
@@ -82,12 +85,20 @@ exports.dataToBitMap = function(data, width, height, bpp, depth) {
         }
         pxPos++;
       }
+      //console.log("R", pxData[pxPos - 4], "G", pxData[pxPos - 3], "B", pxData[pxPos - 2], "A", pxData[pxPos - 1]);
       rawPos += bpp;
     }
     if (depth !== 8) {
       bits.resetAfterLine();
     }
   }
+  if (depth === 8) {
+    if (rawPos !== data.length) {
+      throw new Error("extra data found");
+    }
+  } else {
+    bits.end();
+  }
 
   return pxData;
 };
diff --git a/lib/filter.js b/lib/filter.js
index 15077f4..e5a599d 100755
--- a/lib/filter.js
+++ b/lib/filter.js
@@ -68,7 +68,7 @@ Filter.prototype._reverseFilterLine = function(rawData) {
 
     var filter = rawData[0];
 
-    var xComparison = this._depth === 8 ? this._Bpp : 1;
+    var xComparison = this._depth >= 8 ? ((this._depth === 16) ? this._Bpp * 2 : this._Bpp) : 1;
     var xBiggerThan = xComparison - 1;
 
     for (var x = 0; x < this._byteWidth; x++) {
diff --git a/lib/parser.js b/lib/parser.js
index ac138ef..a20d14c 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -164,7 +164,7 @@ Parser.prototype._parseIHDR = function(data) {
   //     'compr', compr, 'filter', filter, 'interlace', interlace
   // );
 
-  if (depth !== 8 && depth !== 4 && depth !== 2 && depth !== 1) {
+  if (depth !== 8 && depth !== 4 && depth !== 2 && depth !== 1 && depth !== 16) {
     this.error(new Error('Unsupported bit depth ' + depth));
     return;
   }
@@ -312,17 +312,11 @@ Parser.prototype.reverseFiltered = function(data, depth, width, height) {
         var pxPos = pxRowPos + (x << 2),
           color = this._palette[data[pxPos]];
 
-        if (!color) {
-          console.error("data - " + data[pxPos] + " got no colour");
-          console.log("depth is ", depth);
-          return;
-        }
-
         for (var i = 0; i < 4; i++)
           data[pxPos + i] = color[i];
       }
     }
-  } else if (depth !== 8) {
+  } else if (depth < 8) {
     //console.log("adjusting");
     var pxLineLength = width << 2;
     var maxOutSample = 255;
diff --git a/test/test.js b/test/test.js
index dadd8d9..531d73e 100644
--- a/test/test.js
+++ b/test/test.js
@@ -12,8 +12,7 @@ fs.readdir(__dirname + '/in/', function(err, files) {
 
         var expectedError = false;
         if (file.match(/^x/) ||
-            file.match(/^...i/) ||// interlace
-            file.match(/^......(16)/) // 1/2/4/16 bit
+            file.match(/^...i/) // interlace
         ) {
             expectedError = true;
         }