Interlace support

lib/bitmapper.js

@@ -1,8 +1,13 @@
+var interlaceUtils = require('./interlace');
+
 function bitRetriever(data, depth) {
 
   var leftOver = [];
   var i = 0;
   function split() {
+    if (i === data.length) {
+      throw new Error("Ran out of data");
+    }
     var byte = data[i];
     i++;
     switch(depth) {
@@ -60,36 +65,67 @@ function bitRetriever(data, depth) {
   };
 }
 
-exports.dataToBitMap = function(data, width, height, bpp, depth) {
+exports.dataToBitMap = function(data, width, height, bpp, depth, interlace) {
 
   if (depth !== 8) {
     var bits = bitRetriever(data, depth);
   }
   var pxData = new Buffer(width * height * 4);
-  var pxPos = 0;
   var maxBit = depth >= 8 ? 255 : (Math.pow(2, depth) - 1);
   var rawPos = 0;
   var pixelData;
+  var images;
+  var getPxPos;
 
-  for(var y = 0; y < height; y++) {
-    for(var x = 0; x < width; x++) {
-      if (depth !== 8) {
-        pixelData = bits.get(bpp);
-      }
-      for (var i = 0; i < 4; i++) {
-        var idx = pixelBppMap[bpp][i];
-        if (depth === 8) {
-          pxData[pxPos] = idx !== 0xff ? data[idx + rawPos] : maxBit;
-        } else {
-          pxData[pxPos] = idx !== 0xff ? pixelData[idx] : maxBit;
-        }
-        pxPos++;
-      }
-      //console.log("R", pxData[pxPos - 4], "G", pxData[pxPos - 3], "B", pxData[pxPos - 2], "A", pxData[pxPos - 1]);
-      rawPos += bpp;
+  if (interlace) {
+    images = interlaceUtils.getImagePasses(width, height);
+    getPxPos = interlaceUtils.getInterlaceIterator(width, height);
+  } else {
+    var nonInterlacedPxPos = 0;
+    getPxPos = function() {
+      var returner = nonInterlacedPxPos;
+      nonInterlacedPxPos += 4;
+      return returner;
+    };
+    images = [{width: width, height: height}];
+  }
+
+  for (var y = 0; y < height; y++) {
+    for (var x = 0; x < width; x++) {
+      pxData[(y * 4 * width) + (x * 4) + 0] = 255;
+      pxData[(y * 4 * width) + (x * 4) + 1] = 0;
+      pxData[(y * 4 * width) + (x * 4) + 2] = 0;
+      pxData[(y * 4 * width) + (x * 4) + 3] = 255;
     }
-    if (depth !== 8) {
-      bits.resetAfterLine();
+  }
+
+  for(var imageIndex = 0; imageIndex < images.length; imageIndex++) {
+    var imageWidth = images[imageIndex].width;
+    var imageHeight = images[imageIndex].height;
+    for (var y = 0; y < imageHeight; y++) {
+      for (var x = 0; x < imageWidth; x++) {
+        if (depth !== 8) {
+          pixelData = bits.get(bpp);
+        }
+        var pxPos = getPxPos(x, y, imageIndex);
+        //console.log(x,y,imageIndex, pxPos);
+        for (var i = 0; i < 4; i++) {
+          var idx = pixelBppMap[bpp][i];
+          if (depth === 8) {
+            if (i === data.length) {
+              throw new Error("Ran out of data");
+            }
+            pxData[pxPos + i] = idx !== 0xff ? data[idx + rawPos] : maxBit;
+          } else {
+            pxData[pxPos + i] = idx !== 0xff ? pixelData[idx] : maxBit;
+          }
+        }
+        //console.log("R", pxData[pxPos], "G", pxData[pxPos + 1], "B", pxData[pxPos + 2], "A", pxData[pxPos + 3]);
+        rawPos += bpp;
+      }
+      if (depth !== 8) {
+        bits.resetAfterLine();
+      }
     }
   }
   if (depth === 8) {

lib/filter-async.js

@@ -25,12 +25,12 @@ var util = require('util'),
   Filter = require('./filter');
 
 
-var FilterAsync = module.exports = function(width, height, Bpp, depth, options) {
+var FilterAsync = module.exports = function(width, height, Bpp, depth, interlace, options) {
     ChunkStream.call(this);
 
     var buffers = [];
     var that = this;
-    this._filter = new Filter(width, height, Bpp, depth, options, {
+    this._filter = new Filter(width, height, Bpp, depth, interlace, options, {
         read: this.read.bind(this),
         complete: function(width, height) {
             that.emit('complete', Buffer.concat(buffers), width, height)

lib/filter-sync.js

@@ -24,11 +24,11 @@ var SyncReader = require('./sync-reader'),
   Filter = require('./filter');
 
 
-exports.process = function(buffer, width, height, Bpp, depth, options) {
+exports.process = function(buffer, width, height, Bpp, depth, interlace, options) {
 
     var buffers = [];
     var reader = new SyncReader(buffer);
-    var filter = new Filter(width, height, Bpp, depth, options, {
+    var filter = new Filter(width, height, Bpp, depth, interlace, options, {
         read: reader.read.bind(reader),
         write: function(buffer) {
             buffers.push(buffer);

lib/filter.js

@@ -20,10 +20,17 @@
 
 'use strict';
 
-var util = require('util');
+var interlaceUtils = require('./interlace');
 
+function getByteWidth(width, bpp, depth) {
+    var byteWidth = width * bpp;
+    if (depth !== 8) {
+        byteWidth = Math.ceil(byteWidth / (8 / depth));
+    }
+    return byteWidth;
+}
 
-var Filter = module.exports = function(width, height, Bpp, depth, options, dependencies) {
+var Filter = module.exports = function(width, height, Bpp, depth, interlace, options, dependencies) {
 
     this._width = width;
     this._height = height;
@@ -31,8 +38,6 @@ var Filter = module.exports = function(width, height, Bpp, depth, options, depen
     this._depth = depth;
     this._options = options;
 
-    this._line = 0;
-
     if (!('filterType' in options) || options.filterType == -1) {
         options.filterType = [0, 1, 2, 3, 4];
     } else if (typeof options.filterType == 'number') {
@@ -51,27 +56,41 @@ var Filter = module.exports = function(width, height, Bpp, depth, options, depen
     this.write = dependencies.write;
     this.complete = dependencies.complete;
 
-    var byteWidth = this._width * this._Bpp;
-    if (this._depth !== 8) {
-        byteWidth = Math.ceil(byteWidth / (8 / this._depth));
+    this._imageIndex = 0;
+    this._images = [];
+    if (interlace) {
+        var passes = interlaceUtils.getImagePasses(width, height);
+        for(var i = 0; i < passes.length; i++) {
+            this._images.push({
+                byteWidth: getByteWidth(passes[i].width, Bpp, depth),
+                height: passes[i].height,
+                lineIndex: 0
+            });
+        }
+    } else {
+        this._images.push({
+            byteWidth: getByteWidth(width, Bpp, depth),
+            height: height,
+            lineIndex: 0
+        });
     }
-    this._byteWidth = byteWidth;
 };
 
 Filter.prototype.start = function() {
-    this.read(this._byteWidth + 1, this._reverseFilterLine.bind(this));
+    this.read(this._images[this._imageIndex].byteWidth + 1, this._reverseFilterLine.bind(this));
 };
 
 Filter.prototype._reverseFilterLine = function(rawData) {
 
-    var line = new Buffer(this._byteWidth);
+    var currentImage = this._images[this._imageIndex];
+    var line = new Buffer(currentImage.byteWidth);
 
     var filter = rawData[0];
 
     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++) {
+    for (var x = 0; x < currentImage.byteWidth; x++) {
         var rawByte = rawData[1 + x];
         switch(filter) {
             case 0:
@@ -106,14 +125,20 @@ Filter.prototype._reverseFilterLine = function(rawData) {
         //}
     }
 
-    this._line++;
-    this._lastLine = line;
     this.write(line);
 
-    if (this._line < this._height) {
-        this.read(this._byteWidth + 1, this._reverseFilterLine.bind(this));
-    } else {
+    currentImage.lineIndex++;
+    if (currentImage.lineIndex >= currentImage.height) {
         this._lastLine = null;
+        this._imageIndex++;
+        currentImage = this._images[this._imageIndex];
+    } else {
+        this._lastLine = line;
+    }
+
+    if (currentImage) {
+        this.read(currentImage.byteWidth + 1, this._reverseFilterLine.bind(this));
+    } else {
         this.complete(this._width, this._height);
     }
 };

lib/interlace.js

@@ -0,0 +1,85 @@
+exports.getImagePasses = function(width, height) {
+  var images = [];
+  var xLeftOver = width % 8;
+  var yLeftOver = height % 8;
+  var xRepeats = (width - xLeftOver) / 8;
+  var yRepeats = (width - yLeftOver) / 8;
+  for(var i = 0; i < imagePasses.length; i++) {
+    var pass = imagePasses[i];
+    var passWidth = xRepeats * pass.x.length;
+    var passHeight = yRepeats * pass.y.length;
+    for(var j = 0; j < pass.x.length; j++) {
+      if (pass.x[j] < xLeftOver) {
+        passWidth++;
+      }
+      else {
+        break;
+      }
+    }
+    for(j = 0; j < pass.y.length; j++) {
+      if (pass.y[j] < yLeftOver) {
+        passHeight++;
+      }
+      else {
+        break;
+      }
+    }
+    if (passWidth > 0 && passHeight > 0) {
+      images.push({ width: passWidth, height: passHeight});
+    }
+  }
+  return images;
+};
+
+exports.getInterlaceIterator = function(width, height) {
+  return function(x, y, pass) {
+    var outerXLeftOver = x % imagePasses[pass].x.length;
+    var outerX = (((x - outerXLeftOver)/ imagePasses[pass].x.length) * 8) + imagePasses[pass].x[outerXLeftOver];
+    var outerYLeftOver = y % imagePasses[pass].y.length;
+    var outerY = (((y - outerYLeftOver) / imagePasses[pass].y.length) * 8) + imagePasses[pass].y[outerYLeftOver];
+    return (outerX * 4) + (outerY * width * 4);
+  };
+};
+
+// Adam 7
+//   0 1 2 3 4 5 6 7
+// 0 x 6 4 6 x 6 4 6
+// 1 7 7 7 7 7 7 7 7
+// 2 5 6 5 6 5 6 5 6
+// 3 7 7 7 7 7 7 7 7
+// 4 3 6 4 6 3 6 4 6
+// 5 7 7 7 7 7 7 7 7
+// 6 5 6 5 6 5 6 5 6
+// 7 7 7 7 7 7 7 7 7
+
+
+var imagePasses = [
+  { // pass 1 - 1px
+    x: [0],
+    y: [0]
+  },
+  { // pass 2 - 1px
+    x: [4],
+    y: [0]
+  },
+  { // pass 3 - 2px
+    x: [0, 4],
+    y: [4]
+  },
+  { // pass 4 - 4px
+    x: [2, 6],
+    y: [0, 4]
+  },
+  { // pass 5 - 8px
+    x: [0, 2, 4, 6],
+    y: [2, 6]
+  },
+  { // pass 6 - 16px
+    x: [1, 3, 5, 7],
+    y: [0, 2, 4, 6]
+  },
+  { // pass 7 - 32px
+    x: [0, 1, 2, 3, 4, 5, 6, 7],
+    y: [1, 3, 5, 7]
+  }
+];

lib/packer.js

@@ -51,7 +51,7 @@ Packer.prototype.pack = function(data, width, height) {
 
     // filter pixel data
     //TODO {}
-    var filter = new Filter(width, height, 4, 8, this._options, {});
+    var filter = new Filter(width, height, 4, 8, false, this._options, {});
     var data = filter.filter(data);
 
     // compress it

lib/parser-async.js

@@ -73,15 +73,17 @@ ParserAsync.prototype._inflateData = function(data) {
     this._inflate.write(data);
 };
 
-ParserAsync.prototype._createData = function(width, height, bpp, depth) {
+ParserAsync.prototype._createData = function(width, height, bpp, depth, interlace) {
 
     this._bpp = bpp;
     this._depth = depth;
+    this._interlace = interlace;
 
     this._filter = new FilterAsync(
       width, height,
       bpp,
       depth,
+      interlace,
       this._options
     );
 };
@@ -100,7 +102,8 @@ ParserAsync.prototype._complete = function(data, width, height) {
 
     data = bitmapper.dataToBitMap(data, width, height,
       this._bpp,
-      this._depth);
+      this._depth,
+      this._interlace);
 
     data = this._parser.reverseFiltered(data, this._depth, width, height);
 

lib/parser-sync.js

@@ -57,12 +57,14 @@ var ParserSync = module.exports = function(buffer, options) {
       this._width, this._height,
       this._bpp,
       this._depth,
+      this._interlace,
       this._options
     );
 
     this._data = bitmapper.dataToBitMap(data, this._width, this._height,
       this._bpp,
-      this._depth);
+      this._depth,
+      this._interlace);
     // todo yuck
     this.data = this._parser.reverseFiltered(this._data, this._depth, this._width, this._height);
 };
@@ -83,11 +85,12 @@ ParserSync.prototype._inflateData = function(data) {
     this._inflateDataList.push(data);
 };
 
-ParserSync.prototype._createData = function(width, height, bpp, depth) {
+ParserSync.prototype._createData = function(width, height, bpp, depth, interlace) {
     this._data = new Buffer(width * height * 4);
     this._bpp = bpp;
     this._width = width;
     this._height = height;
     this._depth = depth;
+    this._interlace = interlace;
     return this._data;
 };

lib/parser.js

@@ -180,14 +180,14 @@ Parser.prototype._parseIHDR = function(data) {
     this.error(new Error('Unsupported filter method'));
     return;
   }
-  if (interlace != 0) {
+  if (interlace != 0 && interlace !== 1) {
     this.error(new Error('Unsupported interlace method'));
     return;
   }
 
   this._colorType = colorType;
 
-  this.createData(width, height, colorTypeToBppMap[this._colorType], depth);
+  this.createData(width, height, colorTypeToBppMap[this._colorType], depth, interlace);
 
   this._hasIHDR = true;
 

test/test.js

@@ -7,22 +7,20 @@ fs.readdir(__dirname + '/in/', function(err, files) {
 
     files.forEach(function(file) {
 
-        if (!file.match(/\.png$/i))
+        if (!file.match(/.*\.png$/i))
             return;
 
         var expectedError = false;
-        if (file.match(/^x/) ||
-            file.match(/^...i/) // interlace
-        ) {
+        if (file.match(/^x/)) {
             expectedError = true;
         }
 
         var data = fs.readFileSync(__dirname + '/in/' + file);
         try {
-            console.log("Sync: parsing..", file);
             var png = PNG.sync.read(data);
         } catch (e) {
             if (!expectedError) {
+                console.log("Unexpected error parsing.." + file);
                 console.log(e);
                 console.log(e.stack);
             }
@@ -30,7 +28,7 @@ fs.readdir(__dirname + '/in/', function(err, files) {
         }
 
         if (expectedError) {
-            console.log("Error expected, parsed fine", file);
+            console.log("Error expected, parsed fine ..", file);
         }
 
         var outpng = new PNG();