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DCTDecode; text and images vertical inversion fix #29

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merged 1 commit into from
Jun 20, 2011
Merged

DCTDecode; text and images vertical inversion fix #29

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71 changes: 59 additions & 12 deletions pdf.js
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Original file line number Diff line number Diff line change
Expand Up @@ -509,9 +509,38 @@ var FlateStream = (function() {
return constructor;
})();

var JpegStream = (function() {
function constructor(bytes, dict) {
// TODO per poppler, some images may have "junk" before that need to be removed
this.bytes = bytes;
this.dict = dict;

// create DOM image
var buffer = "", i, n = bytes.length;
for (i = 0; i < n; ++i) {
buffer += String.fromCharCode(bytes[i]);
}
var img = new Image();
img.src = "data:image/jpeg;base64," + window.btoa(buffer);
this.domImage = img;
}

constructor.prototype = {
getChar: function() {
TODO("read direct pixels data");
},
getImage: function() {
return this.domImage;
}
};

return constructor;
})();

var PredictorStream = (function() {
function constructor(stream, params) {
this.stream = stream;
this.dict = stream.dict;
this.predictor = params.get("Predictor") || 1;
if (this.predictor <= 1) {
return stream; // no prediction
Expand Down Expand Up @@ -1177,15 +1206,15 @@ var Parser = (function() {
this.encAlgorithm,
this.keyLength);
}
stream = this.filter(stream, dict);
stream = this.filter(stream, dict, length);
stream.parameters = dict;
return stream;
},
filter: function(stream, dict) {
filter: function(stream, dict, length) {
var filter = dict.get2("Filter", "F");
var params = dict.get2("DecodeParms", "DP");
if (IsName(filter))
return this.makeFilter(stream, filter.name, params);
return this.makeFilter(stream, filter.name, length, params);
if (IsArray(filter)) {
var filterArray = filter;
var paramsArray = params;
Expand All @@ -1196,18 +1225,21 @@ var Parser = (function() {
params = null;
if (IsArray(paramsArray) && (i in paramsArray))
params = paramsArray[i];
stream = this.makeFilter(stream, filter.name, params);
stream = this.makeFilter(stream, filter.name, length, params);
}
}
}
return stream;
},
makeFilter: function(stream, name, params) {
makeFilter: function(stream, name, length, params) {
if (name == "FlateDecode" || name == "Fl") {
if (params) {
return new PredictorStream(new FlateStream(stream), params);
}
return new FlateStream(stream);
} else if (name == "DCTDecode") {
var bytes = stream.getBytes(length);
return new JpegStream(bytes, stream.dict);
} else {
error("filter '" + name + "' not supported yet");
}
Expand Down Expand Up @@ -2398,11 +2430,17 @@ var CanvasGraphics = (function() {

var fontName = "";
var fontDescriptor = font.get("FontDescriptor");
if (fontDescriptor.num) {
if (fontDescriptor && fontDescriptor.num) {
var fontDescriptor = this.xref.fetchIfRef(fontDescriptor);
fontName = fontDescriptor.get("FontName").name.replace("+", "_");
Fonts.active = fontName;
}
if (!fontName) {
// fontDescriptor is not available, fallback to default font (TODO ?)
this.current.fontSize = size;
this.ctx.font = this.current.fontSize + 'px sans-serif';
return;
}

this.current.fontSize = size;
this.ctx.font = this.current.fontSize +'px "' + fontName + '"';
Expand Down Expand Up @@ -2431,9 +2469,9 @@ var CanvasGraphics = (function() {
},
showText: function(text) {
this.ctx.save();
this.ctx.translate(0, 2 * this.current.y);
this.ctx.scale(1, -1);
this.ctx.transform.apply(this.ctx, this.current.textMatrix);
this.ctx.scale(1, -1);
this.ctx.translate(0, -2 * this.current.y);
this.ctx.fillText(Fonts.chars2Unicode(text), this.current.x, this.current.y);
this.current.x += this.ctx.measureText(text).width;

Expand Down Expand Up @@ -2679,8 +2717,17 @@ var CanvasGraphics = (function() {
error("Invalid image width or height");

var ctx = this.ctx;

// scale the image to the unit square
ctx.scale(1/w, 1/h);
ctx.scale(1/w, -1/h);

if (image instanceof JpegStream) {
var domImage = image.getImage();
ctx.drawImage(domImage, 0, 0, domImage.width, domImage.height,
0, -h, w, h);
this.restore();
return;
}

var interpolate = dict.get2("Interpolate", "I");
if (!IsBool(interpolate))
Expand Down Expand Up @@ -2786,7 +2833,7 @@ var CanvasGraphics = (function() {
switch (numComps) {
case 1:
for (var i = 0; i < length; i += 4) {
var p = imgArray[imageIdx++];
var p = imgArray[imgIdx++];
pixels[i] = p;
pixels[i+1] = p;
pixels[i+2] = p;
Expand All @@ -2813,7 +2860,7 @@ var CanvasGraphics = (function() {
switch (numComps) {
case 1:
for (var i = 0; i < length; i += 4) {
var p = imgArray[imageIdx++];
var p = imgArray[imgIdx++];
pixels[i] = p;
pixels[i+1] = p;
pixels[i+2] = p;
Expand All @@ -2833,7 +2880,7 @@ var CanvasGraphics = (function() {
}
}
tmpCtx.putImageData(imgData, 0, 0);
ctx.drawImage(tmpCanvas, 0, 0);
ctx.drawImage(tmpCanvas, 0, -h);
this.restore();
},

Expand Down