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Selection working
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@arturadib
arturadib committed Oct 28, 2011
1 parent 6c5d2ac commit e7d08e3
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Showing 4 changed files with 117 additions and 22 deletions.
118 changes: 102 additions & 16 deletions src/canvas.js
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ var CanvasGraphics = (function canvasGraphics() {
// if we execute longer then `kExecutionTime`.
var kExecutionTimeCheck = 500;

function constructor(canvasCtx, objs) {
function constructor(canvasCtx, objs, textLayer, textScale) {
this.ctx = canvasCtx;
this.current = new CanvasExtraState();
this.stateStack = [];
Expand All @@ -69,6 +69,8 @@ var CanvasGraphics = (function canvasGraphics() {
this.xobjs = null;
this.ScratchCanvas = ScratchCanvas;
this.objs = objs;
this.textLayer = textLayer;
this.textScale = textScale;
}

var LINE_CAP_STYLES = ['butt', 'round', 'square'];
Expand All @@ -95,6 +97,7 @@ var CanvasGraphics = (function canvasGraphics() {
break;
}
this.ctx.scale(cw / mediaBox.width, ch / mediaBox.height);
this.textDivs = [];
},

executeIRQueue: function canvasGraphicsExecuteIRQueue(codeIR,
Expand Down Expand Up @@ -150,6 +153,17 @@ var CanvasGraphics = (function canvasGraphics() {

endDrawing: function canvasGraphicsEndDrawing() {
this.ctx.restore();

// Text selection-specific
var textLayer = this.textLayer;
var textDivs = this.textDivs;
for (var i = 0, length = textDivs.length; i < length; ++i) {
if (textDivs[i].dataset.textLength>1) { // avoid div by zero
textLayer.appendChild(textDivs[i]);
// Adjust div width to match canvas text width
textDivs[i].style.letterSpacing = ((textDivs[i].dataset.canvasWidth - textDivs[i].offsetWidth)/(textDivs[i].dataset.textLength-1)) + 'px';
}
}
},

// Graphics state
Expand Down Expand Up @@ -414,6 +428,12 @@ var CanvasGraphics = (function canvasGraphics() {
this.moveText(0, this.current.leading);
},
showText: function canvasGraphicsShowText(text) {
function unicodeToChar(unicode) {
return (unicode >= 0x10000) ?
String.fromCharCode(0xD800 | ((unicode - 0x10000) >> 10),
0xDC00 | (unicode & 0x3FF)) : String.fromCharCode(unicode);
};

var ctx = this.ctx;
var current = this.current;
var font = current.font;
Expand All @@ -423,6 +443,8 @@ var CanvasGraphics = (function canvasGraphics() {
var wordSpacing = current.wordSpacing;
var textHScale = current.textHScale;
var glyphsLength = glyphs.length;
var text = { chars:'', width:0 };

if (font.coded) {
ctx.save();
ctx.transform.apply(ctx, current.textMatrix);
Expand All @@ -446,11 +468,12 @@ var CanvasGraphics = (function canvasGraphics() {
this.restore();

var transformed = Util.applyTransform([glyph.width, 0], fontMatrix);
var width = transformed[0] * fontSize + charSpacing;

ctx.translate(width, 0);
current.x += width;
var charWidth = transformed[0] * fontSize + charSpacing;
ctx.translate(charWidth, 0);
current.x += charWidth;

text.chars += unicodeToChar(glyph.unicode);
text.width += charWidth;
}
ctx.restore();
} else {
Expand All @@ -459,7 +482,6 @@ var CanvasGraphics = (function canvasGraphics() {
ctx.scale(1, -1);
ctx.translate(current.x, -1 * current.y);
ctx.transform.apply(ctx, font.fontMatrix || IDENTITY_MATRIX);

ctx.scale(1 / textHScale, 1);

var width = 0;
Expand All @@ -471,36 +493,100 @@ var CanvasGraphics = (function canvasGraphics() {
continue;
}

var unicode = glyph.unicode;
var char = (unicode >= 0x10000) ?
String.fromCharCode(0xD800 | ((unicode - 0x10000) >> 10),
0xDC00 | (unicode & 0x3FF)) : String.fromCharCode(unicode);

var char = unicodeToChar(glyph.unicode);
var charWidth = glyph.width * fontSize * 0.001 + charSpacing;
ctx.fillText(char, width, 0);
width += glyph.width * fontSize * 0.001 + charSpacing;
width += charWidth;

text.chars += char;
text.width += charWidth;
}
current.x += width;

ctx.restore();
}
return text;
},

showSpacedText: function canvasGraphicsShowSpacedText(arr) {
var ctx = this.ctx;
var current = this.current;
var fontSize = current.fontSize;
var textHScale = current.textHScale;
var arrLength = arr.length;
var textLayer = this.textLayer;
var font = current.font;
var text = {str:'', length:0, canvasWidth:0, spaceWidth:0, geom:{}};

// Text selection-specific
text.spaceWidth = this.current.font.charsToGlyphs(' ')[0].width;
if (!text.spaceWidth>0) {
// Hack (space is sometimes not encoded)
text.spaceWidth = this.current.font.charsToGlyphs('i')[0].width;
}

// Compute text.geom
// TODO: refactor the series of transformations below, and share it with showText()
ctx.save();
ctx.transform.apply(ctx, current.textMatrix);
ctx.scale(1, -1);
ctx.translate(current.x, -1 * current.y);
ctx.transform.apply(ctx, font.fontMatrix || IDENTITY_MATRIX);
ctx.scale(1 / textHScale, 1);
var inv = ctx.mozCurrentTransform;
if (inv) {
var bl = Util.applyTransform([0, 0], inv);
var tr = Util.applyTransform([1, 1], inv);
text.geom.x = bl[0];
text.geom.y = bl[1];
text.geom.xFactor = tr[0] - bl[0];
text.geom.yFactor = tr[1] - bl[1];
}
ctx.restore();

for (var i = 0; i < arrLength; ++i) {
var e = arr[i];
if (isNum(e)) {
current.x -= e * 0.001 * fontSize * textHScale;
var spacingLength = -e * 0.001 * fontSize * textHScale;
current.x += spacingLength;

// Text selection-specific
// Emulate arbitrary spacing via HTML spaces
text.canvasWidth += spacingLength;
if (e<0 && text.spaceWidth>0) { // avoid div by zero
var numFakeSpaces = Math.round(-e / text.spaceWidth);
for (var j = 0; j < numFakeSpaces; ++j)
text.str += '&nbsp;';
text.length += numFakeSpaces>0 ? 1 : 0;
}
} else if (isString(e)) {
this.showText(e);
var shownText = this.showText(e);

// Text selection-specific
if (shownText.chars === ' ') {
text.str += '&nbsp;';
} else {
text.str += shownText.chars;
}
text.canvasWidth += shownText.width;
text.length += e.length;
} else {
malformed('TJ array element ' + e + ' is not string or num');
}
}

if (textLayer) {
var div = document.createElement('div');
var fontHeight = text.geom.yFactor * fontSize;
div.style.fontSize = fontHeight + 'px';
// TODO: family should be '= font.loadedName', but some fonts don't
// have spacing info (cf. fonts.js > Font > fields > htmx)
div.style.fontFamily = 'serif';
div.style.left = text.geom.x + 'px';
div.style.top = (text.geom.y - fontHeight) + 'px';
div.innerHTML = text.str;
div.dataset.canvasWidth = text.canvasWidth * text.geom.xFactor;
div.dataset.textLength = text.length;
this.textDivs.push(div);
}
},
nextLineShowText: function canvasGraphicsNextLineShowText(text) {
this.nextLine();
Expand Down
7 changes: 5 additions & 2 deletions src/core.js
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Original file line number Diff line number Diff line change
Expand Up @@ -157,7 +157,7 @@ var Page = (function pagePage() {
IRQueue, fonts) {
var self = this;
this.IRQueue = IRQueue;
var gfx = new CanvasGraphics(this.ctx, this.objs);
var gfx = new CanvasGraphics(this.ctx, this.objs, this.textLayer, this.textScale);
var startTime = Date.now();

var displayContinuation = function pageDisplayContinuation() {
Expand Down Expand Up @@ -243,6 +243,7 @@ var Page = (function pagePage() {
startIdx = gfx.executeIRQueue(IRQueue, startIdx, next);
if (startIdx == length) {
self.stats.render = Date.now();
gfx.endDrawing();
if (callback) callback();
}
}
Expand Down Expand Up @@ -305,9 +306,11 @@ var Page = (function pagePage() {
}
return links;
},
startRendering: function(ctx, callback) {
startRendering: function(ctx, callback, textLayer, textScale) {
this.ctx = ctx;
this.callback = callback;
this.textLayer = textLayer;
this.textScale = textScale;

this.startRenderingTime = Date.now();
this.pdf.startRendering(this);
Expand Down
6 changes: 6 additions & 0 deletions web/viewer.css
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Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,12 @@ canvas {
line-height:1.3;
}

::selection { background:rgba(0,0,255,0.3); }
::-moz-selection { background:rgba(0,0,255,0.3); }
/* TODO: file FF bug to support ::-moz-selection:window-inactive
so we can override the opaque grey background when the window is inactive;
see also http://css-tricks.com/9288-window-inactive-styling */

#viewer {
margin: 44px 0px 0px;
padding: 8px 0px;
Expand Down
8 changes: 4 additions & 4 deletions web/viewer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -475,9 +475,9 @@ var PageView = function pageView(container, content, id, pageWidth, pageHeight,
canvas.mozOpaque = true;
div.appendChild(canvas);

var textDiv = document.createElement('div');
textDiv.className = 'textLayer';
div.appendChild(textDiv);
var textLayer = document.createElement('div');
textLayer.className = 'textLayer';
div.appendChild(textLayer);

var scale = this.scale;
canvas.width = pageWidth * scale;
Expand All @@ -491,7 +491,7 @@ var PageView = function pageView(container, content, id, pageWidth, pageHeight,
ctx.translate(-this.x * scale, -this.y * scale);

stats.begin = Date.now();
this.content.startRendering(ctx, this.updateStats, textDiv, scale);
this.content.startRendering(ctx, this.updateStats, textLayer, scale);

setupLinks(this.content, this.scale);
div.setAttribute('data-loaded', true);
Expand Down

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