konva/src/plugins/shapes/TextPath.js

385 lines
13 KiB
JavaScript

///////////////////////////////////////////////////////////////////////
// Text Path
///////////////////////////////////////////////////////////////////////
/**
* Path constructor.
* @author Jason Follas
* @constructor
* @augments Kinetic.Shape
* @param {Object} config
*/
Kinetic.Plugins.TextPath = Kinetic.Shape.extend({
init : function (config) {
this.setDefaultAttrs({
fontFamily : 'Calibri',
fontSize : 12,
fontStyle : 'normal',
detectionType : 'path',
text : ''
});
this.dummyCanvas = document.createElement('canvas');
this.shapeType = "TextPath";
this.dataArray = [];
var that = this;
config.drawFunc = function (context) {
var charArr = this.charArr;
context.font = this.attrs.fontStyle + ' ' + this.attrs.fontSize + 'pt ' + this.attrs.fontFamily;
context.textBaseline = 'middle';
context.textAlign = 'left';
context.save();
var glyphInfo = this.glyphInfo;
for (var i = 0; i < glyphInfo.length; i++) {
context.save();
var p0 = glyphInfo[i].p0;
var p1 = glyphInfo[i].p1;
var ht = parseFloat(this.attrs.fontSize);
context.translate(p0.x, p0.y);
context.rotate(glyphInfo[i].rotation);
this.fillText(context, glyphInfo[i].text);
this.strokeText(context, glyphInfo[i].text);
context.restore();
//// To assist with debugging visually, uncomment following
// context.beginPath();
// if (i % 2)
// context.strokeStyle = 'cyan';
// else
// context.strokeStyle = 'green';
// context.moveTo(p0.x, p0.y);
// context.lineTo(p1.x, p1.y);
// context.stroke();
}
context.restore();
};
// call super constructor
this._super(config);
this.dataArray = Kinetic.Plugins.PathHelper.parsePathData(this.attrs.data);
this.on('dataChange', function () {
that.dataArray = Kinetic.Plugins.PathHelper.parsePathData(that.attrs.data);
});
// update text data for certain attr changes
var attrs = ['text', 'textStroke', 'textStrokeWidth'];
for (var n = 0; n < attrs.length; n++) {
var attr = attrs[n];
this.on(attr + 'Change', that._setTextData);
}
that._setTextData();
},
/**
* get text width in pixels
* @name getTextWidth
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
getTextWidth : function () {
return this.textWidth;
},
/**
* get text height in pixels
* @name getTextHeight
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
getTextHeight : function () {
return this.textHeight;
},
_getTextSize : function (text) {
var dummyCanvas = this.dummyCanvas;
var context = dummyCanvas.getContext('2d');
context.save();
context.font = this.attrs.fontStyle + ' ' + this.attrs.fontSize + 'pt ' + this.attrs.fontFamily;
var metrics = context.measureText(text);
context.restore();
return {
width : metrics.width,
height : parseInt(this.attrs.fontSize, 10)
};
},
/**
* set text data.
*/
_setTextData : function () {
var that = this;
var size = this._getTextSize(this.attrs.text);
this.textWidth = size.width;
this.textHeight = size.height;
this.glyphInfo = [];
var charArr = this.attrs.text.split('');
var p0,
p1,
pathCmd;
var pIndex = -1;
var currentT = 0;
var getNextPathSegment = function () {
currentT = 0;
var pathData = that.dataArray;
for (var i = pIndex + 1; i < pathData.length; i++) {
if (pathData[i].pathLength > 0) {
pIndex = i;
return pathData[i];
} else if (pathData[i].command == 'M') {
p0 = {
x : pathData[i].points[0],
y : pathData[i].points[1]
};
}
}
return {};
};
var findSegmentToFitCharacter = function (c, before) {
var glyphWidth = that._getTextSize(c).width;
var currLen = 0;
var attempts = 0;
var needNextSegment = false;
p1 = undefined;
while (Math.abs(glyphWidth - currLen) / glyphWidth > 0.01 && attempts < 25) {
attempts++;
var cumulativePathLength = currLen;
while (pathCmd === undefined) {
pathCmd = getNextPathSegment();
if (pathCmd && cumulativePathLength + pathCmd.pathLength < glyphWidth) {
cumulativePathLength += pathCmd.pathLength;
pathCmd = undefined;
}
}
if (pathCmd === {} || p0 === undefined)
return undefined;
var needNewSegment = false;
switch (pathCmd.command) {
case 'L':
if (Kinetic.Plugins.PathHelper.getLineLength(p0.x, p0.y, pathCmd.points[0], pathCmd.points[1]) > glyphWidth) {
p1 = Kinetic.Plugins.PathHelper.getPointOnLine(glyphWidth, p0.x, p0.y, pathCmd.points[0], pathCmd.points[1], p0.x, p0.y);
} else
pathCmd = undefined;
break;
case 'A':
var start = pathCmd.points[4]; // 4 = theta
var dTheta = pathCmd.points[5]; // 5 = dTheta
var end = pathCmd.points[4] + dTheta;
if (currentT === 0)
currentT = start + 0.00000001; // Just in case start is 0
else if (glyphWidth > currLen)
currentT += (Math.PI / 180.0) * dTheta / Math.abs(dTheta);
else
currentT -= Math.PI / 360.0 * dTheta / Math.abs(dTheta);
if (Math.abs(currentT) > Math.abs(end)) {
currentT = end;
needNewSegment = true;
}
p1 = Kinetic.Plugins.PathHelper.getPointOnEllipticalArc(pathCmd.points[0], pathCmd.points[1], pathCmd.points[2], pathCmd.points[3], currentT, pathCmd.points[6]);
break;
case 'C':
if (currentT === 0) {
if (glyphWidth > pathCmd.pathLength)
currentT = 0.00000001;
else
currentT = glyphWidth / pathCmd.pathLength;
} else if (glyphWidth > currLen)
currentT += (glyphWidth - currLen) / pathCmd.pathLength;
else
currentT -= (currLen - glyphWidth) / pathCmd.pathLength;
if (currentT > 1.0) {
currentT = 1.0;
needNewSegment = true;
}
p1 = Kinetic.Plugins.PathHelper.getPointOnCubicBezier(currentT, pathCmd.start.x, pathCmd.start.y, pathCmd.points[0], pathCmd.points[1], pathCmd.points[2], pathCmd.points[3], pathCmd.points[4], pathCmd.points[5]);
break;
case 'Q':
if (currentT === 0)
currentT = glyphWidth / pathCmd.pathLength;
else if (glyphWidth > currLen)
currentT += (glyphWidth - currLen) / pathCmd.pathLength;
else
currentT -= (currLen - glyphWidth) / pathCmd.pathLength;
if (currentT > 1.0) {
currentT = 1.0;
needNewSegment = true;
}
p1 = Kinetic.Plugins.PathHelper.getPointOnQuadraticBezier(currentT, pathCmd.start.x, pathCmd.start.y, pathCmd.points[0], pathCmd.points[1], pathCmd.points[2], pathCmd.points[3]);
break;
}
if (p1 !== undefined) {
currLen = Kinetic.Plugins.PathHelper.getLineLength(p0.x, p0.y, p1.x, p1.y);
}
if (needNewSegment) {
needNewSegment = false;
pathCmd = undefined;
}
}
};
for (var i = 0; i < charArr.length; i++) {
// Find p1 such that line segment between p0 and p1 is approx. width of glyph
findSegmentToFitCharacter(charArr[i]);
if (p0 === undefined || p1 === undefined)
break;
var width = Kinetic.Plugins.PathHelper.getLineLength(p0.x, p0.y, p1.x, p1.y);
// Note: Since glyphs are rendered one at a time, any kerning pair data built into the font will not be used.
// Can foresee having a rough pair table built in that the developer can override as needed.
var kern = 0; // placeholder for future implementation
var midpoint = Kinetic.Plugins.PathHelper.getPointOnLine(kern + width / 2.0, p0.x, p0.y, p1.x, p1.y);
var rotation = Math.atan2((p1.y - p0.y), (p1.x - p0.x));
this.glyphInfo.push({
transposeX : midpoint.x,
transposeY : midpoint.y,
text : charArr[i],
rotation : rotation,
p0 : p0,
p1 : p1
});
p0 = p1;
}
}
});
// add setters and getters
Kinetic.Node.addGettersSetters(Kinetic.Plugins.TextPath, ['fontFamily', 'fontSize', 'fontStyle', 'textFill', 'textStroke', 'textStrokeWidth', 'text']);
/**
* set font family
* @name setFontFamily
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {String} fontFamily
*/
/**
* set font size
* @name setFontSize
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {int} fontSize
*/
/**
* set font style. Can be "normal", "italic", or "bold". "normal" is the default.
* @name setFontStyle
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {String} fontStyle
*/
/**
* set text fill color
* @name setTextFill
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {String} textFill
*/
/**
* set text stroke color
* @name setFontStroke
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {String} textStroke
*/
/**
* set text stroke width
* @name setTextStrokeWidth
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {int} textStrokeWidth
*/
/**
* set text
* @name setText
* @methodOf Kinetic.Plugins.TextPath.prototype
* @param {String} text
*/
/**
* get font family
* @name getFontFamily
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get font size
* @name getFontSize
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get font style
* @name getFontStyle
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get text fill color
* @name getTextFill
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get text stroke color
* @name getTextStroke
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get text stroke width
* @name getTextStrokeWidth
* @methodOf Kinetic.Plugins.TextPath.prototype
*/
/**
* get text
* @name getText
* @methodOf Kinetic.Plugins.TextPath.prototype
*/