var IMPLEMENTATION = "canvas",
SHAPE = "shape",
SPLITPATHPATTERN = /[a-z][^a-z]*/ig,
SPLITARGSPATTERN = /[-]?[0-9]*[0-9|\.][0-9]*/g,
DOCUMENT = Y.config.doc,
Y_LANG = Y.Lang,
AttributeLite = Y.AttributeLite,
CanvasShape,
CanvasPath,
CanvasRect,
CanvasEllipse,
CanvasCircle,
CanvasPieSlice,
Y_DOM = Y.DOM,
Y_Color = Y.Color,
PARSE_INT = parseInt,
PARSE_FLOAT = parseFloat,
IS_NUMBER = Y_LANG.isNumber,
RE = RegExp,
TORGB = Y_Color.toRGB,
TOHEX = Y_Color.toHex,
_getClassName = Y.ClassNameManager.getClassName;
/**
* <a href="http://www.w3.org/TR/html5/the-canvas-element.html">Canvas</a> implementation of the <a href="Drawing.html">`Drawing`</a> class.
* `CanvasDrawing` is not intended to be used directly. Instead, use the <a href="Drawing.html">`Drawing`</a> class.
* If the browser lacks <a href="http://www.w3.org/TR/SVG/">SVG</a> capabilities but has
* <a href="http://www.w3.org/TR/html5/the-canvas-element.html">Canvas</a> capabilities, the <a href="Drawing.html">`Drawing`</a>
* class will point to the `CanvasDrawing` class.
*
* @module graphics
* @class CanvasDrawing
* @constructor
*/
function CanvasDrawing()
{
}
CanvasDrawing.prototype = {
/**
* Maps path to methods
*
* @property _pathSymbolToMethod
* @type Object
* @private
*/
_pathSymbolToMethod: {
M: "moveTo",
m: "relativeMoveTo",
L: "lineTo",
l: "relativeLineTo",
C: "curveTo",
c: "relativeCurveTo",
Q: "quadraticCurveTo",
q: "relativeQuadraticCurveTo",
z: "closePath",
Z: "closePath"
},
/**
* Current x position of the drawing.
*
* @property _currentX
* @type Number
* @private
*/
_currentX: 0,
/**
* Current y position of the drqwing.
*
* @property _currentY
* @type Number
* @private
*/
_currentY: 0,
/**
* Parses hex color string and alpha value to rgba
*
* @method _toRGBA
* @param {Object} val Color value to parse. Can be hex string, rgb or name.
* @param {Number} alpha Numeric value between 0 and 1 representing the alpha level.
* @private
*/
_toRGBA: function(val, alpha) {
alpha = (alpha !== undefined) ? alpha : 1;
if (!Y_Color.re_RGB.test(val)) {
val = TOHEX(val);
}
if(Y_Color.re_hex.exec(val)) {
val = 'rgba(' + [
PARSE_INT(RE.$1, 16),
PARSE_INT(RE.$2, 16),
PARSE_INT(RE.$3, 16)
].join(',') + ',' + alpha + ')';
}
return val;
},
/**
* Converts color to rgb format
*
* @method _toRGB
* @param val Color value to convert.
* @private
*/
_toRGB: function(val) {
return TORGB(val);
},
/**
* Sets the size of the graphics object.
*
* @method setSize
* @param w {Number} width to set for the instance.
* @param h {Number} height to set for the instance.
* @private
*/
setSize: function(w, h) {
if(this.get("autoSize"))
{
if(w > this.node.getAttribute("width"))
{
this.node.style.width = w + "px";
this.node.setAttribute("width", w);
}
if(h > this.node.getAttribute("height"))
{
this.node.style.height = h + "px";
this.node.setAttribute("height", h);
}
}
},
/**
* Tracks coordinates. Used to calculate the start point of dashed lines.
*
* @method _updateCoords
* @param {Number} x x-coordinate
* @param {Number} y y-coordinate
* @private
*/
_updateCoords: function(x, y)
{
this._xcoords.push(x);
this._ycoords.push(y);
this._currentX = x;
this._currentY = y;
},
/**
* Clears the coordinate arrays. Called at the end of a drawing operation.
*
* @method _clearAndUpdateCoords
* @private
*/
_clearAndUpdateCoords: function()
{
var x = this._xcoords.pop() || 0,
y = this._ycoords.pop() || 0;
this._updateCoords(x, y);
},
/**
* Moves the shape's dom node.
*
* @method _updateNodePosition
* @private
*/
_updateNodePosition: function()
{
var node = this.get("node"),
x = this.get("x"),
y = this.get("y");
node.style.position = "absolute";
node.style.left = (x + this._left) + "px";
node.style.top = (y + this._top) + "px";
},
/**
* Queues up a method to be executed when a shape redraws.
*
* @method _updateDrawingQueue
* @param {Array} val An array containing data that can be parsed into a method and arguments. The value at zero-index
* of the array is a string reference of the drawing method that will be called. All subsequent indices are argument for
* that method. For example, `lineTo(10, 100)` would be structured as:
* `["lineTo", 10, 100]`.
* @private
*/
_updateDrawingQueue: function(val)
{
this._methods.push(val);
},
/**
* Draws a line segment from the current drawing position to the specified x and y coordinates.
*
* @method lineTo
* @param {Number} point1 x-coordinate for the end point.
* @param {Number} point2 y-coordinate for the end point.
*/
lineTo: function()
{
this._lineTo.apply(this, [Y.Array(arguments), false]);
},
/**
* Draws a line segment from the current drawing position to the relative x and y coordinates.
*
* @method lineTo
* @param {Number} point1 x-coordinate for the end point.
* @param {Number} point2 y-coordinate for the end point.
*/
relativeLineTo: function()
{
this._lineTo.apply(this, [Y.Array(arguments), true]);
},
/**
* Implements lineTo methods.
*
* @method _lineTo
* @param {Array} args The arguments to be used.
* @param {Boolean} relative Indicates whether or not to use relative coordinates.
* @private
*/
_lineTo: function(args, relative)
{
var point1 = args[0],
i,
len,
x,
y,
wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
relativeX = relative ? parseFloat(this._currentX) : 0,
relativeY = relative ? parseFloat(this._currentY) : 0;
if(!this._lineToMethods)
{
this._lineToMethods = [];
}
len = args.length - 1;
if (typeof point1 === 'string' || typeof point1 === 'number') {
for (i = 0; i < len; i = i + 2) {
x = parseFloat(args[i]);
y = parseFloat(args[i + 1]);
x = x + relativeX;
y = y + relativeY;
this._updateDrawingQueue(["lineTo", x, y]);
this._trackSize(x - wt, y - wt);
this._trackSize(x + wt, y + wt);
this._updateCoords(x, y);
}
}
else
{
for (i = 0; i < len; i = i + 1)
{
x = parseFloat(args[i][0]);
y = parseFloat(args[i][1]);
this._updateDrawingQueue(["lineTo", x, y]);
this._lineToMethods[this._lineToMethods.length] = this._methods[this._methods.length - 1];
this._trackSize(x - wt, y - wt);
this._trackSize(x + wt, y + wt);
this._updateCoords(x, y);
}
}
this._drawingComplete = false;
return this;
},
/**
* Moves the current drawing position to specified x and y coordinates.
*
* @method moveTo
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
moveTo: function()
{
this._moveTo.apply(this, [Y.Array(arguments), false]);
},
/**
* Moves the current drawing position relative to specified x and y coordinates.
*
* @method relativeMoveTo
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
relativeMoveTo: function()
{
this._moveTo.apply(this, [Y.Array(arguments), true]);
},
/**
* Implements moveTo methods.
*
* @method _moveTo
* @param {Array} args The arguments to be used.
* @param {Boolean} relative Indicates whether or not to use relative coordinates.
* @private
*/
_moveTo: function(args, relative) {
var wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
relativeX = relative ? parseFloat(this._currentX) : 0,
relativeY = relative ? parseFloat(this._currentY) : 0,
x = parseFloat(args[0]) + relativeX,
y = parseFloat(args[1]) + relativeY;
this._updateDrawingQueue(["moveTo", x, y]);
this._trackSize(x - wt, y - wt);
this._trackSize(x + wt, y + wt);
this._updateCoords(x, y);
this._drawingComplete = false;
return this;
},
/**
* Draws a bezier curve.
*
* @method curveTo
* @param {Number} cp1x x-coordinate for the first control point.
* @param {Number} cp1y y-coordinate for the first control point.
* @param {Number} cp2x x-coordinate for the second control point.
* @param {Number} cp2y y-coordinate for the second control point.
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
curveTo: function() {
this._curveTo.apply(this, [Y.Array(arguments), false]);
},
/**
* Draws a bezier curve relative to the current coordinates.
*
* @method curveTo
* @param {Number} cp1x x-coordinate for the first control point.
* @param {Number} cp1y y-coordinate for the first control point.
* @param {Number} cp2x x-coordinate for the second control point.
* @param {Number} cp2y y-coordinate for the second control point.
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
relativeCurveTo: function() {
this._curveTo.apply(this, [Y.Array(arguments), true]);
},
/**
* Implements curveTo methods.
*
* @method _curveTo
* @param {Array} args The arguments to be used.
* @param {Boolean} relative Indicates whether or not to use relative coordinates.
* @private
*/
_curveTo: function(args, relative) {
var w,
h,
cp1x,
cp1y,
cp2x,
cp2y,
x,
y,
pts,
right,
left,
bottom,
top,
i,
len,
relativeX = relative ? parseFloat(this._currentX) : 0,
relativeY = relative ? parseFloat(this._currentY) : 0;
len = args.length - 5;
for(i = 0; i < len; i = i + 6)
{
cp1x = parseFloat(args[i]) + relativeX;
cp1y = parseFloat(args[i + 1]) + relativeY;
cp2x = parseFloat(args[i + 2]) + relativeX;
cp2y = parseFloat(args[i + 3]) + relativeY;
x = parseFloat(args[i + 4]) + relativeX;
y = parseFloat(args[i + 5]) + relativeY;
this._updateDrawingQueue(["bezierCurveTo", cp1x, cp1y, cp2x, cp2y, x, y]);
this._drawingComplete = false;
right = Math.max(x, Math.max(cp1x, cp2x));
bottom = Math.max(y, Math.max(cp1y, cp2y));
left = Math.min(x, Math.min(cp1x, cp2x));
top = Math.min(y, Math.min(cp1y, cp2y));
w = Math.abs(right - left);
h = Math.abs(bottom - top);
pts = [[this._currentX, this._currentY] , [cp1x, cp1y], [cp2x, cp2y], [x, y]];
this._setCurveBoundingBox(pts, w, h);
this._currentX = x;
this._currentY = y;
}
},
/**
* Draws a quadratic bezier curve.
*
* @method quadraticCurveTo
* @param {Number} cpx x-coordinate for the control point.
* @param {Number} cpy y-coordinate for the control point.
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
quadraticCurveTo: function() {
this._quadraticCurveTo.apply(this, [Y.Array(arguments), false]);
},
/**
* Draws a quadratic bezier curve relative to the current position.
*
* @method relativeQuadraticCurveTo
* @param {Number} cpx x-coordinate for the control point.
* @param {Number} cpy y-coordinate for the control point.
* @param {Number} x x-coordinate for the end point.
* @param {Number} y y-coordinate for the end point.
*/
relativeQuadraticCurveTo: function() {
this._quadraticCurveTo.apply(this, [Y.Array(arguments), true]);
},
/**
* Implements quadraticCurveTo methods.
*
* @method _quadraticCurveTo
* @param {Array} args The arguments to be used.
* @param {Boolean} relative Indicates whether or not to use relative coordinates.
* @private
*/
_quadraticCurveTo: function(args, relative) {
var cpx,
cpy,
x,
y,
w,
h,
pts,
right,
left,
bottom,
top,
i,
len = args.length - 3,
wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
relativeX = relative ? parseFloat(this._currentX) : 0,
relativeY = relative ? parseFloat(this._currentY) : 0;
for(i = 0; i < len; i = i + 4)
{
cpx = parseFloat(args[i]) + relativeX;
cpy = parseFloat(args[i + 1]) + relativeY;
x = parseFloat(args[i + 2]) + relativeX;
y = parseFloat(args[i + 3]) + relativeY;
this._drawingComplete = false;
right = Math.max(x, cpx);
bottom = Math.max(y, cpy);
left = Math.min(x, cpx);
top = Math.min(y, cpy);
w = Math.abs(right - left);
h = Math.abs(bottom - top);
pts = [[this._currentX, this._currentY] , [cpx, cpy], [x, y]];
this._setCurveBoundingBox(pts, w, h);
this._updateDrawingQueue(["quadraticCurveTo", cpx, cpy, x, y]);
this._updateCoords(x, y);
}
return this;
},
/**
* Draws a circle. Used internally by `CanvasCircle` class.
*
* @method drawCircle
* @param {Number} x y-coordinate
* @param {Number} y x-coordinate
* @param {Number} r radius
* @protected
*/
drawCircle: function(x, y, radius) {
var startAngle = 0,
endAngle = 2 * Math.PI,
wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
circum = radius * 2;
circum += wt;
this._drawingComplete = false;
this._trackSize(x + circum, y + circum);
this._trackSize(x - wt, y - wt);
this._updateCoords(x, y);
this._updateDrawingQueue(["arc", x + radius, y + radius, radius, startAngle, endAngle, false]);
return this;
},
/**
* Draws a diamond.
*
* @method drawDiamond
* @param {Number} x y-coordinate
* @param {Number} y x-coordinate
* @param {Number} width width
* @param {Number} height height
* @protected
*/
drawDiamond: function(x, y, width, height)
{
var midWidth = width * 0.5,
midHeight = height * 0.5;
this.moveTo(x + midWidth, y);
this.lineTo(x + width, y + midHeight);
this.lineTo(x + midWidth, y + height);
this.lineTo(x, y + midHeight);
this.lineTo(x + midWidth, y);
return this;
},
/**
* Draws an ellipse. Used internally by `CanvasEllipse` class.
*
* @method drawEllipse
* @param {Number} x x-coordinate
* @param {Number} y y-coordinate
* @param {Number} w width
* @param {Number} h height
* @protected
*/
drawEllipse: function(x, y, w, h) {
var l = 8,
theta = -(45/180) * Math.PI,
angle = 0,
angleMid,
radius = w/2,
yRadius = h/2,
i,
centerX = x + radius,
centerY = y + yRadius,
ax, ay, bx, by, cx, cy,
wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0;
ax = centerX + Math.cos(0) * radius;
ay = centerY + Math.sin(0) * yRadius;
this.moveTo(ax, ay);
for(i = 0; i < l; i++)
{
angle += theta;
angleMid = angle - (theta / 2);
bx = centerX + Math.cos(angle) * radius;
by = centerY + Math.sin(angle) * yRadius;
cx = centerX + Math.cos(angleMid) * (radius / Math.cos(theta / 2));
cy = centerY + Math.sin(angleMid) * (yRadius / Math.cos(theta / 2));
this._updateDrawingQueue(["quadraticCurveTo", cx, cy, bx, by]);
}
this._trackSize(x + w + wt, y + h + wt);
this._trackSize(x - wt, y - wt);
this._updateCoords(x, y);
return this;
},
/**
* Draws a rectangle.
*
* @method drawRect
* @param {Number} x x-coordinate
* @param {Number} y y-coordinate
* @param {Number} w width
* @param {Number} h height
*/
drawRect: function(x, y, w, h) {
var wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0;
this._drawingComplete = false;
this.moveTo(x, y);
this.lineTo(x + w, y);
this.lineTo(x + w, y + h);
this.lineTo(x, y + h);
this.lineTo(x, y);
return this;
},
/**
* Draws a rectangle with rounded corners.
*
* @method drawRect
* @param {Number} x x-coordinate
* @param {Number} y y-coordinate
* @param {Number} w width
* @param {Number} h height
* @param {Number} ew width of the ellipse used to draw the rounded corners
* @param {Number} eh height of the ellipse used to draw the rounded corners
*/
drawRoundRect: function(x, y, w, h, ew, eh) {
var wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0;
this._drawingComplete = false;
this.moveTo( x, y + eh);
this.lineTo(x, y + h - eh);
this.quadraticCurveTo(x, y + h, x + ew, y + h);
this.lineTo(x + w - ew, y + h);
this.quadraticCurveTo(x + w, y + h, x + w, y + h - eh);
this.lineTo(x + w, y + eh);
this.quadraticCurveTo(x + w, y, x + w - ew, y);
this.lineTo(x + ew, y);
this.quadraticCurveTo(x, y, x, y + eh);
return this;
},
/**
* Draws a wedge.
*
* @method drawWedge
* @param {Number} x x-coordinate of the wedge's center point
* @param {Number} y y-coordinate of the wedge's center point
* @param {Number} startAngle starting angle in degrees
* @param {Number} arc sweep of the wedge. Negative values draw clockwise.
* @param {Number} radius radius of wedge. If [optional] yRadius is defined, then radius is the x radius.
* @param {Number} yRadius [optional] y radius for wedge.
* @private
*/
drawWedge: function(x, y, startAngle, arc, radius, yRadius)
{
var wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
segs,
segAngle,
theta,
angle,
angleMid,
ax,
ay,
bx,
by,
cx,
cy,
i = 0;
yRadius = yRadius || radius;
this._drawingComplete = false;
// move to x,y position
this._updateDrawingQueue(["moveTo", x, y]);
yRadius = yRadius || radius;
// limit sweep to reasonable numbers
if(Math.abs(arc) > 360)
{
arc = 360;
}
// First we calculate how many segments are needed
// for a smooth arc.
segs = Math.ceil(Math.abs(arc) / 45);
// Now calculate the sweep of each segment.
segAngle = arc / segs;
// The math requires radians rather than degrees. To convert from degrees
// use the formula (degrees/180)*Math.PI to get radians.
theta = -(segAngle / 180) * Math.PI;
// convert angle startAngle to radians
angle = (startAngle / 180) * Math.PI;
// draw the curve in segments no larger than 45 degrees.
if(segs > 0)
{
// draw a line from the center to the start of the curve
ax = x + Math.cos(startAngle / 180 * Math.PI) * radius;
ay = y + Math.sin(startAngle / 180 * Math.PI) * yRadius;
this.lineTo(ax, ay);
// Loop for drawing curve segments
for(i = 0; i < segs; ++i)
{
angle += theta;
angleMid = angle - (theta / 2);
bx = x + Math.cos(angle) * radius;
by = y + Math.sin(angle) * yRadius;
cx = x + Math.cos(angleMid) * (radius / Math.cos(theta / 2));
cy = y + Math.sin(angleMid) * (yRadius / Math.cos(theta / 2));
this._updateDrawingQueue(["quadraticCurveTo", cx, cy, bx, by]);
}
// close the wedge by drawing a line to the center
this._updateDrawingQueue(["lineTo", x, y]);
}
this._trackSize(-wt , -wt);
this._trackSize((radius * 2) + wt, (radius * 2) + wt);
return this;
},
/**
* Completes a drawing operation.
*
* @method end
*/
end: function() {
this._closePath();
return this;
},
/**
* Ends a fill and stroke
*
* @method closePath
*/
closePath: function()
{
this._updateDrawingQueue(["closePath"]);
this._updateDrawingQueue(["beginPath"]);
},
/**
* Clears the graphics object.
*
* @method clear
*/
/**
* Returns a linear gradient fill
*
* @method _getLinearGradient
* @return CanvasGradient
* @private
*/
_getLinearGradient: function() {
var isNumber = Y.Lang.isNumber,
fill = this.get("fill"),
stops = fill.stops,
opacity,
color,
stop,
i,
len = stops.length,
gradient,
x = 0,
y = 0,
w = this.get("width"),
h = this.get("height"),
r = fill.rotation || 0,
x1, x2, y1, y2,
cx = x + w/2,
cy = y + h/2,
offset,
radCon = Math.PI/180,
tanRadians = parseFloat(parseFloat(Math.tan(r * radCon)).toFixed(8));
if(Math.abs(tanRadians) * w/2 >= h/2)
{
if(r < 180)
{
y1 = y;
y2 = y + h;
}
else
{
y1 = y + h;
y2 = y;
}
x1 = cx - ((cy - y1)/tanRadians);
x2 = cx - ((cy - y2)/tanRadians);
}
else
{
if(r > 90 && r < 270)
{
x1 = x + w;
x2 = x;
}
else
{
x1 = x;
x2 = x + w;
}
y1 = ((tanRadians * (cx - x1)) - cy) * -1;
y2 = ((tanRadians * (cx - x2)) - cy) * -1;
}
gradient = this._context.createLinearGradient(x1, y1, x2, y2);
for(i = 0; i < len; ++i)
{
stop = stops[i];
opacity = stop.opacity;
color = stop.color;
offset = stop.offset;
if(isNumber(opacity))
{
opacity = Math.max(0, Math.min(1, opacity));
color = this._toRGBA(color, opacity);
}
else
{
color = TORGB(color);
}
offset = stop.offset || i/(len - 1);
gradient.addColorStop(offset, color);
}
return gradient;
},
/**
* Returns a radial gradient fill
*
* @method _getRadialGradient
* @return CanvasGradient
* @private
*/
_getRadialGradient: function() {
var isNumber = Y.Lang.isNumber,
fill = this.get("fill"),
r = fill.r,
fx = fill.fx,
fy = fill.fy,
stops = fill.stops,
opacity,
color,
stop,
i,
len = stops.length,
gradient,
x = 0,
y = 0,
w = this.get("width"),
h = this.get("height"),
x1, x2, y1, y2, r2,
xc, yc, xn, yn, d,
offset,
ratio,
stopMultiplier;
xc = x + w/2;
yc = y + h/2;
x1 = w * fx;
y1 = h * fy;
x2 = x + w/2;
y2 = y + h/2;
r2 = w * r;
d = Math.sqrt( Math.pow(Math.abs(xc - x1), 2) + Math.pow(Math.abs(yc - y1), 2) );
if(d >= r2)
{
ratio = d/r2;
//hack. gradient won't show if it is exactly on the edge of the arc
if(ratio === 1)
{
ratio = 1.01;
}
xn = (x1 - xc)/ratio;
yn = (y1 - yc)/ratio;
xn = xn > 0 ? Math.floor(xn) : Math.ceil(xn);
yn = yn > 0 ? Math.floor(yn) : Math.ceil(yn);
x1 = xc + xn;
y1 = yc + yn;
}
//If the gradient radius is greater than the circle's, adjusting the radius stretches the gradient properly.
//If the gradient radius is less than the circle's, adjusting the radius of the gradient will not work.
//Instead, adjust the color stops to reflect the smaller radius.
if(r >= 0.5)
{
gradient = this._context.createRadialGradient(x1, y1, r, x2, y2, r * w);
stopMultiplier = 1;
}
else
{
gradient = this._context.createRadialGradient(x1, y1, r, x2, y2, w/2);
stopMultiplier = r * 2;
}
for(i = 0; i < len; ++i)
{
stop = stops[i];
opacity = stop.opacity;
color = stop.color;
offset = stop.offset;
if(isNumber(opacity))
{
opacity = Math.max(0, Math.min(1, opacity));
color = this._toRGBA(color, opacity);
}
else
{
color = TORGB(color);
}
offset = stop.offset || i/(len - 1);
offset *= stopMultiplier;
if(offset <= 1)
{
gradient.addColorStop(offset, color);
}
}
return gradient;
},
/**
* Clears all values
*
* @method _initProps
* @private
*/
_initProps: function() {
this._methods = [];
this._lineToMethods = [];
this._xcoords = [0];
this._ycoords = [0];
this._width = 0;
this._height = 0;
this._left = 0;
this._top = 0;
this._right = 0;
this._bottom = 0;
this._currentX = 0;
this._currentY = 0;
},
/**
* Indicates a drawing has completed.
*
* @property _drawingComplete
* @type Boolean
* @private
*/
_drawingComplete: false,
/**
* Creates canvas element
*
* @method _createGraphic
* @return HTMLCanvasElement
* @private
*/
_createGraphic: function(config) {
var graphic = Y.config.doc.createElement('canvas');
return graphic;
},
/**
* Returns the points on a curve
*
* @method getBezierData
* @param Array points Array containing the begin, end and control points of a curve.
* @param Number t The value for incrementing the next set of points.
* @return Array
* @private
*/
getBezierData: function(points, t) {
var n = points.length,
tmp = [],
i,
j;
for (i = 0; i < n; ++i){
tmp[i] = [points[i][0], points[i][1]]; // save input
}
for (j = 1; j < n; ++j) {
for (i = 0; i < n - j; ++i) {
tmp[i][0] = (1 - t) * tmp[i][0] + t * tmp[parseInt(i + 1, 10)][0];
tmp[i][1] = (1 - t) * tmp[i][1] + t * tmp[parseInt(i + 1, 10)][1];
}
}
return [ tmp[0][0], tmp[0][1] ];
},
/**
* Calculates the bounding box for a curve
*
* @method _setCurveBoundingBox
* @param Array pts Array containing points for start, end and control points of a curve.
* @param Number w Width used to calculate the number of points to describe the curve.
* @param Number h Height used to calculate the number of points to describe the curve.
* @private
*/
_setCurveBoundingBox: function(pts, w, h)
{
var i = 0,
left = this._currentX,
right = left,
top = this._currentY,
bottom = top,
len = Math.round(Math.sqrt((w * w) + (h * h))),
t = 1/len,
wt = this._stroke && this._strokeWeight ? this._strokeWeight : 0,
xy;
for(i = 0; i < len; ++i)
{
xy = this.getBezierData(pts, t * i);
left = isNaN(left) ? xy[0] : Math.min(xy[0], left);
right = isNaN(right) ? xy[0] : Math.max(xy[0], right);
top = isNaN(top) ? xy[1] : Math.min(xy[1], top);
bottom = isNaN(bottom) ? xy[1] : Math.max(xy[1], bottom);
}
left = Math.round(left * 10)/10;
right = Math.round(right * 10)/10;
top = Math.round(top * 10)/10;
bottom = Math.round(bottom * 10)/10;
this._trackSize(right + wt, bottom + wt);
this._trackSize(left - wt, top - wt);
},
/**
* Updates the size of the graphics object
*
* @method _trackSize
* @param {Number} w width
* @param {Number} h height
* @private
*/
_trackSize: function(w, h) {
if (w > this._right) {
this._right = w;
}
if(w < this._left)
{
this._left = w;
}
if (h < this._top)
{
this._top = h;
}
if (h > this._bottom)
{
this._bottom = h;
}
this._width = this._right - this._left;
this._height = this._bottom - this._top;
}
};
Y.CanvasDrawing = CanvasDrawing;
