snap.svg.free_transform.js

'use strict';

Snap.plugin(function(Snap, Element, Paper, global, Fragment) {
    Element.prototype.show = function() {
        this.attr('display', '');
    };

    Element.prototype.hide = function() {
        this.attr('display', 'none');
    };

    Paper.prototype.freeTransform = function(subject, options, callback) {
        // Enable method chaining.
        if (subject.freeTransform) {
            return subject.freeTransform;
        }

        // Add Array.map if the browser doesn't support it.
        if (!Array.prototype.hasOwnProperty('map')) {
            Array.prototype.map = function(callback, arg) {
                var i, mapped = [];
                for (i in this) {
                    if (this.hasOwnProperty(i)) {
                        mapped[i] = callback.call(arg, this[i], i, this);
                    }
                    return mapped;
                }
            };
        }

        // Add Array.indexOf if not builtin.
        if (!Array.prototype.hasOwnProperty('indexOf')) {
            Array.prototype.indexOf = function(obj, start) {
                for (var i = (start || 0), j = this.length; i < j; i++) {
                    if (this[i] === obj) {
                        return i;
                    }
                }
                return -1;
            };
        }

        var paper = this,
            bbox = subject.getBBox(true);

        var ft = subject.freeTransform = {
            // Keep track of transformations.
            attrs: {
                x: bbox.x,
                y: bbox.y,
                size: {
                    x: bbox.width,
                    y: bbox.height
                },
                center: {
                    x: bbox.x + bbox.width / 2,
                    y: bbox.y + bbox.height / 2
                },
                rotate: 0,
                scale: {
                    x: 1,
                    y: 1
                },
                translate: {
                    x: 0,
                    y: 0
                },
                ratio: 1
            },
            axes: null,
            bbox: null,
            callback: null,
            items: [],
            handles: {
                center: null,
                x: null,
                y: null
            },
            offset: {
                rotate: 0,
                scale: {
                    x: 1,
                    y: 1
                },
                translate: {
                    x: 0,
                    y: 0
                }
            },
            opts: {
                attrs: {
                    fill: '#fff',
                    stroke: '#1e609d'
                },
                distance: 1.2,
                drag: true,
                draw: ['bbox'],
                keepRatio: false,
                range: {
                    rotate: [-180, 180],
                    scale: [-99999, 99999]
                },
                rotate: true,
                scale: true,
                snap: {
                    rotate: 0,
                    scale: 0,
                    drag: 0
                },
                snapDist: {
                    rotate: 0,
                    scale: 0,
                    drag: 7
                },
                size: 4
            },
            subject: subject
        };

        /**
         * Update handles based on the element's transformations.
         */
        ft.updateHandles = function() {
            if (ft.handles.bbox || ft.opts.rotate.indexOf('self') >= 0) {
                var corners = getBBox();
            }

            // Get the element's rotation.
            var rad = {
                x: Snap.rad(ft.attrs.rotate),
                y: Snap.rad(ft.attrs.rotate + 90)
            };

            var radius = {
                x: ft.attrs.size.x / 2 * ft.attrs.scale.x,
                y: ft.attrs.size.y / 2 * ft.attrs.scale.y
            };

            // If the rotation is disabled, hide the handle.
            if (ft.opts.rotate.length) {
                ft.axes.map(function(axis) {
                    if (!ft.handles[axis]) {
                        return;
                    }
                    var cx = ft.attrs.center.x + ft.attrs.translate.x + (radius[axis] + 25) * Math.cos(rad[axis]),
                        cy = ft.attrs.center.y + ft.attrs.translate.y + (radius[axis] + 25) * Math.sin(rad[axis]);

                    ft.handles[axis].disc.attr({
                        cx: cx,
                        cy: cy
                    });

                    var end_x = ft.attrs.center.x + ft.attrs.translate.x + radius[axis] * Math.cos(rad[axis]),
                        end_y = ft.attrs.center.y + ft.attrs.translate.y + radius[axis] * Math.sin(rad[axis]);

                    ft.handles[axis].line.attr({
                        path: [
                            ['M', end_x, end_y],
                            ['L', cx, cy]
                        ]
                    });
                });
            }

            if (ft.bbox) {
                ft.bbox.attr({
                    path: [
                        ['M', corners[0].x, corners[0].y],
                        ['L', corners[1].x, corners[1].y],
                        ['L', corners[2].x, corners[2].y],
                        ['L', corners[3].x, corners[3].y],
                        ['L', corners[0].x, corners[0].y]
                    ]
                });

                // Allowed x, y scaling directions for bbox handles.
                var bboxHandleDirection = [
                    [-1, -1], [1, -1], [1, 1], [-1, 1],
                    [0, -1], [1,  0], [0, 1], [-1, 0]
                ];

                if (ft.handles.bbox) {
                    ft.handles.bbox.map(function(handle, i) {
                        var cx, cy, j, k;

                        if (handle.isCorner) {
                            cx = corners[i].x;
                            cy = corners[i].y;
                        } else {
                            j  = i % 4;
                            k  = (j + 1) % corners.length;
                            cx = (corners[j].x + corners[k].x) / 2;
                            cy = (corners[j].y + corners[k].y) / 2;
                        }

                        handle.element.attr({
                            x: cx - (handle.isCorner ? ft.opts.size.bboxCorners : ft.opts.size.bboxSides),
                            y: cy - (handle.isCorner ? ft.opts.size.bboxCorners : ft.opts.size.bboxSides),
                            transform: 'R' + ft.attrs.rotate
                        });

                        handle.x = bboxHandleDirection[i][0];
                        handle.y = bboxHandleDirection[i][1];
                    });
                }
            }

            if (ft.circle) {
                ft.circle.attr({
                    cx: ft.attrs.center.x + ft.attrs.translate.x,
                    cy: ft.attrs.center.y + ft.attrs.translate.y,
                    r:  Math.max(radius.x, radius.y) * ft.opts.distance
                });
            }

            if (ft.handles.center) {
                ft.handles.center.disc.attr({
                    cx: ft.attrs.center.x + ft.attrs.translate.x,
                    cy: ft.attrs.center.y + ft.attrs.translate.y
                });
            }

            return ft;
        };

        /**
         * Add handles.
         */
        ft.showHandles = function() {
            ft.hideHandles();

            ft.axes.map(function(axis) {
                ft.handles[axis] = {};

                ft.handles[axis].line = paper
                    .path([
                        ['M', ft.attrs.center.x + ft.attrs.size.x / 2, ft.attrs.center.y]
                    ])
                    .attr({
                        stroke: ft.opts.attrs.stroke,
                        'stroke-dasharray': '4,3',
                        opacity: .5
                    });

                ft.handles[axis].disc = paper
                    .circle(ft.attrs.center.x, ft.attrs.center.y, ft.opts.size.axes)
                    .attr(ft.opts.attrs)
                    .attr('cursor', 'crosshair');

                // If the rotation is disabled, hide the handle.
                if (!ft.opts.rotate.length) {
                    ft.handles[axis].disc.hide();
                }
            });

            if (ft.opts.draw.indexOf('bbox') >= 0) {
                ft.bbox = paper
                    .path('')
                    .attr({
                        stroke: ft.opts.attrs.stroke,
                        'stroke-dasharray': '4,3',
                        fill: 'none',
                        opacity: .5
                    });

                ft.handles.bbox = [];

                var i, handle, cursor;

                for (i = (ft.opts.scale.indexOf('bboxCorners') >= 0 ? 0 : 4); i < (ft.opts.scale.indexOf('bboxSides') === -1 ? 4 : 8); i ++) {
                    handle = {
                        axis: i % 2 ? 'x' : 'y',
                        isCorner: i < 4
                    };

                    if (!handle.isCorner) {
                        cursor = (handle.axis == 'x') ? 'e-resize' : 'n-resize';
                    } else {
                        cursor = (handle.axis == 'x') ? 'sw-resize' : 'nw-resize';
                    }

                    handle.element = paper
                        .rect(ft.attrs.center.x, ft.attrs.center.y, ft.opts.size[handle.isCorner ? 'bboxCorners' : 'bboxSides'] * 2, ft.opts.size[handle.isCorner ? 'bboxCorners' : 'bboxSides'] * 2)
                        .attr(ft.opts.attrs)
                        .attr('cursor', cursor);

                    ft.handles.bbox[i] = handle;
                }
            }

            if (ft.opts.draw.indexOf('circle') !== -1) {
                ft.circle = paper
                    .circle(0, 0, 0)
                    .attr({
                        stroke: ft.opts.attrs.stroke,
                        'stroke-dasharray': '4,3',
                        opacity: .3
                    });
            }

            if (ft.opts.drag.indexOf('center') !== -1) {
                ft.handles.center = {};

                ft.handles.center.disc = paper
                    .circle(ft.attrs.center.x, ft.attrs.center.y, ft.opts.size.center)
                    .attr(ft.opts.attrs);
            }

            // Drag x, y handles.
            ft.axes.map(function(axis) {
                if (!ft.handles[axis]) {
                    return;
                }

                var rotate = ft.opts.rotate.indexOf('axis' + axis.toUpperCase()) !== -1,
                    scale  = ft.opts.scale .indexOf('axis' + axis.toUpperCase()) !== -1;

                ft.handles[axis].disc.drag(function(dx, dy) {
                    var cx = dx + ft.handles[axis].disc.ox,
                        cy = dy + ft.handles[axis].disc.oy;

                    var mirrored = {
                        x: ft.o.scale.x < 0,
                        y: ft.o.scale.y < 0
                    };

                    if (rotate) {
                        var rad = Math.atan2(cy - ft.o.center.y - ft.o.translate.y, cx - ft.o.center.x - ft.o.translate.x);

                        ft.attrs.rotate = Snap.deg(rad) - (axis === 'y' ? 90 : 0);

                        if (mirrored[axis]) {
                            ft.attrs.rotate -= 180;
                        }
                    }

                    var radius = Math.sqrt(Math.pow(cx - ft.o.center.x - ft.o.translate.x, 2) + Math.pow(cy - ft.o.center.y - ft.o.translate.y, 2));

                    applyLimits();

                    // Maintain aspect ratio.
                    if (ft.opts.keepRatio.indexOf('axis' + axis.toUpperCase()) !== -1) {
                        keepRatio(axis);
                    } else {
                        ft.attrs.ratio = ft.attrs.scale.x / ft.attrs.scale.y;
                    }

                    if (ft.attrs.scale.x && ft.attrs.scale.y) {
                        ft.apply();
                    }

                    asyncCallback([rotate ? 'rotate' : null, scale ? 'scale' : null]);
                }, function() {
                    // Offset values.
                    ft.o = cloneObj(ft.attrs);

                    ft.handles[axis].disc.ox = parseInt(this.attr('cx'));
                    ft.handles[axis].disc.oy = parseInt(this.attr('cy'));

                    asyncCallback([rotate ? 'rotate start' : null, scale ? 'scale start' : null]);
                }, function() {
                    asyncCallback([rotate ? 'rotate end' : null, scale ? 'scale end' : null]);
                });
            });

            // Drag bbox handles.
            if (ft.opts.draw.indexOf('bbox') >= 0 && (ft.opts.scale.indexOf('bboxCorners') !== -1 || ft.opts.scale.indexOf('bboxSides') !== -1)) {
                ft.handles.bbox.map(function(handle) {
                    handle.element.drag(function(dx, dy) {
                        var sin, cos, rx, ry, rdx, rdy, mx, my, sx, sy,
                            previous = cloneObj(ft.attrs);

                        sin = ft.o.rotate.sin;
                        cos = ft.o.rotate.cos;

                        // First rotate dx, dy to element alignment.
                        rx = dx * cos - dy * sin;
                        ry = dx * sin + dy * cos;

                        rx *= Math.abs(handle.x);
                        ry *= Math.abs(handle.y);

                        // And finally rotate back to canvas alignment.
                        rdx = rx * cos + ry * sin;
                        rdy = rx * -sin + ry * cos;

                        ft.attrs.translate = {
                            x: ft.o.translate.x + rdx / 2,
                            y: ft.o.translate.y + rdy / 2
                        };

                        // Mouse position, relative to element center after translation.
                        mx = ft.o.handlePos.cx + dx - ft.attrs.center.x - ft.attrs.translate.x;
                        my = ft.o.handlePos.cy + dy - ft.attrs.center.y - ft.attrs.translate.y;

                        // Position rotated to align with element.
                        rx = mx * cos - my * sin;
                        ry = mx * sin + my * cos;

                        // Maintain aspect ratio.
                        if (handle.isCorner && ft.opts.keepRatio.indexOf('bboxCorners') !== -1) {
                            var ratio = (ft.attrs.size.x * ft.attrs.scale.x) / (ft.attrs.size.y * ft.attrs.scale.y),
                                tdy = rx * handle.x * ( 1 / ratio ),
                                tdx = ry * handle.y * ratio;

                            if (tdx > tdy * ratio) {
                                rx = tdx * handle.x;
                            } else {
                                ry = tdy * handle.y;
                            }
                        }

                        // Scale element so that handle is at mouse position
                        sx = rx * 2 * handle.x / ft.o.size.x;
                        sy = ry * 2 * handle.y / ft.o.size.y;

                        ft.attrs.scale = {
                            x: sx || ft.attrs.scale.x,
                            y: sy || ft.attrs.scale.y
                        };

                        // Check boundaries.
                        if (!isWithinBoundaries().x || !isWithinBoundaries().y) {
                            ft.attrs = previous;
                        }

                        applyLimits();

                        // Maintain aspect ratio.
                        if ((handle.isCorner && ft.opts.keepRatio.indexOf('bboxCorners') !== -1) || (!handle.isCorner && ft.opts.keepRatio.indexOf('bboxSides') !== -1)) {
                            keepRatio(handle.axis);

                            var trans = {
                                x: (ft.attrs.scale.x - ft.o.scale.x) * ft.o.size.x * handle.x,
                                y: (ft.attrs.scale.y - ft.o.scale.y) * ft.o.size.y * handle.y
                            };

                            rx = trans.x * cos + trans.y * sin;
                            ry = -trans.x * sin + trans.y * cos;

                            ft.attrs.translate.x = ft.o.translate.x + rx / 2;
                            ft.attrs.translate.y = ft.o.translate.y + ry / 2;
                        }

                        ft.attrs.ratio = ft.attrs.scale.x / ft.attrs.scale.y;

                        asyncCallback(['scale']);

                        ft.apply();
                    }, function() {
                        var rotate = Snap.rad((360 - ft.attrs.rotate) % 360),
                            handlePos = {
                                x: parseInt(handle.element.attr('x')),
                                y: parseInt(handle.element.attr('y'))
                            };

                        // Offset values.
                        ft.o = cloneObj(ft.attrs);

                        ft.o.handlePos = {
                            cx: handlePos.x + ft.opts.size[handle.isCorner ? 'bboxCorners' : 'bboxSides'],
                            cy: handlePos.y + ft.opts.size[handle.isCorner ? 'bboxCorners' : 'bboxSides']
                        };

                        // Pre-compute rotation sin & cos for efficiency.
                        ft.o.rotate = {
                            sin: Math.sin(rotate),
                            cos: Math.cos(rotate)
                        };

                        asyncCallback(['scale start']);
                    }, function() {
                        asyncCallback(['scale end']);
                    });
                });
            }

            // Drag element and center handle.
            var draggables = [];

            if (ft.opts.drag.indexOf('self') >= 0 && ft.opts.scale.indexOf('self') === -1 && ft.opts.rotate.indexOf('self') === -1) {
                draggables.push(subject);
            }

            if (ft.opts.drag.indexOf('center') >= 0) {
                draggables.push(ft.handles.center.disc);
            }

            ft.attachHandlers(draggables);

            var rotate = ft.opts.rotate.indexOf('self') >= 0,
                scale  = ft.opts.scale.indexOf('self') >= 0;

            if (rotate || scale) {
                subject.drag(function(dx, dy, x, y) {
                    if (rotate) {
                        var rad = Math.atan2(y - ft.o.center.y - ft.o.translate.y, x - ft.o.center.x - ft.o.translate.x);
                        ft.attrs.rotate = ft.o.rotate + Snap.deg(rad) - ft.o.deg;
                    }

                    var mirrored = {
                        x: ft.o.scale.x < 0,
                        y: ft.o.scale.y < 0
                    };

                    if (scale) {
                        var radius = Math.sqrt(Math.pow(x - ft.o.center.x - ft.o.translate.x, 2) + Math.pow(y - ft.o.center.y - ft.o.translate.y, 2));

                        ft.attrs.scale.x = ft.attrs.scale.y = (mirrored.x ? -1 : 1) * ft.o.scale.x + (radius - ft.o.radius) / (ft.o.size.x / 2);

                        if (mirrored.x) {
                            ft.attrs.scale.x *= -1;
                        }
                        if (mirrored.y) {
                            t.attrs.scale.y *= -1;
                        }
                    }

                    applyLimits();

                    ft.apply();

                    asyncCallback([rotate ? 'rotate' : null, scale ? 'scale' : null]);
                }, function(x, y) {
                    // Offset values
                    ft.o = cloneObj(ft.attrs);

                    ft.o.deg = Math.atan2(y - ft.o.center.y - ft.o.translate.y, x - ft.o.center.x - ft.o.translate.x) * 180 / Math.PI;

                    ft.o.radius = Math.sqrt(Math.pow(x - ft.o.center.x - ft.o.translate.x, 2) + Math.pow(y - ft.o.center.y - ft.o.translate.y, 2));

                    asyncCallback([rotate ? 'rotate start' : null, scale ? 'scale start' : null]);
                }, function() {
                    asyncCallback([rotate ? 'rotate end' : null, scale ? 'scale end' : null]);
                });
            }

            ft.updateHandles();

            return ft;
        };

        /**
         * Remove handles.
         */
        ft.hideHandles = function(opts) {
            var opts = opts || {}

            if (opts.undrag === undefined) {
                opts.undrag = true;
            }

            if (opts.undrag) {
                ft.items.map(function(item) {
                    item.el.undrag();
                });
            }

            if (ft.handles.center) {
                ft.handles.center.disc.remove();
                ft.handles.center = null;
            }

            ['x', 'y'].map(function(axis) {
                if (ft.handles[axis]) {
                    ft.handles[axis].disc.remove();
                    ft.handles[axis].line.remove();
                    ft.handles[axis] = null;
                }
            });

            if (ft.bbox) {
                ft.bbox.remove();
                ft.bbox = null;

                if (ft.handles.bbox) {
                    ft.handles.bbox.map(function(handle) {
                        handle.element.remove();
                    });
                    ft.handles.bbox = null;
                }
            }

            if (ft.circle) {
                ft.circle.remove();
                ft.circle = null;
            }

            return ft;
        };

        ft.attachHandlers = function(draggables) {
            draggables.map(function (draggable) {
                draggable.drag(function (dx, dy) {
                    ft.attrs.translate.x = ft.o.translate.x + dx;
                    ft.attrs.translate.y = ft.o.translate.y + dy;

                    var bbox = cloneObj(ft.o.bbox);

                    bbox.x += dx;
                    bbox.y += dy;

                    applyLimits(bbox);

                    asyncCallback(['drag']);

                    ft.apply();
                }, function() {
                    // Offset values.
                    ft.o = cloneObj(ft.attrs);

                    if (ft.opts.snap.drag) {
                        ft.o.bbox = subject.getBBox();
                    }

                    ft.axes.map(function(axis) {
                        if (ft.handles[axis]) {
                            ft.handles[axis].disc.ox = parseInt(ft.handles[axis].disc.attr('cx'));
                            ft.handles[axis].disc.oy = parseInt(ft.handles[axis].disc.attr('cy'));
                        }
                    });

                    asyncCallback(['drag start']);
                }, function() {
                    asyncCallback(['drag end']);
                });
            });
        };

        /**
         * Override defaults.
         */
        ft.setOpts = function(options, callback) {
            if (callback !== undefined) {
                ft.callback = typeof callback === 'function' ? callback : false;
            }

            var i, j;

            for (i in options) {
                if (options[i] && options[i].constructor === Object) {
                    if (ft.opts[i] === false) {
                        ft.opts[i] = {};
                    }
                    for (j in options[i]) {
                        if (options[i].hasOwnProperty(j)) {
                            ft.opts[i][j] = options[i][j];
                        }
                    }
                } else {
                    ft.opts[i] = options[i];
                }
            }

            if (ft.opts.drag === true) {
                ft.opts.drag = ['self'];
            }
            if (ft.opts.keepRatio === true) {
                ft.opts.keepRatio = ['bboxCorners', 'bboxSides'];
            }
            if (ft.opts.rotate === true) {
                ft.opts.rotate = ['axisX', 'axisY'];
            }
            if (ft.opts.scale === true) {
                ft.opts.scale = ['axisX', 'axisY', 'bboxCorners', 'bboxSides'];
            }

            ['drag', 'draw', 'keepRatio', 'rotate', 'scale'].map(function (option) {
                if (ft.opts[option] === false) {
                    ft.opts[option] = [];
                }
            });

            ft.axes = [];

            if (ft.opts.rotate.indexOf('axisX') >= 0 || ft.opts.scale.indexOf('axisX') >= 0) {
                ft.axes.push('x');
            }

            ['drag', 'rotate', 'scale'].map(function (option) {
                if (!ft.opts.snapDist[option]) {
                    ft.opts.snapDist[option] = ft.opts.snap[option];
                }
            });

            // Force numbers.
            ft.opts.range = {
                rotate: [parseFloat(ft.opts.range.rotate[0]), parseFloat(ft.opts.range.rotate[1])],
                scale:  [parseFloat(ft.opts.range.scale[0]), parseFloat(ft.opts.range.scale[1])]
            };

            ft.opts.snap = {
                drag: parseFloat(ft.opts.snap.drag),
                rotate: parseFloat(ft.opts.snap.rotate),
                scale: parseFloat(ft.opts.snap.scale)
            };

            ft.opts.snapDist = {
                drag: parseFloat(ft.opts.snapDist.drag),
                rotate: parseFloat(ft.opts.snapDist.rotate),
                scale: parseFloat(ft.opts.snapDist.scale)
            };

            if (typeof ft.opts.size === 'string') {
                ft.opts.size = parseFloat(ft.opts.size);
            }

            if (!isNaN(ft.opts.size)) {
                ft.opts.size = {
                    axes: ft.opts.size,
                    bboxCorners: ft.opts.size,
                    bboxSides: ft.opts.size,
                    center: ft.opts.size
                };
            }

            ft.showHandles();

            asyncCallback(['init']);

            return ft;
        };

        ft.setOpts(options, callback);

        /**
         * Apply transformations, optionally update attributes manually.
         */
        ft.apply = function() {
            ft.items.map(function(item, i) {
                // Take offset values into account.
                var center = {
                        x: ft.attrs.center.x + ft.offset.translate.x,
                        y: ft.attrs.center.y + ft.offset.translate.y
                    },
                    rotate = ft.attrs.rotate - ft.offset.rotate,
                    scale = {
                        x: ft.attrs.scale.x / ft.offset.scale.x,
                        y: ft.attrs.scale.y / ft.offset.scale.y
                    },
                    translate = {
                        x: ft.attrs.translate.x - ft.offset.translate.x,
                        y: ft.attrs.translate.y - ft.offset.translate.y
                    };

                item.el.transform([
                    'R' + rotate, center.x, center.y,
                    'S' + scale.x, scale.y, center.x, center.y,
                    'T' + translate.x, translate.y
                ].join());

                asyncCallback(['apply']);

                ft.updateHandles();
            });

            return ft;
        };

        /**
         * Clean exit.
         */
        ft.unplug = function() {
            var attrs = ft.attrs;

            ft.hideHandles();

            delete subject.freeTransform;

            return attrs;
        };

        // Store attributes for each item
        function scan(subject) {
            (subject.type === 'set' ? subject.items : [subject]).map(function (item) {
                if (item.type === 'set') {
                    scan(item);
                } else {
                    ft.items.push({
                        el: item,
                        attrs: {
                            rotate: 0,
                            scale: { x: 1, y: 1 },
                            translate: { x: 0, y: 0 }
                        },
                        transformString: item.transform().toString()
                    });
                }
            });
        }

        ft.scanItems = function() {
            ft.items = [];
            scan(subject);

            // Get the current transform values for each item
            ft.items.map(function(item, i) {
                if (item.el._ && item.el._.transform && typeof item.el._.transform === 'object') {
                    item.el._.transform.map(function(transform) {
                        if (transform[0]) {
                            switch (transform[0].toUpperCase()) {
                                case 'T':
                                    ft.items[i].attrs.translate.x += transform[1];
                                    ft.items[i].attrs.translate.y += transform[2];
                                    break;
                                case 'S':
                                    ft.items[i].attrs.scale.x *= transform[1];
                                    ft.items[i].attrs.scale.y *= transform[2];
                                    break;
                                case 'R':
                                    ft.items[i].attrs.rotate += transform[1];
                                    break;
                            }
                        }
                    });
                }
            });
        };

        ft.scanItems();

        // If subject is not of type set, the first item _is_ the subject
        if (subject.type !== 'set') {
            ft.attrs.rotate = ft.items[0].attrs.rotate;
            ft.attrs.scale = ft.items[0].attrs.scale;
            ft.attrs.translate = ft.items[0].attrs.translate;

            ft.items[0].attrs = {
                rotate: 0,
                scale: {
                    x: 1, y: 1
                },
                translate: {
                    x: 0,
                    y: 0
                }
            };

            ft.items[0].transformString = '';
        }

        ft.attrs.ratio = ft.attrs.scale.x / ft.attrs.scale.y;

        /**
         * Get rotated bounding box
         */
        function getBBox() {
            var rad = {
                x: Snap.rad(ft.attrs.rotate),
                y: Snap.rad(ft.attrs.rotate + 90)
            };

            var radius = {
                x: ft.attrs.size.x / 2 * ft.attrs.scale.x,
                y: ft.attrs.size.y / 2 * ft.attrs.scale.y
            };

            var corners = [],
                signs   = [
                    {x: -1, y: -1},
                    {x: 1, y: -1},
                    {x: 1, y: 1},
                    {x: -1, y: 1}
                ];

            signs.map(function(sign) {
                corners.push({
                    x: (ft.attrs.center.x + ft.attrs.translate.x + sign.x * radius.x * Math.cos(rad.x)) + sign.y * radius.y * Math.cos(rad.y),
                    y: (ft.attrs.center.y + ft.attrs.translate.y + sign.x * radius.x * Math.sin(rad.x)) + sign.y * radius.y * Math.sin(rad.y)
                });
            });

            return corners;
        }

        /**
         * Apply limits.
         */
        function applyLimits(bbox) {
            // Snap to grid
            if (bbox && ft.opts.snap.drag) {
                var x = bbox.x,
                    y = bbox.y,
                    dist = {
                        x: 0,
                        y: 0
                    },
                    snap = {
                        x: 0,
                        y: 0
                    };

                [0, 1].map(function() {
                    // Top and left sides first.
                    dist.x = x - Math.round(x / ft.opts.snap.drag) * ft.opts.snap.drag;
                    dist.y = y - Math.round(y / ft.opts.snap.drag) * ft.opts.snap.drag;

                    if (Math.abs(dist.x) <= ft.opts.snapDist.drag) {
                        snap.x = dist.x;
                    }
                    if (Math.abs(dist.y) <= ft.opts.snapDist.drag) {
                        snap.y = dist.y;
                    }

                    // Repeat for bottom and right sides.
                    x += bbox.width - snap.x;
                    y += bbox.height - snap.y;
                });

                ft.attrs.translate.x -= snap.x;
                ft.attrs.translate.y -= snap.y;
            }

            // Snap to angle, rotate with increments.
            dist = Math.abs(ft.attrs.rotate % ft.opts.snap.rotate);
            dist = Math.min(dist, ft.opts.snap.rotate - dist);

            if (dist < ft.opts.snapDist.rotate) {
                ft.attrs.rotate = Math.round(ft.attrs.rotate / ft.opts.snap.rotate) * ft.opts.snap.rotate;
            }

            // Snap to scale, scale with increments.
            dist = {
                x: Math.abs((ft.attrs.scale.x * ft.attrs.size.x) % ft.opts.snap.scale),
                y: Math.abs((ft.attrs.scale.y * ft.attrs.size.x) % ft.opts.snap.scale)
            };

            dist = {
                x: Math.min(dist.x, ft.opts.snap.scale - dist.x),
                y: Math.min(dist.y, ft.opts.snap.scale - dist.y)
            };

            if (dist.x < ft.opts.snapDist.scale) {
                ft.attrs.scale.x = Math.round(ft.attrs.scale.x * ft.attrs.size.x / ft.opts.snap.scale) * ft.opts.snap.scale / ft.attrs.size.x;
            }

            if (dist.y < ft.opts.snapDist.scale) {
                ft.attrs.scale.y = Math.round(ft.attrs.scale.y * ft.attrs.size.y / ft.opts.snap.scale) * ft.opts.snap.scale / ft.attrs.size.y;
            }

            // Limit range of rotation.
            if (ft.opts.range.rotate) {
                var deg = (360 + ft.attrs.rotate) % 360;

                if (deg > 180) {
                    deg -= 360;
                }

                if (deg < ft.opts.range.rotate[0]) {
                    ft.attrs.rotate += ft.opts.range.rotate[0] - deg;
                }
                if (deg > ft.opts.range.rotate[1]) {
                    ft.attrs.rotate += ft.opts.range.rotate[1] - deg;
                }
            }

            // Limit scale.
            if (ft.opts.range.scale) {
                if (ft.attrs.scale.x * ft.attrs.size.x < ft.opts.range.scale[0]) {
                    ft.attrs.scale.x = ft.opts.range.scale[0] / ft.attrs.size.x;
                }

                if (ft.attrs.scale.y * ft.attrs.size.y < ft.opts.range.scale[0]) {
                    ft.attrs.scale.y = ft.opts.range.scale[0] / ft.attrs.size.y;
                }

                if (ft.attrs.scale.x * ft.attrs.size.x > ft.opts.range.scale[1]) {
                    ft.attrs.scale.x = ft.opts.range.scale[1] / ft.attrs.size.x;
                }

                if (ft.attrs.scale.y * ft.attrs.size.y > ft.opts.range.scale[1]) {
                    ft.attrs.scale.y = ft.opts.range.scale[1] / ft.attrs.size.y;
                }
            }
        }

        function isWithinBoundaries() {
            return {
                x: ft.attrs.scale.x * ft.attrs.size.x >= ft.opts.range.scale[0] && ft.attrs.scale.x * ft.attrs.size.x <= ft.opts.range.scale[1],
                y: ft.attrs.scale.y * ft.attrs.size.y >= ft.opts.range.scale[0] && ft.attrs.scale.y * ft.attrs.size.y <= ft.opts.range.scale[1]
            };
        }

        function keepRatio(axis) {
            if (axis === 'x') {
                ft.attrs.scale.y = ft.attrs.scale.x / ft.attrs.ratio;
            } else {
                ft.attrs.scale.x = ft.attrs.scale.y * ft.attrs.ratio;
            }
        }

        /**
         * Recursive copy of object.
         */
        function cloneObj(obj) {
            var i, clone = {};
            for (i in obj) {
                clone[i] = typeof obj[i] === 'object' ? cloneObj(obj[i]) : obj[i];
            }
            return clone;
        }

        var timeout = false;

        /**
         * Call callback asynchronously for better performance
         */
        function asyncCallback(e) {
            if (!ft.callback) {
                return;
            }
            // Remove empty values
            var events = [];

            e.map(function(e, i) {
                if (e) {
                    events.push(e);
                }
            });

            clearTimeout(timeout);

            timeout = setTimeout(function() {
                if (ft.callback) {
                    ft.callback(ft, events);
                }
            }, 1);
        }

        ft.updateHandles();

        // Enable method chaining
        return ft;
    };
});