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module Plottable {
export class DragZoomLayer extends Components.SelectionBoxLayer {
private _dragInteraction: Interactions.Drag;
private _doubleClickInteraction: Interactions.DoubleClick;
private xDomainToRestore: any[];
private yDomainToRestore: any[];
private isZoomed = false;
private easeFn: (t: number) => number = d3.ease("cubic-in-out");
private _animationTime = 750;
/* Constructs a SelectionBoxLayer with an attached DragInteraction and ClickInteraction.
* On drag, it triggers an animated zoom into the box that was dragged.
* On double click, it zooms back out to the original view, before any zooming.
* The zoom animation uses an easing function (default d3.ease("cubic-in-out")) and is customizable.
* Usage: Construct the selection box layer and attach x and y scales, and then add the layer
* over the plot you are zooming on using a Component Group.
* TODO(danmane) - merge this into Plottable
*/
constructor(xScale: QuantitativeScale<number | { valueOf(): number }>,
yScale: QuantitativeScale<number | { valueOf(): number }>) {
super();
this.xScale(xScale);
this.yScale(yScale);
this._dragInteraction = new Interactions.Drag();
this._dragInteraction.attachTo(this);
this._doubleClickInteraction = new Interactions.DoubleClick();
this._doubleClickInteraction.attachTo(this);
this.setupCallbacks();
}
private setupCallbacks() {
let dragging = false;
this._dragInteraction.onDragStart((startPoint: Point) => {
this.bounds({
topLeft: startPoint,
bottomRight: startPoint,
});
});
this._dragInteraction.onDrag((startPoint, endPoint) => {
this.bounds({topLeft: startPoint, bottomRight: endPoint});
this.boxVisible(true);
dragging = true;
});
this._dragInteraction.onDragEnd((startPoint, endPoint) => {
this.boxVisible(false);
this.bounds({topLeft: startPoint, bottomRight: endPoint});
if (dragging) {
this.zoom();
}
dragging = false;
});
this._doubleClickInteraction.onDoubleClick(this.unzoom.bind(this));
}
/* Set the time (in ms) over which the zoom will interpolate.
* 0 implies no interpolation. (ie zoom is instant)
*/
public animationTime(): number;
public animationTime(animationTime: number): DragZoomLayer;
public animationTime(animationTime?: number): any {
if (animationTime == null) {
return this._animationTime;
}
if (animationTime < 0) {
throw new Error("animationTime cannot be negative");
}
this._animationTime = animationTime;
return this;
}
/* Set the easing function, which determines how the zoom interpolates over time. */
public ease(fn: (t: number) => number): DragZoomLayer {
if (typeof(fn) !== "function") {
throw new Error("ease function must be a function");
}
if (fn(0) !== 0 || fn(1) !== 1) {
Utils.Window.warn("Easing function does not maintain invariant f(0)==0 && f(1)==1. Bad behavior may result.");
}
this.easeFn = fn;
return this;
}
// Zoom into extent of the selection box bounds
private zoom() {
let x0: number = this.xExtent()[0].valueOf();
let x1: number = this.xExtent()[1].valueOf();
let y0: number = this.yExtent()[1].valueOf();
let y1: number = this.yExtent()[0].valueOf();
if (x0 === x1 || y0 === y1) {
return;
}
if (!this.isZoomed) {
this.isZoomed = true;
this.xDomainToRestore = this.xScale().domain();
this.yDomainToRestore = this.yScale().domain();
}
this.interpolateZoom(x0, x1, y0, y1);
}
// Restore the scales to their state before any zoom
private unzoom() {
if (!this.isZoomed) {
return;
}
this.isZoomed = false;
this.interpolateZoom(this.xDomainToRestore[0], this.xDomainToRestore[1],
this.yDomainToRestore[0], this.yDomainToRestore[1]);
}
// If we are zooming, disable interactions, to avoid contention
private isZooming(isZooming: boolean) {
this._dragInteraction.enabled(!isZooming);
this._doubleClickInteraction.enabled(!isZooming);
}
private interpolateZoom(x0f: number, x1f: number, y0f: number, y1f: number) {
let x0s: number = this.xScale().domain()[0].valueOf();
let x1s: number = this.xScale().domain()[1].valueOf();
let y0s: number = this.yScale().domain()[0].valueOf();
let y1s: number = this.yScale().domain()[1].valueOf();
// Copy a ref to the ease fn, so that changing ease wont affect zooms in progress
let ease = this.easeFn;
let interpolator = (a: number, b: number, p: number) => d3.interpolateNumber(a, b)(ease(p));
this.isZooming(true);
let start = Date.now();
let draw = () => {
let now = Date.now();
let passed = now - start;
let p = this._animationTime === 0 ? 1 : Math.min(1, passed / this._animationTime);
let x0 = interpolator(x0s, x0f, p);
let x1 = interpolator(x1s, x1f, p);
let y0 = interpolator(y0s, y0f, p);
let y1 = interpolator(y1s, y1f, p);
this.xScale().domain([x0, x1]);
this.yScale().domain([y0, y1]);
if (p < 1) {
Utils.DOM.requestAnimationFramePolyfill(draw);
} else {
this.isZooming(false);
}
};
draw();
}
}
}
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