import { DoCheck } from 'angular2/lifecycle_hooks';
import { KeyValueDiffers } from 'angular2/src/core/change_detection';
import { ElementRef } from 'angular2/src/core/linker';
import { Renderer } from 'angular2/src/core/render';
/**
 * The `NgStyle` directive changes styles based on a result of expression evaluation.
 *
 * An expression assigned to the `ng-style` property must evaluate to an object and the
 * corresponding element styles are updated based on changes to this object. Style names to update
 * are taken from the object's keys, and values - from the corresponding object's values.
 *
 *##Syntax
 *
 * - `<div [ng-style]="{'font-style': style}"></div>`
 * - `<div [ng-style]="styleExp"></div>` - here the `styleExp` must evaluate to an object
 *
 * ### Example ([live demo](http://plnkr.co/edit/YamGS6GkUh9GqWNQhCyM?p=preview)):
 *
 * ```
 * import {Component, NgStyle} from 'angular2/angular2';
 *
 * @Component({
 *  selector: 'ng-style-example',
 *  template: `
 *    <h1 [ng-style]="{'font-style': style, 'font-size': size, 'font-weight': weight}">
 *      Change style of this text!
 *    </h1>
 *
 *    <hr>
 *
 *    <label>Italic: <input type="checkbox" (change)="changeStyle($event)"></label>
 *    <label>Bold: <input type="checkbox" (change)="changeWeight($event)"></label>
 *    <label>Size: <input type="text" [value]="size" (change)="size = $event.target.value"></label>
 *  `,
 *  directives: [NgStyle]
 * })
 * export class NgStyleExample {
 *    style = 'normal';
 *    weight = 'normal';
 *    size = '20px';
 *
 *    changeStyle($event: any) {
 *      this.style = $event.target.checked ? 'italic' : 'normal';
 *    }
 *
 *    changeWeight($event: any) {
 *      this.weight = $event.target.checked ? 'bold' : 'normal';
 *    }
 * }
 * ```
 *
 * In this example the `font-style`, `font-size` and `font-weight` styles will be updated
 * based on the `style` property's value changes.
 */
export declare class NgStyle implements DoCheck {
    private _differs;
    private _ngEl;
    private _renderer;
    constructor(_differs: KeyValueDiffers, _ngEl: ElementRef, _renderer: Renderer);
    rawStyle: any;
    doCheck(): void;
    private _applyChanges(changes);
    private _setStyle(name, val);
}