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// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import {assertFalse, assertTrue} from '../base/logging';
import {TimeSpan} from '../common/time';
const MAX_ZOOM_SPAN_SEC = 1e-6; // 1us.
/**
* Defines a mapping between number and seconds for the entire application.
* Linearly scales time values from boundsMs to pixel values in boundsPx and
* back.
*/
export class TimeScale {
private timeBounds: TimeSpan;
private _startPx: number;
private _endPx: number;
private secPerPx = 0;
constructor(timeBounds: TimeSpan, boundsPx: [number, number]) {
this.timeBounds = timeBounds;
this._startPx = boundsPx[0];
this._endPx = boundsPx[1];
this.updateSlope();
}
private updateSlope() {
this.secPerPx = this.timeBounds.duration / (this._endPx - this._startPx);
}
deltaTimeToPx(time: number): number {
return Math.round(time / this.secPerPx);
}
timeToPx(time: number): number {
return this._startPx + (time - this.timeBounds.start) / this.secPerPx;
}
pxToTime(px: number): number {
return this.timeBounds.start + (px - this._startPx) * this.secPerPx;
}
deltaPxToDuration(px: number): number {
return px * this.secPerPx;
}
setTimeBounds(timeBounds: TimeSpan) {
this.timeBounds = timeBounds;
this.updateSlope();
}
setLimitsPx(pxStart: number, pxEnd: number) {
assertFalse(pxStart === pxEnd);
assertTrue(pxStart >= 0 && pxEnd >= 0);
this._startPx = pxStart;
this._endPx = pxEnd;
this.updateSlope();
}
timeInBounds(time: number): boolean {
return this.timeBounds.isInBounds(time);
}
get startPx(): number {
return this._startPx;
}
get endPx(): number {
return this._endPx;
}
}
export function computeZoom(
scale: TimeScale, span: TimeSpan, zoomFactor: number, zoomPx: number):
TimeSpan {
const startPx = scale.startPx;
const endPx = scale.endPx;
const deltaPx = endPx - startPx;
const deltaTime = span.end - span.start;
const newDeltaTime = Math.max(deltaTime * zoomFactor, MAX_ZOOM_SPAN_SEC);
const clampedZoomPx = Math.max(startPx, Math.min(endPx, zoomPx));
const zoomTime = scale.pxToTime(clampedZoomPx);
const r = (clampedZoomPx - startPx) / deltaPx;
const newStartTime = zoomTime - newDeltaTime * r;
const newEndTime = newStartTime + newDeltaTime;
return new TimeSpan(newStartTime, newEndTime);
}
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