Hector Dearman | 9e06154 | 2018-09-27 11:00:25 +0100 | [diff] [blame] | 1 | // Copyright (C) 2018 The Android Open Source Project |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | // TODO(hjd): Dedupe these. |
| 16 | const SLICE_HEIGHT = 30; |
| 17 | const TRACK_PADDING = 5; |
| 18 | |
| 19 | /** |
| 20 | * Checker board the range [leftPx, rightPx]. |
| 21 | */ |
| 22 | export function checkerboard( |
| 23 | ctx: CanvasRenderingContext2D, leftPx: number, rightPx: number): void { |
| 24 | const widthPx = rightPx - leftPx; |
| 25 | ctx.font = '12px Google Sans'; |
| 26 | ctx.fillStyle = '#eee'; |
| 27 | ctx.fillRect(leftPx, TRACK_PADDING, widthPx, SLICE_HEIGHT); |
| 28 | ctx.fillStyle = '#666'; |
| 29 | ctx.fillText( |
| 30 | 'loading...', |
| 31 | leftPx + widthPx / 2, |
| 32 | TRACK_PADDING + SLICE_HEIGHT / 2, |
| 33 | widthPx); |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * Checker board everything between [startPx, endPx] except [leftPx, rightPx]. |
| 38 | */ |
| 39 | export function checkerboardExcept( |
| 40 | ctx: CanvasRenderingContext2D, |
| 41 | startPx: number, |
| 42 | endPx: number, |
| 43 | leftPx: number, |
| 44 | rightPx: number): void { |
| 45 | // [leftPx, rightPx] doesn't overlap [startPx, endPx] at all: |
| 46 | if (rightPx <= startPx || leftPx >= endPx) { |
| 47 | checkerboard(ctx, startPx, endPx); |
| 48 | return; |
| 49 | } |
| 50 | |
| 51 | // Checkerboard [startPx, leftPx]: |
| 52 | if (leftPx > startPx) { |
| 53 | checkerboard(ctx, startPx, leftPx); |
| 54 | } |
| 55 | |
| 56 | // Checkerboard [rightPx, endPx]: |
| 57 | if (rightPx < endPx) { |
| 58 | checkerboard(ctx, rightPx, endPx); |
| 59 | } |
| 60 | } |