File size: 4,688 Bytes
2409829
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
<script lang="ts" context="module">
	export type RulerDirection = "Horizontal" | "Vertical";
</script>

<script lang="ts">
	import { onMount } from "svelte";

	const RULER_THICKNESS = 16;
	const MAJOR_MARK_THICKNESS = 16;
	const MINOR_MARK_THICKNESS = 6;
	const MICRO_MARK_THICKNESS = 3;

	export let direction: RulerDirection = "Vertical";
	export let origin: number;
	export let numberInterval: number;
	export let majorMarkSpacing: number;
	export let minorDivisions = 5;
	export let microDivisions = 2;

	let rulerInput: HTMLDivElement | undefined;
	let rulerLength = 0;
	let svgBounds = { width: "0px", height: "0px" };

	$: svgPath = computeSvgPath(direction, origin, majorMarkSpacing, minorDivisions, microDivisions, rulerLength);
	$: svgTexts = computeSvgTexts(direction, origin, majorMarkSpacing, numberInterval, rulerLength);

	function computeSvgPath(direction: RulerDirection, origin: number, majorMarkSpacing: number, minorDivisions: number, microDivisions: number, rulerLength: number): string {
		const isVertical = direction === "Vertical";
		const lineDirection = isVertical ? "H" : "V";

		const offsetStart = mod(origin, majorMarkSpacing);
		const shiftedOffsetStart = offsetStart - majorMarkSpacing;

		const divisions = majorMarkSpacing / minorDivisions / microDivisions;
		const majorMarksFrequency = minorDivisions * microDivisions;

		let dPathAttribute = "";
		let i = 0;
		for (let location = shiftedOffsetStart; location < rulerLength; location += divisions) {
			let length;
			if (i % majorMarksFrequency === 0) length = MAJOR_MARK_THICKNESS;
			else if (i % microDivisions === 0) length = MINOR_MARK_THICKNESS;
			else length = MICRO_MARK_THICKNESS;
			i += 1;

			const destination = Math.round(location) + 0.5;
			const startPoint = isVertical ? `${RULER_THICKNESS - length},${destination}` : `${destination},${RULER_THICKNESS - length}`;
			dPathAttribute += `M${startPoint}${lineDirection}${RULER_THICKNESS} `;
		}

		return dPathAttribute;
	}

	function computeSvgTexts(direction: RulerDirection, origin: number, majorMarkSpacing: number, numberInterval: number, rulerLength: number): { transform: string; text: string }[] {
		const isVertical = direction === "Vertical";

		const offsetStart = mod(origin, majorMarkSpacing);
		const shiftedOffsetStart = offsetStart - majorMarkSpacing;

		const svgTextCoordinates = [];

		let labelNumber = (Math.ceil(-origin / majorMarkSpacing) - 1) * numberInterval;

		for (let location = shiftedOffsetStart; location < rulerLength; location += majorMarkSpacing) {
			const destination = Math.round(location);
			const x = isVertical ? 9 : destination + 2;
			const y = isVertical ? destination + 1 : 9;

			let transform = `translate(${x} ${y})`;
			if (isVertical) transform += " rotate(270)";

			const text = numberInterval >= 1 ? `${labelNumber}` : labelNumber.toFixed(Math.abs(Math.log10(numberInterval))).replace(/\.0+$/, "");

			svgTextCoordinates.push({ transform, text });

			labelNumber += numberInterval;
		}

		return svgTextCoordinates;
	}

	export function resize() {
		if (!rulerInput) return;

		const isVertical = direction === "Vertical";

		const newLength = isVertical ? rulerInput.clientHeight : rulerInput.clientWidth;
		const roundedUp = (Math.floor(newLength / majorMarkSpacing) + 1) * majorMarkSpacing;

		if (roundedUp !== rulerLength) {
			rulerLength = roundedUp;
			const thickness = `${RULER_THICKNESS}px`;
			const length = `${roundedUp}px`;
			svgBounds = isVertical ? { width: thickness, height: length } : { width: length, height: thickness };
		}
	}

	// Modulo function that works for negative numbers, unlike the JS `%` operator
	function mod(n: number, m: number): number {
		const remainder = n % m;
		return Math.floor(remainder >= 0 ? remainder : remainder + m);
	}

	onMount(resize);
</script>

<div class={`ruler-input ${direction.toLowerCase()}`} bind:this={rulerInput}>
	<svg style:width={svgBounds.width} style:height={svgBounds.height}>
		<path d={svgPath} />
		{#each svgTexts as svgText}
			<text transform={svgText.transform}>{svgText.text}</text>
		{/each}
	</svg>
</div>

<style lang="scss" global>
	.ruler-input {
		flex: 1 1 100%;
		background: var(--color-2-mildblack);
		overflow: hidden;
		position: relative;
		box-sizing: border-box;

		&.horizontal {
			height: 16px;
			border-bottom: 1px solid var(--color-5-dullgray);
		}

		&.vertical {
			width: 16px;
			border-right: 1px solid var(--color-5-dullgray);

			svg text {
				text-anchor: end;
			}
		}

		svg {
			position: absolute;

			path {
				stroke-width: 1px;
				stroke: var(--color-5-dullgray);
			}

			text {
				font-size: 12px;
				fill: var(--color-8-uppergray);
			}
		}
	}
</style>