29:null 2a:["$","title",null,{"children":"Input: Two-variables input | Sylvain Lesage | Observable"}] 2f:Tf0f,function XYPad(x, y, options) { const w = (options && +options.w > 0 && Math.round(+options.w)) || 100; const h = (options && +options.h > 0 && Math.round(+options.h)) || 100; const dpr = devicePixelRatio; const canvas = html`

`; const ctx = canvas.getContext('2d'); ctx.scale(dpr, dpr); const xMin = 0; const yMin = 0; const xMax = w; const yMax = h; const xDefault = Math.round(xMax / 2); const yDefault = Math.round(yMax / 2); const parseX = value => value !== undefined && +value >= xMin && +value <= xMax ? Math.round(+value) : xDefault; const parseY = value => value !== undefined && +value >= yMin && +value <= yMax ? Math.round(+value) : yDefault; Object.defineProperties(canvas, { _x: { value: x || xDefault, enumerable: false, writable: true }, _y: { value: y || yDefault, enumerable: false, writable: true }, x: { get: function() { return this._x; }, set: function(value) { // Note that no 'input' event is emittted when the x property is set programatically const x = parseX(value); if (this._x !== x) { this._x = x; renderX(); } }, enumerable: true }, y: { get: function() { return this._y; }, set: function(value) { // Note that no 'input' event is emittted when the y property is set programatically const y = parseY(value); if (this._y !== y) { this._y = y; renderY(); } }, enumerable: true }, value: { get: function() { return { x: this.x, y: this.y }; }, set: function(value) { // Note that no 'input' event is emittted when the value property is set programatically const x = parseX(value && value.x); const y = parseY(value && value.y); if (this._x !== x && this._y !== y) { // Both have changed, do only one update this._x = x; this._y = y; render(); } else { // Let the setters do the work this.x = x; this.y = y; } }, enumerable: true } }); canvas.onclick = function(e) { const rect = canvas.getBoundingClientRect(); const x = Math.round(e.clientX - rect.left); const y = Math.round(e.clientY - rect.top); const xChanged = this.x !== x; const yChanged = this.y !== y; // We separate the four cases, as a template for // future more complex controls if (xChanged && yChanged) { this.value = { x, y }; this.dispatchEvent(new CustomEvent("inputX")); this.dispatchEvent(new CustomEvent("inputY")); this.dispatchEvent(new CustomEvent("input")); } else if (xChanged) { this.x = x; this.dispatchEvent(new CustomEvent("inputX")); this.dispatchEvent(new CustomEvent("input")); } else if (yChanged) { this.y = y; this.dispatchEvent(new CustomEvent("inputY")); this.dispatchEvent(new CustomEvent("input")); } }; // Init and return render(); return canvas; function renderX() { // Might be optimized if only x has changed render(); } function renderY() { // Might be optimized if only y has changed render(); } function render() { const ctx = canvas.getContext('2d'); const lineWidth = 1; const radius = 4; ctx.clearRect(0, 0, w, h); ctx.moveTo(canvas.x + radius, canvas.y); ctx.beginPath(); ctx.arc(canvas.x, canvas.y, radius, 0, 2 * Math.PI); ctx.moveTo(0, 0); ctx.rect(lineWidth / 2, lineWidth / 2, w - lineWidth, h - lineWidth); ctx.lineWidth = lineWidth; ctx.stroke(); } }30:[] 2d:{"id":"802dcf544f30c774","slug":"input-two-variables-input","title":"Input: Two-variables input","thumbnail":"e41042817c70058c9cefeb50cf505b8295416b6099d9b78fe80b422234a4bdc7","access_level":"public","create_time":"$D2020-03-05T23:29:06.664Z","update_time":"$D2020-03-06T01:16:39.147Z","view_time":null,"first_public_time":"$D2020-03-06T01:13:15.907Z","has_unpublished_edits":null,"fork":false,"stars":2,"starred":false,"owner":{"type":"team","id":"5c7b4ebed88da11a","login":"severo","name":"Sylvain Lesage","avatar_url":"https://avatars-next.observableusercontent.com/7713195c83e5bfd8090ffe70c871c23e743c711e9e712675c99a8960ca8c7944","tier":"starter_2024"},"version":209,"publish_version":209,"role":null,"authored":false,"authors":[{"type":"individual","id":"bf1872cca880d345","login":"severo","name":"Sylvain Lesage","avatar_url":"https://avatars-next.observableusercontent.com/7713195c83e5bfd8090ffe70c871c23e743c711e9e712675c99a8960ca8c7944","tier":null}],"members":[{"type":"individual","id":"bf1872cca880d345","login":"severo","name":"Sylvain Lesage","avatar_url":"https://avatars-next.observableusercontent.com/7713195c83e5bfd8090ffe70c871c23e743c711e9e712675c99a8960ca8c7944","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":1,"collection":{"id":"a048411b727e4888","slug":"inputs","title":"Inputs","owner":{"id":"5c7b4ebed88da11a","login":"severo","name":"Sylvain Lesage"}},"type":"notebook","body":{"title":"Input: Two-variables input","cells":[{"id":0,"value":"md`# Input: Two-variables input\n\nThe main purpose of this notebook is to design a user control that allows to set two variables independently.\n\nHere the two variables \\`x\\` and \\`y\\` can be set independently by the user when clicking, or programmatically using the setters. The view is (not but could be) rendered only partially when one variable or the other is modified, saving unneeded operations. Two independent events are emitted when the variables change, allowing a listener to only react to changes on one of the variables.\n\nClicking on the XYPad component will set the (x, y) coordinates.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"viewof point = XYPad()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":13,"value":"point","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":27,"value":"md`It's a \\`