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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
"use strict";
const EventEmitter = require("resource://devtools/shared/event-emitter.js");
const {
getCurrentZoom,
setIgnoreLayoutChanges,
} = require("resource://devtools/shared/layout/utils.js");
const {
CanvasFrameAnonymousContentHelper,
} = require("resource://devtools/server/actors/highlighters/utils/markup.js");
// Maximum size, in pixel, for the horizontal ruler and vertical ruler
// used by RulersHighlighter
const RULERS_MAX_X_AXIS = 10000;
const RULERS_MAX_Y_AXIS = 15000;
// Number of steps after we add a graduation, marker and text in
// RulersHighliter; currently the unit is in pixel.
const RULERS_GRADUATION_STEP = 5;
const RULERS_MARKER_STEP = 50;
const RULERS_TEXT_STEP = 100;
/**
* The RulersHighlighter is a class that displays both horizontal and
* vertical rules on the page, along the top and left edges, with pixel
* graduations, useful for users to quickly check distances
*/
class RulersHighlighter {
constructor(highlighterEnv) {
this.env = highlighterEnv;
this.markup = new CanvasFrameAnonymousContentHelper(
highlighterEnv,
this._buildMarkup.bind(this)
);
this.isReady = this.markup.initialize();
const { pageListenerTarget } = highlighterEnv;
pageListenerTarget.addEventListener("scroll", this);
pageListenerTarget.addEventListener("pagehide", this);
}
ID_CLASS_PREFIX = "rulers-highlighter-";
_buildMarkup() {
const prefix = this.ID_CLASS_PREFIX;
const createRuler = (axis, size) => {
let width, height;
let isHorizontal = true;
if (axis === "x") {
width = size;
height = 16;
} else if (axis === "y") {
width = 16;
height = size;
isHorizontal = false;
} else {
throw new Error(
`Invalid type of axis given; expected "x" or "y" but got "${axis}"`
);
}
const g = this.markup.createSVGNode({
nodeType: "g",
attributes: {
id: `${axis}-axis`,
},
parent: svg,
prefix,
});
this.markup.createSVGNode({
nodeType: "rect",
attributes: {
y: isHorizontal ? 0 : 16,
width,
height,
},
parent: g,
});
const gRule = this.markup.createSVGNode({
nodeType: "g",
attributes: {
id: `${axis}-axis-ruler`,
},
parent: g,
prefix,
});
const pathGraduations = this.markup.createSVGNode({
nodeType: "path",
attributes: {
class: "ruler-graduations",
width,
height,
},
parent: gRule,
prefix,
});
const pathMarkers = this.markup.createSVGNode({
nodeType: "path",
attributes: {
class: "ruler-markers",
width,
height,
},
parent: gRule,
prefix,
});
const gText = this.markup.createSVGNode({
nodeType: "g",
attributes: {
id: `${axis}-axis-text`,
class: (isHorizontal ? "horizontal" : "vertical") + "-labels",
},
parent: g,
prefix,
});
let dGraduations = "";
let dMarkers = "";
let graduationLength;
for (let i = 0; i < size; i += RULERS_GRADUATION_STEP) {
if (i === 0) {
continue;
}
graduationLength = i % 2 === 0 ? 6 : 4;
if (i % RULERS_TEXT_STEP === 0) {
graduationLength = 8;
this.markup.createSVGNode({
nodeType: "text",
parent: gText,
attributes: {
x: isHorizontal ? 2 + i : -i - 1,
y: 5,
},
}).textContent = i;
}
if (isHorizontal) {
if (i % RULERS_MARKER_STEP === 0) {
dMarkers += `M${i} 0 L${i} ${graduationLength}`;
} else {
dGraduations += `M${i} 0 L${i} ${graduationLength} `;
}
} else if (i % 50 === 0) {
dMarkers += `M0 ${i} L${graduationLength} ${i}`;
} else {
dGraduations += `M0 ${i} L${graduationLength} ${i}`;
}
}
pathGraduations.setAttribute("d", dGraduations);
pathMarkers.setAttribute("d", dMarkers);
return g;
};
const container = this.markup.createNode({
attributes: { class: "highlighter-container" },
});
const root = this.markup.createNode({
parent: container,
attributes: {
id: "root",
class: "root",
},
prefix,
});
const svg = this.markup.createSVGNode({
nodeType: "svg",
parent: root,
attributes: {
id: "elements",
class: "elements",
width: "100%",
height: "100%",
hidden: "true",
},
prefix,
});
createRuler("x", RULERS_MAX_X_AXIS);
createRuler("y", RULERS_MAX_Y_AXIS);
return container;
}
handleEvent(event) {
switch (event.type) {
case "scroll":
this._onScroll(event);
break;
case "pagehide":
// If a page hide event is triggered for current window's highlighter, hide the
// highlighter.
if (event.target.defaultView === this.env.window) {
this.destroy();
}
break;
}
}
_onScroll(event) {
const prefix = this.ID_CLASS_PREFIX;
const { scrollX, scrollY } = event.view;
this.markup
.getElement(`${prefix}x-axis-ruler`)
.setAttribute("transform", `translate(${-scrollX})`);
this.markup
.getElement(`${prefix}x-axis-text`)
.setAttribute("transform", `translate(${-scrollX})`);
this.markup
.getElement(`${prefix}y-axis-ruler`)
.setAttribute("transform", `translate(0, ${-scrollY})`);
this.markup
.getElement(`${prefix}y-axis-text`)
.setAttribute("transform", `translate(0, ${-scrollY})`);
}
_update() {
const { window } = this.env;
setIgnoreLayoutChanges(true);
const zoom = getCurrentZoom(window);
const isZoomChanged = zoom !== this._zoom;
if (isZoomChanged) {
this._zoom = zoom;
this.updateViewport();
}
setIgnoreLayoutChanges(false, window.document.documentElement);
this._rafID = window.requestAnimationFrame(() => this._update());
}
_cancelUpdate() {
if (this._rafID) {
this.env.window.cancelAnimationFrame(this._rafID);
this._rafID = 0;
}
}
updateViewport() {
const { devicePixelRatio } = this.env.window;
// in order to get the "real" device pixel ratio, we need divide by `zoom`
const pixelRatio = devicePixelRatio / this._zoom;
// The "real" device pixel ratio is used to calculate the max stroke
// width we can actually assign: on retina, for instance, it would be 0.5,
// where on non high dpi monitor would be 1.
const minWidth = 1 / pixelRatio;
const strokeWidth = Math.min(minWidth, minWidth / this._zoom);
this.markup
.getElement(this.ID_CLASS_PREFIX + "root")
.setAttribute("style", `stroke-width:${strokeWidth};`);
}
destroy() {
this.hide();
const { pageListenerTarget } = this.env;
if (pageListenerTarget) {
pageListenerTarget.removeEventListener("scroll", this);
pageListenerTarget.removeEventListener("pagehide", this);
}
this.markup.destroy();
EventEmitter.emit(this, "destroy");
}
show() {
this.markup.removeAttributeForElement(
this.ID_CLASS_PREFIX + "elements",
"hidden"
);
this._update();
return true;
}
hide() {
this.markup.setAttributeForElement(
this.ID_CLASS_PREFIX + "elements",
"hidden",
"true"
);
this._cancelUpdate();
}
}
exports.RulersHighlighter = RulersHighlighter;