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import { FloatingPanel } from "./floating-panel.js";
import {
DensityPalette,
DensityRampHex,
DiscGeometry,
ErrorHex,
MaxDensity,
MinDensity,
RegionStyles,
RegionPalette,
UnformattedHex,
clampZoom,
renderTracks,
trackPulseDensity,
trackRegions,
} from "../disc-surface.js";
/** 300 rpm. */
const RevolutionMs = 200;
/** Not on either palette: the head and the index marker have to sit clear of the surface. */
const HeadColour = "#eb6834";
const IndexColour = "#c3c2b7";
const HoverColour = "#ffffff";
const MarkOutline = "#0d0d0d";
const ScanBudgetMs = 16;
/** A trackpad reports deltas in the tens, a mouse notch about 100. */
const WheelZoomRate = 0.003;
/** Firefox reports wheel deltas in lines, not pixels. */
const PixelsPerWheelLine = 16;
const Views = {
density: {
palette: DensityPalette,
analyse: (track) => ({ codes: trackPulseDensity(track) }),
describe: ({ codes }, word) => (codes[word] === 0 ? "no flux" : `${codes[word]} pulses`),
legend: () =>
swatch(UnformattedHex, "unformatted") +
`<span class="disc-legend-item disc-legend-grow">${MinDensity}` +
`<span class="disc-legend-ramp" style="background:linear-gradient(to right, ${DensityRampHex.join(", ")})"></span>` +
`${MaxDensity} pulses per 64µs</span>`,
},
format: {
palette: RegionPalette,
analyse: (track, warn) => trackRegions(track, warn),
describe: ({ codes, sectorNumbers, errors }, word) => {
const what = RegionStyles[codes[word]].name;
const named = sectorNumbers[word] < 0 ? what : `sector ${sectorNumbers[word]} ${what}`;
const error = errors.find(({ firstWord, lastWord }) =>
lastWord <= firstWord ? word >= firstWord || word < lastWord : word >= firstWord && word < lastWord,
);
return `${named}${error ? ` · ${error.kind} error` : ""}`;
},
legend: () => RegionStyles.map(({ hex, name }) => swatch(hex, name)).join("") + swatch(ErrorHex, "CRC error"),
},
};
const ignoreWarning = () => {};
/** These lines are rewritten every frame, so skip the ones that have not changed. */
function setText(element, text) {
if (element.textContent !== text) element.textContent = text;
}
/** One atomic legend entry, so a swatch never gets orphaned from its label by a line break. */
function swatch(colour, label) {
return `<span class="disc-legend-item"><span class="disc-legend-swatch" style="background:${colour}"></span>${label}</span>`;
}
/**
* The disc surface panel: one side of one drive's disc drawn as the physical platter, coloured
* either by raw pulse density or by what the decoder makes of each word, with the head drawn
* where it sits.
*/
export class DiscVisualiser {
/**
* @param {object} options
* @param {object} options.fdc
*/
constructor({ fdc }) {
this._fdc = fdc;
this.panel = document.getElementById("disc-panel");
this.surfaceCanvas = document.getElementById("disc-surface");
this.overlayCanvas = document.getElementById("disc-overlay");
this.statusElem = document.getElementById("disc-status");
this.nameElem = document.getElementById("disc-name");
this.hoverWhereElem = document.getElementById("disc-hover-where");
this.hoverWhatElem = document.getElementById("disc-hover-what");
this.legendElem = document.getElementById("disc-legend");
this.sideControls = document.getElementById("disc-side-controls");
this.openBtn = document.getElementById("disc-visualiser-open");
this._view = "density";
this._driveIndex = 0;
this._isSideUpper = false;
this._disc = null;
this._geometry = null;
this._imageData = null;
this._pixels = null;
/** @type {(Uint8Array|null)[]} */
this._codes = [];
/** @type {(object|null)[]} */
this._info = [];
this._staleTracks = new Set();
this._needsFullRepaint = true;
this._scanCursor = 0;
this._scanHandle = null;
this._hover = null;
this._pan = null;
this._surfaceStale = false;
this._frameHandle = null;
this._onTrackWrite = (isSideUpper, trackNum) => {
if (isSideUpper === this._isSideUpper) this._staleTracks.add(trackNum);
};
this._onResize = () => this._resize();
this.openBtn.addEventListener("click", (e) => {
e.preventDefault();
this.toggle();
});
this.floating = new FloatingPanel({
panel: this.panel,
header: this.panel.querySelector(".disc-header"),
closeButton: document.getElementById("disc-close"),
});
this.floating.addEventListener("open", () => this._start());
this.floating.addEventListener("close", () => this._stop());
this._bindChoice("[data-drive]", (button) => this._select(Number(button.dataset.drive), this._isSideUpper));
this._bindChoice("[data-side]", (button) => this._select(this._driveIndex, button.dataset.side === "1"));
this._bindChoice("[data-view]", (button) => this._setView(button.dataset.view));
this.overlayCanvas.addEventListener("mousemove", (e) => (this._hover = this._canvasPoint(e)));
this.overlayCanvas.addEventListener("mouseleave", () => (this._hover = null));
this._bindZoomAndPan();
this._buildLegend();
}
_bindZoomAndPan() {
const canvas = this.overlayCanvas;
canvas.addEventListener("wheel", (e) => {
e.preventDefault();
Iif (!this._geometry) return;
const { x, y } = this._canvasPoint(e);
const at = this._geometry.toDisc(x, y);
const lines = e.deltaMode === WheelEvent.DOM_DELTA_LINE ? PixelsPerWheelLine : 1;
const zoom = clampZoom(this._geometry.zoom * Math.exp(-e.deltaY * lines * WheelZoomRate));
// Keep whatever is under the pointer under the pointer.
this._setViewport(zoom, at.x - x / zoom, at.y - y / zoom);
});
canvas.addEventListener("pointerdown", (e) => {
if (e.button !== 0) return;
const { originX, originY } = this._geometry;
this._pan = { pointerId: e.pointerId, ...this._canvasPoint(e), originX, originY, moved: false };
canvas.setPointerCapture(e.pointerId);
});
canvas.addEventListener("pointermove", (e) => {
if (this._pan?.pointerId !== e.pointerId) return;
const { x, y } = this._canvasPoint(e);
const { zoom } = this._geometry;
this._pan.moved = true;
this._setViewport(
zoom,
this._pan.originX - (x - this._pan.x) / zoom,
this._pan.originY - (y - this._pan.y) / zoom,
);
});
for (const ending of ["pointerup", "pointercancel"])
canvas.addEventListener(ending, (e) => {
if (this._pan?.pointerId !== e.pointerId) return;
if (this._pan.moved) this._surfaceStale = true;
this._pan = null;
});
canvas.addEventListener("dblclick", () => this._setViewport(1, 0, 0));
}
/** @returns {{x: number, y: number}} the event's position in canvas pixels */
_canvasPoint(e) {
const rect = this.overlayCanvas.getBoundingClientRect();
const scale = this.overlayCanvas.width / rect.width;
return { x: (e.clientX - rect.left) * scale, y: (e.clientY - rect.top) * scale };
}
_setViewport(zoom, originX, originY) {
const was = { ...this._geometry };
this._geometry.setView(zoom, originX, originY);
Eif (
was.zoom !== this._geometry.zoom ||
was.originX !== this._geometry.originX ||
was.originY !== this._geometry.originY
)
this._surfaceStale = true;
}
_bindChoice(selector, onClick) {
for (const button of this.panel.querySelectorAll(selector))
button.addEventListener("click", () => {
onClick(button);
this.update();
});
}
get isOpen() {
return this.floating.isOpen;
}
toggle() {
this.floating.toggle();
}
open() {
this.floating.open();
}
close() {
this.floating.close();
}
/** Opens the panel showing the given drive's lower side. */
openOn(driveIndex) {
this._select(driveIndex, false);
this.open();
this.update();
}
_start() {
window.addEventListener("resize", this._onResize);
this._resize();
this._tick();
}
_stop() {
Eif (this._frameHandle !== null) cancelAnimationFrame(this._frameHandle);
this._frameHandle = null;
this._cancelScan();
this._detach();
this._hover = null;
this._needsFullRepaint = true;
window.removeEventListener("resize", this._onResize);
}
_tick() {
this.update();
this._frameHandle = requestAnimationFrame(() => this._tick());
}
/** Cheap enough to call every frame. */
update() {
if (!this.isOpen || !this._geometry) return;
const disc = this._drive?.disc ?? null;
Iif (this._isSideUpper && !disc?.isDoubleSided) this._select(this._driveIndex, false);
if (disc !== this._disc) this._attach(disc);
if (this._needsFullRepaint) this._beginFullRepaint();
else if (this._surfaceStale) this._repaintSurface();
else Iif (this._staleTracks.size && !this._scanning) this._repaintStaleTracks();
this._drawOverlay();
this._updateStatus();
}
get _drive() {
return this._fdc.drives[this._driveIndex];
}
get _showingHead() {
const drive = this._drive;
return !!drive?.disc && drive.isSideUpper === this._isSideUpper;
}
get _scanning() {
return this._geometry !== null && this._scanCursor <= this._geometry.numTracks;
}
_setView(view) {
Iif (view === this._view || !Views[view]) return;
this._view = view;
this._needsFullRepaint = true;
this._buildLegend();
}
_select(driveIndex, isSideUpper) {
Iif (driveIndex === this._driveIndex && isSideUpper === this._isSideUpper) return;
this._driveIndex = driveIndex;
this._isSideUpper = isSideUpper;
this._detach();
this._needsFullRepaint = true;
}
_attach(disc) {
this._detach();
this._disc = disc;
disc?.addTrackWriteListener(this._onTrackWrite);
this._needsFullRepaint = true;
}
_detach() {
this._disc?.removeTrackWriteListener(this._onTrackWrite);
this._disc = null;
this._staleTracks.clear();
}
_resize() {
const size = Math.round(this.surfaceCanvas.clientWidth * (window.devicePixelRatio || 1));
Iif (size <= 0 || size === this._geometry?.size) return;
for (const canvas of [this.surfaceCanvas, this.overlayCanvas]) {
canvas.width = size;
canvas.height = size;
}
const previous = this._geometry;
this._geometry = new DiscGeometry(size, IbmDiscFormat.tracksPerDisc);
Iif (previous) this._geometry.adoptView(previous);
this._imageData = this.surfaceCanvas.getContext("2d").createImageData(size, size);
this._pixels = new Uint32Array(this._imageData.data.buffer);
this._needsFullRepaint = true;
}
/** @returns {{codes: Uint8Array, sectorNumbers: Int16Array|null, errors: object[]|null}|null} */
_analyse(trackNum) {
if (!this._disc) return null;
return Views[this._view].analyse(this._disc.getTrack(this._isSideUpper, trackNum), ignoreWarning);
}
_blit() {
this.surfaceCanvas.getContext("2d").putImageData(this._imageData, 0, 0);
}
_beginFullRepaint() {
this._needsFullRepaint = false;
this._cancelScan();
const count = this._geometry.numTracks;
this._codes = new Array(count).fill(null);
this._info = new Array(count).fill(null);
this._scanCursor = 0;
this._pixels.fill(0);
this._advanceScan();
}
_cancelScan() {
Iif (this._scanHandle !== null) cancelAnimationFrame(this._scanHandle);
this._scanHandle = null;
}
/** Driven by requestAnimationFrame rather than the emulator's loop, so it completes while paused. */
_advanceScan() {
const count = this._geometry.numTracks;
const deadline = performance.now() + ScanBudgetMs;
do {
if (this._scanCursor < count) this._analyseInto(this._scanCursor);
// A track's edge pixels sample its neighbours, so paint one behind the scan.
const paintTrack = this._scanCursor - 1;
if (paintTrack >= 0)
renderTracks(this._pixels, this._geometry, this._codes, this._palette, paintTrack, paintTrack);
this._scanCursor++;
} while (this._scanCursor <= count && performance.now() < deadline);
this._blit();
Iif (this._scanning) this._scanHandle = requestAnimationFrame(() => this._advanceScan());
else this._scanHandle = null;
}
get _palette() {
return Views[this._view].palette;
}
_repaintStaleTracks() {
const deadline = performance.now() + ScanBudgetMs;
for (const trackNum of this._staleTracks) {
this._repaintTrack(trackNum);
this._staleTracks.delete(trackNum);
if (performance.now() >= deadline) break;
}
this._blit();
}
/** For when the view moved rather than the disc. */
_repaintSurface() {
this._surfaceStale = false;
this._pixels.fill(0);
// Mid-drag the whole surface is redrawn every frame, so trade smoothed edges for the frame rate.
const supersample = this._pan ? 1 : undefined;
const last = this._geometry.numTracks - 1;
renderTracks(this._pixels, this._geometry, this._codes, this._palette, 0, last, supersample);
this._blit();
}
_analyseInto(trackNum) {
const analysis = this._analyse(trackNum);
this._info[trackNum] = analysis;
this._codes[trackNum] = analysis?.codes ?? null;
}
_repaintTrack(trackNum) {
if (trackNum >= this._geometry.numTracks) return;
this._analyseInto(trackNum);
renderTracks(this._pixels, this._geometry, this._codes, this._palette, trackNum, trackNum);
}
_drawOverlay() {
const geometry = this._geometry;
const ctx = this.overlayCanvas.getContext("2d");
const scale = window.devicePixelRatio || 1;
ctx.clearRect(0, 0, geometry.size, geometry.size);
const centreX = geometry.screenCentreX;
const centreY = geometry.screenCentreY;
ctx.lineWidth = scale;
ctx.strokeStyle = `${IndexColour}44`;
ctx.beginPath();
ctx.arc(centreX, centreY, geometry.outerRadius * geometry.zoom, 0, 2 * Math.PI);
ctx.moveTo(centreX + geometry.hubRadius * geometry.zoom, centreY);
ctx.arc(centreX, centreY, geometry.hubRadius * geometry.zoom, 0, 2 * Math.PI);
ctx.stroke();
this._strokeRadial(ctx, 0, `${IndexColour}66`, scale);
this._drawErrors(ctx, scale);
const drive = this._drive;
if (this._showingHead) {
const track = Math.min(drive.track, geometry.numTracks - 1);
const fraction = drive.positionFraction;
ctx.globalAlpha = drive.spinning ? 1 : 0.45;
ctx.strokeStyle = `${HeadColour}55`;
ctx.lineWidth = Math.max(geometry.trackPitch * geometry.zoom, 2 * scale);
ctx.beginPath();
ctx.arc(centreX, centreY, geometry.screenRadiusOf(track), 0, 2 * Math.PI);
ctx.stroke();
this._strokeRadial(ctx, fraction, `${HeadColour}66`, scale);
const { x, y } = geometry.pointAt(track, fraction);
ctx.fillStyle = HeadColour;
ctx.beginPath();
ctx.arc(x, y, 3.5 * scale, 0, 2 * Math.PI);
ctx.fill();
ctx.globalAlpha = 1;
}
const hover = this._hoverPosition();
if (hover) {
ctx.strokeStyle = `${HoverColour}55`;
ctx.lineWidth = scale;
ctx.beginPath();
ctx.arc(centreX, centreY, geometry.screenRadiusOf(hover.track), 0, 2 * Math.PI);
ctx.stroke();
}
}
_drawErrors(ctx, scale) {
const geometry = this._geometry;
const width = Math.max(geometry.trackPitch * geometry.zoom, 2.5 * scale);
for (let trackNum = 0; trackNum < this._info.length; ++trackNum) {
const info = this._info[trackNum];
Eif (!info?.errors?.length) continue;
const radius = geometry.screenRadiusOf(trackNum);
for (const error of info.errors) {
const start = error.firstWord / info.codes.length;
let end = error.lastWord / info.codes.length;
if (end <= start) end += 1;
for (const [lineWidth, style] of [
[width + 3 * scale, MarkOutline],
[width, ErrorHex],
]) {
ctx.lineWidth = lineWidth;
ctx.strokeStyle = style;
ctx.beginPath();
ctx.arc(
geometry.screenCentreX,
geometry.screenCentreY,
radius,
geometry.angleOf(start),
geometry.angleOf(end),
);
ctx.stroke();
}
}
}
}
_strokeRadial(ctx, fraction, style, scale) {
const geometry = this._geometry;
const angle = geometry.angleOf(fraction);
const cos = Math.cos(angle);
const sin = Math.sin(angle);
const inner = geometry.innerRadius * geometry.zoom;
const outer = geometry.outerRadius * geometry.zoom;
ctx.strokeStyle = style;
ctx.lineWidth = scale;
ctx.beginPath();
ctx.moveTo(geometry.screenCentreX + inner * cos, geometry.screenCentreY + inner * sin);
ctx.lineTo(geometry.screenCentreX + outer * cos, geometry.screenCentreY + outer * sin);
ctx.stroke();
}
/** @returns {{track: number, fraction: number}|null} */
_hoverPosition() {
return this._hover ? this._geometry.positionAt(this._hover.x, this._hover.y) : null;
}
_updateStatus() {
const drive = this._drive;
const disc = drive?.disc;
this.sideControls.hidden = !disc?.isDoubleSided;
this._markActive("[data-drive]", (button) => Number(button.dataset.drive) === this._driveIndex);
this._markActive("[data-side]", (button) => (button.dataset.side === "1") === this._isSideUpper);
this._markActive("[data-view]", (button) => button.dataset.view === this._view);
const name = disc?.name ?? "";
setText(this.nameElem, name);
if (this.nameElem.title !== name) this.nameElem.title = name;
if (!disc) {
setText(this.statusElem, `Drive ${this._driveIndex}: no disc`);
} else {
const head = this._showingHead
? `head track ${drive.track} · ${(drive.positionFraction * RevolutionMs).toFixed(1)} ms`
: `head track ${drive.track}, other side`;
const spin = drive.spinning ? "spinning" : "stopped";
const zoom = this._geometry.zoom > 1 ? ` · ${this._geometry.zoom.toFixed(1)}x` : "";
setText(this.statusElem, `${spin} · ${head}${zoom}${this._scanNote()}`);
}
const { where, what } = this._describeHover();
setText(this.hoverWhereElem, where);
setText(this.hoverWhatElem, what);
}
_markActive(selector, isActive) {
for (const button of this.panel.querySelectorAll(selector)) button.classList.toggle("active", isActive(button));
}
_scanNote() {
Iif (this._scanning) return " · reading surface…";
const errors = this._info.reduce((count, info) => count + (info?.errors?.length ?? 0), 0);
Eif (!errors) return "";
return ` · ${errors} CRC error${errors === 1 ? "" : "s"}`;
}
/** @returns {{where: string, what: string}} the pointer's position, and what the surface holds */
_describeHover() {
const hover = this._hoverPosition();
if (!hover) return { where: "Point at the surface to read it", what: "" };
const info = this._info[hover.track];
Iif (!info?.codes?.length) return { where: `Track ${hover.track}`, what: "not read yet" };
const word = Math.min((hover.fraction * info.codes.length) | 0, info.codes.length - 1);
const ms = (hover.fraction * RevolutionMs).toFixed(1);
return {
where: `Track ${hover.track} · word ${word} of ${info.codes.length} · ${ms} ms`,
what: Views[this._view].describe(info, word),
};
}
_buildLegend() {
this.legendElem.innerHTML = Views[this._view].legend();
}
}
|