361 lines
14 KiB
JavaScript
361 lines
14 KiB
JavaScript
/**
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* page-manager-enhanced.ts — Enhanced PageManager with performance optimizations
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*
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* Extends the original PageManager with:
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* - Better integration with render system
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* - Adaptive quality support
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* - Memory-efficient canvas management
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* - Smooth transitions during quality changes
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*/
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const MAX_CANVAS_PIXELS = 16777216; // 4096 × 4096
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/**
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* Clamp render scale so the canvas pixel count stays within the budget.
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* CSS dimensions stay correct — pages appear at the right size, just at
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* reduced effective DPI when zoomed very high.
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*/
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function clampedRenderScale(vpWidth, vpHeight, desiredScale, dpr, quality = 1.0) {
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const effectiveScale = desiredScale * quality;
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const w = vpWidth * effectiveScale * dpr;
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const h = vpHeight * effectiveScale * dpr;
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const pixels = w * h;
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if (pixels <= MAX_CANVAS_PIXELS)
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return effectiveScale * dpr;
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return effectiveScale * dpr * Math.sqrt(MAX_CANVAS_PIXELS / pixels);
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}
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const State = Object.freeze({
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PLACEHOLDER: 0,
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RENDERING: 1,
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RENDERED: 2,
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QUALITY_ADJUSTING: 3 // New state for quality transitions
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});
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export class EnhancedPageManager {
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/**
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* @param wrapper - #pages-wrapper container (already in DOM)
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* @param viewports - scale=1 viewports (0-indexed)
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* @param initialScale - initial display scale
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* @param dpr - devicePixelRatio
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* @param dispatchRender - (pageNum, scale, vpWidth, vpHeight, gen, quality) => void
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*/
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constructor(wrapper, viewports, initialScale, dpr, dispatchRender) {
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this._wrapper = wrapper;
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this._viewports = viewports;
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this._scale = initialScale;
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this._dpr = dpr;
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this._dispatchRender = dispatchRender;
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this._renderGen = 0;
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this._inFlight = 0;
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this._zooming = false;
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this._states = new Array(viewports.length).fill(State.PLACEHOLDER);
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this._canvases = new Array(viewports.length).fill(null);
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this._wrappers = [];
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this._currentQualities = new Array(viewports.length).fill(1.0); // Track quality per page
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this._targetQualities = new Array(viewports.length).fill(1.0); // Target quality for transitions
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this._needsQualityUpdate = false;
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this._buildPlaceholders();
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}
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get pageWrappers() { return this._wrappers; }
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get numPages() { return this._viewports.length; }
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get renderGen() { return this._renderGen; }
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/** Called by ZoomController to suppress canvas teardown during CSS zoom. */
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setZooming(z) { this._zooming = z; }
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setScale(scale) {
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this._scale = scale;
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}
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setQualityForPage(pageNum, quality) {
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const i = pageNum - 1;
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if (i >= 0 && i < this._viewports.length) {
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this._targetQualities[i] = quality;
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// If page is rendered and quality changed significantly, trigger re-render
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if (this._states[i] === State.RENDERED &&
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Math.abs(quality - this._currentQualities[i]) > 0.1) {
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this._startQualityAdjustment(i);
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}
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}
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}
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setGlobalQuality(quality) {
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for (let i = 0; i < this._targetQualities.length; i++) {
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this._targetQualities[i] = quality;
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}
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// Re-render visible pages with new quality
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this._needsQualityUpdate = true;
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}
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_buildPlaceholders() {
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for (let i = 0; i < this._viewports.length; i++) {
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const vp = this._viewports[i];
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const wrap = document.createElement("div");
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wrap.className = "page-wrapper";
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wrap.dataset.page = String(i + 1);
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wrap.style.width = vp.width * this._scale + "px";
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wrap.style.height = vp.height * this._scale + "px";
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this._wrapper.appendChild(wrap);
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this._wrappers.push(wrap);
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}
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}
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/**
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* Called on each IntersectionObserver tick.
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* Renders pages entering the buffer; cleans up pages leaving it.
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* Visible pages are prioritized in the render queue.
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*
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* @param bufferSet - 1-based page numbers in the buffer zone
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* @param visibleSet - 1-based page numbers currently on screen
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*/
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reconcile(bufferSet, visibleSet) {
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const gen = this._renderGen;
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// Prioritize visible pages, then the rest of the buffer
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const toRender = [
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...[...visibleSet].sort((a, b) => a - b),
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...[...bufferSet].filter(p => !visibleSet.has(p)).sort((a, b) => a - b),
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];
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for (const pageNum of toRender) {
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const i = pageNum - 1;
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if (i < 0 || i >= this._viewports.length)
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continue;
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if (this._states[i] === State.PLACEHOLDER) {
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this._startRender(i, gen);
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}
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else if (this._states[i] === State.QUALITY_ADJUSTING) {
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// Already handling quality transition
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}
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else if (this._needsQualityUpdate && this._states[i] === State.RENDERED) {
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// Apply quality updates if needed
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if (Math.abs(this._targetQualities[i] - this._currentQualities[i]) > 0.05) {
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this._startQualityAdjustment(i);
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}
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}
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}
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// Clean up pages no longer in the buffer
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for (let i = 0; i < this._viewports.length; i++) {
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const pageNum = i + 1;
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if (!this._zooming && !bufferSet.has(pageNum) && this._states[i] === State.RENDERED) {
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this._cleanup(i);
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}
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// Cancel stale RENDERING pages outside the buffer
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if (!bufferSet.has(pageNum) && (this._states[i] === State.RENDERING || this._states[i] === State.QUALITY_ADJUSTING)) {
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if (this._states[i] === State.RENDERING)
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this._inFlight--;
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this._states[i] = State.PLACEHOLDER;
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}
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}
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this._needsQualityUpdate = false;
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}
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get allRendered() { return this._inFlight === 0; }
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getPageElement(pageNum) {
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const i = pageNum - 1;
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if (i >= 0 && i < this._wrappers.length) {
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return this._wrappers[i];
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}
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return null;
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}
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_startRender(i, gen) {
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const vp = this._viewports[i];
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const quality = this._targetQualities[i];
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const scale = clampedRenderScale(vp.width, vp.height, this._scale, this._dpr, quality);
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this._states[i] = State.RENDERING;
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this._inFlight++;
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this._dispatchRender(i + 1, this._scale, vp.width, vp.height, gen, quality);
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}
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_startQualityAdjustment(i) {
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// Transition to quality adjustment state
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this._states[i] = State.QUALITY_ADJUSTING;
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const pageNum = i + 1;
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const gen = ++this._renderGen; // Increment gen to cancel any pending renders
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const vp = this._viewports[i];
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const quality = this._targetQualities[i];
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const scale = clampedRenderScale(vp.width, vp.height, this._scale, this._dpr, quality);
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this._inFlight++;
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this._dispatchRender(pageNum, this._scale, vp.width, vp.height, gen, quality);
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}
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_cleanup(i) {
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if (this._states[i] === State.RENDERING || this._states[i] === State.QUALITY_ADJUSTING) {
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this._inFlight--;
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}
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this._states[i] = State.PLACEHOLDER;
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const canvas = this._canvases[i];
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if (canvas) {
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canvas.remove();
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this._canvases[i] = null;
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}
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// Also remove the text and annotation layers
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const wrap = this._wrappers[i];
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wrap.querySelector(".text-layer")?.remove();
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wrap.querySelector(".annot-layer")?.remove();
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}
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/**
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* Called when the worker returns a rendered bitmap.
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*
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* @param pageNum
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* @param gen - render generation the bitmap was rendered for
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* @param bitmap
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* @param quality - quality at which this bitmap was rendered
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*/
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onRendered(pageNum, gen, bitmap, quality) {
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if (gen !== this._renderGen) {
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bitmap.close();
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return;
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}
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const i = pageNum - 1;
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if (i < 0 || i >= this._viewports.length ||
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(this._states[i] !== State.RENDERING && this._states[i] !== State.QUALITY_ADJUSTING)) {
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bitmap.close();
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return;
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}
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this._inFlight--;
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this._currentQualities[i] = quality;
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const vp = this._viewports[i];
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const wrap = this._wrappers[i];
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const cssW = vp.width * this._scale;
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const cssH = vp.height * this._scale;
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// For quality adjustments, we want smooth transitions
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const wasQualityAdjustment = this._states[i] === State.QUALITY_ADJUSTING;
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this._states[i] = State.RENDERED;
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// Remove the old canvas
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const old = wrap.querySelector("canvas");
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if (old) {
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if (wasQualityAdjustment) {
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// For quality adjustments, fade out the old canvas for smooth transition
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old.style.transition = "opacity 0.15s ease-out";
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old.style.opacity = "0";
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setTimeout(() => old.remove(), 150);
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}
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else {
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old.remove();
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}
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}
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const canvas = document.createElement("canvas");
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canvas.width = bitmap.width;
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canvas.height = bitmap.height;
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canvas.style.width = cssW + "px";
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canvas.style.height = cssH + "px";
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// Zero-copy display — fall back to drawImage if bitmaprenderer unavailable
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const ctx = canvas.getContext("bitmaprenderer");
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if (ctx) {
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ctx.transferFromImageBitmap(bitmap);
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}
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else {
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const ctx2d = canvas.getContext("2d");
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if (ctx2d) {
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ctx2d.drawImage(bitmap, 0, 0);
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bitmap.close();
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}
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}
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// For quality adjustments, fade in the new canvas
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if (wasQualityAdjustment) {
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canvas.style.opacity = "0";
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canvas.style.transition = "opacity 0.15s ease-in";
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wrap.appendChild(canvas);
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requestAnimationFrame(() => {
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canvas.style.opacity = "1";
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});
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}
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else {
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wrap.appendChild(canvas);
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}
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this._canvases[i] = canvas;
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}
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/**
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* Get the canvas element for a specific page
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*/
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getPageCanvas(pageNum) {
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const i = pageNum - 1;
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if (i >= 0 && i < this._canvases.length) {
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return this._canvases[i];
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}
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return null;
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}
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/**
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* Called after the zoom debounce fires.
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* Increments renderGen (cancels stale work), resizes all placeholders,
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* then re-renders the buffer pages at the new resolution.
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*
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* @param newScale
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* @param bufferSet
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* @param visibleSet
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*/
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onScaleChange(newScale, bufferSet, visibleSet) {
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this._scale = newScale;
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this._renderGen++;
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for (let i = 0; i < this._viewports.length; i++) {
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const pageNum = i + 1;
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const vp = this._viewports[i];
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const wrap = this._wrappers[i];
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const cssW = vp.width * newScale;
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const cssH = vp.height * newScale;
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wrap.style.width = cssW + "px";
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wrap.style.height = cssH + "px";
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wrap.style.zoom = "1";
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if (bufferSet.has(pageNum)) {
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// Keep the old canvas visible (stretched to the new CSS size) so there
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// is no blank flash while the new render is in flight.
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const canvas = this._canvases[i];
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if (canvas) {
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canvas.style.width = cssW + "px";
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canvas.style.height = cssH + "px";
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}
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if (this._states[i] === State.RENDERING || this._states[i] === State.QUALITY_ADJUSTING) {
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this._inFlight--;
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}
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this._states[i] = State.PLACEHOLDER;
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}
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else {
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// Off-screen: clean up immediately — not visible, so no flash.
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const canvas = this._canvases[i];
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if (canvas) {
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canvas.remove();
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this._canvases[i] = null;
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}
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this._states[i] = State.PLACEHOLDER;
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}
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}
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this.reconcile(bufferSet, visibleSet);
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}
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/**
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* Returns the 1-based number of the topmost visible page.
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*
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* @param visibleSet
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*/
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getCurrentPage(visibleSet) {
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// Defensive programming: handle null/undefined visibleSet
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if (!visibleSet || visibleSet.size === 0) {
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// Fall back to scroll position
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const top = this._wrapper.parentElement?.getBoundingClientRect().top ?? 0;
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for (const wrap of this._wrappers) {
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if (wrap.getBoundingClientRect().bottom > top + 4) {
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return parseInt(wrap.dataset.page || '1', 10);
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}
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}
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return 1;
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}
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return Math.min(...visibleSet);
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}
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/**
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* Get the current quality for a specific page
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*/
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getPageQuality(pageNum) {
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const i = pageNum - 1;
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if (i >= 0 && i < this._currentQualities.length) {
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return this._currentQualities[i];
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}
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return 1.0;
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}
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/**
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* Get the current render state for a page
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*/
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getPageState(pageNum) {
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const i = pageNum - 1;
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if (i >= 0 && i < this._states.length) {
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return this._states[i];
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}
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return State.PLACEHOLDER;
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}
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/**
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* Force cleanup of all resources
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*/
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cleanup() {
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for (let i = 0; i < this._viewports.length; i++) {
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this._cleanup(i);
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}
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this._inFlight = 0;
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this._renderGen = 0;
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}
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}
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//# sourceMappingURL=page-manager-enhanced.js.map
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