private static _computeMinimapLayout()

in src/vs/editor/common/config/editorOptions.ts [1897:2061]
140 lines of code
39 McCabe index (conditional complexity)

	private static _computeMinimapLayout(input: IMinimapLayoutInput, memory: ComputeOptionsMemory): EditorMinimapLayoutInfo {
		const outerWidth = input.outerWidth;
		const outerHeight = input.outerHeight;
		const pixelRatio = input.pixelRatio;

		if (!input.minimap.enabled) {
			return {
				renderMinimap: RenderMinimap.None,
				minimapLeft: 0,
				minimapWidth: 0,
				minimapHeightIsEditorHeight: false,
				minimapIsSampling: false,
				minimapScale: 1,
				minimapLineHeight: 1,
				minimapCanvasInnerWidth: 0,
				minimapCanvasInnerHeight: Math.floor(pixelRatio * outerHeight),
				minimapCanvasOuterWidth: 0,
				minimapCanvasOuterHeight: outerHeight,
			};
		}

		// Can use memory if only the `viewLineCount` and `remainingWidth` have changed
		const stableMinimapLayoutInput = memory.stableMinimapLayoutInput;
		const couldUseMemory = (
			stableMinimapLayoutInput
			// && input.outerWidth === lastMinimapLayoutInput.outerWidth !!! INTENTIONAL OMITTED
			&& input.outerHeight === stableMinimapLayoutInput.outerHeight
			&& input.lineHeight === stableMinimapLayoutInput.lineHeight
			&& input.typicalHalfwidthCharacterWidth === stableMinimapLayoutInput.typicalHalfwidthCharacterWidth
			&& input.pixelRatio === stableMinimapLayoutInput.pixelRatio
			&& input.scrollBeyondLastLine === stableMinimapLayoutInput.scrollBeyondLastLine
			&& input.minimap.enabled === stableMinimapLayoutInput.minimap.enabled
			&& input.minimap.side === stableMinimapLayoutInput.minimap.side
			&& input.minimap.size === stableMinimapLayoutInput.minimap.size
			&& input.minimap.showSlider === stableMinimapLayoutInput.minimap.showSlider
			&& input.minimap.renderCharacters === stableMinimapLayoutInput.minimap.renderCharacters
			&& input.minimap.maxColumn === stableMinimapLayoutInput.minimap.maxColumn
			&& input.minimap.scale === stableMinimapLayoutInput.minimap.scale
			&& input.verticalScrollbarWidth === stableMinimapLayoutInput.verticalScrollbarWidth
			// && input.viewLineCount === lastMinimapLayoutInput.viewLineCount !!! INTENTIONAL OMITTED
			// && input.remainingWidth === lastMinimapLayoutInput.remainingWidth !!! INTENTIONAL OMITTED
			&& input.isViewportWrapping === stableMinimapLayoutInput.isViewportWrapping
		);

		const lineHeight = input.lineHeight;
		const typicalHalfwidthCharacterWidth = input.typicalHalfwidthCharacterWidth;
		const scrollBeyondLastLine = input.scrollBeyondLastLine;
		const minimapRenderCharacters = input.minimap.renderCharacters;
		let minimapScale = (pixelRatio >= 2 ? Math.round(input.minimap.scale * 2) : input.minimap.scale);
		const minimapMaxColumn = input.minimap.maxColumn;
		const minimapSize = input.minimap.size;
		const minimapSide = input.minimap.side;
		const verticalScrollbarWidth = input.verticalScrollbarWidth;
		const viewLineCount = input.viewLineCount;
		const remainingWidth = input.remainingWidth;
		const isViewportWrapping = input.isViewportWrapping;

		const baseCharHeight = minimapRenderCharacters ? 2 : 3;
		let minimapCanvasInnerHeight = Math.floor(pixelRatio * outerHeight);
		const minimapCanvasOuterHeight = minimapCanvasInnerHeight / pixelRatio;
		let minimapHeightIsEditorHeight = false;
		let minimapIsSampling = false;
		let minimapLineHeight = baseCharHeight * minimapScale;
		let minimapCharWidth = minimapScale / pixelRatio;
		let minimapWidthMultiplier: number = 1;

		if (minimapSize === 'fill' || minimapSize === 'fit') {
			const { typicalViewportLineCount, extraLinesBeyondLastLine, desiredRatio, minimapLineCount } = EditorLayoutInfoComputer.computeContainedMinimapLineCount({
				viewLineCount: viewLineCount,
				scrollBeyondLastLine: scrollBeyondLastLine,
				height: outerHeight,
				lineHeight: lineHeight,
				pixelRatio: pixelRatio
			});
			// ratio is intentionally not part of the layout to avoid the layout changing all the time
			// when doing sampling
			const ratio = viewLineCount / minimapLineCount;

			if (ratio > 1) {
				minimapHeightIsEditorHeight = true;
				minimapIsSampling = true;
				minimapScale = 1;
				minimapLineHeight = 1;
				minimapCharWidth = minimapScale / pixelRatio;
			} else {
				let fitBecomesFill = false;
				let maxMinimapScale = minimapScale + 1;

				if (minimapSize === 'fit') {
					const effectiveMinimapHeight = Math.ceil((viewLineCount + extraLinesBeyondLastLine) * minimapLineHeight);
					if (isViewportWrapping && couldUseMemory && remainingWidth <= memory.stableFitRemainingWidth) {
						// There is a loop when using `fit` and viewport wrapping:
						// - view line count impacts minimap layout
						// - minimap layout impacts viewport width
						// - viewport width impacts view line count
						// To break the loop, once we go to a smaller minimap scale, we try to stick with it.
						fitBecomesFill = true;
						maxMinimapScale = memory.stableFitMaxMinimapScale;
					} else {
						fitBecomesFill = (effectiveMinimapHeight > minimapCanvasInnerHeight);
						if (isViewportWrapping && fitBecomesFill) {
							// remember for next time
							memory.stableMinimapLayoutInput = input;
							memory.stableFitRemainingWidth = remainingWidth;
						} else {
							memory.stableMinimapLayoutInput = null;
							memory.stableFitRemainingWidth = 0;
						}
					}
				}

				if (minimapSize === 'fill' || fitBecomesFill) {
					minimapHeightIsEditorHeight = true;
					const configuredMinimapScale = minimapScale;
					minimapLineHeight = Math.min(lineHeight * pixelRatio, Math.max(1, Math.floor(1 / desiredRatio)));
					minimapScale = Math.min(maxMinimapScale, Math.max(1, Math.floor(minimapLineHeight / baseCharHeight)));
					if (minimapScale > configuredMinimapScale) {
						minimapWidthMultiplier = Math.min(2, minimapScale / configuredMinimapScale);
					}
					minimapCharWidth = minimapScale / pixelRatio / minimapWidthMultiplier;
					minimapCanvasInnerHeight = Math.ceil((Math.max(typicalViewportLineCount, viewLineCount + extraLinesBeyondLastLine)) * minimapLineHeight);
					if (isViewportWrapping && fitBecomesFill) {
						memory.stableFitMaxMinimapScale = minimapScale;
					}
				}
			}
		}

		// Given:
		// (leaving 2px for the cursor to have space after the last character)
		// viewportColumn = (contentWidth - verticalScrollbarWidth - 2) / typicalHalfwidthCharacterWidth
		// minimapWidth = viewportColumn * minimapCharWidth
		// contentWidth = remainingWidth - minimapWidth
		// What are good values for contentWidth and minimapWidth ?

		// minimapWidth = ((contentWidth - verticalScrollbarWidth - 2) / typicalHalfwidthCharacterWidth) * minimapCharWidth
		// typicalHalfwidthCharacterWidth * minimapWidth = (contentWidth - verticalScrollbarWidth - 2) * minimapCharWidth
		// typicalHalfwidthCharacterWidth * minimapWidth = (remainingWidth - minimapWidth - verticalScrollbarWidth - 2) * minimapCharWidth
		// (typicalHalfwidthCharacterWidth + minimapCharWidth) * minimapWidth = (remainingWidth - verticalScrollbarWidth - 2) * minimapCharWidth
		// minimapWidth = ((remainingWidth - verticalScrollbarWidth - 2) * minimapCharWidth) / (typicalHalfwidthCharacterWidth + minimapCharWidth)

		const minimapMaxWidth = Math.floor(minimapMaxColumn * minimapCharWidth);
		const minimapWidth = Math.min(minimapMaxWidth, Math.max(0, Math.floor(((remainingWidth - verticalScrollbarWidth - 2) * minimapCharWidth) / (typicalHalfwidthCharacterWidth + minimapCharWidth))) + MINIMAP_GUTTER_WIDTH);

		let minimapCanvasInnerWidth = Math.floor(pixelRatio * minimapWidth);
		const minimapCanvasOuterWidth = minimapCanvasInnerWidth / pixelRatio;
		minimapCanvasInnerWidth = Math.floor(minimapCanvasInnerWidth * minimapWidthMultiplier);

		const renderMinimap = (minimapRenderCharacters ? RenderMinimap.Text : RenderMinimap.Blocks);
		const minimapLeft = (minimapSide === 'left' ? 0 : (outerWidth - minimapWidth - verticalScrollbarWidth));

		return {
			renderMinimap,
			minimapLeft,
			minimapWidth,
			minimapHeightIsEditorHeight,
			minimapIsSampling,
			minimapScale,
			minimapLineHeight,
			minimapCanvasInnerWidth,
			minimapCanvasInnerHeight,
			minimapCanvasOuterWidth,
			minimapCanvasOuterHeight,
		};
	}