modules/chart_engine/static/lib/chart_utils/text.js

// Text sizing, measuring, and truncation helpers.
(function (root) {
    const chartUtils = root.chartUtils;
    const text = chartUtils.text;

    text.font = (options = {}) => {
        const fontWeight = options.fontWeight || options.weight || "normal";
        const fontSize = text.fontSize(options.fontSize || options.size || 12);
        const fontFamily = options.fontFamily || options.family || "Arial";
        return `${fontWeight} ${fontSize}px ${fontFamily}`;
    };

    text.fontSize = value => {
        if (typeof value === "number") return value;
        const parsed = parseFloat(value);
        return Number.isFinite(parsed) ? parsed : 12;
    };

    text.estimate = (value, options = {}) => {
        const valueText = value == null ? "" : String(value);
        const fontSize = text.fontSize(options.fontSize || options.size || 12);
        const factor = options.factor == null ? 0.6 : options.factor;
        return {
            width: valueText.length * fontSize * factor,
            height: fontSize * 1.2,
        };
    };

    text.measure = (context, value, options = {}) => {
        const valueText = value == null ? "" : String(value);
        const fontSize = text.fontSize(options.fontSize || options.size || 12);
        const fontFamily = options.fontFamily || options.family || null;
        const fontWeight = options.fontWeight || options.weight || "normal";
        if (context && typeof context.append === "function") {
            const node = context.append("text")
                .attr("visibility", "hidden")
                .attr("x", -9999)
                .attr("y", -9999)
                .style("font-size", `${fontSize}px`)
                .style("font-weight", fontWeight)
                .text(valueText);
            if (fontFamily) node.style("font-family", fontFamily);
            const element = node.node();
            const width = element.getComputedTextLength ? element.getComputedTextLength() : element.getBBox().width;
            const height = element.getBBox().height || fontSize * 1.2;
            node.remove();
            return { width, height };
        }
        if (typeof document !== "undefined") {
            const canvas = document.createElement("canvas");
            const ctx = canvas.getContext("2d");
            ctx.font = text.font({ fontSize, fontFamily, fontWeight });
            return {
                width: ctx.measureText(valueText).width,
                height: fontSize * 1.2,
            };
        }
        return text.estimate(valueText, options);
    };

    text.contextSize = (context, value, options = {}) => {
        const valueText = value == null ? "" : String(value);
        const fontSize = text.fontSize(options.fontSize || options.size || 12);
        if (context && typeof context.measureText === "function") {
            return {
                width: context.measureText(valueText).width,
                height: fontSize * 1.2,
            };
        }
        return text.measure(null, valueText, options);
    };

    text.contextWidth = (context, value, options = {}) => text.contextSize(context, value, options).width;

    text.nodeSize = (node, options = {}) => {
        if (!node) return { width: 0, height: 0 };
        const method = options.method || "auto";
        const canUseComputed = typeof node.getComputedTextLength === "function";
        const canUseBBox = typeof node.getBBox === "function";
        let bbox = null;
        let width = null;

        const readBBox = () => {
            if (!canUseBBox) return null;
            try {
                return node.getBBox();
            } catch (error) {
                return null;
            }
        };

        if ((method === "computed" || method === "auto") && canUseComputed) {
            try {
                width = node.getComputedTextLength();
            } catch (error) {
                width = null;
            }
        }

        if ((method === "bbox" || !Number.isFinite(width)) && canUseBBox) {
            bbox = readBBox();
            if (bbox && Number.isFinite(bbox.width)) {
                width = bbox.width;
            }
        }

        if (!Number.isFinite(width)) {
            width = text.estimate(node.textContent || "", options).width;
        }

        if (!bbox && canUseBBox) {
            bbox = readBBox();
        }

        const fallbackHeight = text.fontSize(options.fontSize || options.size || 12) * 1.2;
        const height = bbox && Number.isFinite(bbox.height) ? bbox.height : fallbackHeight;
        const x = bbox && Number.isFinite(bbox.x) ? bbox.x : 0;
        const y = bbox && Number.isFinite(bbox.y) ? bbox.y : 0;
        return { width, height, x, y };
    };

    text.nodeWidth = (node, options = {}) => text.nodeSize(node, options).width;

    text.truncate = (value, maxWidth, options = {}) => {
        const valueText = value == null ? "" : String(value);
        const ellipsis = options.ellipsis == null ? "..." : options.ellipsis;
        const measure = candidate => text.measure(options.context, candidate, options).width;
        if (measure(valueText) <= maxWidth) return valueText;
        if (maxWidth <= 0 || measure(ellipsis) > maxWidth) return "";
        let low = 0;
        let high = valueText.length;
        while (low < high) {
            const mid = Math.ceil((low + high) / 2);
            if (measure(valueText.slice(0, mid) + ellipsis) <= maxWidth) {
                low = mid;
            } else {
                high = mid - 1;
            }
        }
        return valueText.slice(0, low) + ellipsis;
    };

})(globalThis);