pdf-lib-table/lib/columns/widthDistributionStrtegies.js

table creation add on for pdf-lib

import { sumColumnProperties, fileterObject } from "../";

export function distributeExcessTableWidth(columnDimensions, options){ // more options could be added here
    const { maxTableWidth } = options;
    const columnTotals = sumColumnProperties(columnDimensions);

    //All columns can take as much space as they need. No wraping is required
    if(columnTotals.intrinsicPercentageWidth <= 100) {
        return assignFullColumnWidths(columnDimensions, maxTableWidth, columnTotals);
    }
    
    //Some column warpping will occore
    if(columnTotals.intrinsicPercentageWidth > 100 && columnTotals.columnMinWidth < maxTableWidth) {
        //the column min widths fit in the table
        return assignIntrinsicBasedColumnWidths(columnDimensions, maxTableWidth, columnTotals);
    }

    if(columnTotals.intrinsicPercentageWidth > 100 && columnTotals.columnMinWidth > maxTableWidth) {
        throw new Error(`Table Overflow!! minTableWidth: ${columnTotals.columnMinWidth} maxTableWidth: ${maxTableWidth}`);
    }
};


export function assignIntrinsicBasedColumnWidths(columnDimensions, maxTableWidth, columnTotals) {
    //the measurment will start at the min width then then distrubute excess based on the intrinsicPercentageWidth
    let actialWidth = {};

    const columnsRecivingWidth = fileterObject(columnDimensions, obj => obj.columnMinWidth !== obj.maxColumnWidth);
    const columnsRecivingWidthintrinsicPercentageTotal = Object.values(columnsRecivingWidth).reduce((acc, obj)  => acc + obj.intrinsicPercentageWidth , 0);
    const excessWidth = maxTableWidth - columnTotals.columnMinWidth;

    Object.keys(columnDimensions).forEach((col) => {
        const { columnMinWidth, intrinsicPercentageWidth, maxColumnWidth } = columnDimensions[col];
        
        if(columnMinWidth == maxColumnWidth) actialWidth[col] = {...columnDimensions[col], actualWidth: columnMinWidth};
        
        if(columnMinWidth != maxColumnWidth) {
            const width = excessWidth * (intrinsicPercentageWidth / columnsRecivingWidthintrinsicPercentageTotal) + columnMinWidth;
            actialWidth[col] = {...columnDimensions[col], actualWidth: width}
        };

    });

    return actialWidth
}

export function assignFullColumnWidths(columnDimensions, maxTableWidth, columnTotals) {
    //set all columns to there max width. Then give any extra space out evenly
    let actialWidth = {};
    
    const numberofColumns = Object.keys(columnDimensions).length;
    const excessWidth = maxTableWidth - columnTotals.maxColumnWidth;
    const widthToAddToEachColumn = excessWidth / numberofColumns;

    Object.keys(columnDimensions).forEach((col) => actialWidth[col] = {...columnDimensions[col], actualWidth: columnDimensions[col].maxColumnWidth + widthToAddToEachColumn});

    return actialWidth
}