Delphi for Construction: Capturing Logic in Blueprint Estimation Tools

If you are still calculating concrete pours, lumber waste, and structural load requirements using a Delphi 7 application from 2004, you aren't just sitting on technical debt—you’re sitting on a ticking time bomb. In the construction industry, the "secret sauce" of a firm isn't just its people; it’s the proprietary estimation logic baked into legacy desktop software. When that software finally fails or becomes incompatible with modern Windows environments, the cost isn't just the price of a new license—it’s the loss of decades of refined, specialized business rules.

Delphi construction capturing logic is the single greatest challenge for enterprise architects in the AEC (Architecture, Engineering, and Construction) sector. These legacy systems often contain complex geometric calculations and material pricing algorithms that are no longer documented. According to Replay’s analysis, 67% of legacy systems lack any form of up-to-date documentation, leaving developers to "archeologically" dig through Object Pascal code to understand how a blueprint is actually being priced.

TL;DR: Legacy Delphi estimation tools hold critical business logic that is often undocumented. Manual rewrites take an average of 18 months and have a 70% failure rate. By using Replay, construction firms can utilize visual reverse engineering to capture this logic, reducing modernization time from 40 hours per screen to just 4 hours, and converting legacy UIs into documented React components and Design Systems.

The Architectural Crisis in Construction Estimation#

The $3.6 trillion global technical debt isn't just a number for Silicon Valley; it’s a reality for a construction company trying to run a 20-year-old

on a modern tablet in the field. Delphi was the gold standard for building high-performance Windows desktop applications in the 90s and early 2000s. Its VCL (Visual Component Library) allowed for rapid UI development, but it also encouraged a "fat client" architecture where business logic, database queries, and UI state were tightly coupled.

When we talk about delphi construction capturing logic, we are referring to the process of untangling these dependencies. In a blueprint estimation tool, the logic might involve:

• •Dynamic calculation of "waste factors" based on specific material types.
• •Complex nested conditional logic for labor costs (e.g., union vs. non-union rates).
• •Geometric interpolation for irregular roof pitches or foundation footprints.

Industry experts recommend that instead of a "big bang" rewrite—which fails 70% of the time—firms should adopt a visual-first approach to extraction. This is where Replay changes the math.

Visual Reverse Engineering is the process of recording real user workflows in a legacy application and using AI-driven analysis to generate modern, documented code that replicates the behavior and appearance of the original system.

Why Manual Rewrites of Delphi Tools Fail#

The traditional approach to modernizing a Delphi estimation tool involves hiring a team of consultants to read the original Pascal source code. There are several problems with this:

1. •Source Code Loss: Often, the original
   text

   .pas
   files are missing or exist in versions that won't compile on modern machines.
2. •Logic Drift: The code might say one thing, but years of "hotfixes" and database triggers might have changed the actual output.
3. •The Talent Gap: Finding developers who are experts in both 1990s Object Pascal and 2024 React/TypeScript is nearly impossible.

According to Replay's analysis, a manual rewrite of a single complex estimation screen takes approximately 40 hours. When you multiply that by the hundreds of screens in a typical enterprise ERP, you arrive at the 18-month average enterprise rewrite timeline.

Comparison: Manual vs. Replay-Assisted Modernization#

Strategies for Delphi Construction Capturing Logic#

To successfully execute delphi construction capturing logic, you must move beyond the code level and look at the functional level. If a user enters "500 sq ft" and "Grade A Oak," and the system outputs "$4,250," that transformation is the logic you need to capture.

Replay allows you to record these interactions. By recording the "Flows" within the legacy Delphi app, Replay’s AI Automation Suite identifies the components (buttons, grids, input fields) and the underlying data transformations.

Step 1: Mapping the Visual State#

In Delphi, a

might be used to display material lists. In a modern React application, this should be a complex, accessible data table. Replay captures the visual properties—spacing, font weights, and layout—and maps them to a modern Design System.

Step 2: Extracting the Calculation Logic#

Instead of manually translating Pascal

blocks, Replay observes the state changes. If you are interested in how a blueprint estimation tool handles "delphi construction capturing logic" for load-bearing walls, you record the workflow of adding a load-bearing wall to a project. Replay extracts the resulting UI state and provides the structural scaffolding for the React component.

Step 3: Generating the React Component Library#

Once the visual and functional data is captured, Replay generates documented React code. This isn't "spaghetti code" produced by a simple converter; it is structured, modular TypeScript.

Technical Implementation: From Pascal to React#

Let's look at what a typical piece of estimation logic looks like in Delphi and how it translates to a modern React hook after being processed through Replay.

Legacy Delphi Logic (Object Pascal)#

pascal
procedure TEstimateForm.CalculateMaterialTotal(Sender: TObject);
var
  Area, WasteFactor, UnitPrice: Double;
begin
  Area := StrToFloatDef(edtArea.Text, 0);
  WasteFactor := 1.15; // Hardcoded 15% waste for masonry
  UnitPrice := GetCurrentPrice('MASONRY_UNIT');
  
  if (cbHighGrade.Checked) then
    UnitPrice := UnitPrice * 1.2;

  lblTotalCost.Caption := FloatToStrF(Area * WasteFactor * UnitPrice, ffCurrency, 15, 2);
end;

This code is problematic because the waste factor is hardcoded and the UI logic is mixed with the calculation logic. When performing delphi construction capturing logic, we want to separate these concerns.

Modern React Implementation (Generated/Refined via Replay)#

After recording the interaction in Replay, the platform generates a clean, functional component. The logic is extracted into a custom hook, ensuring it can be unit-tested—something nearly impossible in the original Delphi app.

typescript
import React, { useState, useMemo } from 'react';

interface EstimationProps {
  basePrice: number;
  onCalculationComplete: (total: number) => void;
}

/**
 * Replay-Generated Component: MaterialEstimator
 * Captured from: TEstimateForm (Legacy Delphi Construction Tool)
 */
export const MaterialEstimator: React.FC<EstimationProps> = ({ basePrice, onCalculationComplete }) => {
  const [area, setArea] = useState<number>(0);
  const [isHighGrade, setIsHighGrade] = useState<boolean>(false);

  const WASTE_FACTOR = 1.15;

  const totalCost = useMemo(() => {
    let price = basePrice;
    if (isHighGrade) price *= 1.2;
    return area * WASTE_FACTOR * price;
  }, [area, isHighGrade, basePrice]);

  return (
    <div className="p-6 bg-slate-50 rounded-lg shadow-md">
      <h3 className="text-lg font-semibold mb-4">Material Estimation</h3>
      <div className="space-y-4">
        <label className="block">
          <span className="text-gray-700">Area (sq ft)</span>
          <input 
            type="number" 
            className="mt-1 block w-full rounded-md border-gray-300 shadow-sm"
            onChange={(e) => setArea(Number(e.target.value))}
          />
        </label>
        <label className="flex items-center">
          <input 
            type="checkbox" 
            className="rounded border-gray-300 text-blue-600 shadow-sm"
            onChange={(e) => setIsHighGrade(e.target.checked)}
          />
          <span className="ml-2 text-gray-700">High Grade Material</span>
        </label>
        <div className="mt-6 p-4 bg-blue-100 rounded">
          <span className="text-sm uppercase tracking-wide text-blue-800">Total Estimated Cost</span>
          <div className="text-2xl font-bold text-blue-900">
            ${totalCost.toLocaleString(undefined, { minimumFractionDigits: 2 })}
          </div>
        </div>
      </div>
    </div>
  );
};

The Role of Design Systems in Construction Modernization#

A major hurdle in delphi construction capturing logic is the user interface consistency. Construction professionals are used to high-density layouts. They need to see a lot of data at once—grid views, material lists, and cost breakdowns.

Replay's Library feature allows architects to build a cohesive Design System from the legacy UI. Instead of guessing what the "corporate blue" was or how much padding a button should have, Replay extracts these tokens directly from the recording.

Video-to-code is the process of converting screen recordings of legacy software interactions into clean, documented React components and TypeScript logic. This ensures that the new web-based estimation tool feels familiar to the power users who have spent 20 years mastering the Delphi version.

For more on how to manage this transition, read our guide on Modernizing Legacy UI with Design Systems.

Scaling the Extraction: Flows and Blueprints#

In a large-scale construction estimation suite, you aren't just capturing one screen; you are capturing hundreds of interconnected "Flows."

1. •The Project Setup Flow: Setting up site coordinates and client data.
2. •The Takeoff Flow: Importing blueprints and measuring dimensions.
3. •The Bidding Flow: Exporting the final estimate to a PDF or CSV.

Replay’s "Flows" feature allows you to map the architecture of the entire application. By visualizing how data moves from the "Takeoff" screen to the "Bidding" screen, you can capture the complex delphi construction capturing logic that governs the entire business process.

According to Replay's analysis, using "Blueprints" (the platform's visual editor) allows non-technical stakeholders—like the estimators themselves—to verify that the captured logic is correct before a single line of production-ready code is deployed. This bridge between the "old guard" who knows the business and the "new guard" who knows the tech is vital for a successful migration.

Security and Compliance in Regulated Industries#

Construction often intersects with government contracts, requiring high levels of security and compliance. When modernizing Delphi tools, you cannot afford to leak proprietary estimation algorithms or sensitive project data.

Replay is built for these environments, offering:

• •SOC2 and HIPAA-ready infrastructure.
• •On-Premise deployment options for firms that cannot move their legacy logic to the cloud.
• •Audit Trails that show exactly how logic was transformed from the legacy recording to the final React component.

This level of rigor is essential when dealing with the Modernization of Financial Systems or government-adjacent construction projects.

Conclusion: The Path to 70% Time Savings#

The math is simple: the global technical debt is growing, and the pool of Delphi developers is shrinking. If you continue to rely on manual interpretation for delphi construction capturing logic, you are accepting a high risk of project failure and an 18-month timeline that your business probably can't afford.

By using Replay, you shift the paradigm from "manual reconstruction" to "visual reverse engineering." You save 70% of the time typically lost to manual coding and documentation. You move from a fragile, 32-bit desktop environment to a resilient, cloud-native React architecture without losing the decades of intelligence built into your estimation tools.

Frequently Asked Questions#

How does Replay handle complex Delphi third-party components?#

Replay's visual reverse engineering doesn't rely on the underlying source code of third-party VCL components. Instead, it observes the rendered output and the user interactions. This means it can accurately capture the behavior and appearance of even the most obscure or custom-built Delphi components, converting them into modern, standards-compliant React components.

Is it possible to capture database logic using visual reverse engineering?#

While Replay focuses on the UI and the logic that drives the user experience, it captures the "data shape" of the application. By observing how data is populated in grids and forms, Replay helps architects define the API contracts and TypeScript interfaces needed for the new backend, effectively mapping out the delphi construction capturing logic as it relates to data flow.

Can Replay work with legacy apps that only run on Windows XP?#

Yes. Replay captures the visual state of the application. As long as the application can be run and recorded (even in a virtualized environment or via RDP), Replay can analyze the workflow and generate the corresponding modern code. This is a primary use case for firms stuck on aging hardware due to software dependencies.

What happens to the hardcoded business rules in the Delphi source?#

During the recording process, Replay's AI identifies patterns in how inputs are transformed into outputs. This allows developers to identify where those hardcoded rules exist. Once the React components are generated, these rules can be extracted into clean, maintainable configuration files or backend services, moving away from the "spaghetti" nature of legacy Delphi code.

Ready to modernize without rewriting? Book a pilot with Replay