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TransparencyDemo

A Delphi VCL application demonstrating multiple window transparency and blur techniques on Windows.

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README

Delphi Transparency Demo

A Delphi VCL application demonstrating multiple window transparency and blur techniques on Windows.

This project showcases several distinct methods to apply window transparency and blur effects to a native Delphi form: SetWindowCompositionAttribute (Acrylic), DWM Blur Behind, Windows Magnification API, AlphaBlend (Simple), AlphaBlend (Complex), and Smooth Acrylic (Hybrid).

Overview

This tool allows developers to experiment with different Windows transparency techniques in a single VCL form. Users can switch between methods via a combo box, and the application ensures that switching methods fully resets previous effects, preventing overlaps or visual artifacts.

Supported methods:

  1. None — No transparency applied
  2. AlphaBlend (Simple) — Standard layered window alpha blending
  3. AlphaBlend (Complex) — Gradient alpha blending with per-pixel control
  4. SetWindowCompositionAttribute (Acrylic) — Modern blur/alpha effect (requires HDR-capable hardware for best results)
  5. DWM Blur Behind — Classic Aero blur (performance may vary on HDR displays)
  6. Windows Magnification API — Custom alpha blending using the Magnifier window
  7. Smooth Acrylic (Hybrid) — Dynamic SWCA blur that adapts during window resizing (optimized for HDR-capable GPUs)

Features

  • Native Delphi VCL Win32 / Win64 implementation
  • Switchable transparency methods at runtime
  • Automatic clearing of previous effects
  • ComboBox and form controls remain interactive
  • Magnifier API window placed behind controls to avoid input blocking
  • Smooth Acrylic dynamically adapts during resize
  • Lightweight and self-contained (no external dependencies)
  • Certain blur effects may require HDR-capable hardware for proper rendering

Requirements

  • Windows 10 / 11
  • Magnification.dll available (built-in to Windows)
  • Delphi 12 or compatible version for compilation
  • HDR-capable hardware (GPU + Monitor) recommended for Acrylic / Smooth Acrylic effects

Project Structure

Core components:

  • ApplyAlphaBlend — Applies simple layered window alpha blending
  • ApplyComplexAlphaBlend — Creates per-pixel alpha gradient effects
  • ApplySWCA — Sets Acrylic blur using SetWindowCompositionAttribute
  • ApplyDwmBlur — Enables DWM Blur Behind
  • ApplyMagnifier — Uses Windows Magnification API for alpha blending
  • ApplySmoothAcrylic — Hybrid Acrylic effect with dynamic WndProc adjustments
  • SetSWCAAccent — Helper to set specific SWCA accent states
  • ClearEffects — Resets all previously applied transparency effects
  • ApplyMethod — Switches between methods safely
  • ComboBox for runtime selection of transparency technique

Intended Use

  • Learning Windows transparency APIs
  • UI experimentation with blur and alpha effects
  • Prototype effects for Delphi VCL applications

Limitations

  • All methods have potential for performance impact
  • SWCA/Acrylic and Smooth Acrylic effects perform best on HDR-capable hardware
  • Visual appearance may vary based on OS theme and hardware acceleration
  • Some older GPUs & Monitors may not fully support advanced rendering methods

⚠️ This readme (documentation) was generated with the assistance of AI.

⚠️ All code is human written.