To fix common rendering issues with the TAdvSmoothProgressBar component from the TMS VCL UI Pack, you need to address how the VCL layer, GDI+ graphics, and the Windows OS coordinate redrawing. Because this specific component relies on GDI+ for its advanced gradients, glow effects, and smooth transitions, it is prone to distinct visual glitches like violent flickering, black backgrounds, or progress “jumping” if not configured correctly.
The most effective strategies to eliminate these rendering issues include double-buffering configurations, parent control styling adjustments, throttled drawing methods, and transparency management. 1. Fix Black Rectangles and Artifacts with Double Buffering
Enabling standard VCL double buffering can sometimes conflict with GDI+ components, causing a infamous bug where black squares or borders appear around the smooth component.
The Fix: Instead of using the global DoubleBuffered := True property on the form or control arbitrarily, place the TAdvSmoothProgressBar inside a TAdvPanel or TPanel. Set the panel’s DoubleBuffered property to True.
VCL Style Conflicts: If you are using custom Delphi VCL Styles, ensure that ParentBackground is set to False on the container panels. This prevents the style engine from continuously overriding the background layer and creating artifacts. 2. Eliminate Intense Flickering During Frequent Updates
If you are updating the progress bar inside a tight loop or a high-frequency timer (e.g., every 10–50 ms), the component will continuously force full canvas repaints, causing heavy stutter or strobe-like flicker.
Disable Unnecessary Transparency: If your progress bar is sitting on a solid color background, set Transparent := False. When Transparent is true, the progress bar forces its parent container to repaint itself before drawing the bar, multiplying the CPU and GPU load.
Turn Off Full Repaint on Containers: If the progress bar is housed inside a TPanel, change the panel’s property to FullRepaint := False. This stops the entire panel from redrawing when only the progress bar’s position changes. 3. Decouple Processing Code via Threading (Fix “Frozen” UI)
Updating TAdvSmoothProgressBar.Position directly inside your main data processing loop forces the main UI thread to halt processing, paint the complex GDI+ graphics, and then resume. This results in an unresponsive UI and a jerky, lagging progress bar.
The Fix: Shift your heavy processing workload into a background thread (TThread).
Throttled Pull Method: Instead of pushing updates from the thread to the UI every single iteration, let the thread update a thread-safe integer variable. Run a TTimer on your main form set to an interval of 100ms or 200ms to “pull” the current status and update the progress bar position. This drastically reduces the CPU time wasted on UI rendering. 4. Correct “Jumping” and Stuttering Progress Animations TProgressBar Not Updating Fast Enough? – Žarko Gajić