IT Log

Record various IT issues and difficulties.

Solving Fuzzy Text in QGraphicsView When Displaying Images


To address the issue of fuzzy text displayed on a QGraphicsView when rendering images, I conducted an extensive investigation and implemented several solutions.

Solution:

  1. Rendering Settings Adjustment:
  2. Anti-Aliasing Enablement: The primary cause of the fuzzy text was identified as insufficient anti-aliasing in the rendering process. By enabling high-quality anti-aliasing using setRenderHint(QGraphicsView::Antialiasing), the text sharpness improved significantly.
  3. Quality Mode Enhancement: Upgrading the render hint to include HighQualityAntialiasing further optimized text clarity, ensuring smoother edges.

  4. Font Configuration:

  5. System Font Replacement: Replacing the default system font with a more screen-friendly typeface like Arial or another sans-serif font was found to enhance readability and reduce fuzziness.
  6. Dynamic Size Adjustment: Implementing dynamic font size adjustment based on the view’s scale factor ensured text remains sharp across different zoom levels, preventing pixelation.

  7. Transformation Review:

  8. Scaling Check: Any transformations that scaled text were reviewed and adjusted to avoid non-integer scaling factors, which can cause text stretching and fuzziness.
  9. Rotation Handling: Ensuring that text rotation is applied after rendering and painting operations helped maintain text clarity without distortion.

  10. Scene Background Optimization:

  11. Background Simplification: The scene’s background was simplified to reduce visual noise, improving the overall readability of the text by providing a cleaner backdrop.

Implementation Steps:

// Replace system font with a more readable typeface
QFont newFont(“Arial”);
newFont.setPointSize(10); // Adjust point size as needed
qApp->setFont(newFont);

// Ensure proper transformation order and scaling adjustments
QGraphicsScene* scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

// Simplify or set a solid background color for better text readability
scene->setBackgroundBrush(Qt::white); // or any other preferred color
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By systematically addressing rendering settings, font configuration, transformations, and scene background, the issue of fuzzy text in QGraphicsView was successfully resolved.


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