Skip to content

Image Effects

The Image Effects dialog provides users with basic image beautification parameters including frames, background padding, shadows, and text watermarking.

Core Mechanics

When an effect is applied via the "✨ Effects..." toolbar button inside the Image Editor, it acts as a destructive flattening operation on the current canvas state.

  1. Canvas Rasterization: All independent vector items (Text, Arrows, Rectangles, Freehand) currently drawn on the canvas are temporarily mapped onto a flat 32-bit QImage.
  2. Dimension Expansion: The application math dynamically calculates the necessary new dimensions of the image canvas required to securely fit any applied Padding, Border Width, and the maximum mathematical outer bounding box required by the Shadow Radius and its specific [X, Y] directional offsets.
  3. Layer Composite Rendering:
    • The new expanded canvas is completely filled with the designated Background Color (or transparent if omitted).
    • A native QGraphicsDropShadowEffect is applied to a temporary off-screen QGraphicsPixmapItem buffer containing the flattened pre-effects image.
    • The scene renders the casted shadow directly into the expanded background, followed by the padded image itself.
    • Any selected Border is drawn directly onto the image's inner edge footprint.
    • The Watermark overlay is painted as the absolute top-level object on the composite with the user's requested opacity.
  4. Scene Replacement and Undo Stack: Once flattened, all physical vector objects from the scene are scrubbed. The active Image view is completely swapped out for this new final master image.
    • Because this uses QUndoCommand, pressing Ctrl+Z reverses the operation instantly: The old untouched original image is restored, and all vectors mapped to it are repopulated identically back into their independent movable states.

Border & Shadow Features

  • Border Width & Color: Adds an even solid-color stroke wrapping directly inside the edge-boundary of the original screenshot.
  • Background Padding: Adds an even transparent or solid-color spacer between the image/border and the final edge of the file.
  • Background Color: The color of the padding layer.
  • Drop Shadow: Uses high-quality variable-radius blur logic from Qt.
    • Radius: Controls the softness/spread of the shadow.
    • Offset X/Y: Controls the directional light-casting of the shadow independently.

Watermark Features

  • Custom Text: An arbitrary watermark string.
  • Opacity: A 0.0 (invisible) to 1.0 (solid) alpha scale dictating transparency.
  • Position: Provides snap locations:
    • Bottom Right
    • Bottom Left
    • Top Right
    • Top Left
    • Center
    • Tiled Grid: Specifically repeats the text infinitely across the entire expanded dimensions of the new canvas, leaving ~50 pixels of safe spacing between each word vertically and horizontally.