Graphics32

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GR32_Paths🞂TCustomPathClass

TCustomPath

Abstract base class for vector path builders, managing coordinate states and vector path directives.

Inheritance:TObject 🞂 TPersistent 🞂 TPlainInterfacedPersistent 🞂 TNotifiablePersistent 🞂 TThreadPersistent 🞂 TCustomPath

Declaration ​

pascal
TCustomPath = class abstract(TThreadPersistent)

Description ​

TCustomPath is the abstract base class for vector path construction in Graphics32. It establishes a vector drawing interface inspired by SVG path commands, offering absolute and relative directives for straight lines, cubic Bezier curves, quadratic (conic) Bezier curves, circular arcs, rectangles, rounded rectangles, ellipses, circles, polylines, and polygons.

Key features of TCustomPath include:

  • Path Position Management: Maintains the active drawing coordinate in CurrentPoint updated by movement, line, and curve commands.
  • Absolute and Relative Commands: Provides paired absolute (e.g. LineTo, CurveTo, ConicTo) and relative commands (e.g. LineToRelative, CurveToRelative, ConicToRelative).
  • Smooth Curve Continuation: Automatically reflects control points when chaining smooth cubic (CurveTo(C2, P)) or quadratic (ConicTo(P)) Bezier segments.
  • Geometric Primitives: Provides convenient methods for adding shapes such as Rectangle, RoundRect, Ellipse, Circle, Polygon, and PolyPolygon.

Derived classes (such as TFlattenedPath and TCanvas32) override internal point generation routines (AddPoint, EndPath) to convert high-level path commands into flattened polygonal vertex lists or render them directly onto bitmap targets.