THotPDF.RegisterMultiStopRadialGradient Method

Registers a reusable native PDF radial shading that interpolates two or more color stops between an inner circle and an outer circle

Declaration

function RegisterMultiStopRadialGradient(X0, Y0, R0, X1, Y1, R1: Single; const StopPositions: array of Single; const StopColors: array of Single; ComponentsPerStop: Integer): AnsiString;

Unit

HPDFDoc

Parameters

Name	Purpose
`X0`, `Y0`, `R0`	Center and non-negative radius of the inner circle
`X1`, `Y1`, `R1`	Center and non-negative radius of the outer circle
`StopPositions`	Two or more strictly increasing finite offsets in the inclusive range zero to one
`StopColors`	Flat-packed finite color components in the inclusive range zero to one
`ComponentsPerStop`	`1` selects DeviceGray, `3` selects DeviceRGB, and `4` selects DeviceCMYK

Return value

Returns the generated Pattern resource name for THPDFPage.SetFillPattern or THPDFPage.SetStrokePattern

Behavior

Builds one PDF Function Type 3 stitching function from bounded Function Type 2 segments
Emits a Shading Type 3 dictionary and wraps it in a reusable Pattern Type 2 resource
Extends the first and last stop colors beyond the radial domain
Rejects non-finite coordinates, negative radii, malformed color arrays, duplicate offsets, and offsets or color components outside their valid ranges
Requires PDF 1.3 and follows the document version-lock policy

Example

PatternName := Document.RegisterMultiStopRadialGradient(
  300, 400, 0, 300, 400, 250,
  [0.0, 0.5, 1.0],
  [1.0, 0.0, 0.0,
   0.0, 1.0, 0.0,
   0.0, 0.0, 1.0], 3);
Document.CurrentPage.SetFillPattern(PatternName);