THotPDF.RegisterCoonsPatchMesh Method

Оголошує PDF 1.3+ Coons patch mesh shading (ISO 32000-1 8.7.4.5.6, /ShadingType 6) і wraps його в inline Pattern Type 2 entry у page Resources/Pattern dictionary Кожен patch bounded by four cubic Bezier curves і має one color per corner; renderer fits Coons surface between four edges, утворюючи довільно curved color-bearing quad Використовуйте це, коли straight-edge triangle meshes не дають потрібної кривої форми

function RegisterCoonsPatchMesh(XMin, YMin, XMax, YMax: Single; NumComponents: Integer; const Patches: array of Extended): AnsiString;

AnsiString RegisterCoonsPatchMesh(float XMin, float YMin, float XMax, float YMax, int NumComponents, const Extended* Patches, int PatchesElementCount);

Shading emitиться як indirect stream з /ShadingType 6, /BitsPerCoordinate 16, /BitsPerComponent 8 і /BitsPerFlag 8 Кожен patch packed as 1 flag byte (always 0 for independent patches), 12 control points і 4 corner colors, total 1 + 48 + 4 * NumComponents bytes per patch /Decode maps 16-bit coordinates назад у supplied user-space rectangle

The 12 control points are numbered c1..c12 in clockwise order around the patch boundary starting from corner 1. The four corners are c1 / c4 / c7 / c10, and the remaining eight (c2, c3 between c1 and c4; c5, c6 between c4 and c7; c8, c9 between c7 and c10; c11, c12 between c10 and c1) are the inner Bezier handles of each cubic edge. When the inner handles sit at 1/3 and 2/3 along the straight line between adjacent corners, the Coons surface degenerates to bilinear interpolation - visually equivalent to a 4-vertex Type 4 mesh.

XMin, YMin, XMax, YMax - user-space rectangle, що bounds encoded coordinates Ці values стають першими entries of /Decode Control points outside this rectangle clamped during encoding Розміщуйте їх у same user-space coordinates, у які буде paint

NumComponents - кількість color components per corner Передайте 1 для DeviceGray, 3 для DeviceRGB або 4 для DeviceCMYK Будь-яке інше value raises exception

Patches - flat array Extended values Кожен patch contains 24 + 4 * NumComponents values: 24 floats для 12 control points і 4 * NumComponents floats для corner colors Array length має бути positive multiple of this stride Усі emitted patches carry flag = 0; continuation flags 1 / 2 / 3 не exposed in this overload

Return value: auto-generated pattern name (Sh1, Sh2, ...), registered у Resources/Pattern dictionary current page Повертає empty string, коли StrictVersionLock on і active Version нижча за PDF 1.3; інакше document version auto-bumps to 1.3

Code Example

// Single straight-edge Coons patch covering a 200x200 quad. Inner
// control points placed at 1/3 / 2/3 along each edge => bilinear
// surface. Four corner colours = red / green / yellow / blue
var
  Doc: THotPDF;
  PatName: AnsiString;
  Patches: array[0..35] of Extended;   // 12 ctrl pts * 2 + 4 corners * 3 = 36
  H, XMin, YMin, XMax, YMax, W: Single;
begin
  Doc := THotPDF.Create(nil);
  try
    Doc.Version := pdf14;
    Doc.BeginDoc;
    H := Doc.CurrentPage.Height;
    XMin := 0; YMin := H - 200; XMax := 200; YMax := H;
    W := 200;
    // c1..c12 clockwise. Inner handles at 1/3 / 2/3 => straight edges
    Patches[ 0] := XMin;            Patches[ 1] := YMax;             // c1  TL
    Patches[ 2] := XMin + W / 3;    Patches[ 3] := YMax;             // c2
    Patches[ 4] := XMin + 2*W / 3;  Patches[ 5] := YMax;             // c3
    Patches[ 6] := XMax;            Patches[ 7] := YMax;             // c4  TR
    Patches[ 8] := XMax;            Patches[ 9] := YMax - W / 3;     // c5
    Patches[10] := XMax;            Patches[11] := YMax - 2*W / 3;   // c6
    Patches[12] := XMax;            Patches[13] := YMin;             // c7  BR
    Patches[14] := XMax - W / 3;    Patches[15] := YMin;             // c8
    Patches[16] := XMax - 2*W / 3;  Patches[17] := YMin;             // c9
    Patches[18] := XMin;            Patches[19] := YMin;             // c10 BL
    Patches[20] := XMin;            Patches[21] := YMin + W / 3;     // c11
    Patches[22] := XMin;            Patches[23] := YMin + 2*W / 3;   // c12
    // 4 corner colours (c1 / c4 / c7 / c10)
    Patches[24] := 1.0; Patches[25] := 0.0; Patches[26] := 0.0;  // red
    Patches[27] := 0.0; Patches[28] := 1.0; Patches[29] := 0.0;  // green
    Patches[30] := 1.0; Patches[31] := 1.0; Patches[32] := 0.0;  // yellow
    Patches[33] := 0.0; Patches[34] := 0.0; Patches[35] := 1.0;  // blue
    PatName := Doc.RegisterCoonsPatchMesh(XMin, YMin, XMax, YMax, 3, Patches);
    Doc.CurrentPage.SetFillPattern(PatName);
    Doc.CurrentPage.Rectangle(0, 0, 200, 200);
    Doc.CurrentPage.Fill;
    Doc.EndDoc;
  finally
    Doc.Free;
  end;
end;