GDI+ 紋理筆刷平鋪模式：TWrapMode 完整指南

當紋理圖像小於填充區域時，TWrapMode 決定紋理如何重複排列。TGPTextureBrush 建構子可選擇性指定平鋪模式，亦可事後透過 SetWrapMode 修改。

建構子語法

TGPTextureBrush.Create(
  image: TGPImage;              { 紋理圖像 }
  wrapMode: TWrapMode = WrapModeTile { 平鋪樣式，可選 }
);

WrapMode 列舉值對照表

程式碼實作

下拉選單切換五種平鋪模式，填充整個客戶區：

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    ComboBox1: TComboBox;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
uses GDIPOBJ, GDIPAPI, TypInfo;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  for i := 0 to 4 do
    ComboBox1.Items.Add(GetEnumName(TypeInfo(TWrapMode), i));
  ComboBox1.ItemIndex := 0;
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  r: TGPRect;
  img: TGPImage;
  tb: TGPTextureBrush;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  r := MakeRect(ClientRect);
  img := TGPImage.Create('c:\temp\cat.png');
  tb := TGPTextureBrush.Create(img);
  tb.SetWrapMode(TWrapMode(ComboBox1.ItemIndex));
  g.FillRectangle(tb, r);
  img.Free;
  tb.Free;
  g.Free;
end;

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
  Repaint;
end;

end.

表單設計 (DFM)

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 263
  ClientWidth = 352
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object ComboBox1: TComboBox
    Left = 242
    Top = 2
    Width = 107
    Height = 21
    ItemHeight = 13
    TabOrder = 0
    Text = 'ComboBox1'
    OnChange = ComboBox1Change
  end
end

執行效果

切換模式可觀察到：Tile 為無縫重複；FlipX/Y/XY 產生鏡像拼接效果，消除邊緣銜接痕跡；Clamp 僅繪製一次紋理，其餘區域以邊緣色延伸。選擇適當模式可避免明顯的平鋪痕跡。