WinAPI: GetPath 获取路径中的点

本例效果图:

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代码文件:

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormPaint(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormPaint(Sender: TObject);
type
  TPArr = array[0..0] of TPoint;
  TTArr = array[0..0] of Byte;
var
  pts: ^TPArr;
  types: ^TTArr;  {上面四行只是为了记录数据位置的起始点, 直接用指针也可以, 但用数组方便}
  count: Integer;
  i,x,y: Integer;
begin
  Canvas.Font.Size := 150;
  Canvas.Font.Style := [fsBold];
  SetBkMode(Canvas.Handle, TRANSPARENT);

  {路径}
  BeginPath(Canvas.Handle);
  Canvas.TextOut(2, 0, '万');
  EndPath(Canvas.Handle);

  Canvas.Pen.Color := clWhite;

  {GetPath 最后一个参数是 0, 可以先获取点总数}
  count := GetPath(Canvas.Handle, pts^, types^, 0);

  {分配内存}
  GetMem(pts, count*SizeOf(TPoint));
  GetMem(types, count);

  {获取点序列, 同时也获取了点类型序列}
  count := GetPath(Canvas.Handle, pts^, types^, count);
  Text := '路径中点的总数是: ' + IntToStr(count);

  {路径描边}
  StrokePath(Canvas.Handle);

  Memo1.Clear;
  Canvas.Brush.Color := clRed;

  {显示和绘制点序列}
  for i := 0 to count - 1 do
  begin
    x := pts^[i].X;
    y := pts^[i].Y;
    Memo1.Lines.Add(Format('x:%d;' + #9 + 'y:%d', [x, y]));
    Canvas.FillRect(Rect(x-1,y-1,x+1,y+1));
  end;

  {释放内存}
  FreeMem(pts);
  FreeMem(types);
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 329
  Top = 269
  Caption = 'Form1'
  ClientHeight = 235
  ClientWidth = 331
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesigned
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object Memo1: TMemo
    Left = 216
    Top = 0
    Width = 115
    Height = 235
    Align = alRight
    Lines.Strings = (
      'Memo1')
    ScrollBars = ssBoth
    TabOrder = 0
    ExplicitHeight = 264
  end
end